Lead; Identification of Dangerous Levels of Lead

SUMMARY: In accordance with section 403 of the Toxic Substances Control

Act (TSCA), as amended by the Residential Lead-Based Paint Hazard

Reduction Act of 1992, also known as ``Title X,'' EPA is proposing a

regulation to establish standards for lead-based paint hazards in most

pre-1978 housing and child-occupied facilities. This proposed

regulation is a focal point of the Federal lead program and supports

the implementation of regulations already promulgated and others under

development which deal with worker training and certification, lead

hazard disclosure in real estate transactions, requirements for lead

cleanup under State authorities, lead hazard evaluation and control in

Federally-owned and Federally-assisted housing, and U.S. Department of

Housing and Urban Development (HUD) grants to assist in lead hazard

abatement. In addition, today's action also proposes, under the

authority of TSCA section 402, residential lead dust cleanup levels and

amendments to dust and soil sampling requirements and, under the

authority of TSCA section 404, amendments to State program

authorization requirements. By supporting the implementation of the

national lead program, this proposed regulation would help to prevent

lead poisoning in children under the age of 6.

DATES: Written comments in response to this proposed rule must be

received on or before September 1, 1998.

ADDRESSES: Each comment must bear the docket control number OPPTS-

62156. All comments should be sent in triplicate to: OPPT Document

Control Officer (7407), Office of Pollution Prevention and Toxics,

Environmental Protection Agency, 401 M St., SW., Rm. G099, East Tower,

Washington, DC 20460.

Comments and data may also be submitted electronically to:

[email protected]. Follow the instructions under Unit X. of

this document. No Confidential Business Information (CBI) should be

submitted through e-mail.

All comments which contain information claimed as CBI must be

clearly marked as such. Three copies, sanitized of any comments

containing information claimed as CBI, must also be submitted and will

be placed in the public record for this rulemaking. Persons submitting

information, any portion of which they believe is entitled to treatment

as CBI by EPA, must assert a business confidentiality claim in

accordance with 40 CFR 2.203(b) for each such portion. This claim must

be made at the time that the information is submitted to EPA. If a

submitter does not assert a confidentiality claim at the time of

submission, EPA will consider this as a waiver of any confidentiality

claim and the information may be made available to the public by EPA

without further notice to the submitter.

If requested, EPA will schedule public meetings where oral comments

will be heard. EPA will announce in the Federal Register the time and

place of any public meetings. Oral statements will be scheduled on a

first come first served basis by calling the telephone number listed in

the Federal Register notice that announces these meetings. All

statements will be made part of the public record and will be

considered in the development of the final rule.

FOR FURTHER INFORMATION CONTACT: For general information contact:

National Lead Information Center's Clearinghouse, 1-800-424-LEAD(5323).

For specific technical and policy questions contact: Jonathan Jacobson,

(202) 260-3779; [email protected].

SUPPLEMENTARY INFORMATION:

I. Overview

This overview identifies entities potentially affected by the rule,

summarizes the proposed rule, describes the uses and key limitations of

the proposal's scope, and provides a roadmap of the preamble.

A. Regulated Entities

The following table identifies the entities that would be involved

in the implementation of regulations that would be affected by today's

proposal and the effect of the proposal on implementation of those

regulations.

------------------------------------------------------------------------

Examples of

Category Entities Effect of Proposal

------------------------------------------------------------------------

Lead abatement professionals Workers, Provides standards

supervisors, that risk

inspectors, risk assessors would

assessors, and use to identify

project designers hazards and

engaged in lead- evaluate

based paint clearance tests;

activities helps determine

when certified

professionals

would be required

to perform

abatements

Training providers Firms providing Provides standards

training services that training

in lead-based providers would

paint activities have to teach in

their courses

HUD and other Federal agencies Proposed standards

that own residential property identify hazards

that Federal

agencies would

have to abate in

pre-1960 housing

prior to sale

Property owners who receive State and city Proposed standards

assistance through Federal public housing identify hazards

housing programs authorities, that property

owners of multi- owners would have

family rental to abate or

properties who reduce as

receive project- specified by

based assistance, regulations

owners of rental currently be

properties who developed by HUD

lease units under under authority

HUD's tenant- of Title X,

based assistance section 1012

program

Property owners Owner occupants, Proposed standards

rental property identify hazards

owners, public that would have

housing to be disclosed

authorities, under EPA/HUD

Federal agencies joint regulations

promulgated under

Title X, section

1018

------------------------------------------------------------------------

This table is not intended to be exhaustive, but rather provides a

guide for readers likely to be affected by this action through

implementation of the elements of the programs discussed in this

proposal. To determine whether

[[Page 30303]]

you, your business, or your agency is affected, you should carefully

examine the Requirements for Lead-Based Paint Activities at 40 CFR part

745, subpart L and subpart Q and Lead-Based Paint Disclosure at 40 CFR

part 745, subpart F and 24 CFR part 35, subpart H. The regulations

covering evaluation and control of lead-based paint hazards in HUD-

associated and Federally-owned housing are currently under development.

Proposed regulations were published in the Federal Register on June 7,

1996 (61 FR 29169). If you have any questions regarding the

applicability of this action to a particular entity, consult the person

listed in the ``FOR FURTHER INFORMATION CONTACT'' section.

B. Summary of the Proposed Rule

1. Lead-Based Paint Hazard Standards. EPA is proposing the

amendments in this document primarily under the authority of section

403 of TSCA. Section 403 requires EPA to promulgate regulations that

``identify . . . lead-based paint hazards, lead-contaminated dust and

lead-contaminated soil'' for purposes of the entire Title X which

includes Title IV of TSCA. Lead-based paint hazards, under TSCA section

401, 15 U.S.C. 2681, are defined as of conditions of lead-based paint

and lead-contaminated dust and soil that ``would result'' in adverse

human health effects (15 U.S.C. 2681(10)). Lead-based paint hazards

from all three sources apply to target housing (i.e., most pre-1978

housing) and child-occupied facilities.

The proposed standard for the paint component, called hazardous

lead-based paint, is lead-based paint in poor condition. Paint in poor

condition is defined as more than 10 square feet (ft2) of

deteriorated paint on exterior components with large surface areas,

more than 2 ft2 of deteriorated paint on interior components

with large surface areas (e.g., walls, ceilings, floors), or

deteriorated paint more than 10 percent of the total surface area of

exterior or interior components with small surface areas (e.g., trim,

baseboards). The proposed standards for dust-lead hazards are the

average levels of lead in dust that equals or exceeds 50 micrograms per

square foot (g/ft2) on uncarpeted floors and 250

g/ft2 on interior window sills. The proposed

standard for soil-lead hazards is the total lead that equals or exceeds

2,000 parts per million (ppm) based on a yard-wide average soil-lead

concentration rather than maximum or worst-case values.

Although the proposed regulation does not require property owners

to respond to the presence of lead-based paint hazards, EPA would

recommend that appropriate measures should be taken, commensurate with

the risk reduction achieved, to reduce or eliminate the hazards. Small

amounts of hazardous lead-based paint can be addressed by repairing

deteriorated paint. Larger amounts of hazardous lead-based paint should

be abated, meaning that the paint can be removed from the component,

the component can be replaced, or the paint can be enclosed.

Dust-lead hazards should be addressed through intensive cleaning.

If household surfaces are smooth and cleanable, regular household

cleaning can probably maintain acceptably low levels of lead in dust in

the absence of any event (e.g., remodeling project) that reintroduces

large amounts of dust contaminated with lead. Soil-lead hazards should

be eliminated. Currently available options include soil removal and

permanently covering the soil (i.e., paving).

In addition, this document proposes to identify a soil-lead level

of concern of 400 ppm based on a yard-wide average, which represents a

level at which risk should be communicated to the public as compared to

the more active risk reduction measures recommended for hazards. This

level will not be included in the regulation because it would impose no

legally recognizable requirements on any person or entities subject to

this regulation. Nevertheless, if a soil-lead hazard is not present,

but lead in soil exceeds the level of concern, EPA recommends that low

cost measures, which may be sufficient to reduce exposure, be

implemented. These measures include but are not limited to covering

bare soil, placement of washable doormats, more frequent washing of

hands and toys, and access restrictions. Access restrictions should

only be used if there are other parts of the yard that are available to

the residents.

EPA is planning to develop a guidance document to accompany the

final regulation that will explain these recommended responses to lead-

based paint hazards and the soil-lead level of concern in greater

detail.

It is important to note that the proposed standards are intended to

be used prospectively. That is, they should be used to identify

properties that present risks to children before children are harmed.

These standards would not be appropriate to use when identifying the

sources of exposure for a lead-poisoned child. When a property is being

evaluated in response to the identification of a lead-poisoned child,

the risk assessor in cooperation of a local public health official

should identify and consider all sources of lead exposure.

The proposed TSCA section 403 standards are based on the best data

and analytical tools currently available to the Agency. EPA expects

that the standards may need to be modified over time as better tools

and data become available. The Agency, however, believes that issuing

standards now, even in the face of considerable uncertainty, is

consistent both with the public's need for information from EPA and the

statutory intent to develop standards with currently available

information.

In this document, EPA is also proposing amendments to the existing

rules issued under TSCA sections 402 and 404, including: (1)

Requirements for interpreting the results of sampling of lead materials

for purposes of assessing risk; (2) clearance standards for cleaning up

hazardous lead dust of 50 g/ft2 for uncarpeted

floors, 250 g/ft2 for interior window sills, and

800 g/ft2 for window troughs; (3) amendments to the

dust and soil sampling locations in the risk assessment work practice

standards at 40 CFR 745.227; (4) work practice standards for the

management of soil removed during a soil abatement; and (5) amendments

to the State and Tribal program authorization requirements under 40 CFR

part 745, subpart Q.

C. Uses of the Standards

The TSCA section 403 standards support implementation of key

provisions of Title X which would require action with respect to lead-

based paint hazards by both private parties and the government,

principally for EPA and programs under the auspices of the Department

of Housing and Urban Development (HUD). These provisions include

eligibility criteria for the Department of Housing and Urban

Development's (HUD) lead hazard control grant program (section 1011 of

Title X), which authorizes grants to clean up lead-based paint hazards.

In addition, Title X imposes certain requirements on owners of HUD-

associated housing (section 1012 of Title X) and Federal agencies

selling residential properties they own to evaluate and control lead-

based paint hazards (section 1013 of Title X). Sellers and lessors of

housing built before 1978 have obligations to disclose known lead-based

paint and lead-based paint hazards prior to sale or rental (section

1018 of Title X). Regulations also impose requirements to use certified

workers for evaluation and cleanup of

[[Page 30304]]

lead-based paint hazards (section 402 of TSCA). These provisions are

described in more detail in Unit VIII. of this preamble.

EPA does note, however, that the regulations would not require

private property owners to undertake hazard control actions when

hazards are identified. Instead, EPA expects that concern about

children's health, liability exposure and other market forces will

provide incentive for property owners to take action voluntarily.

In addition to their applicability within Title X, EPA anticipates

that the TSCA section 403 regulations will have broader uses. The

proposed regulations will play a significant role in public education,

communicating the Agency's best judgment concerning the identification

of lead-based paint hazards to property owners, State and local

officials, tenants, and other decision-makers. EPA also expects that

public and private institutions may incorporate the standards into

State and local laws, housing codes, and lending and insurance

underwriting standards.

D. Limitations of the Proposed Rule

During the regulatory development process, it became clear that

significant confusion and uncertainty exists about the requirements and

purpose of the TSCA section 403 regulations. To address this confusion

and uncertainty, EPA wishes to highlight the major limitations and

other issues related to the scope and use of today's proposal.

First, this proposal does not establish a new definition for lead-

based paint, defined by statute as paint with lead levels equal to or

exceeding 1.0 milligrams per square centimeter (mg/cm2) or

0.5 percent by weight (see section 302(c) of the Lead-Poisoning

Prevention Act, 42 U.S.C. 4822(c) and TSCA section 401(9)). Under Title

X, only the Secretary of Housing and Urban Development has the

authority to change the standard for lead-based paint in target housing

(see TSCA section 401(9)). Title IV provides EPA the authority to

change the standard only for lead-based paint in non-residential

applications (e.g., public and commercial buildings, steel structures)

(see TSCA section 401(9)). This proposal does not include any changes

to this statutory definition.

Second, the proposed standards are intended to identify lead-based

paint hazards when the lead-based paint risk assessment is performed.

Because the conditions of lead-based paint and the levels of lead in

dust and soil are constantly changing, the results of the risk

assessment communicate conditions at the time the measurements are

taken and the observations made. The proposed standards do not address

the potential for hazards to develop. EPA recognizes, however, that

potential hazards (e.g., intact lead-based paint on a ceiling) may

become actual hazards as conditions change over time. Periodic

reevaluation of a property would enable a property owner to determine

whether potential hazards have become actual hazards. Recommendations

concerning reevaluation will be provided in a separate guidance

document that EPA is planning to issue.

Third, because the TSCA section 403 standards are established for

the purposes of Title X and TSCA Title IV, they do not apply to housing

and facilities occupied by children built during or after 1978, as well

as some pre-1978 housing that is not included in the definition of

target housing (e.g., 0-bedroom dwellings). EPA recognizes, however,

that property owners and other decision-makers may be concerned about

the presence of elevated levels of lead in dust and soil in housing and

facilities occupied by children not covered by the standards. In such

cases, EPA encourages these owners and decision-makers to use the

standards to help determine whether actions should be taken to reduce

risks to young children.

Fourth, the proposed regulations do not set standards that can be

used to identify housing that is free from risks associated with

exposure to lead. Such standards would be difficult to define,

unworkable in practice, and inconsistent with the intent of Title X.

Virtually all target housing has some lead present in paint, dust, and/

or soil, which, under certain circumstances, may present risk to

children. Furthermore, these risks often will depend on circumstances

that may change quickly, such as the physical condition of the

property. Thus, housing that presents minimal risks when examined may

present substantial risks later.

E. Preamble Overview

The remainder of this preamble consists of eleven units. Unit II.

provides background information, including: a description of the

residential lead-based paint problem; Title X as a legislative

response; key aspects of the regulatory development process; and the

Agency's general standard-setting approach. Unit III. is a section-by-

section review of the proposed regulatory provisions. Unit IV. presents

EPA's interpretation of the statutory authority for the proposed TSCA

section 403 standards, the Agency's policy basis for the proposed

standards, and EPA's decisions for the proposed TSCA section 403

standards. This unit includes a summary of the technical analyses

conducted by the Agency to support these decisions. Unit V. discusses a

range of issues that affected EPA's decision-making during the

regulatory development process. Unit VI. presents EPA's rationale and

decisions for requirements on comparing risk assessment sampling

results to the TSCA section 403 standards. Unit VII. describes the

Agency's rationale and decisions concerning clearance standards and

other amendments to the TSCA section 402 regulations related to work

practice standards and TSCA section 404 regulations concerning EPA

authorization of State and Tribal programs. Unit VIII. describes the

effect that today's proposal will have on other Title X regulations and

programs, and Unit IX. discusses the relationship between the proposed

regulations and other EPA programs. Unit X. provides information on the

public record supporting this regulation (``the docket''). Unit XI.

presents the bibliographic references cited in the preamble, which are

also part of the docket. Unit XII. presents a summary of the regulatory

assessment analyses and Agency determinations conducted in response to

various Federal laws and Executive orders concerning the public health

and economic impact of the proposed regulation.

