Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Dye and Pigment Industries; Land Disposal Restrictions for Newly Identified Wastes; CERCLA Hazardous Substance Designation and Reportable Quantities

SUMMARY: The EPA is proposing to list two of three wastes from the dyes

and pigment industries as hazardous wastes under the Resource,

Conservation, and Recovery Act (RCRA), which direct EPA to determine

whether certain wastes from the dye and pigment industries present a

hazard to human health or the environment. The effect of listing these

wastes will be to subject them to stringent management and treatment

standards and to emergency notification requirements if there are

releases of these hazardous wastes to the environment. EPA is proposing

concentration-based listings for the two wastes, such that waste

generators have the option of determining that their specific waste is

nonhazardous. To have their waste classified as nonhazardous,

generators must determine the levels of constituents in their wastes,

and certify to EPA that their wastes are below the regulatory levels of

concern.

DATES: EPA will accept public comments on this proposed rule until

September 21, 1999; comments postmarked after this date will be marked

``late'' and may not be considered. Any person may request a public

hearing on this proposal by filing a request with Mr. David Bussard,

whose address appears below, by August 6, 1999.

ADDRESSES: If you wish to comment on this proposed rule, you must send

an original and two copies of the comments referencing docket number F-

1999-DPIP-FFFFF to: RCRA Docket Information Center, Office of Solid

Waste (5305G), U.S. Environmental Protection Agency Headquarters (EPA,

HQ), 401 M Street, SW, Washington, DC 20460. Hand deliveries of

comments should be made to the Arlington, VA, address listed below. You

may also submit comments electronically by sending electronic mail

through the Internet to: [email protected]. See the beginning

of Supplementary Information for instructions on electronic submission.

You should not submit electronically any confidential business

information (CBI). You must submit an original and two copies of CBI

under separate cover to: RCRA CBI Document Control Officer, Office of

Solid Waste (5305W), U.S. EPA, 401 M Street, SW, Washington, DC 20460.

See the beginning of Supplementary Information for information of

viewing public comments and supporting materials.

Address requests for a hearing to Mr. David Bussard at: Office of

Solid Waste, Hazardous Waste Identification Division (5304W), U.S.

Environmental Protection Agency 401 M Street, SW, Washington, DC 20460,

(703)308-8880.

FOR FURTHER INFORMATION CONTACT: For general information, contact the

RCRA Hotline at (800) 424-9346 or TDD (800) 553-7672 (hearing

impaired). In the Washington, DC, metropolitan area, call (703) 412-

9810 or TDD (703) 412-3323. For information on specific aspects of the

rule, contact Narendra Chaudhari or Robert Kayser, Office of Solid

Waste (5304W), U.S. Environmental Protection Agency, 401 M Street, SW,

Washington, DC 20460. [E-mail addresses and telephone numbers:

[email protected], (703) 308-0454;

[email protected], (703) 308-7304)].

SUPPLEMENTARY INFORMATION: You should identify comments in electronic

format with the docket number F-1999-DPIP-FFFFF. You must submit all

electronic comments as an ASCII (text) file, avoiding the use of

special characters and any form of encryption. If you do not submit

comments electronically, EPA is asking prospective commenters to

voluntarily submit one additional copy of their comments on labeled

personal computer diskettes in ASCII (text) format or a word processing

format that can be converted to ASCII (text). It is essential to

specify on the disk label the word processing software and version/

edition as well as the commenter's name. This will allow EPA to convert

the comments into one of the word processing formats utilized by the

Agency. Please use mailing envelopes designed to physically protect the

submitted diskettes. EPA emphasizes that submission of comments on

diskettes is not mandatory, nor will it result in any advantage or

disadvantage to any commenter. Supporting documents in the docket for

this Notice are also available in electronic format on the Internet.

Follow these instructions to access these documents.

WWW: http://www.epa.gov/epaoswer/hazwaste/id

FTP: ftp.epa/gov

Login: anonymous

Password: your Internet address

Files are located in /pub/gopher/OSWRCRA.

EPA will keep the official record for this action in paper form.

Accordingly, we will transfer all comments received electronically into

paper form and place them in the official record, which will also

include all comments submitted directly in writing. The official record

is the paper record maintained at the address in ADDRESSES at the

beginning of this document.

EPA responses to comments, whether the comments are written or

electronic, will be in a notice in the Federal Register or in a

response to comments document placed in the official record for this

rulemaking. We will not immediately reply to commenters electronically

other than to seek clarification of electronic comments that may be

garbled in transmission or during conversion to paper form, as

discussed above.

You may view public comments and supporting materials in the RCRA

Information Center (RIC), located at Crystal Gateway I, First Floor,

1235 Jefferson Davis Highway, Arlington, VA. The RIC is open from 9

a.m. to 4 p.m., Monday through Friday, excluding federal holidays. To

review docket materials, we recommend that you make an appointment by

calling (703) 603-9230. You may copy a maximum of 100 pages from any

regulatory docket at no charge. Additional copies cost $0.15/page. For

information on accessing paper and/or electronic copies of the

document, see the Supplementary Information section.

How Can I Influence EPA's Thinking on This Proposed Rule?

In developing this proposal, we tried to address the concerns of

all our stakeholders. Your comments will help us improve this rule. We

invite you to provide different views on options we propose, new

approaches we haven't considered, new data, how this proposed rule may

effect you, or other relevant information. We welcome your views on all

aspects of this proposed rule, but request comments on specific issues

throughout this notice. We grouped these specific requests near the end

of the sections in which we discuss the relevant issues. Your comments

will be most effective if you follow the suggestions below:

[[Page 40193]]

Explain your views and reasoning as clearly as possible.

Provide solid technical and cost data to support your

views.

If you estimate potential costs, explain how you arrived

at the estimate.

Tell us which parts you support, as well as those with

which you disagree.

Provide specific examples to illustrate your concerns.

Offer specific alternatives.

Refer your comments to specific sections of the proposal,

such as the units or page numbers of the preamble, or the regulatory

sections.

Be sure to include the name, date, and docket number with

your comments.

Contents of This Proposed Rule

The following outline lists the contents of the preamble to this

proposed rule:

I. Overview

A. Who Would Potentially be Affected by This Proposed Rule?

B. Why Does This Proposed Rule Read Differently From Other

Listing Rules?

C. What Are the Statutory Authorities for This Proposed Rule?

II. Background

A. How Does EPA Define a Hazardous Wastes?

B. What Industries Are Covered in This Proposed Rule?

C. Confidential Business Information (CBI) Issues Regarding This

Rule

D. What Wastes Are Covered in Today's Proposed Rule?

E. What Information Did EPA Collect and Use?

III. Approach Used in This Proposed Listing

A. Summary of Today's Action

B. What Is a Concentration-Based Listing?

C. Why Is a Concentration-Based Approach Being Used for This

Listing?