II. Background

A. Nature of the Problem

Elemental lead is a heavy, soft, and malleable bluish metal that

has been used for thousands of years. Its favorable physical and

chemical properties account for its versatility and extensive use in

many common products including lead acid batteries, ammunition,

chemicals (e.g., plastic stabilizers, pigments, and ceramic glazes),

alloys (e.g., solder in piping and electronics), pipe/sheet lead, and

radiation and cable sheathing. Centuries of mining, smelting, and use

have released millions of tons of lead into the environment. With no

known or foreseeable technology to render anthropogenic sources of

environmental lead harmless, it remains ubiquitous in air, water, soil,

dust, and in older homes and commercial structures. As a result,

practically all people have some exposure to lead of anthropogenic

origin.

Lead affects virtually every system of the human body. Exposure to

high doses of lead can cause coma, convulsions,

[[Page 30305]]

and even death. Exposure to low levels of lead can cause harm gradually

and imperceptibly, with no obvious symptoms. In adults, chronic

exposure to low levels of lead may cause memory and concentration

problems, hypertension, cardiovascular disease, and damage to the male

reproductive system. Exposure to lead before or during pregnancy can

alter fetal development and cause miscarriages. A more detailed

description of the health effects of lead can be found in Chapter 2 of

the Risk Analysis to Support Standards for Lead in Paint, Dust, and

Soil, which can be found in the public record for this proposal (Ref.

1).

While potentially harmful to individuals of all ages, lead exposure

is especially harmful to children. Their rapidly developing nervous

systems are particularly sensitive to the effects of lead. In addition,

children absorb a greater portion of the lead to which they are exposed

than adults do. Excessive exposure to lead in children causes learning

disabilities, lower intelligence, behavioral problems, growth

impairment, permanent hearing and visual impairment, and other damage

to the brain and nervous system.

The concentration of lead in a child's blood is typically used as

an index of lead exposure. As recent studies have identified previously

unrecognized effects of exposure to lead at lower levels, there has

been increasing concern about blood-lead levels once thought to be

safe. Since 1975, the Centers for Disease Control and Prevention (CDC)

have lowered the blood-lead level considered elevated for children from

40 g/dl (micrograms per deciliter) to 10 g/dl (Ref.

2). Although the scientific community has not been able to identify a

threshold of exposure below which adverse health effects do not occur,

the evidence of health effects below 10 g/dl is not

sufficiently strong to warrant concern.

Ingestion of lead-contaminated dust and soil through normal hand-

to-mouth activity appears to be the primary pathway of lead exposure to

U.S. children under 6 years of age. (Refs. 3 and 4.), Dust is

contaminated by lead when: lead-based paint deteriorates; lead-based

paint is disturbed in the course of renovation, repair, or abatement

activity; or lead is tracked into, blown into, or otherwise enters the

home from soil in the yard or other external sources (e.g., workplace).

Soil contaminated with lead from deterioration of exterior lead-based

paint, industrial emissions, and/or deposition of lead from past use of

leaded gasoline may be ingested directly or contribute to indoor levels

of lead-contaminated dust when tracked into the home. Children may also

be exposed to lead through the ingestion of lead-based paint chips from

flaking walls, windows, and doors or from chewing on surfaces covered

with lead-based paint. Other sources of lead exposure include, but are

not limited to, lead-contaminated food and drinking water and

occupational exposure to dust and airborne lead particles.

Considerable progress has been made in reducing environmental lead

levels. Concrete steps taken by the Federal government to eliminate

sources of lead include the phase-out of leaded gasoline by EPA (40 CFR

part 80) and the ban by the Consumer Product Safety Commission (CPSC)

of the production and sale of lead-based paint for residential use in

1978 (16 CFR part 1303). The CPSC action placed a maximum limit on the

amount of lead in paint (0.06 percent by weight) for residential use,

as well as for furniture and toys. In addition, EPA has implemented

more stringent standards for lead in drinking water, and the domestic

canning industry voluntarily eliminated the use of lead in solder to

seal food cans (40 CFR parts 141 and 142).

Consistent with these improvements, the percentage of children with

elevated blood-lead levels has declined over the last 20 years. The

National Health and Nutrition Examination Survey (NHANES) conducted by

the National Center for Health Statistics indicates that over the past

2 decades the average child's blood-lead level has decreased from 12.8

micrograms/deciliters (g/dl) to 2.8 g/dl (Ref. 5).

According to NHANES III Phase 2, completed in 1994, approximately

900,000 U.S. children of ages 1 to 5 years had blood-lead levels equal

to or exceeding the 10 g/dl (Ref. 6).

Excessive exposure to lead affects children across all socio-

economic strata and in all regions of the country. Children in poor

inner-city families, however, are disproportionately affected because

lead-based paint hazards are more prevalent in older housing and the

overall ambient level of environmental lead from all sources tends to

be higher in inner cities (Ref. 7). Studies indicate that children

living in central cities are three to four times more likely to have

blood-lead levels equal to or exceeding 10 g/dl than those

outside central cities, with the highest prevalence in cities where

populations exceed 1 million (Ref. 7).

According to EPA's report on the HUD National Survey of Lead-Based

Paint in Housing, 83 percent of privately-owned, occupied homes built

before 1980, or 64.4 million homes, contain some lead-based paint (Ref.

8). The likelihood, extent, and concentration of lead-based paint vary

with the age of the building. Eighty-eight percent of privately-owned,

occupied housing units constructed before 1940, 92 percent of units

constructed between 1940 and 1959, and 76 percent of units constructed

between 1960 and 1979 contain some lead-based paint (Ref. 8). Over 12

million (or 19 percent) of these pre-1980 homes with some lead-based

paint have children aged 7 years or younger in residence (Ref. 8). (The

HUD National Survey presents results for children aged 7 years or

younger; Title X, which was enacted after the survey was conducted,

focuses upon children younger than 6 years.)

All homes containing lead-based paint pose a potential future

hazard to the occupants if the paint is not managed properly. Intact

lead-based paint may deteriorate over time to create a hazardous

condition. According to EPA's analysis of the HUD National Survey,

about 19 percent of pre-1980 privately-owned units contained non-intact

lead-based paint in 1989-90, which was defined at the time of the

survey as greater than 5 square feet of peeling, chipping, or otherwise

deteriorated paint (Ref. 8). Assuming that the percent of pre-1980

homes with non-intact lead-based paint that have young children is the

same as the percent of pre-1980 homes with some lead-based paint that

have young children (19 percent), about four percent of pre-1980 homes

in the United States contained both non-intact lead-based paint and

young children.

Based on the HUD National Survey, EPA estimates that 13 million or

17 percent of pre-1980 privately-owned homes have ``elevated'' lead

dust levels, which were defined at the time of the Survey as lead dust

exceeding 200 g/ft2 on floors, 500 g/

ft2 on window sills, or 800 g/ft2 on

window troughs (Ref. 8). Homes with non-intact lead-based paint were

five times more likely to have elevated lead dust levels than homes

with intact lead-based paint (Ref. 9).

EPA's analysis of the HUD National Survey also estimates that

approximately 16 million or 21 percent of privately-owned pre-1980

housing units have soil-lead concentrations exceeding 400 ppm (Ref. 8).

The prevalence of soil-lead levels exceeding 400 ppm varies greatly

with the age of housing. Sixty percent of pre-1940 units, but only

eight percent of 1940-1959 units and four percent of 1960-

[[Page 30306]]

1979 units have such soil-lead concentrations (Ref. 9).

B. Structure of Basic Legal Authorities

The Housing and Community Development Act of 1992 (Pub. L. 102-

550), enacted on October 29, 1992, contains 16 titles amending and

extending a number of laws relating to housing and community

development. Title X of this Act, entitled the ``Residential Lead-Based

Paint Hazard Reduction Act of 1992,'' contains five subtitles extending

and establishing programs for reducing exposure to lead, principally,

in paint and residential dust and soil. Provisions of Title X are

codified in the United States Code (U.S.C.) at volume 42, section 4851

and at various other sections of volume 42, as well as of volumes 12

and 15.

Subtitle A of Title X (codified at volume 42 U.S.C. 4852, and at

various other sections of volumes 42 and 12) applies primarily to

grants and other programs under the jurisdiction of the Secretary of

Housing and Urban Development (HUD). Subtitle B of Title X amends the

Toxic Substances Control Act (TSCA), 15 U.S.C. 2601, et. seq., by

adding Title IV, which requires EPA to establish requirements for

training and accreditation of contractors performing lead-based paint

related work, issue the standards being proposed today, sponsor public

education programs, establish programs for studying the effectiveness

of lead-based paint hazard evaluation and control products, and

establish a laboratory accreditation program. Subtitle C of Title X

deals with worker protection and training under jurisdiction of the

Occupational Safety and Health Administration (OSHA) and the National

Institute of Occupational Safety and Health (NIOSH). Subtitles D and E

provide for research and reporting on various aspects of lead-based

paint activities. These last three subtitles are codified at volume 42

U.S.C. 4853 to 4856.

An overview of the particular regulatory sections in the Subparts

of Title X that relate to this proposed rule follows.

1. EPA responsibilities. Under TSCA section 402 (15 U.S.C. 2682),

EPA has promulgated regulations governing the training and

certification of individuals and firms engaged in lead-based paint

activities, the accreditation of programs to train such individuals,

and work practice standards for conducting lead-based paint activities.

These regulations were published in the Federal Register of August 29,

1996 (61 FR 45778) (FRL-5389-9), and are codified at 40 CFR part 745,

subpart L. EPA will amend these regulations at a later date to address

deleading in public and commercial buildings, and other structures,

such as bridges.

In conjunction with these activities, EPA developed specific

guidelines under section 402(c)(1) for renovation and remodeling

activities that may create a risk of exposure to dangerous levels of

lead (Ref. 10). Under TSCA section 402(c)(3), EPA is required to revise

the certification and accreditation regulations under 40 CFR part 745,

subpart L, to address renovation and remodeling activities that create

lead-based paint hazards, after conducting a study of such activities.

In conjunction with the TSCA section 402 rule, EPA, under TSCA

section 404 (15 U.S.C. 2684), developed a Model State Program, which

States and Indian Tribes are encouraged to reference and use as

guidance to develop their own Federally-authorized lead-based paint

activities programs. The regulations in 40 CFR part 745, subpart Q,

include procedures for States and Indian Tribes to follow when applying

to EPA for authorization to administer and enforce a State or Tribal

training, accreditation, and certification program.

Under TSCA section 406(a) (15 U.S.C. 2686(a)), EPA, HUD, and CPSC

jointly released a lead hazard information pamphlet, Protect Your

Family from Lead in Your Home (60 FR 39167, August 1, 1995) (FRL-4966-

6). The pamphlet is designed to educate families about the potential

health risks associated with lead exposure and ways to avoid such

exposure.

Under TSCA section 406(b), EPA has promulgated a regulation to

require persons performing renovation work for compensation in

residential housing built before 1978 to provide owners and occupants

with a lead hazard information pamphlet before renovation begins.

Under Title X, section 1018 (42 U.S.C. 4852(d)), EPA and HUD have

jointly developed regulations requiring a seller or lessor of most pre-

1978 housing to disclose the presence of any known lead-based paint or

lead-based paint hazards to the purchaser or lessee (24 CFR part 35,

subpart H; 40 CFR part 745, subpart F). Under these rules, the seller

or lessor also must provide the purchaser or lessee any available

records or reports pertaining to such paint or hazards and a copy of

the lead hazard information pamphlet. Additionally, the seller must

allow the purchaser 10 days to conduct an inspection or risk assessment

for the presence of lead-based paint or lead-based paint hazards.

Finally, the sale or leasing contract must include certain disclosure

and acknowledgment provisions, and real estate agents must ensure

compliance with these standards.

2. HUD responsibilities. In addition, to the joint regulations

issued with EPA under section 1018 of Title X, HUD has a number of

programs under its own authorities that will be affected by the rule.

Under section 1011 of Title X (42 U.S.C. 4852), HUD provides grants

to State and local governments to evaluate and reduce lead-based paint

hazards in pre-1978 housing that qualifies as affordable housing and is

not Federally-assisted, Federally-owned, or public housing.

Under Title X sections 1012 and 1013, HUD is required to establish

lead-based paint hazard notification, evaluation, and reduction

requirements for HUD-associated housing and Federally-owned housing

under provisions codified at various parts of 42 U.S.C. These

regulations, which HUD proposed on June 7, 1996 (61 FR 29170), will

establish programmatic lead-based paint hazard notification,

evaluation, and reduction requirements and will describe how these

activities should be performed. The latter set of standards are based

on the detailed HUD Guidelines for the Evaluation and Control of Lead-

Based Paint Hazards in Housing (hereinafter HUD Guidelines) (Ref. 11),

which HUD developed under Title X section 1017 (42 U.S.C. 4852c), and

on EPA's TSCA section 402 standards described above. The HUD Guidelines

reflect input from housing, public health, and environmental

professionals with broad experience in lead-based paint hazard

identification and control.

3. Other agencies. The Department of Health and Human Services

(HHS), CPSC, the Department of Labor, and other Federal agencies have

contributed to the development of standards and other programs under

Title X, including through their consultation with EPA and HUD. EPA,

HUD, and CPSC jointly released the lead hazard information pamphlet in

consultation with CDC. Under section 1031 of Title X (subpart C), OSHA

promulgated interim final employee protection requirements for

construction workers exposed to lead, which apply to lead-based paint

activities in residential housing and other construction settings (29

CFR 1926.62).

C. Regulatory Development Process

EPA began development of the proposed rule immediately following

enactment of Title X. The Agency quickly encountered significant

challenges in its design and

[[Page 30307]]

implementation of the risk and economic analyses needed to guide

selection of the standards. Recognizing the growing need for advice on

this issue, EPA released an interim guidance document in July 1994 to

provide public and private decision-makers with guidance on identifying

and prioritizing lead-based paint hazards for control. The

recommendations in the guidance represented the Agency's best judgment

given the state of knowledge at the time. EPA subsequently published

the interim guidance document in the Federal Register of September 11,

1995 (60 FR 47248) (FRL-4969-6). The interim guidance will continue to

serve as EPA's official policy until EPA promulgates final standards

under TSCA section 403.

The TSCA section 403 regulations are a significant component of the

national lead-based paint hazard reduction program. As such, these

regulations will likely have a broad impact on public health and

housing. In light of these potential impacts as well as intense

interest in this proposed rule expressed by a large number of

stakeholders, EPA established a Dialogue Process to provide a forum

where EPA could obtain input early in the rulemaking process from

representatives of a range of groups that have an interest in the TSCA

section 403 regulations. Interested parties included lead-poisoning

prevention experts, environmental advocates, housing providers, the

lead industry, State and local governments, the banking and insurance

industries, and the lead risk assessment and abatement industry. EPA

did not use the Dialogue Process to develop a consensus among the

participants, but rather used the Process to gather individual points

of view. Meetings were open to the public and a summary of each meeting

was placed in the public record for this proposed rule (Refs. 12-16).

EPA held five meetings using the Dialogue Process: October 19,

1995; December 14, 1995; February 15, 1996; March 21, 1996; and

November 12, 1997. The first four meetings focused on a range of policy

and implementation issues for which EPA presented a range of potential

options. Participants commented on these options and sometimes

suggested options EPA had not previously considered. Dialogue Process

participants also identified issues EPA had not presented to the group.

The Dialogue Process did not address questions related to the risk

analysis or the technical basis for the rule. These are important and

difficult issues but were beyond the scope of the policy level input

EPA was seeking from the Dialogue. The Agency, instead, presented its

risk analysis document for an expedited peer review in August 1997.

Comments provided by the reviewers can be found in the public record

for this proposed rule. EPA will also ask its Science Advisory Board

(SAB) to review the risk analysis during the public comment period for

today's proposed rule. The SAB report will also be placed in the public

record, and EPA will consider this report in its development of the

final rule.

At the final meeting, EPA staff presented a draft of the options

for the proposed rule being recommended to senior Agency managers. This

meeting provided an opportunity for interested parties to express their

concerns about the current direction of the proposed rule and allowed

EPA to address these concerns by clarifying the Agency's rationale or

by seeking additional input. By addressing the concerns of interested

parties in the proposal, EPA hopes to facilitate the process of

finalizing the proposed regulations.

In addition to the Dialogue Process, EPA staff met with the public

in a variety of other forums to discuss issues related to the rule.

These forums included conferences sponsored by trade associations,

seminars sponsored by real estate groups (e.g., Owners and Managers

Group of the Mid-Atlantic Region, Real Estate Board of New York) and

legal publications (e.g., New York Law Journal), and meetings with

interested parties. In most of these settings, EPA staff provided an

update on the status of the rulemaking and responded to questions.

Occasionally, EPA met with interested parties to obtain information on

specific issues of concern. For example, Agency staff met with

representatives of rental property owners to gauge owner response to

the regulatory standards. In several instances, interested parties

requested meetings with EPA to provide their perspective on specific

regulatory and/or technical issues. EPA has placed a summary of all

meetings between its staff and interested parties in the public record

for this proposed rule (Ref. 17). EPA did not prepare summaries of

presentations delivered at conferences and seminars.

D. General Approach to Standard Setting

Before EPA could formulate and analyze options for the TSCA section

403 standards, the Agency had to develop an overall approach for the

rulemaking. EPA's standard-setting approach was based on the outcome of

two decisions. The first decision was whether the Agency should develop

uniform national standards or standards that are targeted (e.g., to

specific communities or populations). The second decision was whether

EPA should develop independent, media-specific standards or joint

standards. This unit presents EPA's analysis of these issues and its

decisions.

1. Uniform, national standards, or targeted standards. The

establishment of the standards in today's proposal required estimates

of the relationship between environmental lead levels (from paint,

dust, and soil) and their effects on the health of exposed children.

This relationship is extremely complex, and is dependent upon numerous

site-specific and child-specific factors. These estimates are more

accurate on a smaller (residence or community) scale, where more site-

specific factors can be considered.

A targeted approach to standard-setting (i.e., community- or

resident-specific standards) would result in numerically different

standards for each residence or community. Developing national

standards, on the other hand, would produce the same numerical standard

for all residences and communities, but with an attendant loss of

accuracy. That is, national standards would be more protective at some

locations and less protective at others because national standards

would not account for community- or residence-specific factors.

EPA decided, based on considerations of feasibility and ease of

implementation, that national standards are the most appropriate

regulatory approach. First, the data needed to establish standards at a

smaller scale are neither collected under the Title X program nor

available for communities nationwide. Much of the necessary residence-

specific data could be collected to establish residence-specific

standards, but lead-based paint risk assessments would have to be

broader in scope (i.e., include water sampling and sampling of other

ambient environmental levels) and more costly than currently

envisioned. Even then, residence-specific standards would not account

for variability in exposure influenced by child-specific factors (e.g.,

hand-to-mouth behavior, hygiene, nutrition). Community-specific data

would require new resource-intensive data collection efforts (e.g,

patterns of soil contamination, water lead levels). In contrast,

national data on lead in paint, dust, and soil are currently available.

Second, uniform national standards are easier to implement.

National standards provide a fixed basis of comparison for all homes.

National standards can also be used to compare

[[Page 30308]]

properties and establish priorities. In contrast, with residence-

specific standards, there would be millions of standards. Such a

regulation would be largely unworkable. Property owners and other

decision-makers would not know what standard would apply until a hazard

evaluation was conducted. Rental property owners who own multiple

properties would be working with a different standard for each

property. In addition, residence-specific standards would not help

establish priorities because it would be extremely difficult to compare

the relative needs of different properties.

In making this decision, the Agency was also mindful that certain

segments of the population have a higher incidence of elevated blood-

lead levels (e.g., some minority children in inner-city neighborhoods)

and a case could be made for proposing more stringent standards for

particular neighborhoods. However, estimates of the relationship

between environmental lead levels and children's health effects are not

sufficiently refined to distinguish relationships for particular

subsets of the general population of children.

In light of the recently released NHANES III, Phase 2 data, EPA

considered an alternative option under which uniform standards would

only be effective in higher risk communities. EPA, however, rejected

this option because there is insufficient data to definitively identify

these higher risk communities. In addition, the development of

standards for higher risk communities would introduce significant

complexities. First, EPA would have to establish criteria for

identifying these communities. Second, the Agency would have to develop

a set of standards for each category of community. Third, EPA would

have to develop an approach for addressing neighborhoods that border on

higher risk communities. As an alternative, the Agency believes that an

effective and simpler approach to address vulnerable communities is

through program implementation (e.g., training, education, and

environmental justice grants).

EPA also wishes to note that Congress envisioned that important

elements of the Title X program would be delegated to the States.

Accordingly, the Agency preferred to establish a simple, minimal set of

standards that could easily be adopted by States and allow them to

tailor the standards (i.e., by considering more site-specific factors),

should they so choose. Consequently, States will have greater

flexibility in establishing and implementing their programs while a

national, baseline level of protection to children is maintained.

Because the decision to set uniform national standards has a

significant impact on the standard-setting process, EPA is interested

in obtaining comment on this issue. The Agency would like specific

input on how EPA should set standards that will ensure national

resources are targeted commensurate with risk.

2. Joint, media-specific standards vs. joint standards. The second

issue that shaped EPA's standard-setting approach involves the fact

that a child's total lead exposure is the sum of contributions from

numerous sources, including paint, dust, soil, and others.

Specifically, EPA had to decide whether to set separate, independent

standards for paint, dust, and soil or to integrate the standards.

Under the first option, EPA would establish the standard for each

medium without considering the conditions in the other media. For

example, the standard for soil would not be affected by the level of

lead in dust. The soil standard would remain constant, regardless of

whether dust lead levels were high or low. The chief advantage of this

option is that the standards are simple to understand and use. The main

disadvantage is that the standard for each medium may not correspond to

total exposure and risk.

[GRAPHIC] [TIFF OMITTED] TP03JN98.000

Under the second option, EPA would set standards to account for

total lead exposure from all media. Under a joint standard, the

standard for each medium would vary, depending on the conditions in the

other media. For example, the Agency could graphically represent

combinations of hazardous levels of lead in dust and soil with a

downward sloping line. In this graph, shown in Figure 1, the horizontal

axis could depict the level of lead in soil.

[[Page 30309]]

The vertical axis could depict the level of lead in dust. Any point on

this chart, therefore, would illustrate a combination of lead dust and

lead soil levels. The downward sloping line would intersect the

horizontal axis at the point representing the highest acceptable level

of lead in soil if there is no lead in dust. The line would intersect

the vertical axis at the point representing the highest acceptable

level of lead in dust if there were no lead in soil. All points above

the line would be defined as hazardous. To incorporate the condition of

paint into the joint dust and soil standards, the Agency, in theory,

could establish two downward sloping lines: one for homes with no

deteriorated lead-based paint and another for homes with deteriorated

lead-based paint. The major advantage of the joint standards is that

they better reflect the total exposure and risk. On the other hand,

joint standards are more difficult to explain, understand, and use.

Normally, EPA would tend to favor the approach that better reflects

risk to human health. Certainly the joint standard approach described

above would be the approach of choice in evaluating the environmental

risks to a child in a specific house. In the context of this proposed

rule, however, EPA has concluded that single, medium-specific standards

would be far more workable than joint standards for many of the same

reasons that national standards are more workable than targeted

standards. First, media-specific standards provide a fixed basis of

comparison for all homes and can be used to compare properties and

establish priorities. Second, EPA believes that fixed numerical

standards are more easily understood than standards that require an

understanding of mathematical relationships. In addition, the Agency

does not currently possess the analytical techniques necessary to

relate dust loadings to soil concentrations, the measurement basis for

the dust and soil standards. Consequently, EPA lacks a technical method

to establish joint standards.

III. Section-by-Section Review of the Proposed Rule

This unit of the preamble provides a section-by-section explanation

of the proposed regulations. The proposed regulations consist of five

components: the proposed section 403 standards for lead-based paint

hazards; amendments to the final section 402 regulations; amendments to

the final section 404 regulations; and definitions for specific terms.

The unit focuses on the proposed section 403 standards, the proposed

amendments to the final section 402 regulations, and the amendments to

the final section 404 regulation. The definitions are discussed in

relation to the relevant proposed regulatory provisions. Furthermore,

the definitions in proposed Sec. 745.63 that already exist in 40 CFR

745.223 are not subject to public comment.

A. Proposed Section 403 Standards

The TSCA section 403 standards consist of three parts: scope and

applicability; the standards for lead-based paint hazards; and

provisions for implementing the standards.

1. Scope and applicability. The scope and applicability part of the

standards, which is stated in proposed Sec. 745.61, would establish

that the proposed standards would apply to target housing (i.e., most

pre-1978 housing) and child-occupied facilities.

This part of the proposed rule also makes it clear that the TSCA

section 403 standards do not require the owner of properties covered by

this proposed rule to evaluate his/her properties for the presence of

lead-based paint hazards, or to take any action to control these

conditions if one or more of them is identified.

2. Standards for lead-based paint hazards. The proposed standards

for lead-based paint hazards are codified in proposed Sec. 745.65.

Proposed Sec. 745.65(a) states that hazardous lead-based paint includes

lead-based paint in poor condition. Proposed Sec. 745.63 defines paint

in poor condition as more than 10 square feet of deteriorated paint on

exterior components with large surface areas, more than 2 square feet

of deteriorated paint on interior components with large surface areas

(e.g., walls, ceilings, floors), or deteriorated paint on more than 10

percent of the total surface area of interior or exterior components

with small surface areas (e.g., trim, baseboards). EPA is not proposing

hazardous lead-based paint standards for accessible surfaces and

friction and impact surfaces. The Agency, instead, has presented a

range of options for these standards, which are discussed in Unit

IV.D.2 and IV.D.3. of this preamble. EPA is seeking public comment on

these options and will promulgate standards as part of the final rule

based on these options and consideration of public input.

Proposed Sec. 745.65(b) identifies dust-lead hazards in terms of

lead loading and location. Lead loading is the quantity of lead present

per unit of surface area (e.g., micrograms per square foot). The

proposed dust-lead hazard standard is 50 g/ft2 for

uncarpeted floors and 250 g/ft2 for interior window

sills. The proposed rule does not include a dust-lead hazard standard

for carpeted floors or for window troughs.

Proposed Sec. 745.65(c) identifies soil-lead hazards in terms of

lead concentration. Lead concentration is the relative content of lead

within the soil measured in parts per million by weight. The proposed

standard for soil-lead hazard is 2,000 ppm.

3. Proposed requirements for implementing the standards. This part

of the proposal describes the requirements for how a certified risk

assessor would compare on-site observations and sampling results to the

standards to determine whether lead-based paint hazards are present.

The general requirements are in Sec. 745.69. EPA has incorporated the

specific requirements, which are summarized in Table 1 below, into the

work practice standards for lead-based paint activities found at 40 CFR

745.227.

Proposed Sec. 745.69 would establish that the determination

requirements are applicable to the standards for lead-based paint

hazards. It also states that the determination would have to be made by

a certified risk assessor performing a risk assessment according to the

risk assessment work practice standards. Third, the proposed

regulations state that, for purposes of determining the presence of a

dust-lead hazard, the risk assessor must compare the weighted

arithmetic means of the samples to the applicable standard. For

purposes of determining the presence of soil-lead hazards, the risk

assessor must compare the arithmetic means of the samples to the

applicable standard.

Table 1.--Summary of Regulations for Determining the Presence of Lead-

Based Paint Hazards

------------------------------------------------------------------------

Type and Location of Hazard/Contamination Method

------------------------------------------------------------------------

Hazardous lead-based paint: lead-based Visual assessment for

paint in poor condition condition of paint; test

paint; assume all like

surfaces that have similar

painting history contain

lead-based paint if tested

component has lead-based

paint

[[Page 30310]]

Dust-lead hazard: uncarpeted floors Compare weighted arithmetic

(single-family and sampled units and mean lead loading of all

common areas in multi-family) samples for uncarpeted

floors to the hazard

standard for floors

Dust-lead hazard: interior window sills Compare weighted arithmetic

(single-family and sampled units and mean lead loading of all

common areas in multi-family) samples for interior window

sills to the hazard standard

for sills

Dust-lead hazard: uncarpeted floors Assumed to be hazard if

(unsampled units and common areas in hazard is present in any

multi-family) sampled unit or common area

of the same type

Dust-lead hazard: interior window sills Assumed to be hazard if

(unsampled units and common areas in hazard is present in any

multi-family) sampled unit or common area

of the same type

Soil-lead hazard Compare arithmetic mean of

dripline and mid-yard

samples to hazard standard

------------------------------------------------------------------------

Proposed Sec. 745.227(h) would establish the specific requirements

for how to determine whether lead-based paint hazards are present. To

determine whether hazardous lead-based paint is present, the risk

assessor must test paint that is in poor condition. The paint on all

surfaces with paint in poor condition need not be tested. The risk

assessor, however, must assume that untested surfaces contain lead-

based paint if tested surfaces that have a similar painting history

contain lead-based paint.

To determine whether a dust-lead hazard is present, the risk

assessor must compare the weighted mean (i.e., weighted average) of all

single surface samples or all composite samples to the appropriate

dust-lead hazard standard (i.e., uncarpeted floors, interior window

sills).

In multi-family housing, where risk assessors have the option not

to collect dust samples in every residential unit or common area, the

approach described in the previous paragraph applies to all sampled

residential units and common areas where samples were collected. For

residential units or common areas where samples are not collected, the

risk assessor would have to make assumptions based on the results of

sampled residential units and common areas. If at least one sampled

residential unit or common area exceeds the hazard standard for a

specific surface (i.e, floors, sills), then the risk assessor would

have to assume that hazards exist on that surface in all unsampled

residential units and common areas. It should be noted that risk

assessors always have the option to collect samples from all units and

common areas at a multi-family property.

Proposed Sec. 745.227(h) also would establish the requirements for

how to determine whether a soil-lead hazard is present. Under the

proposal, the risk assessor must compare the mean of a composite sample

from the dripline and a composite sample from the mid-yard for each

residential building to the standards to determine whether a hazard is

present. If the risk assessor collects more than one composite in

either the dripline or the mid-yard for a building, he or she should

compute the average of the composites from each area and use those

averages to compute the average concentration for the dripline and the

mid-yard.

Proposed Sec. 745.63 defines the dripline and mid-yard. The

dripline is the area within 3 feet surrounding the perimeter of a

building. The mid-yard is the part of yard that lies halfway between

the outermost edge of the dripline and property line or between the

outermost edge of the dripline and the outermost edge of the dripline

of another residential building on the same property. This approach

applies to both properties with a single residential building and to

those with more than one residential building.