D. What Risk Assessment Approach Did EPA Use?

E. How Did EPA Estimate Exposure Concentrations?

F. What Exposure Assumptions and Toxicity Levels Did EPA Use?

G. What Uncertainties Are Associated With the Risk Assessment?

H. What Risk Level Do the Concentration Levels Represent?

I. What Are the Proposed Listing Levels?

IV. Proposed Listing Determinations and Regulations

A. What Are the Proposed Regulations for the Two Wastes?

B. What Are We Proposing for Anthraquinone Sludges?

C. What Is the Status of Landfill Leachate From Previously

Disposed Wastes?

V. Generator Requirements for Implementation of Concentration-Based

Listings

A. Do I Have to Determine Whether or Not My Waste Is Hazardous?

B. How Do I Manage My Waste During the Period Between the

Effective Date of the Final Rule and Initial Hazardous Waste

Determination for My Waste?

C. What Are the Steps I Must Follow to Determine Whether or Not

My Waste Is Hazardous?

D. What Are the Requirements for a Waste Determined to be

Nonhazardous, and How Do I Claim My Waste to Be Nonhazardous?

E. What Records Am I Required to Keep On-site to Support a

Nonhazardous Claim for My Waste?

F. What Happens if I Do Not Meet the Notification and

Recordkeeping Requirements for a Waste That I Have Determined to be

Nonhazardous?

G. What Are the Follow-up Waste Analysis Requirements for My

Nonhazardous Waste?

H. What Happens If My Waste Constituent Concentrations Are No

Longer Below the Listing Concentrations?

I. Can I Treat My Waste to Below Listing Concentrations and Then

Claim My Waste to Be Nonhazardous?

J. Alternative Implementation Approach

VI. Proposed Treatment Standards Under RCRA's Land Disposal

Restrictions

A. What are EPA's Land Disposal Restrictions (LDRs)?

B. How Does EPA Develop LDR Treatment Standards?

C. What Treatment Standards Are Proposed?

D. Other LDR-Related Provisions

E. Is There Treatment and Management Capacity Available for

These Proposed Newly Identified Wastes

VII. State Authority and Compliance

A. How Are States Authorized Under RCRA?

B. What Is the Effect of Today's Proposal on State

Authorizations?

C. Who Must Notify EPA That They Have a Hazardous Waste?

D. What Do Generators and Transporters Have to Do?

E. Which Facilities Are Subject to Permitting?

VIII. CERCLA Designation and Reportable Quantities

A. What Is the Relationship Between RCRA and CERCLA?

B. Is EPA Proposing to Add Dye and Pigment Production Wastes to

CERCLA?

C. Is EPA Proposing to Adjust the Statutory One Pound RQ for

K167 and K168 Wastes?

D. When Do I Need to Report a Release of K167 and K168 Wastes

Under CERCLA?

E. How Do I Report a Release?

F. What Is the Statutory Authority for This Program?

IX. Analytical and Regulatory Requirements

A. Is This a Significant Regulatory Action? (Executive Order

12866)

B. Why Is This Proposed Rule Necessary?

C. What Regulatory Options Were Considered?

D. What Are the Potential Cost Impacts of Today's Proposed Rule?

E. What Are the Potential Economic Impacts to Industry From the

Proposed Rule?

F. What Are the Potential Benefits From the Proposed Rule?

G. What Consideration Was Given to Small Entities?

H. What Consideration Was Given to Children's Health?

I. What Consideration Was Given to Environmental Justice?

J. What Consideration Was Given to Unfunded Mandates?

K. What Consideration Was Given to Tribal Governments Analysis?

L. Was the National Technology Transfer and Advancement Act

Considered?

M. How is the Paperwork Reduction Act Considered in Today's

Proposal?

I. Overview

A. Who Would Potentially Be Affected by This Proposed Rule?

The action, if finalized, could potentially affect those who handle

the waste streams proposed for listing on EPA's RCRA list of hazardous

wastes. This action may also affect entities that may need to respond

to releases of these wastes as CERCLA hazardous substances. Those

affected may include:

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

Category Affected entities

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

Industry..................... Generators of the following listed

wastes, or entities that treat, store,

transport, or dispose of these wastes or

materials derived from them.

K167 Spent filter aids, diatomaceous

earth, or adsorbents used in the

production of azo, anthraquinone, or

triarylmethane dyes, pigments, or FD&C

colorants.

K168 Wastewater treatment sludges from

the production of triarylmethane dyes

and pigments (excluding triarylmethane

pigments using aniline as a feedstock).

State, Local, Tribal Govt.... State and Local Emergency Planning

entities.

Federal Govt................. National Response Center, and any Federal

Agency that handle the listed waste or

chemical.

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

We do not intend this table to be exhaustive, but rather our aim is

to provide a guide for readers regarding entities likely to be

regulated by this action. This table lists those entities that EPA now

is aware potentially could be

[[Page 40194]]

affected by this action. However, this action may affect other entities

not listed in the table. To determine whether your facility is

regulated by this action, you should examine 40 CFR parts 260 and 261

carefully in concert with the amended rules found at the end of this

Federal Register document. Furthermore, we are proposing this rule as a

concentration-based listing, such that waste generators have the option

of determining that their specific waste is nonhazardous (see Sections

IV and V of today's rule). If you have questions regarding the

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

listed in the preceding section entitled FOR FURTHER INFORMATION

CONTACT.

B. Why Does This Proposed Rule Read Differently From Other Listing

Rules?

Today's proposed listing determination preamble and regulations are

written in ``readable regulations'' format. The authors tried to use

active rather than passive voice, plain language, a question-and-answer

format, the pronouns ``we'' for EPA and ``you'' for the owner/

generator, and other techniques to make the information in today's

proposed rule easier to read and understand. This new format is part of

the Agency's efforts at regulatory reinvention, and it makes today's

proposed rule read differently from other listing rules. The Agency

believes that this new format will increase readers' abilities to

understand the regulations, which should then increase compliance, make

enforcement easier, and foster better relationships between EPA and the

regulated community.

All of the requirements found in today's proposed regulations would

constitute binding, enforceable legal requirements. The plain language

format used in today's proposed regulations may appear different from

other rules, but it would establish binding, enforceable legal

requirements just as those in the existing regulations.

C. What Are the Statutory Authorities for This Proposed rule?

EPA is proposing these regulations under the authority of Sections

2002(a), 3001 (a), (b) and (e)(2), 3004 (g) and (m), and 3007(a) of the

Solid Waste Disposal Act (commonly referred to as RCRA), as amended by

the Hazardous and Solid Waste Amendments of 1984 (HSWA). These statutes

are codified in Volume 42 of the United States Code (U.S.C.), sections

6901 to 6992(k).