B. Proposed Amendments to the Final Section 402 Regulations

Today's action includes proposed amendments to the final TSCA

section 402 work practice regulations for lead-based paint activities

at 40 CFR 745.227. The proposed amendments would establish clearance

standards for dust, limit reuse of abated soil, add a requirement for

interpreting composite dust clearance samples, and change risk

assessment and clearance sampling requirements to ensure compatibility

between sampling results and the TSCA section 403 standards and section

402 clearance standards. Unit IX. of this preamble discusses these

amendments and the Agency's rationale and supporting analyses for its

decisions.

Today's action proposes to amend the abatement work practice

standards at 40 CFR 745.227(e) by adding clearance standards for dust.

A risk assessor performs clearance testing to evaluate the adequacy of

post-abatement dust cleaning. The proposed clearance standards are 50

g/ft2 for uncarpeted floors, 250 g/

ft2 for interior window sills, and 800 g/ft2

for window troughs.

Second, today's action includes a proposed amendment to the

abatement work practice standards at 40 CFR 745.227(e) to prohibit the

reuse of soil removed during an abatement as top soil in another

residential yard or child-occupied facility. The current regulations do

not provide any management controls for the soil.

Third, today's proposal includes an amendment to the abatement work

practice standards at 40 CFR 745.227(e) to add a requirement for

interpreting composite dust samples for clearance. The current

regulation does not differentiate between single surface samples and

composite samples. The proposed amendment would require the risk

assessor to compare the composite sample to the clearance standard

divided by the number of subsamples in the composite. For example, if

the composite contains four subsamples, the risk assessor would compare

the composite to the clearance standard divided by four.

Fourth, the Agency is proposing that the risk assessment work

practice standards at 40 CFR 745.227 be amended to require that risk

assessor collect dust samples from uncarpeted floors and interior

window sills because EPA is proposing dust-lead hazard standards for

uncarpeted floors and window sills. Today's proposal also includes an

amendment to the abatement work practice standards at 40 CFR 745.227(e)

to require that a risk assessor collect dust clearance samples from

uncarpeted floors, window sills, and window troughs because EPA is

proposing clearance standards for all three surfaces. The current risk

assessment and abatement work practice standards require risk assessors

to collect dust samples from windows without specifying the part of the

window. The Agency is also proposing to amend the risk assessment work

practice standards to change the

[[Page 30311]]

location of soil samples from the dripline and ``play area'' to the

dripline and mid-yard.

C. Proposed Amendments to the Final Section 404 Regulations

Today's action includes proposed amendments to the final TSCA

section 404 States/Tribal program authorization regulations found at 40

CFR part 745, subpart Q. These proposed amendments would require

States/Tribes that are seeking program authorization and States/Tribes

that already have applied for authorization and wish to retain it to

incorporate lead-based paint hazard standards that are as protective as

the Federal standards no later than their first report to EPA after

years following the promulgation of the TSCA section 403 standards.

States/Tribes seeking authorization for the first time would

include their standards in their program application, the requirements

for which are described in 40 CFR 745.320 to 40 CFR 745.325. Proposed

amendments to Sec. 745.325, would explicitly clarify that lead-based

paint hazard standards and implementation requirements are necessary

components of the risk assessment work practice standards in

Sec. 745.325(d)(2). States/Tribes seeking to retain program

authorization would describe their standards in their regular report to

EPA in accordance with 40 CFR 745.324(h).

IV. Development of this Proposed Rule

This unit of the preamble presents EPA's analysis of its legal

authority, and describes the Agency's policy basis, technical analyses,

and decisions for the proposed section 403 standards. Section A

discusses EPA's legal authority and policy basis for the standards.

Section B discusses the technical analysis to support the development

of the proposed standards for dust and soil. Section C presents EPA's

analysis of the options for dust and soil standards and explains the

Agency's decisions. Section D presents the analysis of the options for

the paint hazard standard and explains the Agency's decisions. The

standard for lead-based paint, as further explained below, is defined

by statute and EPA is not modifying that standard in this proposed

rule.

A. Authority for Today's Action

1. Statutory mandate and related definitions. Section 403 of TSCA

is the key statutory provision for today's proposed regulation. It

requires EPA to identify three terms--lead-based paint hazards, lead-

contaminated dust, and lead-contaminated soil. For reasons explained

below, EPA needs to first define lead-contaminated dust and soil before

it may define lead-based paint hazards. These three terms and other

definitions that help define them are found in both TSCA section 401

(15 U.S.C. 2681) and in section 1004 of Title X (42 U.S.C. 4851b).

Because the definitions in both of these sections are identical for

practical purposes, the remainder of this preamble will cite the TSCA

definitions. Below, EPA explains how the definitions affect the

Agency's responsibilities in this proposed rule.

TSCA section 401(10) defines ``lead-based paint hazard'' to mean

any condition that causes exposure to lead from lead-contaminated dust,

lead-contaminated soil, lead-contaminated paint that is deteriorated or

present in accessible surfaces, friction surfaces, or impact surfaces

that would result in adverse human health effects . . . [emphasis

added].

Thus, there are three sources that may contribute to the existence of a

lead-based paint hazard--lead-contaminated paint, lead-contaminated

dust, and lead-contaminated soil.

EPA interprets lead-contaminated paint to mean the same as ``lead-

based paint,'' which is defined by TSCA section 401(9) to mean paint or

other surface coatings that contain lead in concentrations equaling or

exceeding limits established under section 302(c) of the Lead Based

Paint Poisoning Prevention Act (42 U.S.C. 4822(c)). Currently, this

limit is lead content that equals or exceeds 1.0 milligrams per square

centimeter (mg/cm2) or 0.5 percent by weight. EPA is not

taking any action in this proposed rule to redefine lead-based paint.

It must be emphasized that lead-based paint is not a risk-based

term. It is only a benchmark that identifies material subject to the

jurisdiction of various authorities of TSCA and Title X. Instead, the

term ``lead-based paint hazard'' will identify those conditions of

lead-based paint that would result in adverse health effects. The

statutory language makes it clear that not all lead-based paint is to

be considered a lead-based paint hazard. In fact, for lead paint to be

a hazard it must, at least, be deteriorated or be present on friction

or impact surfaces or on surfaces accessible for young children to

mouth or chew. Deteriorated paint is defined in TSCA 401(3). Friction,

impact, and accessible surfaces are defined in TSCA 401(2), (5) and

(6).

Lead-based paint hazards, furthermore, are not limited to the

hazards from paint, alone, because they include conditions that cause

exposure to residential lead-contaminated dust and soil, regardless of

the source of lead. EPA is responsible in this proposed rule for

identifying what constitutes lead-contaminated dust and soil. Both

terms are limited to dust and soil in residences, in contrast to lead

paint, which may be found in public and commercial buildings and in

other structures, such as bridges or superstructures (e.g., water

towers).

Lead-contaminated dust means surface dust in residential dwellings

that contains lead determined by EPA to pose a threat of adverse health

effects in pregnant women or young children [emphasis added] (TSCA

401(11)). Lead-contaminated soil means bare soil on residential

property that contains lead that is determined to be hazardous to human

health by EPA (TSCA 401(12)) [emphasis added].

The lead-based paint hazard definition contains the overarching

legal standard applicable to today's proposed regulation. In pertinent

part, the definition means any condition that causes exposure to lead-

contaminated dust, soil, or paint that would result in adverse human

health effects. To determine what constitutes lead-contaminated dust or

soil, on the other hand, EPA interprets the statute to require a less

rigorous level of certainty regarding the likelihood of adverse effects

occurring to establish the standards.

2. Statutory criteria for lead-contaminated dust and soil, and

lead-based paint hazards. Given the definitions of lead-based paint

hazards, lead-contaminated dust, and lead-contaminated soil in TSCA

section 401, EPA needs to establish standards for lead-contaminated

dust and soil separately from lead-based paint hazards. Put simply, not

all lead-contaminated dust or lead-contaminated soil (or lead-based

paint) needs to be considered hazardous. In fact, as explained below,

the definitions in TSCA section 401 support the Agency's adoption of a

weight of evidence approach for setting the varying standards.

To help differentiate between lead-contaminated dust and soil and

lead-contaminated dust and soil that are lead-based paint hazards, and

to alleviate the confusion created by this terminology, the Agency will

generally refer to lead-contaminated dust and soil that meet the lead-

based paint hazard criteria as dust-lead hazards and soil-lead hazards.

EPA will refer to the paint component of lead-based paint hazards as

hazardous lead-based paint.

a. Contamination standards. As indicated above, EPA believes that

the term ``poses a threat,'' used to define

[[Page 30312]]

lead-contaminated dust, connotes a lower level of certainty regarding

risk than the term ``would result in adverse effects,'' used to define

lead-based paint hazard, and indicates that the standard for lead-

contaminated dust requires a lesser weight of evidence of harm. The

level of certainty associated with the term ``hazardous to human

health,'' which is used to define lead-contaminated soil, is less

clear. The overall structure of the definitions in section 401,

however, indicates parallel treatment for lead-contaminated dust and

soil. EPA is, therefore, interpreting ``poses a threat'' and

``hazardous to human health'' to be associated with the same level of

evidence needed to determine risk.

The terms ``lead-contaminated'' dust and soil, therefore, describe

the universe of lead in soil and dust about which there may be some

level of concern. Within this universe are levels of lead-contaminated

dust and soil that result in lead-based paint hazards, which engender

greater concern because there is greater certainty of risk of adverse

human health effects. Identifying hazardous paint, dust, and soil,

therefore, requires a greater weight of evidence of harm.

The terms lead-contaminated dust and lead-contaminated soil, while

necessary components of the definition of lead-based paint hazards, do

not appear anywhere else in Title X. Thus, they have no direct effect

on any activities subject to regulation under Title X. For example, no

certification requirements are imposed for persons who remove lead-

contaminated soil, only soil associated with soil-lead hazards. EPA

concludes from this observation that the purpose for identifying lead-

contaminated dust and soil separately from hazardous dust and soil is

to identify levels of dust and soil contamination for which there are

lower levels of certainty regarding adverse effects and general

population concern, but about which owners and occupants of residential

property should be aware. Individual owners and occupants may wish to

make decisions based on the lesser level of certainty. To convey this

message, EPA has decided to call the standards for lead-contaminated

dust and soil, dust-lead and soil-lead ``levels of concern.'' EPA has

decided that the levels of concern should be based solely on their

potential to pose a threat to human health, without regard to whether

taking action on these levels could result in significant risk

reduction, or whether the resources that persons may choose to expend

on dealing with dust and soil at these levels are commensurate with any

potential risk reduction.

Because the level of concern does not affect other activities under

Title X or TSCA Title IV, EPA has decided not to include the levels of

concern in the proposed regulation. Nevertheless, because the level of

concern communicates important risk information to property owners and

occupants, the Agency believes that it is important to include the

levels of concern in the preamble and guidance that will accompany the

rule. At this point, the Agency is only proposing to adopt in guidance

a separate level of concern for lead in soil, which is discussed in

detail in Unit IV of this preamble. The Agency has decided that there

should not be a separate dust-lead level of concern, even in guidance,

because EPA's analysis shows that dust-lead level of concern should be

the same as the dust-lead hazard standard. The Agency believes,

therefore, that having a separate dust-lead level of concern would not

provide useful additional information to the public.

EPA is interested in public input with respect to the inclusion of

the levels of concern, particularly for soil, in the regulatory text of

the document. Specifically, EPA is seeking comment on whether the

absence of the soil-lead level of concern in the regulation would

diminish the visibility of the level and reduce its usefulness as a

risk communication tool, or whether the soil-lead level of concern

would be treated as the de facto hazard standard if it were included in

the regulation. EPA does not believe that the public should confuse the

soil-lead level of concern in the guidance, with the soil-lead hazard

standard in the regulation. As indicated above, the Agency is

specifically interested in comments on this issue.

b. Hazard standards. The determination of what constitutes lead-

based paint hazards--hazardous paint, dust, and soil--will require a

more elaborate analysis. Clearly, the statutory criterion for hazard,

``would result in adverse human health effects,'' means that lead-based

paint hazards are associated with a higher level of risk than levels of

concern. The challenge to the Agency is how to identify the higher

level of risk.

Based on the language of section 403, the purposes of Title X and

its legislative history, and basic policy discussions explained below,

EPA determined that it should identify this higher level of risk based

on consideration of the potential for risk reduction of any action

taken (considering uncertainties in the scientific evidence describing

the risks) and whether such risk reductions are commensurate with the

costs of those actions. This is commonly referred to as cost-benefit

balancing.

The use of the term ``would result'' in the statutory criteria --

``would result in adverse human health effects''--implies certainty of

adverse outcome. This interpretation is supported the by legislative

history discussed in the Senate Committee Report (National Affordable

Housing Act Amendments of 1992, Report of the Committee on Banking,

Housing and Urban Affairs, S. Rep. 102-332, 102d Cong., 2nd Sess., at

112 (hereinafter ``Senate Report'')). The Senate Report states that

Title X ``limits the definition of hazard, and thus the scope of the

bill to actual hazards--conditions that cause [ ] exposure to lead . .

. that would result in adverse human effects'' [emphasis added] (Senate

report, page 112).

Dealing with what would constitute an ``actual'' effect is the

dilemma posed by the statutory language. EPA's interpretation of the

broader Title X framework suggests that lead-based paint hazard

standards should not be based on absolute certainty. If the EPA were to

follow Congress' literal wording, available evidence would only allow

the Agency to set unreasonably high dust, soil, or paint hazard

standards. EPA does not believe that this is an appropriate formulation

of Congressional intent. As stated in section 1103(3), one purpose of

Title X is ``to encourage effective action to prevent childhood lead

poisoning'' (emphasis added). To follow this directive, EPA needs to

establish hazard standards that predict adverse health outcomes based

on their environmental observations and measurements. Due to the large

amount of variability in the relationship between environmental lead

levels and blood-lead concentrations, it is not possible to state with

certainty that a given set of environmental conditions would result in

an actual adverse outcome. EPA, therefore, has not used an absolute

certainty criterion but rather interprets the statute to require a

level of certainty regarding risk that is higher than that used for the

contamination standard--the ``level of concern.''

It is possible, however, to state that there is a relatively high

likelihood that an adverse outcome will occur. The dilemma the Agency

faces in this case would be that hazards would be identified only at

the very highest levels. Thus, for example, EPA could say that adverse

effects ``would result'' only when an individual child has a 100

percent probability of having a blood-

[[Page 30313]]

lead concentration equal to or exceeding 10 g/dl. Using this

100 percent probability criterion as the basis for setting hazard

standards, however, would contribute little, if anything, to the

statutory intent of preventing adverse effects. Moreover, the

environmental lead levels associated with this probability level would

be so high that they would likely apply to only a very small number of

situations--for example, soil levels well over 5,000 ppm or dust lead

levels well over 500 g/ft2. Children exposed to

significantly lower levels could be subject to substantial risk that

would be ignored in the national lead program. Therefore, EPA has

elected not to use such a formulation.

Accordingly, EPA examined the statute and its legislative history

for guidance on how to select appropriate parameters for identifying

lead-based paint hazards. Based on this analysis, the Agency concluded,

for the following reasons, that the hazard standards should be based on

a set of parameters identified by balancing the costs of reducing

exposures to lead-based paint hazards with the benefits of avoiding

adverse human health effects.

First, the identification of lead-based paint hazards is linked

with hazard reduction in many provisions of Title X, including sections

1011(e)(8) and (9), 1012(a) and (e), and TSCA section 401(8) and (13).

This linkage suggests that measures taken to reduce hazards should be

consistent with the risks presented. The Senate Report, recognizing

that many property owners would implement interim controls to respond

to lead-based paint hazards, states that ``interim measures should be

commensurate with the degrees of risk reported by the risk assessment''

(p. 115). The Report is most explicit in its discussion of lead-based

paint hazard reduction in Federally assisted and insured housing, where

it states that ``the response would correspond to the degree of danger

and the benefit to be achieved'' (p. 117). Cost-benefit balancing is a

reasonable method that can be used to assist EPA in setting hazard

standards that would promote control activities that are commensurate

with risk.

Second, cost-benefit balancing is a useful method to examine the

potential for adverse effects, the resource allocation that should be

associated with reducing that potential, and methods of public

protection when the available scientific evidence shows there is a wide

range of uncertainty in the risks that may be associated with any

particular levels. The Senate Report recognized that there is a wide

range of responses applicable to lead-based paint and paint hazards

depending on the degree of risk and the likelihood of risk reduction

that could occur from any particular action. In particular, property

owners can choose to reduce hazards through ``abatement'' (permanent

elimination of hazards) or ``interim measures'' (temporary exposure

reduction). See TSCA sections 401(1), (8), and (13). The Senate Report

at 113-115 specifically refers to this wide range of applicable

responses and the need to consider measures commensurate with the risk.

The Senate Report at 113 states that housing owners

will choose to abate or partially abate when they determine that

it is cost effective for them to permanently eliminate the source of

hazards.

Further, the Senate Report at 115 states that interim measures

should be commensurate with the degree of risk reported by the

risk assessment. Thus, where moderately elevated dust levels exist

but there is little deterioration in the paint, an appropriate

interim response might be limited to supercleaning leaded surfaces.

Where children are present and paint is peeling, interim controls

might require a more substantial effort and expense to prevent

exposure from paint chips and dust.

Given these standards, EPA believes that it is a reasonable

interpretation of TSCA section 403 to identify the conditions that

constitute lead-based paint hazards by considering the weight of

evidence on the range of environmental lead levels that would result in

particular blood lead levels, the adverse effects associated with those

blood-lead concentrations, and potential ranges of risk reduction

(reductions in blood-lead concentration) that would result from

eliminating or controlling the levels.

Several purposes of Title X also support the use of cost-benefit

balancing for establishing the hazard standards. According to section

1003(2) of Title X, one purpose of the statute is ``to implement, on a

priority basis, a broad program to evaluate and reduce lead-based paint

hazards in the Nation's housing stock.'' The concept of priority-

setting inherently recognizes that resources are scarce, and that

scarce resources are most effectively employed when decision-makers

apply them to the worst problems first. To develop standards that are

consistent with the need to set priorities, EPA factored in the

resources needed to reduce risks, the benefits of controlling lead-

based paint hazards, and data on the presence of lead in residential

paint, dust, and soil when selecting the proposed standards. Cost-

benefit analysis is a principal analytical tool available to the Agency

to measure the effectiveness of using resources to reduce human health

risks.

Section 1003(3) of Title X also states that a purpose of the

statute is ``to encourage effective action to prevent childhood lead

poisoning by establishing a workable framework for lead-based paint

hazard evaluation and reduction. . . .'' In developing today's

proposal, EPA interprets the term ``workable'' to mean practical,

usable, and realistic. First, a workable framework must be practical;

that is, it should promote priority-setting, focusing resources on the

most significant risks. Overly stringent standards that result in the

identification of lead-based paint hazards in large segments of the

housing stock would not be practical because they would not provide

guidance to decision-makers on where to focus resources.

Second, the standards must be usable by the intended audience. Risk

assessors must be able to use the standards as a tool to evaluate

properties quickly at a modest cost. The standards should not require

extensive and costly environmental measurement. The meaning of the

standards must be sufficiently simple for risk assessors to explain and

property owners, residents, and other decision-makers to understand the

significance of the findings of a risk assessment.

Third, for a framework to be workable, it needs to be based on

realistic goals, goals that are achievable with available resources and

feasible with available technology. The standards for identifying lead-

based paint hazards, therefore, need to recognize resource and

technological constraints. These standards, the primary function of

which is to provide guidance and advice, risk being ignored by their

intended audience and having no value if they are not practical,

usable, and realistic.

Section 1003(3) also refers to the Title X purpose of ``. . .

ending the current confusion over reasonable standards of care.'' EPA

interprets a ``reasonable'' standard to be one that requires exercise

of judgment to balance the probability that harm will occur, and the

magnitude and severity of that harm, against the adverse social and

economic impacts on society of the action taken to reduce the harm. The

reasonableness standard becomes more judgmental in the case of health

risks of lead where, as a practical matter, all the scientific evidence

is uncertain to some degree and EPA is forced to deal in probabilities

that can vary over extreme ranges. Therefore, in evaluating a

reasonable standard of care

[[Page 30314]]

under Title X, EPA will consider the various relationships among such

factors as toxicity, exposure, the effectiveness of interventions, and

the cost of interventions.

EPA, further, believes that consideration of cost is consistent

with the establishment of these lead standards. The purpose of the lead

hazard standards is to protect the public health. To do this within the

framework of Title X, however, requires the expenditure of scarce

public and private resources. Ensuring that these resources are used in

a manner that maximizes health protection means that EPA should

establish lead hazard standards that direct resources to where the

threats to public health are the greatest. EPA recognizes there are

different ways in which the TSCA section 403 standards may be

interpreted and, specifically, requests comment on whether it is

appropriate for the Agency to use the cost-benefit analysis to develop

the hazard standards for this rule.

3. Policy basis for the standards--a. Dust-lead and soil-lead

levels of concern. To implement its decision to treat the dust-lead and

soil-lead levels of concern as risk communication tools, EPA is

proposing that the soil and dust levels of concern should be associated

with a blood-lead concentration of concern and a child's probability of

exceeding that blood-lead concentration (exceedance probability). As

noted previously, EPA is proposing to establish a soil-lead level of

concern for use in guidance and not to include it in the proposed

regulation.

EPA used blood-lead concentration as the measure of human health

risk, because it is the most widely used index of human lead exposure

and risk. By exceedance probability, EPA means an individual child's

risk or probability of having a blood-lead concentration that equals or

exceeds a specified concentration. For example, if the blood-lead

concentration of concern is 10 g/dl, an exceedance probability

of one percent means that a child has a one percent chance of having a

blood-lead concentration that equals or exceeds 10 g/dl.

An exceedance probability is needed because the relationship

between lead in the environment and blood-lead concentration is

characterized by a great deal of variability due to several factors,

including differences among children in behavior and nutrition. The

measurement of lead in the environment and in blood is also subject to

a significant degree of variation. It is not possible, therefore, to

link a specific level of lead in the environment (e.g., soil) to a

specific blood-lead concentration with absolute certainty. Rather, a

specific level of lead in the environment is associated with a

distribution of blood-lead concentrations.

The distribution, which can be thought of as a curve drawn on a

graph, represents the range of blood-lead concentrations and the

relative probability that each blood-lead concentration would actually

occur. A distribution is described by three parameters: the form (i.e.,

shape) of the distribution (e.g., normal distribution or ``bell''

curve, log normal distribution); a measure of central tendency (e.g.,

mean or average); and a measure of variability or spread (e.g.,

standard deviation) around the measure of central tendency. With these

three parameters, the probability of exceeding any blood-lead

concentration can be calculated. For further discussion of standard

deviation, please see Matlack, Statistics for Public Policy and

Management (Ref. 18).

b. Dust-lead and soil-lead hazard standards. Having presented its

rationale, above, for using cost-benefit balancing to help develop the

proposed dust and soil-lead hazard standards, EPA now explains its

intent to use cost-benefit balancing in the hazard standard-setting

process.

It is important to note that the Agency's analyses for dust and

soil began with an examination of quantitative estimates based on

various modeling techniques. These techniques allow the Agency to

arrive at a range of options on which the Agency exercises its

administrative judgment. Thus, the quantitative modeling is used as a

tool to derive the boundaries of the Agency's inquiry, not as the sole

basis for decisions.

Furthermore, the Agency wishes to note that it employed a normative

analysis to support the selection of the dust-lead and soil-lead hazard

standards. A normative analysis estimates costs and benefits based on

the assumption that individuals will make perfectly rationale decisions

in response to the standards. That is, all individuals who should

conduct risk assessments will do so, and all individuals will undertake

appropriate interventions in response to hazards identified by the risk

assessment. This normative analysis also assumes that no action is

being taken in the absence of the standards. In reality, hazards will

not be identified in many homes because risk assessments will not be

performed. Even if hazards are identified, interventions may not be

performed or interventions different from those assumed in the analysis

may be performed. In addition, risk assessments and hazard control

interventions are currently being conducted.

EPA used a normative analysis for two reasons. First, as a

practical matter, it is difficult, if not impossible, to estimate

expected costs and benefits associated with the standards. Such

estimates would require data on the current level of risk assessment

and abatement, which is not available, and the Agency to predict how

property owners and other decision-makers will respond to the

standards. Second, the objective of the analysis is to provide

estimates that allow Agency decision-makers to compare costs and

benefits. Although the normative analysis is likely to overestimate

actual costs and benefits, EPA believes that the relative balance of

costs and benefits estimated by the analysis is unlikely to be very

different from the relative balance of actual costs and benefits.

Therefore, the Agency can use these estimates to evaluate various

options for the dust and soil standards.

With respect to the paint component of the proposed regulation,

data limitations prevented EPA from quantifying the costs and benefits

of the options considered in this proposal. Data that definitively

relate deteriorated paint to blood-lead concentration are not

available, preventing the Agency from estimating the benefits of these

options. EPA could not estimate the costs of these options because the

Agency's decision regarding deteriorated lead-based paint focused on

the area of deterioration on individual components whereas the

available data provide information on the amount of deteriorated paint

in an entire residence. Consequently, EPA's decisions with respect to

the options for the paint component involve a more qualitative judgment

on the part of the Agency.

As part of its economic analysis of the proposed rule, EPA

developed estimates of the costs and benefits of repairing or abating

deteriorated lead-based paint. The preamble presents these estimates in

Unit X. The data limitations identified above as well as other

analytical constraints described in Unit X, however, restrict the

usefulness and call into question the reliability of these estimates in

characterizing the proposed regulatory standards for paint.

While Title X provides no guidance on how to undertake cost-benefit

balancing, the legislative history of TSCA provides a useful and

pertinent explanation of the concept. The House Report on TSCA (H. Rep.

1341, 94th Cong., 2nd Sess. at 13-15, 32)

[[Page 30315]]

acknowledges that cost-benefit balancing for regulation is not precise

but, instead, requires the exercise of judgment by the decision-maker.

It involves the balancing of the probability that harm will occur, and

the magnitude and severity of that harm, against the cost of the

proposed action to reduce that harm. In other words, cost-benefit

balancing involves a weighing of the risks to be reduced by response

actions and the costs of these actions.

The TSCA House Report emphasizes that cost-benefit balancing does

not require a formal quantitative analysis under which a monetary value

is assigned to risks that may be reduced by regulation or the costs to

society. This is because precise values often cannot be assigned to

such risks and costs. Accordingly, cost-benefit balancing is

appropriately used to establish a range of options for the hazard

standards. Using this approach, the Agency then selects its preferred

options based on consideration of relevant factors, including the

weight of the evidence of harm, assumptions and tools that underlie

EPA's analysis, as well as other factors, including health

protectiveness and total costs.

Cost-benefit balancing involves a two-step process: evaluation of

risk and risk-reduction (i.e., benefit), followed by consideration of

the resources needed to achieve varying degrees of risk reduction.

Below, EPA explains first the concept of evaluating risk and risk

reduction, then the concept of evaluating how to balance risk reduction

(benefit) with costs.

With respect to risk, the TSCA House Report states that: ``. .

.risk is measured not solely by the probability of harm, but instead

includes elements both of probability of harm and severity of harm and

those elements may vary in relation to each other'' [emphasis added].

Determining risk becomes more judgmental in the case of health and

environmental risks covered by EPA in cases where the scientific

evidence on hazard and exposure contains a high degree of uncertainty

and variability encompassing numerous relationships among elements of

risk, including consideration of the severity and probability of harm

resulting from the different types of exposure that may occur. Because

of the uncertainty in all of these estimates, there are generally no

definitive answers as to what the risk may be. Therefore, in evaluating

risk, EPA considers various factors, including the strength of the

evidence on toxicity (for example, actual cases of harm from

epidemiology studies or results of high-dose animal tests), the type

and magnitude of effects that are predicted to occur (for example,

severe effects or more subtle ones), and estimates of the numbers of

individuals exposed and the levels of exposure based on mechanistic and

statistical models.

Once the risk is evaluated, with the attendant uncertainties in

hazard evaluation and the variations in exposure probability, the next

step is to consider the costs of the regulatory action. The probability

and severity of harm (in this case, a range of children's health

effects) are weighed against the impact of any action EPA proposes to

take to evaluate whether the costs are commensurate with risk

reduction. There is, however, no set way to apply EPA's chosen approach

for this rulemaking to balancing costs and risk reduction. To

illustrate this point, the Agency provides the following examples.

Where standards would require the high expenditure of resources, the

level of risk reduction (considering both the toxicity of lead and the

probabilities of exposure) and the strength of evidence should be

correspondingly high. On the other hand, if the costs of standards are

relatively low, the level of risk reduction and the strength of the

evidence could be less compelling.

Today's proposed rule takes this balancing into account in

proposing both soil and dust hazard standards. The determination on

soil standards considers the fact that relatively high costs would be

incurred to abate residential soils. Consequently, under a cost-benefit

balancing concept, before selecting an option associated with high

costs, EPA would want a greater measure of confidence that the standard

would result in a higher level of risk reduction. Because the cost of

reducing risk from residential dust is relatively low, EPA could select

a dust-lead hazard standard that would not result in as much risk

reduction.

Finally, EPA believes that this type of analysis is an appropriate

way to deal with the problems caused by lead in paint and residential

dust and soil. Lead is a substance for which there is no clear evidence

that there is a level of exposure below which there is no risk. It is

clear, however, that there is some level of lead where the use of

scarce resources to reduce exposure to lead is warranted. EPA

recognizes that resources needed to address risks from lead-based paint

hazards are limited and would like to set standards to target responses

to these hazards so that the highest risks will be addressed first. In

contrast, spending valuable resources engaging in cleanup activities to

achieve little or no reduction in risk would not be a reasonable

approach.

B. Technical Analyses

To support the development of dust and soil lead levels of concern,

as well as for the hazard standards, EPA requires a tool to relate lead

in the environment to blood-lead concentration. As will be further

explained below, EPA has chosen two types of models to be used for this

purpose: a mechanistic model and a statistical model based on empirical

data. A mechanistic model simulates the human body's response to lead

that is ingested or inhaled. Because biological processes that

mechanistic models are designed to simulate are not completely

understood, these models are typically limited in their predictive

capability. The components of the processes that are understood have to

be simplified and digested into a series of mathematical equations

resulting in another source of error. The data that are used as inputs

into these models may not be truly representative and may contain gaps.

Alternatively, EPA could use observational data to estimate the

relationship between environmental lead and blood lead. Two national

data sets are available to the Agency. EPA has national blood-lead data

from Phase 2 of the third National Health and Nutrition Examination

Survey (NHANES III) (Ref. 6) and national data on levels of lead in

dust and soil and condition of paint from the National Survey of Lead-

Based Paint in Housing, conducted from 1989-1990 by the U.S. Department

of Housing and Urban Development (Ref. 19). These data sets, however,

are not linked. That is, there is no direct observation between blood-

lead in NHANES and the environmental levels in the HUD survey.