Section 102(a) of the Comprehensive Environmental Response,

Compensation, and Liability Act of 1980 (CERCLA), 42 U.S.C. 9602(a), is

the authority for the CERCLA aspects of this proposed rule.

II. Background

A. How Does EPA Define a Hazardous Waste?

EPA's regulations establish two ways of identifying wastes as

hazardous under RCRA. Wastes may be hazardous either if they exhibit

certain properties (``characteristics''), or if the wastes are included

on a specific list of wastes EPA has determined are hazardous

(``listing'' a waste as hazardous). EPA's regulations in the Code of

Federal Regulations (40 CFR) Secs. 261.20 through 261.24 define

characteristic wastes. These regulations classify wastes that exhibit

certain properties as having the characteristic of ignitability,

corrosivity, reactivity, or toxicity. As a generator, you must identify

wastes as characteristic wastes by sampling a waste, or by using

appropriate company records concerning the nature of the waste, to

determine whether a waste has the relevant properties (see

Sec. 262.11(c)). There is no regulatory requirement to conduct

sampling, but persons improperly managing materials that are found to

be characteristic hazardous wastes are subject to enforcement actions

under RCRA.

EPA may ``list'' wastes as hazardous if we conclude that the waste

is capable of posing a substantial present or potential hazard to human

health or the environment when improperly managed. We have established

criteria for listing a hazardous waste at 40 CFR 261.11(a)(3) for

wastes that contain hazardous constituents identified in Appendix VIII

of 40 CFR part 261. In deciding whether a wastes poses a substantial

hazard, we consider the factors given in Sec. 261.11(a)(3). We place

constituents in Appendix VIII if scientific studies have shown a

chemical has toxic effects on life forms (see 261.11(a)(3)). When

listing a waste, we also add the hazardous constituents that serve as

the basis for listing to Appendix VII to part 261.

The regulations at 40 CFR 261.31 through 261.33 contain the various

hazardous wastes the Agency has listed to date. Section 261.31 lists

wastes generated from non-specific sources, known as ``F-wastes,'' and

contains wastes that are usually generated by various industries or

types of facilities, such as ``wastewater treatment sludges from

electroplating operations'' (see code F006). Section 261.32 lists

hazardous wastes generated from specific industry sources, known as

``K-wastes,'' such as ``Spent potliners from primary aluminum

production'' (see code K088). Section 261.33 contains lists of

commercial chemical products and other materials that become hazardous

wastes, known as ``P-wastes'' or ``U-wastes,'' when they are discarded

or intended to be discarded.

The proposed regulations in today's notice would list wastes from a

specific industry and thus these wastes would be added to Sec. 261.32

with K-waste codes. We are proposing to add constituents that serve as

the basis for the proposed listings to Appendix VII, Part 261. For the

chemicals not already listed on the list of Hazardous Constituents in

Appendix VIII, we are also proposing to add these chemicals to that

list.

Wastes listed as hazardous are subject to federal requirements

under RCRA. These regulations affect persons who generate, transport,

treat, store or dispose of such waste. Facilities that must meet the

hazardous waste management requirements, including the need to obtain

permits to operate, commonly are referred to as Subtitle C facilities.

Subtitle C is Congress' original statutory designation for that part of

RCRA that directs EPA to issue those regulations for hazardous wastes

as may be necessary to protect human health or the environment. EPA

standards and procedural regulations implementing Subtitle C are found

generally at 40 CFR Parts 260 through 272.

Solid wastes that are not hazardous wastes may be disposed of at

facilities that are overseen by state and local governments. These are

the so-called Subtitle D facilities, which generally impose less

stringent requirements on management of wastes. Subtitle D is Congress'

original statutory designation for that part of RCRA that deals with

disposal of solid waste. EPA regulations affecting Subtitle D

facilities are found generally at 40 CFR Parts 240 thru 247, and 255

thru 258. Regulations for Subtitle D landfills that accept municipal

waste (``municipal solid waste landfills'') are given in Part 258.

Residuals from the treatment, storage, or disposal of most listed

hazardous wastes are also classified as hazardous wastes based on the

``derived-from'' rule (40 CFR 261.3(c)(2)(i)). For example, ash or

other residuals from treatment of the listed wastes generally carry the

original waste code and are subject to the hazardous waste regulations.

Also, the ``mixture'' rule (40 CFR 261.3(a)(2)(iv)) provides that, with

certain limited exceptions, any mixture of a listed hazardous waste and

a solid waste is itself a RCRA hazardous waste. However, when these

wastes are recycled as described in 40 CFR 261.2(e)(1)(iii) or

261.4(a)(8), they are

[[Page 40195]]

not solid wastes and are not subject to hazardous waste regulations.

For example, if a waste is collected and returned in a closed-loop

fashion to the same process, the waste is not regulated.

All RCRA hazardous wastes are also hazardous substances under the

Comprehensive Environmental Response, Compensation, and Liability Act

(CERCLA), as described in section 101(14)(C) of the CERCLA statute.

This applies to wastes listed in 261.31 through 261.33, as well as any

wastes that exhibit a RCRA characteristic. Table 302.4 at 40 CFR 302.4

lists CERCLA hazardous substances along with their reportable

quantities (RQs). Anyone spilling or releasing a substance at or above

the RQ must report this to the National Response Center, as required in

CERCLA Section 103. In addition, Section 304 of the Emergency Planning

and Community Right-to-Know Act (EPCRA) requires facilities to report

the release of a CERCLA hazardous substance at or above its RQ to State

and local authorities. Today's rule proposes to establish RQs for the

newly listed wastes. EPA is not taking action at this time to adjust

the one-pound statutory RQs for the newly listed hazardous substances.

B. What Industries Are Covered in This Proposed Rule?

1. The Dye and Pigment Industries

Today's proposal applies to the manufacturers of organic dyes and

pigments, and does not affect producers of only inorganic dyes or

pigments. We have already issued final rules governing the

manufacturing of inorganic pigments. Section 261.32 contains wastes

codes K002 through K008 that list wastewater treatment sludges and

other residues from the production of inorganic pigments.

The organic dye and pigment industries are comprised of three

related industries, dye manufacturers, pigment manufacturers, and Food,

Drug, and Cosmetic (FD&C) colorant manufacturers. Dyes are colored or

fluorescent organic substances which impart color to a substrate. When

a dye is applied, it penetrates the substrate in a soluble form, after

which it may or may not become insoluble. Dyes are used to color

fabrics, leather, paper, ink, lacquers, varnishes, plastics, cosmetics,

and some food items. Dye manufacture in the U.S. includes more than

2,000 individual dyes, the majority of which are produced in quantities

of less than 50,000 pounds. The U.S. International Trade Commission's

(USITC) production data for 1994 showed total production of

approximately 156,000 tons for all organic dyes.