Therefore, these data sets cannot be used in combination to estimate

the relationship between lead in dust and soil and blood-lead

concentration.

In light of limited data and imperfect models, the Agency cannot

rely on any single approach to specify the true relationship between

lead in dust and soil and blood lead. EPA, therefore, used several

tools to derive differing estimates of the relationship. The

mechanistic model used for the various analyses in this proposed rule

is the Agency's Integrated Environmental Uptake and Biokinetic (IEUBK)

model. EPA also conducted several analyses for this rule using data

from the Rochester Lead-in-Dust study, which contains data for

children's blood-lead concentrations and dust and soil-lead levels in

their environment (Ref. 20). These tools will be discussed further

below in the sections where they are used.

[[Page 30316]]

The Agency wishes to note that the differing estimates of the

relationship between environmental lead and blood-lead concentration do

not bound the range of options available to EPA for the proposed rule.

The true relationship between blood-lead and dust and soil-lead could

be stronger or weaker than the estimates used in this proposed rule.

1. Dust-lead and soil-lead levels of concern. This section of the

preamble presents the Agency's rationale for its choice of 10

g/dl as the blood-lead concentration of concern, and for its

choice of the appropriate exceedance probability of one to five

percent. EPA then explains how it identified the dust and soil-lead

levels at which the Agency reasonably expects an individual child would

have a probability of approximately one to five percent of having a

blood-lead concentration equal to or exceeding 10 g/dl.

a. Blood-lead concentration of concern. EPA has determined that the

weight of scientific evidence, as discussed below, shows that 10

g/dl is a reasonable level of concern for childhood blood lead

under the applicable statutory standard of ``poses a threat.'' EPA

disagrees that the term ``poses a threat'' suggests that the lead

levels of concern should be based on any non-zero risk (zero-risk

basis). Zero risk equates to a blood-lead concentration of zero because

there is no known health effects threshold for lead. EPA, however,

proposes to reject the zero risk basis for dust and soil-lead levels of

concern for several reasons. First, although some data suggest that

adverse health effects occur at the lowest observed levels, only a

small number of children with such low blood-lead concentrations have

been examined. Furthermore, the health effects at the lowest levels of

exposure are small and subtle, making it difficult to associate effects

with any single factor. Therefore, there is insufficient evidence at

these lowest levels to state that there is a level of risk that

warrants national public concern. Second, standards based on zero risk

would not serve as a useful communication tool because lead is

ubiquitous in the environment and there is no practical way to

eliminate exposure. Third, EPA believes that zero risk-based standards

were not the intent of Congress. If any level of lead in dust and soil

constitutes contamination or a hazard, there would be no need for EPA

to identify these conditions.

Having rejected zero as the blood-lead concentration basis for dust

and soil-lead levels of concern, EPA had to identify an alternative

blood-lead concentration. Numerous human epidemiological and clinical

studies, as well as animal toxicological and in vitro studies indicate

clear signs of toxicity across a wide range of exposures. While the

results of human studies are not uniform, and there is inevitably

uncertainty regarding the precise nature and persistence of effects at

low levels, these studies are predominately similar in their overall

findings. Furthermore, there is consensus within the expert medical

community that even low levels of lead exposure warrant public health

concern.

As listed below, numerous health effects, many of them

neurological, have been related to blood-lead concentrations down to

levels of at least 10-15 g/dl:

1. Altered synthesis of heme as indicated by inhibitions in the

enzymes delta-aminolevulinate dehydrase, pyrimidine-5-nucleotidase, and

red blood cell ATPase, and accumulations of the heme precursor,

erythrocyte protoporphyrin in red blood cells. (e.g., Refs. 21-29).

2. Reduction in vitamin D hormone synthesis in children (e.g., Ref.

30).

3. Alterations of brain electrical activity in children (e.g, Refs.

31-37).

4. Altered nerve conduction in auditory pathway and decreased

hearing acuity in children (e.g., Refs. 34 and 38).

5. Delays in cognitive development and slower sensory-motor

development during infancy (e.g., Refs. 39-41).

6. Other neurobehavioral impacts (e.g., IQ deficits) in children

(e.g., Refs. 42-48).

7. Decreased stature or growth in young children (e.g., Refs. 49-

51).

8. Decreased ability to maintain steady posture in children (e.g.,

Ref. 52).

9. Reduced gestational age and reduced weight at birth, associated

with maternal and cord blood-lead concentrations (e.g., Refs. 53 and

54).

10. Increased blood pressure in adults (e.g., Refs. 5 and 55).

While it is possible that some of these effects are reversible

(e.g., altered heme synthesis), or have unclear medical or functional

implications (e.g., altered brain electrical activity), the Agency

believes that the collective impact of these effects on diverse

physiological functions and organ systems of young children with blood-

lead concentrations as low as 10 g/dl are clearly adverse.

This conclusion is consistent with the findings of other EPA reports,

EPA's Clean Air Scientific Advisory Committee (CASAC), the Centers for

Disease Control and Prevention in their 1991 statement Preventing Lead

Poisoning in Young Children, and the National Academy of Sciences in

their 1993 report Measuring Lead Exposure in Infants, Children, and

Other Sensitive Populations.

U.S. EPA's 1986 Air Quality Criteria Document for Lead (Ref. 56)

concluded that for children: (1) The collective impact of the effects

at blood-lead concentrations above 15 g/dl represents a clear

pattern of adverse effects worthy of avoidance; (2) at levels of 10-15

g/dl there appears to be a convergence of evidence of lead-

induced interference with a diverse set of physiological functions and

processes, particularly evident in several independent studies showing

impaired neurobehavioral function and development; and (3) the

available data do not indicate a clear threshold at 10-15 g/

dl, but rather suggest a continuum of health risks approaching the

lowest levels measured. The health effects below this range are less

well substantiated.

In reviewing the information presented in the 1986 Air Quality

Criteria Document and Addendum, EPA's CASAC concluded various effects

starting at blood-lead concentrations around 10-15 g/dl or

even lower in young children ``may be argued as becoming biomedically

adverse'' (Ref. 57). After reviewing the 1990 Supplement to the

Addendum (Ref. 58), as well as a staff position paper of EPA's Office

of Air Quality Planning and Standards (Ref. 59), CASAC concluded that

blood-lead concentrations above 10 g/dl clearly warrant

avoidance, especially for the development of adverse human health

effects in sensitive populations. The Committee concluded ``that EPA

should seek to establish an air standard which minimizes the number of

children with blood-lead concentrations above a target value of 10

g/dl. In reaching this conclusion, the Committee recognizes

that there is no discernible threshold for several lead effects and

that biological changes can occur at lower levels'' (p. 1, Ref. 57).

In their 1991 Statement, CDC revised the action level for the lead

screening and intervention program from 25 g/dl set in 1985 to

10 g/dl and stated that ``the scientific evidence showing that

some adverse effects occur at blood-lead concentrations at least as low

as 10 g/dl in children has become so overwhelming and

compelling that it must be a major force in determining how we approach

childhood lead exposure'' (p. 1, Ref. 2). While CDC does not specify

which of the many effects associated with low-level lead exposure are

individually considered adverse, the following discussion indicates

that the collective impact of the different effects

[[Page 30317]]

poses risks that should be avoided (pp. 9-10, Ref. 2):

Blood-lead concentrations as low as 10 g/dl, which do not

cause distinctive symptoms, are associated with decreased intelligence

and impaired neurobehavioral development (Refs. 60-61). Many other

effects begin at these low blood-lead concentrations, including

decreased stature or growth (Refs. 49, 50, and 51), decreased hearing

acuity (Ref. 38), and decreased ability to maintain a steady posture

(Ref. 52). Lead's impairment of the synthesis of the active metabolite

1,25-(OH)2 vitamin D is detectable at blood-lead

concentrations of 10-15 g/dl. Maternal and cord blood-lead

concentrations of 10-15 g/dl appear to be associated with

reduced gestational age and reduced weight at birth (Ref. 62). Although

researchers have not yet completely defined the impact of blood-lead

concentrations g/dl on central nervous system function, it

may be that even these levels are associated with adverse effects that

will be clearer with more refined research.

CDC recommends that community-wide interventions (e.g., outreach and

education, surveillance) should be considered by appropriate agencies

if many children have blood-lead concentrations that equal or exceed 10

g/dl (Ref. 2).

The National Academy of Sciences agreed with the CDC assessment of

the existing studies and data, noting that blood-lead concentrations

around 10 g/dl are associated with disturbances in early

physical and mental growth and in later intellectual functioning and

academic achievement (Ref. 63).

For purposes of this proposed rule, EPA is establishing 10

g/dl as the blood-lead concentration of concern. This decision

is based on EPA's review of the scientific evidence and earlier Agency

findings that a number of health effects begin to manifest themselves

at blood levels of 10-15 g/dl and that the collective impact

of these effects poses risks that should be avoided. EPA chose the

level at the lower end of this range to provide an adequate margin of

safety. EPA decided not to establish a level lower than 10 g/

dl because the evidence indicates that health effects at lower levels

of exposure are less well substantiated, based on a limited number of

studies, a limited number of children, and observation of subtle

molecular changes that are not currently thought to be sufficiently

significant to warrant national concern.

b. Exceedance probability. Unlike EPA's choice of the blood-lead

concentration, where there is a body of scientific literature to guide

the decision-making process, there is no scientific evidence to assist

the Agency in selecting the appropriate exceedance probability. EPA's

decision for this value is, instead, guided by judgment about levels of

risk that are achievable and consistent with the statutory criteria.

EPA looked at several options for an appropriate exceedance

probability. The Agency rejected the lowest possible probability, which

is zero, because it is unachievable. The Agency's risk analysis

demonstrated that a very small percentage of children would have blood-

lead concentrations equaling or exceeding 10 g/dl even if

there were no lead-based paint and lead-contaminated soil and dust,

because other sources of exposure (e.g., air, water, diet, and

background levels of lead) remain (Ref. 1).

At the other end of the range considered by EPA was an exceedance

probability of 10 percent. With this distribution of risk, a child

would have a 1.6 percent chance of having a blood-lead concentration

exceeding 15 g/dl and a less than one percent chance of having

a blood-lead concentration exceeding 20 g/dl, the level at

which CDC recommends medical intervention. The Agency rejected this

probability as presenting risks above the threshold that the dust and

soil-lead levels of concern are supposed to communicate.

Consequently, the Agency determined that the range of probabilities

between one and five percent would be consistent with the statutory

criterion for level of concern, ``pose a threat.'' Given the data and

analytical tools available to EPA, the Agency determined that, as a

practical matter, one percent is not distinguishable from five percent.

This overlap is due to the uncertainty and variability related to any

effort to associate levels of lead in the environment to blood-lead

concentrations and limited data.

As a result of exposure to levels of lead in dust and soil

associated with these probabilities, a child would have a relatively

small chance of having a blood-lead concentration equal to or exceeding

10 g/dl. The Agency considers this small chance of exceeding

the blood-lead concentration of concern to be consistent with ``pose a

threat.'' Consequently, EPA is proposing to include in guidance a level

of concern where the levels of lead in dust and soil are associated

with a one to five percent probability that a child would have a blood-

lead concentration equal to or exceeding 10 g/dl.

In seeking comment on this decision, EPA is interested in obtaining

any information that would provide additional support for its decision

or support the selection of another option.

c. Characterizing individual risk. EPA identified several

alternative tools to support the development of the dust and soil-lead

levels of concern: (1) The Agency's IEUBK model; (2) a ``multimedia''

model based on the data from the Rochester Lead-in-Dust study; and (3)

a performance characteristics analysis of the Rochester data. The IEUBK

model was not used to examine dust lead levels because the model uses

dust-lead concentration and, as explained in Unit V. of this preamble,

EPA has decided to propose a loading standard for dust. Conversely, the

multimedia model based on the Rochester data was used only for dust. It

uses dripline soil lead measurements rather than yard-wide average and,

therefore, EPA chose not to use it to examine the levels of concern for

lead in soil in this proposal. EPA used the performance characteristic

analysis of the Rochester data for both the dust and soil-lead levels

of concern.

d. Dust analyses. EPA conducted two analyses to support development

of the dust-lead level of concern: an analysis that used the multimedia

model based on the Rochester data and a performance characteristics

analysis of the Rochester data. The multimedia model was developed

specifically to support the development of options for this proposed

rule. It is a regression model that relates environmental lead levels

in dust and soil observed at a residence to the blood-lead

concentration measured for a child living at the residence. Regression

analysis is a statistical technique used to estimate the dependence of

one variable upon others, in this case the dependence of a child's

blood lead level on the environmental lead levels measured in and

around his or her home. For a detailed discussion of regression

analysis please see Matlack, Statistics for Public Policy and

Management (Ref. 18).

EPA decided to use the data from the Rochester Lead-in-Dust Study

as the basis for the multimedia model for the following reasons: (1)

Dust on all surfaces that are being considered for the TSCA section 403

standards were measured for lead in the Rochester Study; (2) the

Rochester Study includes dust-lead loadings from wipe sampling and the

TSCA section 403 dust standard is expected to be based on dust-lead

loading from wipe sampling; and, (3) the selection of homes and

children in the Rochester Study, although targeted, was more random and

more representative of a general population

[[Page 30318]]

than is the case with other recent epidemiological studies of lead

exposure in urban environments where lead-based paint is a significant

source of lead in dust and soil.

The multimedia model can be used to predict an average blood-lead

concentration for an individual child who is exposed to a given set of

environmental-lead levels. A constant empirical estimate of variability

is applied to this average to estimate a distribution of blood-lead

concentrations. In statistical terminology, this estimate of

variability is referred to as the geometric standard deviation (GSD), a

type of ``standard deviation'' that is used for log normal

distributions. The GSD in this case characterizes biological and

behavioral variability in blood lead for a given set of environmental

exposures. The predicted distribution can then be used to estimate the

probability of a child exceeding a specified blood-lead concentration

for a given level of environmental exposure.

Because, in this case, EPA was interested in determining the

environmental-lead levels that would result in a one to five percent

probability of an individual having a blood-lead concentration equal to

or exceeding 10 g/dl, the Agency started with the specified

range of probabilities of a child having a blood-lead concentration

equal to or exceeding 10 g/dl and calculated the level of lead

in dust needed to predict this distribution.

The Agency selected a GSD of 1.6 for use in the multimedia model,

consistent with the default value used in the IEUBK model. This value

was based upon the GSDs calculated for various sites after differences

in site-specific dust and soil-lead measurements were removed. In this

way, the GSD reflects the behavioral and biological variability in

children as well as repeat sampling variability, sample location

variability, and analytical error. Because EPA is using the multimedia

model to predict a blood lead distribution for a fixed level of lead in

the environment, it is appropriate to use a GSD that accounts for these

sources of variability but not differences in environmental lead

levels. Median GSDs, weighted by sample size within subgroups defined

by age, dust-lead concentration, and soil-lead concentration were

estimated as 1.69 for Midvale, Utah, 1.53 for the Baltimore data from

the Urban Soil Lead Demonstration Project, and 1.60 for Butte, Montana

(see section 4.2.2, Guidance Manual for the Integrated Exposure Uptake

Biokinetic Model for Lead in Children). Given these results, the Agency

believes that 1.6 is a reasonable value for the GSD in this

application.