Organic pigments possess unique characteristics that distinguish

them from dyes and other colorants. The primary difference between

pigments and dyes is that, during the application process, pigments are

usually insoluble in the substrate. Pigments also retain a crystalline

or particulate structure and impart color by selective absorption or by

scattering of light. This is different from dyes, which impart color by

selective absorption. Pigments are used in a variety of applications;

the primary use is in printing inks. There are fewer pigments produced

than dyes, though pigment batches are generally larger in size. The

USITC publication, Industry and Trade Summary: Synthetic Organic

Pigments, USITC (No. 3021, February 1997), indicates that the total

U.S. production was an estimated 71,500 tons of organic pigments in

1995.

FD&C colorants are dyes and pigments that have been approved by the

Food and Drug Administration (FDA) for use in food items, drugs, and/or

cosmetics. Typically, FD&C colorants are azo or triarylmethane dyes and

are similar or identical to larger-volume dye products not used in

food, drugs, and cosmetics. Manufacture of FD&C colorants is typically

the same as that for the corresponding dye or pigment, except that the

colorant undergoes additional purification. Each FD&C colorant batch is

tested and certified by the FDA.

2. Previous Regulations of Wastes From This Industry

The 1984 Hazardous and Solid Waste Amendments (HSWA) to RCRA

require EPA to make listing determinations for wastes from the

production of dyes and pigments (see RCRA section 3001(e)(2)). On June

1991 EPA entered into a proposed consent decree in a lawsuit filed by

the Environmental Defense Fund (EDF v. Browner, Civ. No. 89-0598

(D.D.C.), hereafter referred to as the consent decree). The consent

decree sets out a series of deadlines for promulgating RCRA listing

decisions, and has been amended as necessary. Paragraph 1h. of the

consent decree obligates EPA to determine whether or not to list as

hazardous certain wastes from the production of dyes and pigments.

In the consent decree EPA agreed to examine wastes from the

manufacture of three classes of dyes and pigments for regulation: azo/

benzidine, anthraquinone, and triarylmethane. The agreement specifies

that the listing determination is to address wastes from the azo,

monoazo, diazo, triazo, polyazo, azoic, and benzidine categories of the

azo/benzidine dye and pigment class; the anthraquinone and perylene

categories of the anthraquinone dye and pigment class; and the

triarylmethane, triphenylmethane, and pyrazolone categories of the

triarylmethane dye and pigment class. The settlement agreement also

specifies that the listing determination is to address the following

specific types of wastes where they are found: spent catalysts, reactor

still overheads, vacuum system condensate, process waters, spent

adsorbent, equipment cleaning sludge, product mother liquor, product

standardization filter cake, dust collector filter fines, recovery

still bottoms, treated wastewater effluent, and wastewater treatment

sludge.

Due to the market demand for a wide variety of dye and pigment

products, the dye and pigment industries typically operate successive

batch processes producing varying dye and pigment products. These batch

operations generate a wide variety of solid wastes on a periodic basis.

These wastes generally can be divided into two general types:

commingled wastes and process-specific wastes. Commingled wastes are

wastes combined from multiple processes prior to management (e.g.,

wastewaters). Commingled wastes include secondary wastes generated from

the treatment of other commingled wastes (e.g., wastewater treatment

sludges). Process-specific wastes are wastes that are unique to a

specific process and may be managed independently of one another (e.g.,

spent filter aids).

On December 22, 1994, EPA published a notice that proposed listing

decisions for 11 of the wastes covered in the consent decree. EPA

deferred any listing decisions on three other wastes. (See 59 FR

66072). As a result, EPA and EDF amended the consent decree (paragraph

1h(v)) to establish deadlines for promulgating listing decisions for

two of the deferred wastes. In today's notice, EPA is proposing listing

determinations for all three of the deferred wastes.

C. Confidential Business Information (CBI) Issues Regarding This Rule

For the purpose of developing the supporting data for listing

rulemakings for the dye and pigment industry, a questionnaire was sent

out to industry pursuant to RCRA Section 3007. Some of the information

collected from industry and used in the 1994 proposed rule, as well as

today's proposed rule, was claimed as confidential. As a result of a

consent order and a subsequent preliminary injunction in connection

[[Page 40196]]

with a case brought by some of the dye and pigment industry to prevent

the disclosure of information claimed as CBI, Magruder et al. v. U.S.

EPA, Civ. No. 94-5768 (D.N.J.), the EPA is enjoined from disclosing

information claimed as confidential until all CBI determinations have

been made on the data intended to be published in connection with these

proposed rules.

Therefore, as with the 1994 proposed rule, we have removed

information from this preamble and rule (and supporting background

documents), if the information may disclose information claimed as CBI.

We note the missing information in the text to this rule, where

appropriate. However, we have included data that are not claimed as

CBI, whenever such data are available. We have also included data that

we obtained from public or non-CBI sources. Wherever we are unable to

include pertinent data in a table, the following statement appears in a

footnote: ``Relevant data are not included at the present time due to

business confidentiality concerns.''

At this time EPA expects that this rule will also need some form of

notice of data availability (NODA) or reproposal prior to promulgation

as a final rule because of CBI problems. However, EPA is proceeding as

noted above to allow publication of as much of the proposed rule as can

be shared at this time. Thus, commenters can see as much as possible of

EPA's current thinking and can comment on the basic approach, the

implementation issues, and other portions of the rule that can

reasonably be commented upon, even with the current redactions. We

intend to supplement the public record prior to issuing a final listing

determination.

D. What Wastes Are Covered in Today's Proposed Rule?

Today's proposal applies only to the dye and pigment manufacturing

industries. The end-user markets for dyes and pigments, which include

textiles, paper, leather, ink, paints, coatings, plastics, fibers, and

other low volume markets, are not within the scope of our listing

determination. Consistent with both HSWA Amendments of 1984 and the

consent decree, EPA is only making proposed determinations on wastes

from the production and manufacturing of dyes and pigments.

In the 1994 proposed rule, the Agency deferred action on three

waste streams based on insufficient characterization data, or lack of

health-based levels for specific constituents of concern. The

``deferred'' dye and pigment waste streams are the subject of today's

proposed rule. The three deferred wastes are:

Spent filter aids, diatomaceous earth, or adsorbents used

in the production of azo, anthraquinone, or triarylmethane dyes,

pigments, or FD&C colorants.

Wastewater treatment sludge from the production of

triarylmethane dyes and pigments (excluding triarylmethane pigments

using aniline as a feedstock).

Wastewater treatment sludge from the production of

anthraquinone dyes and pigments.

This proposed rule will refer to these wastes as ``filter aids,''

``TAM sludges,'' and ``anthraquinone sludges'' respectively. Brief

descriptions of the three wastes are given below.