EPA presents a more detailed description of the multimedia model in

the Risk Analysis to Support Standards for Lead in Paint, Dust, and

Soil, which can be found in the public record for this proposal (Ref.

1).

The multimedia model yielded the following results. The levels of

lead in dust on uncarpeted floors associated with an individual child

having from a one to five percent chance of having a blood-lead

concentration equal to or exceeding 10 g/dl range from near

zero to 6.7 g/ft2, depending on the dust-lead

loadings on window sills and the concentration of lead in soil. The

range for dust loadings on window sills is from near zero to 74

g/ft2 depending on dust-lead loadings on floors and

the concentration of lead in soil. The results of this analysis are

presented in Chapter 5 of the Agency's risk analysis document (Ref. 1).

These values are far below current clearance standards in both EPA

guidance and HUD Guidelines and some are near or below background

levels. These results depend on the model that has been fitted to the

Rochester data. If the model changes by including different variables

or selecting a different shape or form, the results could be higher or

lower. Therefore, an alternative approach that does not depend on a

model was also employed to estimate the levels of lead in dust

associated with a one to five percent probability of a child having a

blood-lead concentration equal to or exceeding 10 g/dl.

The non-modeling approach or performance characteristics analysis

of the Rochester data utilizes the concept of negative predictive value

(NPV), which, in this case, is defined as the probability of a child

having a blood-lead concentration below a specified level given that

the observed environmental lead level is below a hypothetical standard.

EPA used the performance characteristics analysis to estimate the dust

loading on uncarpeted floors and interior window sills that would yield

an NPV from 95 percent to 99 percent with a blood-lead concentration

equal to or exceeding 10 g/dl. This range of NPVs is

equivalent to a one to five percent chance of having a blood-lead

concentration equal to or exceeding 10 g/dl.

Table 2 below illustrates how NPV is computed. Homes in the

Rochester study are classified into four categories according to two

factors: (1) whether or not environmental-lead levels measured at the

home were below or above the example standard, and (2) whether or not

the home had a child with a blood-lead concentration above or below 10

g/dl. Using the notation presented in Table 2, the sum a + c

is the number of homes with environmental-lead levels below an example

option for the standards. The NPV is the ratio c/(a + c) and is the

portion of these homes that do not contain a child with a blood-lead

concentration at or above 10 g/dl. An NPV close to one

suggests that almost all of the children living in homes with

environmental-lead levels below the example standards have blood-lead

concentrations less than 10 g/dl. An NPV close to zero

suggests that very few of the children living in homes with

environmental-lead levels below the example standards have blood-lead

concentrations less than 10 g/dl.

The performance characteristics analysis yielded the following

results. For uncarpeted floors, dust-lead loadings ranged from 50

g/ft2 to 400 g/ft2 depending on

the dust-lead loading on interior window sills and the soil-lead

concentration. For interior window sills, dust-lead loadings ranged

from 100 g/ft2 to 800 g/ft2

depending on the dust-lead loading on uncarpeted floors and the soil-

lead concentration. These ranges are significantly higher than the

ranges yielded by the multimedia approach (Ref. 64).

Table 2.--Definition of Negative Predictive Value Based on Empirical

Data from Lead Exposure Studies*

------------------------------------------------------------------------

Media Standard

Blood-Lead Concentration Target ---------------------------------------

Level Below Media Above Media

Standard Standard

------------------------------------------------------------------------

At/Above 10 g/dl a b

Below 10 g/dl c d

------------------------------------------------------------------------

*In the table above, the letter ``a'' represents the number of children

who have a blood-lead concentration above a given blood-lead standard

and who live in a residence with an environmental lead level below a

standard for that environmental medium. Letters ``b,'' ``c,'' and

``d'' represent similar counts. From these counts the negative

predictive value (the probability of a resident child having a low

blood-lead concentration given that the observed levels of lead in the

environmental media are below the standard at the residence) is

calculated as c/(a + c).

There are also limitations in the use of the performance

characteristics model. Like the multimedia model, this approach is

based on data collected from a single city which may not be

representative of the nation and has not been subjected to rigorous

review. In addition, the NPVs associated with some options are based on

small sample sizes, which reduces the reliability of the estimate. It

is also important to note

[[Page 30319]]

that the NPV is purely descriptive and not based on any assumptions

about the true distribution of children's blood-lead concentrations. It

merely describes the characteristics of a given data set.

e. Soil analyses. EPA also used two analyses to support development

of the soil-lead level of concern: an analysis that used the IEUBK

model and one that used the performance characteristics analysis of the

Rochester data. The IEUBK model is a simulation model that estimates

the uptake pathways of environmental lead and the body's biological

response to environmental lead levels to predict a child's body burden

of lead. The model considers exposure (i.e., levels of lead in dust,

soil, air, water, and diet), intake (i.e., rates of ingestion and

inhalation), uptake (i.e., absorption in the lung and gut), and

biokinetics (i.e., movement through the blood and tissues and

elimination). The model predicts a geometric mean (i.e., a type of

average) blood-lead concentration for children exposed at the specified

environmental lead levels. An assumed geometric standard deviation

(GSD) is then applied to estimate the distribution of blood-lead

concentrations from which a probability of exceeding a specified blood-

lead concentration can be derived. As was the case with the multimedia

model analysis for dust, a GSD of 1.6 was assumed for this analysis.

EPA chose to use the IEUBK model to support this rule because it is

the Agency's most rigorously developed and thoroughly reviewed model

for childhood lead exposure. This model has historically been used in

other Agency programs and is the currently recommended tool for site-

specific evaluations in the CERCLA (Superfund) and RCRA corrective

action programs. Also, an earlier version of the model was peer-

reviewed and found acceptable as a tool for setting air lead standards

by EPA's Clean Air Science Advisory Committee of the Science Advisory

Board (Ref. 57). The IEUBK model was calibrated using environmental-

lead and blood-lead data from two western communities: Midvale, UT, a

suburb of Salt Lake City (Ref. 65), and East Helena, MT, a small town

outside of the State capitol at Helena (Ref. 66). Subsequent

evaluations have shown that the IEUBK model provides reasonable

descriptions of other sites, including urban sites (Ref. 67). The most

current version, Version 0.99d, of the IEUBK model was used in the TSCA

section 403 risk assessment.

The IEUBK model yielded the following results. Soil-lead

concentrations generally at or below 500 parts per million (ppm) will

result in a one to five percent probability that a child will have a

blood-lead concentration that equals or exceeds 10 g/dl

depending on the level of lead in dust. The results of this analysis

are presented in Chapter 5 of the Agency's risk analysis document (Ref.

1).

Of course, there are inherent uncertainties in any model that

simulates extremely complex relationships such as that between

environmental lead and blood lead. Not all of the relevant

physiological factors are thoroughly understood and others are

necessarily simplified. Also, there is child-to-child variability in

factors related to both exposure and biokinetic response (e.g., hand-

to-mouth activity, nutritional status). While the IEUBK model

application attempts to address these through selection of the GSD, it

is expected that deviations from the predicted blood-lead distributions

would most likely manifest themselves at the extremes, or ``tails,'' of

the distribution.

Recognizing that such uncertainties exist, the Agency choose to

also make use of a non-modeling approach with data from the Rochester

study. A performance characteristics analysis was conducted, as was

described earlier for dust. The analysis yielded the following results.

Soil-lead concentrations ranged from 200 ppm to 1,500 ppm depending on

dust-lead loadings on uncarpeted floors and interior window sills and

the exceedance probability. The wide range of soil-lead levels is

largely the result of a small number of data points.

2. Dust-lead and soil-lead hazard standards. As discussed in

section A of this unit, EPA believes it is reasonable to use cost-

benefit balancing to develop a range of viable options for the dust and

soil hazard standards. The risk reduction achieved as a result of

interventions designed to control or eliminate hazards constitutes the

benefits of the hazard standard. Dust interventions reduce risk by

reducing dust-lead levels. Soil interventions reduce risk both by

reducing soil-lead levels and by reducing lead contamination of

household dust.

To estimate benefits, the Agency built on the analysis used to

support development of the dust and soil-lead levels of concern. EPA

used the models that relate environmental lead to blood lead to

estimate the current or baseline distribution of blood-lead

concentrations for young children and the predicted blood-lead

distribution following hazard control interventions implemented in

response to the standards. Risk reduction, quantified in terms of

avoided health effects, is measured by looking at the change in blood-

lead distributions. EPA's normative economic analysis calculated

benefits by assigning a dollar value to the avoided adverse health

effects and compared these benefits to the costs of hazard control

interventions.

Before presenting the detailed description of the analysis, EPA

wishes to highlight two issues that the public should consider when

reviewing this proposed regulation. First, the Agency's analysis

estimates the benefits of primary prevention. Primary prevention is the

term used to characterize actions taken to protect people that have not

yet been exposed to a hazard. In this analysis, baseline risk is the

level of risk that the Agency would expect children to experience in

the absence of lead hazard control (i.e., risk associated with exposure

to current conditions). The post-intervention risk is the level of risk

that children, who have had no previous exposure to lead-based paint

hazards, are expected to experience with these controls in place. In

essence, the analysis estimates the level of risk prevented rather than

the level reduced. Where hazards are controlled, the exposure to lead-

based paint hazards never occurs.

The analysis does not estimate the benefits of secondary

prevention, the term used to characterize actions taken to protect

people already exposed to a hazard. Primary prevention is thought to be

more effective than secondary prevention because, with primary

prevention, children's risk remains at the pre-exposure level. With

secondary prevention, risk does not drop to pre-exposure levels because

lead that is stored in bone tissue continues to be released into blood

for some period of time even after environmental levels decline.

Many of the available exposure studies focus on the impacts of

secondary prevention, relating environmental lead to blood lead prior

to and after hazard control interventions. Because the subjects in

these studies have had prior exposure, the magnitude of the risk

reduction is smaller than estimated in EPA's analysis, which focuses on

children who have not had previous exposure.

Second, the majority of the benefits estimated by EPA are derived

from avoided IQ point loss resulting from prevented exposure to lead.

The dollar value placed on these benefits is a tool to assist EPA in

comparing costs and benefits for purposes of this proposed rule. It is

not in any sense a real value of the risk reduction or an Agency

standard for other actions. There are

[[Page 30320]]

plainly many benefits that are not measured in the analysis because EPA

lacks the tools and or data or because some benefits are subjective in

nature. On the other hand, EPA assigns risk reduction value to

fractional losses of an IQ point--tenths and even hundredths of a

point, and it is unclear the extent to which such small changes affect

quality of life of a single individual. By this combination of

underestimating and overestimating dollar values of potential risk

reduction benefits, EPA hopes to arrive at some reasonable range of

values that can be used to inform decision-making.

a. Estimating risk reduction. EPA's risk analysis that was

conducted to support this proposed rule provides a methodology for

measuring risk reduction (i.e., declines in blood-lead concentrations).

Under this methodology, EPA estimates the current national distribution

of blood-lead concentrations for the population of children ages one to

two. The Agency then uses this methodology to predict future changes in

the blood-lead distribution resulting from the implementation of hazard

interventions and expected changes in the nation's housing stock.

EPA used two models to estimate blood-lead concentrations: the

IEUBK model and an empirical model based on the Rochester data. The

empirical model is based on the multimedia model, which was described

earlier in this unit. In order for the multimedia model to be used for

national estimates, it was necessary to modify it to employ

environmental measures from the HUD National Survey (Refs. 8-9 and 19).

The resulting modified model is termed the empirical model. For a full

explanation of the differences between the multimedia model and the

empirical model, please see Chapter 5 of the Agency's risk analysis

document (Ref. 1). As noted above, the multimedia model could not be

used to support the development of the soil-lead of concern. The Agency

is requesting comment on the use of the empirical model to support

development of the soil-lead hazard standard.

To estimate the national distribution of blood-lead concentrations,

EPA had to run the empirical model with nationally representative data

on lead in dust and soil. The Agency used the HUD National Survey,

which is recognized as the leading source of data on environmental lead

levels in residential environments. The design and findings of the HUD

National Survey have been peer-reviewed and published in several

government reports.

For each house in the National Survey, EPA estimated the average

blood-lead concentration by using the HUD data on dust lead and soil

lead as inputs into the empirical and IEUBK models. EPA then applied

the GSD of 1.6 to estimate a geometric mean blood-lead concentration

for each home to derive a distribution of blood-lead concentrations for

each home. An estimate of the baseline national distribution of blood-

lead concentrations was constructed by aggregating the distributions

from each home using population weights based on the 1993 American

Housing Survey (Ref. 68), adjusted to the 1997 population of children

(aged 1 to 2 years). EPA then scaled the estimated national baseline

distribution using the blood-lead data from NHANES.

EPA used the following process to estimate the national blood-lead

distribution associated with each option for dust and soil hazard

standards. The soil and dust levels for each home in the survey were

compared to a set of hazard standard options for dust and soil. For

each set of options, the dust-lead level was adjusted down to reflect

implementation of a dust control intervention if the dust-lead level

exceeded the option for dust. If the soil-lead level exceeded the

option for soil, both the soil and dust lead levels were adjusted down

to reflect implementation of a soil control intervention. If a level

did not exceed an option, no adjustments to the data were made. Once

this comparison was made, the adjusted data were run through both

models to obtain an estimated blood-lead concentration predicted by the

model. The GSD of 1.6 was then applied to generate the blood-lead

distribution for each HUD survey home. The blood-lead distributions for

all homes in the survey were then aggregated using the same weights as

in the baseline analysis described previously.

The use of the IEUBK model to estimate the risk reduction

associated with various options for the dust-lead hazard standard

merits additional explanation. As noted earlier, the IEUBK model could

not be used to develop options for the dust-lead level of concern

because the dust standards are in terms of loading and the IEUBK model

uses dust concentration as its input. How, then, can the IEUBK model be

used to analyze options for the dust-lead hazard standard? In contrast

to the dust-lead level of concern, where a model that directly relates

a dust-loading value to a distribution of blood-lead concentrations is

needed, analysis of the options for the dust-lead hazard standard

requires a model to estimate changes in the blood-lead distribution for

the population of young children. EPA is able to do this with the IEUBK

model by using the model with the HUD National Survey data.

The HUD National Survey data contain both dust-lead loading and

concentration data for each home. To establish the baseline

distribution of blood-lead concentrations, EPA used the dust-lead

concentration value for each home as input for the IEUBK model. To

estimate the blood-lead distribution associated with a set of hazard

standard options for dust and soil, EPA identified the homes that would

exceed the paint, dust (loading), and/or soil standards. For these

homes, the analysis assigned a post-intervention dust-lead

concentration based upon the post-intervention soil concentration and

the presence or absence of deteriorated paint. The analysis then used

these assigned dust-lead concentrations as input to the IEUBK model to

generate post-intervention blood-lead distributions for each of the

homes. For the homes where no standard was exceeded, the measured dust-

lead concentration from the HUD survey was used. The details of the

procedure used to assign post-intervention dust-lead concentrations are

fully explained in Chapter 6 of the Agency's risk analysis document

(Ref. 1). The Agency is requesting comment on the use of this

application of the IEUBK model to support development of a dust-lead

loading hazard standard.