Filter Aids

Manufacturers add filter aids (e.g., diatomaceous earth) to some

reaction processes to remove particulate impurities. The spent filter

aids then are collected in a filter press and the press cake, sometimes

called a clarification sludge, is disposed as waste. In some cases,

facilities also use filter aids following completed reactions to

clarify and purify certain products. The Agency grouped spent filter

aids, diatomaceous earth, and adsorbents used in the production of all

relevant classes of dyes and pigments, because these wastes typically

contain unreacted raw materials, by-products, and impurities. The

constituent composition of these filter aids varies depending on the

dye or pigment produced and the raw materials used. The Agency deferred

a determination as to whether to list Filter Aids in 1994 due to

insufficient waste characterization data for this widely variable waste

(see 59 FR 66103).

TAM Sludges

As described in the 1994 proposed rule, EPA evaluated wastes from

the production of TAM pigments that use aniline as starting material

(``feedstock'') separately from other TAM wastewaters and wastewater

treatment sludges. This was because the process that uses aniline as a

feedstock is somewhat different (see 59 FR 66081 and 66096). We

proposed listing decisions for wastes from TAM pigments derived from

aniline in the 1994 notice, but deferred a decision for wastewater

treatment sludge from the production of TAM dyes and pigments that do

not use aniline. Today's proposed rule addresses the wastewater

treatment sludges from production of TAM dyes and pigments, excluding

TAM pigments using aniline as a feedstock.

The typical wastewater treatment sludge is generated via the

treatment of the following process waste streams: equipment washdown,

plant run-off, spent scrubber liquid and mother liquor. Wastewater

treatment steps usually include: neutralization to adjust pH,

clarification, and biological treatment. Pretreatment sludges may be

generated from precipitation/filtration in neutralization tanks, and

from treatment with adsorbents, such as activated carbon. Biological

treatment can also lead to generation of a wastewater treatment sludge.

Sludge streams are further processed, typically through filtration and

dewatering, prior to disposal. Information related to the management of

TAM sludges is not included due to business confidentiality concerns.

In support of the 1994 proposed rule, we attempted to sample TAM

sludges (from production of TAM pigments that do not use aniline as a

feedstock). However, TAM dyes or pigments were not being produced at

the time EPA collected its samples, and we could not attribute any

constituents detected to TAM production. Thus, EPA deferred any listing

decision for sludges from the production of TAM dyes and pigments

(excluding TAM pigments using aniline as a feedstock) due to

insufficient waste characterization data (see 59 FR 66095).

Anthraquinone Sludges

The typical anthraquinone sludge is generated via the treatment of

process wastewater similar to that described for TAM sludges. From the

data collected for the 1994 proposed rule, the only constituents

detected in the waste that we could attribute to anthraquinone

production did not have health-based benchmarks. EPA was unable to

identify any appropriate surrogate compound of known toxicity to

estimate the toxicity of these constituents. Because of the lack of

health-based benchmarks or reliable surrogates, we deferred any listing

determination in the 1994 proposal. As part of the deferral, we

requested toxicity data or any suitable surrogates for the two waste

constituents (see 59 FR 66101).

E. What Information Did EPA Collect and Use?

1. The RCRA Section 3007 Survey

In support of the 1994 proposed rule, EPA distributed a detailed

RCRA section 3007 survey to dye and pigment manufacturing facilities in

1992. The purpose of the questionnaire was to collect information on

the 12 specific residuals identified in the 1991 consent decree. Most

questions in this survey requested information on waste generation and

management activities in

[[Page 40197]]

1991. From data provided by questionnaire respondents, EPA identified

facilities that manufacture azo, anthraquinone, or triarylmethane dyes

or pigments (the number of facilities is not included due to business

confidentiality concerns). In the questionnaire, EPA collected

information regarding the products manufactured at each facility, raw

materials and additives used, and 1991 production volumes. The

questionnaire also collected information on the management of the

wastes generated by each facility, including waste quantity and how the

wastes were managed and disposed.

EPA contacted companies generating the three deferred wastes at

issue in today's proposed rule to update the information in the 1992

Sec. 3007 survey. The updated information EPA collected includes the

quantities of wastes generated (for the year 1997), and the waste

management practices used by the facilities for each of the wastes. The

Agency used this updated information in its risk assessment, as

described in Section III.D. The following discussion summarizes the

information collected for each waste.

Filter Aids

In response to the 1992 questionnaire, a number of dye and pigment

manufacturers reported generating filter aid wastes. We are not

including information on the number of facilities generating this

waste, nor the waste quantities reported for 1991, due to business

confidentiality concerns. We also cannot include information collected

by EPA in 1998 on the number of generators and the quantities for 1997

for the same reason. Facilities that generated spent filter aids may

generate this waste from the production of a wide variety of different

dyes and pigments. For example, one facility reported generating a

total of 90 Mtons of filter aid wastes in 1997, comprised of 18 filter

aids arising from the production of dyes and/or pigments.

TAM Sludges

In response to the 1992 questionnaire, a number of dye and pigment

manufacturers reported generating TAM wastewater treatment sludges. We

are not including information on the number of facilities generating

this waste, nor the waste quantities reported for 1991, due to business

confidentiality concerns. We also cannot include information collected

by EPA in 1998 on the number of generators and the quantities for 1997

for the same reason. As noted previously, EPA was unable to collect

samples of this waste.

Anthraquinone Sludges

In response to the 1992 questionnaire, a number of dye and pigment

manufacturers reported generating anthraquinone wastewater treatment

sludges. We are not including information on the number of facilities

generating this waste, nor the waste quantities reported for 1991, due

to business confidentiality concerns. We also cannot include

information collected by EPA in 1998 on the number of generators and

the quantities for 1997 for the same reason.

As noted above, the only chemicals detected in sludge that could be

attributed to anthraquinone production in 1994 did not have health-

based benchmarks. EPA did not receive any information in comments on

the 1994 proposal that would assist us in calculating health

benchmarks. Furthermore, EPA has not subsequently found any suitable

surrogates to estimate the toxicity of the compounds in question.

2. Sampling and Analysis Data

For the 1994 proposed rule, the Agency performed sampling to

characterize the wastes generated at dye and pigment manufacturing

facilities. EPA collected a total of 34 waste samples from facilities

to characterize the residuals under evaluation. The analytical results

for all the wastes are summarized in the Background Document for

Identification and Listing of the Deferred Dye and Pigment Wastes,

Appendix A (hereafter called the Listing Background Document) for

today's proposal, which is available in the docket. (Note however, that

we cannot release much of the analytical data due to business

confidentiality concerns). The dye and pigment manufacturers also

provided a limited amount of additional waste sampling and analysis

data in 1994. These additional data include aggregated analytical

results from 19 industry analyses of samples that EPA and the

facilities split during sampling visits. An industry trade group (Color

Pigment Manufacturers' Association, or CPMA) aggregated this analytical

information and submitted this information to EPA in April 1994. CPMA

also included this information in the group's public comments on the

1994 proposed rule (see Docket No. F-94-DPLP-FFFFF, item DPLP-0025). We

used the available sampling data from these sources to identify

potential constituents of concern for use in today's proposed rule.