While all young children could be affected by exposure to lead, the

population of interest for this analysis was U.S. children aged 1 to 2

years. The selection of this age range as the population of interest

derived from the following general observations: the central nervous

system is rapidly developing in this age range, making it highly

susceptible to the effects of lead; synaptic density of the frontal

lobe of the brain peaks in a child's second year, and synaptic

development can be disrupted or delayed as a result of lead exposure;

the existence of a relationship between blood-lead concentration

measured at 1 to 2 years of age and IQ scores measured later in life;

blood-lead concentration tends to peak in this age range, due to an

increased ability to absorb lead; and, hand-to-mouth activity is high

in this age range, thereby increasing the potential for ingesting lead-

contaminated dust, soil, and paint.

b. Estimating costs and benefits. The normative economic impact

analysis estimates the benefits and costs associated with a broad range

of options for hazard standards. Benefits and costs are estimated over

a 50-year time frame.

[[Page 30321]]

Net benefits are computed by subtracting the costs from the benefits

for each option and discounting each to the present using a three

percent rate.

The benefits include a value for each of three health outcomes

associated with declines in blood-lead concentration: avoided IQ points

lost; avoided incidence of IQ below 70; and avoided incidence of blood-

lead concentrations exceeding 20 g/dl. The costs include the

expenditures on the hazard control interventions implemented by

property owners and other decision-makers in response to the standards.

Interventions include dust cleaning, interior and exterior paint repair

and abatement, and soil abatement.

The underlying engine of the normative economic analysis is the

``birth trigger'' model. The chief feature of this model is the

assumption that property owners do not undertake hazard control actions

until a young child who could be harmed by the hazard is present. The

timing of testing and intervention, therefore, is governed by the birth

rate. In the first year of a model run, the model randomly assigns the

arrival of a child to some of the 284 homes in the HUD National Survey

data set. In homes where a child's arrival is predicted to occur, the

model uses the risk analysis methodology to estimate a post-

intervention blood-lead distribution for that home. In the other homes,

interventions are not undertaken, regardless of the environmental

conditions, and there is no change from the baseline blood-lead

distribution. Using the risk analysis methodology, the blood-lead

distributions for each home in the survey are aggregated to develop a

new national blood-lead distribution after the first year. The Agency

compares the post-intervention blood-lead distribution in each year to

the baseline blood-lead distribution to compute the reduction in blood-

lead concentrations associated with the option being evaluated. The

analysis is then repeated for each of the following years through year

50.

The operation of the model in each of the subsequent years differs

from the initial year in two respects. First, the analysis determines

whether interventions need to be repeated. For example, paint repairs

are assumed to last 4 years, and therefore need to be repeated to

maintain their effectiveness. Second, the weights assigned to each home

in the survey, which reflect the proportion of the national housing

stock represented by that sample home, change to reflect ongoing

changes in the housing stock. With each passing year, new homes are

built and old homes are destroyed. In fact, the modernization of the

housing stock results in ``natural'' interventions as older homes that

have lead-based paint are replaced by new homes that do not.

The analysis then converts the change in blood-lead concentrations

into the three health endpoints: avoided lost IQ points, avoided

incidence of IQ below 70, and avoided incidence of blood-lead

concentrations above 20 g/dl. The term ``avoided'' is the

difference in health measures between the baseline scenario which

assumes no intervention activity and post-intervention scenarios, each

of which assumes a different combination of lead hazard standard

options and hence intervention activities.

To estimate the economic value of avoiding lost IQ points, the

analysis must first convert changes in blood-lead concentration to

changes in IQ. The analysis then assigns a monetary value to the IQ

point loss by using an estimate of the foregone lifetime income due to

IQ point loss. The computation of IQ point loss is based on an average

decrease of 0.257 IQ points per increase of one g/dl in blood-

lead concentration (Ref. 48).

IQ affects income through ability, education, and labor force

participation. The estimation procedure, therefore, has two major

steps. First the present value of the earnings stream of an average

newborn is estimated. Second, available economic literature was used to

estimate the percentage increase in lifetime earnings one would expect

from a one point increase in IQ. Based on this procedure, the analysis

assigns a value of $8,346 per IQ point lost (1995 dollars) (Refs. 48,

69-71).

EPA's estimate of the incidence of IQ score less than 70 is based

on results in a paper by Wallsten and Whitfield (1986) on the

relationship between reduced IQ scores and blood-lead concentration

(Ref. 72). The economic value of avoiding cases of IQ less than 70 is

approximated by using avoided special education costs. As defined,

these education costs are incurred from age 7 through age 18.

Avoided cases of blood-lead concentration exceeding 20 g/

dl is obtained directly by comparing the distribution of post-

intervention blood-lead concentrations with the baseline distribution

of blood-lead concentrations. The monetary value was approximated by

using avoided compensatory education costs. In this case, the education

costs are assumed to be incurred from age 7 through age 9. In addition,

there are medical monitoring and intervention costs associated with

children who have blood-lead concentrations that exceed 20 g/

dl (Refs. 2, 73, and 74).

Benefits accrue over time as hazard control interventions are

conducted, reducing children's exposure to lead in paint, dust, and

soil. All benefit estimates are discounted to the present using an

annual rate of three percent. Total benefits are the sum of benefits

calculated for each year or cohort of children protected and represent

the present value of the stream of benefits from the hazard controls.

The costs in this normative analysis are principally the costs of

conducting interventions designed to control lead-based paint hazards.

Interventions assumed to be are conducted only in those media (i.e.,

paint, dust, soil) where hazards are identified. For example, if lead

levels in the soil exceed the hazard standards, then the soil will be

removed and replaced with ``clean'' soil, but there will not be an

interior paint intervention in response to elevated levels of lead in

soil. Some interventions, however, include dust cleaning even if no

dust hazard has been identified initially because the intervention may

increase levels of lead in dust.

For purposes of this normative analysis, EPA identified six hazard

control interventions. These interventions include paint repair or

abatement of interior paint and exterior paint and a single

intervention each for soil and dust. It was assumed that abatement of

interior and exterior paint hazards occur when deteriorated lead-based

paint is extensive. Paint repair occurs when deteriorated lead-based

paint is present but not extensive. Soil intervention activities occur

when the soil-lead concentration exceeds the soil standard. Dust hazard

control occurs when the floor dust-lead loading exceeds the floor dust-

lead standard, the window sill-lead loading exceeds the window sill

dust-lead standard, or when it is required to accompany another

intervention type, such as abatement of interior paint or soil removal.

Some of the intervention actions result in permanent control of lead

hazards; others need to be repeated periodically to maintain their

effectiveness. According to the methodology, non-permanent

interventions are repeated as necessary in a home until the child is 6

years of age.

Drawing on a variety of sources, EPA obtained unit cost estimates,

that is cost per intervention per home, for the six hazard control

interventions identified for the analysis (Refs. 75-79). EPA also

obtained cost estimates for hazard evaluation activities (Refs. 80-83).

The Agency developed separate cost

[[Page 30322]]

estimates for single- and multi-family housing units, by adjusting the

single-family unit cost estimates to reflect the smaller size of multi-

family units and the smaller yards (per unit) of multi-family units.

Table 3 below summarizes these costs for single-family and multi-family

housing.

Table 3.--Hazard Evaluation and Control Costs

(Per activity in 1995 dollars)

------------------------------------------------------------------------

Multi-family (per

Activity Single-Family unit)

------------------------------------------------------------------------

Risk assessment 456 235

Interior paint repair 437 437

Interior paint abatement 6,587 4,687

Exterior paint repair 807 182

Exterior paint abatement 45,706 12,275

Dust cleaning 391 262

Soil removal (dripline; 2,046 399

nonhazardous waste)

Soil removal (mid-yard; 7,878 777

nonhazardous waste)

Soil removal (both areas; 9,008 901

nonhazardous waste)

Soil removal (dripline; 3,443 541

hazardous waste)

Soil removal (mid-yard; 16,486 1,351

hazardous waste)

Soil removal (both areas; 19,013 1,617

hazardous waste)

------------------------------------------------------------------------

The costs of intervention for a specific residence are a function

of when a residence is evaluated, the environmental lead conditions in

the residence, and the length of time that an intervention is effective

(duration). The arrival of a child determines when a hazard evaluation

will be conducted. The choice of intervention activities depends on the

environmental lead conditions in each medium. The frequency with which

interventions need to be repeated depends on the duration of the

intervention. Costs for a residence accrue over time as interventions

are repeated.

For example, paint abatement is assumed to have a duration of 20

years. Therefore, if post-intervention conditions are to be maintained

because a child under age 6 is present, paint abatement is assumed to

be repeated 20 years after the initial intervention, and again 40 years

after the initial paint abatement. Costs incurred after the first year

are discounted back to the present using an annual discount rate of

three percent. The total cost estimate is the sum of the discounted

cost of hazard controls conducted each year.

In estimating costs of each hazard standard option, the model

assumes that either a lead hazard screen (for single-family units

without deteriorated lead-based paint) or a risk assessment (all other

units) is performed. Testing is done at the time the arrival of a child

is expected and testing is not repeated for a unit.

The analysis' computation of net benefits is the difference between

the total benefits estimate and the total cost estimate. Net benefits

are an indicator of the societal gains from hazard controls.

When interpreting the results of EPA's analysis, it is important to

consider a number of limitations, qualifications, and uncertainties

which affect both the estimates of benefits and costs.

With respect to benefits, issues are associated with the

methodology used to estimate baseline and post-intervention blood-lead

concentrations and with efforts to place a monetary value on IQ points

lost. There are important concerns with respect to the cost analysis as

well.

There are four areas of concern with respect to the methodology

used to estimate blood-lead distributions. The first area is associated

with the HUD National Survey data. These include limited numbers of

environmental samples taken at each housing unit, the sampling of only

284 houses to represent the nation's pre-1978 housing stock, the age of

the study, and use of a dust collection device other than the wipe

collection method being adopted by the TSCA section 403 proposal.

The limited number of environmental samples can result in the

mischaracterization of dust and soil-lead levels at a home in the

survey. Combined with the small number of homes sampled,

mischaracterization of dust and soil-lead levels can result in large

errors in EPA's estimates. The age of the study can also introduce

error because environmental-lead levels have most likely changed since

the data were collected in 1989-1990. The use of a dust collection

device other than wipe samples required the development of an equation

to convert these values to wipe-equivalent values which introduces

additional error into the estimates. The introduction of error into the

estimates contributes to overall uncertainty in the analytical results.

A second and significant source of uncertainty is the paucity of

data with respect to the effectiveness of hazard control activities at

reducing exposures to lead in paint, dust, and soil. For example, EPA's

estimate of the effectiveness of interventions on dust-lead loading is

based on a limited number of studies. The Agency's estimate of

effectiveness of interventions on dust-lead concentrations is, in part,

based on limited data and, in part, based on the best judgment of

Agency scientists. Due to the lack of data about the effectiveness of

interim controls to reduce exposure to lead in soil, the Agency did not

include these interventions in its analysis. The Agency would, however,

be interested in any data the public may have concerning the

effectiveness of interim controls that address exposure to lead in

soil.

Third, uncertainty is introduced by using NHANES III, Phase 2 data

to calibrate the national distribution of baseline blood-lead

concentrations. While the national representation of NHANES III results

is widely accepted, some possible limitations in using these data

include ignoring any seasonality effects on blood-lead concentrations

and any further decline in concentrations that may have occurred since

1994.

Fourth, the two models are sources of uncertainty. The limitations

of the IEUBK model were discussed previously in this preamble. The

empirical model shares the limitations of the multimedia model

discussed previously.

Questions regarding the value of IQ points fall into two

categories: the relationship between blood-lead changes and IQ point

changes and the monetary value assigned to IQ point losses.

There are two significant limitations involved in assigning a

monetary value to IQ point losses. The first concerns the

[[Page 30323]]

ability to assign value to fractional losses of an IQ point. The

analysis assigns value to tenths and even hundredths of an IQ point

which may not be of much significance at the individual level. The

second concerns the value of IQ points across the range. The analysis

assigns equal value to any IQ point change; the value of an IQ dropping

from 140 to 135 is treated the same as an IQ dropping from 80 to 75. In

contrast, it is possible that the value of a point may vary depending

where in the range the point is lost.

On the other hand, the Agency notes that there are a range of other

health effects (e.g., neurological, developmental, and others) that are

not considered in its economic analysis (see Appendix B of the Risk

Analysis to Support Standards for Lead in Paint, Dust, and Soil) (Ref.

1). Declines in children's lead exposures will also reduce the

incidence of these effects. In addition, the economic analysis does not

include the benefits of secondary prevention (benefits obtained by

reducing environmental and blood-lead levels in a child already living

in a contaminated environment). Consequently, the value associated with

avoided IQ losses in the economic analysis can reasonably be considered

to serve as a surrogate for benefits associated with these other

effects. Therefore, to the extent that IQ-related benefits may be

overestimated due to the two limitations discussed above, the non-

valued benefits associated with these other effects would tend to

mitigate such overestimates.

With respect to the estimate of costs, there are several sources of

uncertainty. EPA's analysis identifies only a few of the dozens of

responses that property owners and other decision-makers could

undertake. The costs for these activities are based on current data and

could change as competition among providers increases or new

technologies are developed. The frequency with which temporary measures

need to be repeated, which also affects costs, depends on assumptions

the Agency made about the duration of the measures' effectiveness.

These assumptions, in turn, are based upon judgments and extrapolations

from limited data.

c. Results. This section of the preamble discusses the results of

EPA's normative economic analysis of the options for dust and soil-lead

hazard standards. Before presenting the results, however, the Agency

believes that it is important to consider two issues when interpreting

these results.

First, undue emphasis should not be placed on the estimates for

total costs and benefits. As noted earlier, the costs and benefits

estimated by the normative analysis are likely to overstate the actual

costs and benefits associated with the standards. The Agency's analysis

also assumes that technologies and costs will remain unchanged over the

50-year modeling horizon. Over time, as new technologies develop, costs

may decline. In addition, many health benefits were not included in the

analysis because either the relationship between exposure and the

magnitude of health effects is unknown or because the benefits cannot

be monetized.

Estimates of costs and benefits associated with the standards are

also heavily influenced by the number of homes estimated to exceed any

standard option. The estimated number of homes is based on the HUD

National Survey. Although this Survey is the best nationally

representative data on residential lead, it is characterized by several

shortcomings that were described earlier. Among the most significant of

these is the small sample size, which, as was noted, can introduce

errors into EPA's estimates. For example, only seven homes in the

Survey have soil that exceeds 2,000 ppm. Based on the age, location,

and other characteristics of these homes, EPA estimates that these

seven homes represent 2.5 million homes nationally which yields $9

billion in soil intervention costs over the 50-year model period. If

HUD conducted another survey, it is possible that only three homes in

the survey, representing 1 million homes nationally, exceed 2,000 ppm,

reducing costs by 60 percent. Benefits would also be lower because

fewer children would be protected. It is also possible that 10 homes in

the survey, representing 3 million homes nationally, exceed 2,000 ppm,

resulting in higher costs and benefits.

By providing these explanations, EPA does not intend to dismiss the

costs associated with this proposed rule. Although the expected costs

associated with the standards are likely to be significantly less than

costs estimated by the normative analysis, these costs would probably

still be substantial. That is why the Agency considered costs in

evaluating options for the hazard standards and in selecting a

preferred option. It should be remembered, however, that these

activities will protect millions of children who will live in abated

homes over the next 50 years. As was noted earlier, EPA's analysis did

not focus on children already exposed to excessive levels of lead but

on children who have not been born. In the absence of the standards and

assuming other exposures to lead remain unchanged, approximately 10

million children are estimated to have elevated blood-lead levels over

the next 50 years. Of these, one million are estimated to have levels

that require medical attention (Chapter 5, Ref. 83).

Second, the results obtained using each model should be ev

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