For the 1994 proposed rule, EPA collected limited sampling data for

spent filter aids. Our sampling results were inconclusive for TAM

sludges because these products were not manufactured during our

sampling visit. While we did succeed in obtaining samples of

anthraquinone sludge, we do not have health benchmarks for the two

constituents that could be attributed to production of anthraquinone

products.

III. Approach Used in This Proposed Listing

A. Summary of Today's Action

In listings promulgated by EPA, we typically describe the scope of

the listing in terms of the waste material and the industry or process

generating the waste. However, in today's rule we are proposing to use

a new approach in these listings, a ``concentration-based listing.'' In

a concentration-based listing, a waste would be hazardous unless a

determination is made that it does not contain any of the constituents

of concern at or above specified levels of concern. This approach draws

from the concept of the characteristic approach to defining a hazardous

waste, in that whether a waste is hazardous depends on the levels of

key constituents in the wastes. We describe this concept in detail

later in this notice.

We are proposing concentration-based listings for two of the

deferred wastes:

Spent filter aids, diatomaceous earth, or adsorbents used

in the production of azo, anthraquinone, or triarylmethane dyes,

pigments, or FD&C colorants.

Wastewater treatment sludge from the production of

triarylmethane dyes and pigments (excluding triarylmethane pigments

using aniline as a feedstock).

For both wastes, the listings would apply if the wastes contain any

of the constituents identified in the regulation at a concentration

equal to or greater than the hazardous level set for that constituent

(see tables IV-1 and IV-2 for levels). We are also proposing a set of

conditions and requirements that must be met if a facility wishes to

claim its waste does not exceed these levels and is, therefore, not

covered by the listing.

We are proposing not to list as hazardous the third waste

considered:

Wastewater treatment sludge from the production of

anthraquinone dyes and pigments.

In the following sections we describe the concept of a

concentration-based listing and the risk assessment methodology we used

to develop concentration limits for each wastes. We describe our

proposed decisions in more detail in Section IV.

[[Page 40198]]

B. What Is a Concentration-Based Listing?

A concentration-based listing specifies constituent-specific levels

in a waste that causes the waste to become a listed hazardous waste. In

this proposed rule, we identify constituents of concern likely to be

present in two categories of dye and pigment wastes. Using risk

assessment tools developed to support our hazardous waste

identification program, we assessed the potential risks associated with

the constituents of concern. From this analysis, we developed ``listing

concentrations'' for each of the constituents of concern in the two

waste categories.

If you generate any of the wastes included in the two categories of

dye and pigment wastes referenced above, you must either determine

whether or not your waste is hazardous or assume that it is hazardous

as-generated. We are proposing that you determine representative

concentrations for the constituents of concern in your waste through

sampling and analyses, unless you can use process knowledge to

demonstrate that certain constituents are not present in your waste.

Based on this information, you must make a determination as to whether

or not your waste is a listed hazardous waste. Your waste would be a

listed hazardous waste if it contains any of the constituents of

concern at a concentration equal to or greater than the hazardous

concentration identified for that constituent. If all of the

constituents of concern in your waste were below their respective

listing concentrations, you would need to notify EPA that your wastes

are nonhazardous. The detailed descriptions of the steps you would be

required to follow to implement the concentration-based listing are

described later in this proposed rule.

C. Why Is a Concentration-Based Approach Being Used for This Listing?

There are several reasons for using a concentration-based approach

for listing the deferred dyes and pigments wastes. First, these wastes

are generated by an industry that uses batch processes to manufacture a

variety of products, in response to market demand for a wide variety of

dye and pigment products. Batch operations may result in highly

variable wastes at the same facility or different facilities. A

concentration-based approach allows the variable wastes generated at

these facilities to be evaluated individually for hazard, so only the

truly hazardous wastes are listed. This tailored approach is more cost-

effective for the industry than a standard listing, and avoids the

unnecessary regulation of nonhazardous waste.

Alternatively, EPA could have attempted to collect more information

on these specific wastes to support a straightforward listing, i.e.,

without any concentration limits. However, such a data collection

effort would have been difficult due to the wide variety of individual

dye or pigment products produced and the potential variability in the

waste characteristics. For example, one facility generated 18 filter

aid wastes in 1997 arising from the production of different dyes and/or

pigments. Gathering sufficient samples to evaluate all potential filter

aid wastes would require a large commitment of scarce Agency resources

that would have been beyond the reasonable scope of this rulemaking,

especially given the time constraints of the existing Consent Decree.

Given the relatively low quantities of the individual filter aids

produced, EPA does not feel such an effort was justified.

Second, many manufacturers in the dye and pigment industries want

to keep facility-specific product and waste information confidential.

These manufacturers are concerned that release of such information

could cause competitive harm. A concentration-based listing allows us

to rely less on CBI, since we do not use this information directly to

set the listing concentrations. This means we don't use specific

information, such as product formulations or concentrations of

constituents in the wastes, to set hazardous concentration levels for

constituents of concern. As noted earlier, however, in this particular

listing EPA still must resolve the CBI claims on some specific data

prior to release.

Finally, a concentration-based listing approach may provide an

incentive for hazardous waste generating facilities to modify their

manufacturing processes or treat their wastes. For example, if a

facility has a listed hazardous waste based on constituent-specific

concentration levels established by EPA, it also knows the required

concentrations levels of constituents in its waste below which its

waste would become nonhazardous. Therefore, the facility may decide to

modify its manufacturing process in order to generate a nonhazardous

waste. Thus, this approach encourages waste minimization.

Section 1003 of the HSWA indicates that one of RCRA's goals is to

promote protection of human health and the environment and to conserve

valuable material and energy resources by ``minimizing the generation

of hazardous waste and the land disposal of hazardous waste by

encouraging process substitution, materials recovery, properly

conducted recycling, and reuse and treatment.'' Section 1003 further

provides that it is a national policy of the United States that,

whenever feasible, the generation of hazardous waste is to be reduced

or eliminated as expeditiously as possible.

The Pollution Prevention Act of 1990 (42 U.S.C. 13101 et seq., Pub.

L. 101-508, November 5, 1990) provides a hierarchy of pollution

prevention approaches. Pollution should be prevented or reduced;

pollution that cannot be prevented should be recycled or reused in an

environmentally safe manner; pollution that cannot be prevented/reduced

or recycled should be treated; and disposal or release into the

environment should be chosen only as a last resort. A concentration-

based listing may prevent pollution by discouraging generation of

wastes with high levels of toxic constituents. If EPA provides a

concentration-based target in the listing, generators would have the

regulatory and economic incentive to meet the reduced levels.

D. What Risk Assessment Approach Did EPA Use?

Under a concentration-based listing approach, EPA must calculate

concentration levels, or ``listing levels,'' in the waste that would

present a hazard. To accomplish this, the Agency: (1) Selected

constituents of potential concern in the waste, (2) chose a plausible

waste management scenario, (3) calculated exposure concentrations by

modeling the release and transport of the constituents from the waste

management unit to the point of exposure, and (4) calculated waste

concentrations that would yield the target risk level at the point of

exposure.

The following sections present an overview of the analysis EPA used

to calculate risk-based listing levels for filter aids and TAM sludges

generated during the manufacture of organic dye and pigment products.

You will find more details of how we selected the constituents of

concern in the Listing Background Document. Details of the risk

assessment are provided in the document in the docket entitled

Development of Risk-Based Listing Concentrations for Hazardous

Constituents Contained in Spent Filter Aids and Triarylmethane (TAM)

Wastewater Treatment Sludges (hereafter called the Risk Assessment

Background Document).

[[Page 40199]]

1. Choosing the Constituents of Concern

Our initial universe of constituents of potential concern included

any constituent detected in any wastestream from the production of all

classes of dyes and pigments we examined (i.e., all wastes sampled

associated with the production of azo, TAM, and anthraquinone dyes or

pigments, including FD& C colorants). We typically obtain samples from

the specific wastes of concern for a standard listing evaluation.

However, obtaining representative samples of filter aids and TAM

sludges was difficult, as noted in the 1994 proposal (see 59 FR 66095

and 66103), due to widely varying wastes and batch processes. We

believe that the broad universe of constituents detected in all wastes

examined provides an appropriate starting point for selecting

constituents of concern for filter aids, because these wastes may be

generated from the production of many kinds of dyes and pigments.

Because TAM sludge is a much more narrowly defined waste, we relied on

available information regarding constituents used in TAM production to

determine what constituents we expect in the waste.

Our primary source of potential constituents was the set of

analytical data EPA collected to support the 1994 proposed rule

described in Section I.E.2 of today's notice. We also examined the

limited analytical data from industry to confirm the presence of

constituents. These data sets included sampling results for all wastes

under consideration in the 1994 proposal, because the available

analytical data for the three specific wastes at issue are limited. For

filter aids, EPA obtained some samples in support of the 1994 proposed

rule. However, filter aids may potentially contain a variety of

constituents, depending on what products and processes are in use by

different facilities. Therefore, the limited waste analysis data for

filter aids alone were not adequate to establish constituents of

concern. We have no waste analysis data that would allow us to identify

specific constituents of concern for TAM or anthraquinone sludges. As

noted in Section II.D, our sampling results were inconclusive for TAM

sludges because TAM dyes or pigments were not being produced at the

time EPA collected its samples. While we did succeed in obtaining

samples of anthraquinone sludge, we do not have health benchmarks for

the two constituents that could be attributed to production of

anthraquinone products. Thus, we did not pursue a listing for this

waste.

We used the analytical data from all wastes to develop an initial

list of potential chemicals of concern. We then reduced and augmented

this list based on several factors. First, we can only develop a

concentration level if a health benchmark exists for the chemical.

Therefore, we removed constituents without health benchmarks from

further evaluation. The sources we used for health benchmark data are

summarized below; the Risk Assessment Background Document contains

further information (see Appendix E).

Due to the lack of health-based benchmarks, we excluded certain

constituents from consideration in today's proposed rule that we

previously evaluated for azo dye and pigment wastes in the 1994

proposed rule. These constituents are acetoacetanilide (AAA),

acetoacet-o-toluidine (AAOT), and acetoacet-o-anisidine (AAOA). For the

1994 proposal, we derived health based numbers based on a Structural

Activity Relationship (SAR) analysis. The Agency has since reevaluated

and revised the SAR analysis based on comments received in response to

the 1994 proposal. The revised analysis, which has been independently

peer reviewed, concludes that the current available data are

insufficient to make a quantitative estimation of the carcinogenic

potential of these compounds, or to establish provisional non-cancer

benchmarks. The revised toxicological analysis for these compounds and

the peer review documents are provided in Appendix A to the Risk

Assessment Background Document.

We then screened the remaining potential constituents to remove

chemicals that we believed were of little use in defining the hazardous

characteristic of the two wastes at issue. In this screen we considered

the prevalence with which a constituent is used in the manufacturing of

the different classes of dyes and pigments at issue in the consent

decree, the likelihood that a chemical could be attributed to such

production, and the frequency with which a chemical was detected in

wastes samples. In considering if the constituents detected are likely

to be derived from dye or pigment production, we used publicly

available information from the Colour Index International (3rd edition,

1996). For example, we retained any chemicals that were detected that

are commonly used as raw materials in the production of the dyes and

pigments at issue (e.g., aniline is widely used in the production of

azo products; see Colour Index, vol. 4, pages 4009 and 4699). We also

kept some chemicals detected that have no apparent use as raw

materials, because they may be impurities or degradation products from

chemicals used in the manufacturing process (e.g., naphthalene may be

an impurity in a commonly used raw material, beta-naphthol). We removed

some constituents, such as acetone and methylene chloride, that were

detected frequently in samples, because they are common laboratory

contaminants and/or common solvents that have no reported use in the

production of these dyes and pigments. While such constituents may be

present in wastes, we did not consider them further because we could

not reasonably attribute them to dye and pigment production processes

sampled. We dropped other constituents that had little or no reported

use in the Colour Index; the dropped constituents were also rarely

found in waste samples.

We are proposing to include the selected core chemicals in Table

III-1 as constituents of concern for defining the two listed wastes.

This table summarizes the frequency with which we detected the

chemicals in waste samples, and prevalence of use of the chemicals in

the production of the three dye and pigment classes (azo, TAM, and

anthraquinone) as found in the Colour Index. For filter aids we

included constituents on the final list of constituents of concern if

we detected the chemicals with at least a low frequency (i.e, in more

than one sample), and we found some evidence that industry used the

chemicals in the production of the dyes and pigments at issue. We also

selected several chemicals that we believe may be degradation products

of other raw materials (e.g., p-phenylenediamine), or possible

impurities in other starting materials (e.g., naphthalene). Finally, we

included several compounds that may arise from TAM production, as

described below, even though we do not have analytical data showing

these chemicals are present in wastes from this industry. (More details

of our rationale for choosing chemicals of concern are given in the

Listing Background Document, Section 4).

We chose to add two chemicals for consideration as constituents of

concern that were reported to be used in the production of TAM

products, even though we did not find them in any waste samples. In the

case of benzaldehyde, we did not analyze any of the wastes for this

compound. However, this chemical is reported to be used in the

production of TAM products (see Colour Index, vol.4, page 4727). We

analyzed for the other chemical (the

[[Page 40200]]

identity is not given due to business confidentiality concerns), but we

did not find it in any samples. However, the 3007 Survey indicated

significant use of this chemical in the production of TAM dyes. EPA did

not succeed in obtaining waste samples during the production of TAM dye

and pigments (excluding TAM pigments using aniline as a feedstock).

Therefore, based on the known uses in TAM manufacturing, we considered

these two chemicals as potential constituents of concern.

In the case of TAM sludges, we considered proposing the same list

of core constituents used for filter aids. We considered this option

primarily because we have no analytical data that reflects wastes

arising from TAM production. (We do have data for wastes from the

production of TAM pigments using aniline as a feedstock; this subset of

TAM wastes were dealt with in the 1994 proposed rule and is not at

issue in today's notice. We decided to propose a list based on the

constituents that are known to be used in the manufacturing of TAM dyes

or pigments. Using public sources of information (i.e., Colour Index),

we were able to identify reactants reported in use for TAM products.

Except as noted previously, the constituents identified in this way are

consistent with the constituents reported in the 3007 Survey. This

analysis led to the list of constituents of concern for TAM sludges.

The publicly available information we used was consistent with the

information provided by industry in responses to the 3007 Survey,

except in a few cases. In some instances (the identities are not given

due to business confidentiality concerns), the Colour Index showed low

to moderate use of the chemicals that was not confirmed in the 3007

Survey. Conversely, in the case of another chemical (the identity is

not given due to business confidentiality concerns), the 3007 Survey

indicated significant use in the production of TAM dyes, while the

Colour Index did not. In cases where we had these discrepancies, we

relied on the source that showed use and assumed that these chemicals

may be used in production.

In choosing core constituents of concern for a concentration-based

listing for filter aids and TAM sludges, we considered adding other

constituents shown in Table III-2. We considered these chemicals

because they were detected with a moderate frequency, they had some use

in manufacturing the dye and pigment products of concern, or they are

in a class of compounds that have been historically linked to dye

production (benzidines). However, we believe that these constituents

are unlikely to be present in these two specific wastes at levels of

concern. Some of the chemicals in Table III-2 could not be linked to

the production of the dye and pigment classes at issue. We did not

include chemicals in the final list of core constituents of concern

unless we could find some evidence that the presence of a chemical was

related to the production of the classes of the dyes and pigments of

interest (for filter aids, the production of azo, TAM, or anthraquinone

products; for TAM sludges, the production of TAM products, excluding

TAM pigments using aniline as a feedstock). This is because many waste

samples were wastewaters or sludges collected from combined wastewater

treatment systems, and such systems typically receive waste streams

from various other production processes at facilities. We did not

include other chemicals because they were never or rarely detected in

EPA's analysis.

Table III-1.--Core Constituents of Concern in Filter Aids and TAM Sludges

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

Core constituents

of concern for

Constituent filter aids (FA) Frequency of detection\1\ Use in production of dye Comments

and/or TAM sludges and pigment classes\2\

(T)

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

Aniline............................ FA High; S............................... High use (Azo); some use ..........................

in TAM pigment (aniline

based)

Benzaldehyde....................... FA, T Not analyzed.......................... Moderate use in TAM Not analyzed, but common

products**. reactant in TAM

production.

Chloroaniline, p-.................. FA Moderate, S........................... Rare use (Azo)............ Aromatic amine; possible

contaminant.

Cresol, p-......................... FA Moderate, S........................... Low use (Azo) found in Industry split samples did

Colour Index;**. not distinguish meta and

para isomers.

Dimethoxybenzidine, 3,3'-.......... FA Low, S................................ Moderate use (Azo) ..........................

Dimethylaniline, N,N-.............. FA, T Rare.................................. Moderate to high use found Rarely detected, but TAM

for TAM dye production; waste not sampled and

rare use otherwise. common reactant in TAM

production.

Diphenylamine...................... FA, T Moderate.............................. Low use (Azo); rare use in Indistinguishable from N-

TAMs. Nitrosodiphenylamine by

EPA method (GC/MS).

Diphenylhydrazine, 1,2-............ FA Moderate.............................. None reported............. Possible oxidation product

of aniline;

indistinguishable from

azobenzene by EPA method

(GC/MS).

Formaldehyde....................... FA, T Moderate, S........................... Moderate use for TAM; low ..........................

use for others

Naphthalene........................ FA Moderate/High......................... None reported............. Possible impurity in

common Azo raw material

(beta-naphthol).

Phenol............................. FA Moderate/High, S...................... Moderate use (Azo)........ ..........................

Phenylenediamine, p-(4- FA Low/Moderate.......................... Moderate use (Azo)........ Possible hydrolysis

aminoaniline). product of other azo raw

materials

(aminoacetoacetanilide);

indistinguishable from o-

isomer in EPA analysis.

[[Page 40201]]

Toluidine, o-(2-aminotoluene)...... FA, T Moderate, S........................... Moderate use (Azo); low Hydrolysis product of raw

use (TAM). materials (AAOT); EPA

could not separate o-and

p-isomers during

analysis.

Toluidine, p-(4-aminotoluene)...... FA, T Moderate, S........................... Low to moderate uses (TAM EPA could not separate o-

and anthraquinone). and p-isomers during

analysis.

(**)

(**)

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

\1\ As found in EPA analysis of samples of all dye and pigment wastes from production of azo, TAM, and anthraquinone dyes/pigments and FD& C colorants;

``ND'' means not detected; ``S'' denotes reported in industry split samples.

\2\ From the Colour Index International, 3rd edition, 1996.

**Relevant data are not included at the present time for a number of constituents due to business confidentiality concerns.

Table III-2.--Other Constituents of Possible Concern

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

Use in

production of

Constituent Frequency of detection \1\ dye and pigment Comments

classes \2\

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

Benzene...................... Moderate, S..................... None reported.. Found in waste, but no use;

common contaminant from many

industrial processes.

Benzidine.................... Low............................. No reported use Used historically (Azo), but

domestically. no current domestic use

reported; only found in

wastes from processes that do

not use filter aids.

Chlorobenzene................ Moderate, S..................... None reported.. No known use; other uses as

solvent.

Chloroform................... Moderate, S..................... None reported.. No use; contaminant from

treated water supplies; other

uses as solvent.

Dichlorobenzene, 1,2-........ Moderate........................ None reported.. No use in azo/TAM/

anthraquinone production;

solvent uses in other dye

production (Oxazine dyes).\2\

Phenylenediamine, o-(2- (See comments).................. Low use EPA found analytical methods

aminoaniline). (anthraquinone unreliable (very poor

). recoveries); may be

indistinguishable from p-

isomer.

Toluidine, 5-nitro-o-(2- ND, S........................... Moderate use Not detected in any EPA

methyl-5-nitroaniline). (Azo). samples of azo wastes and

reported in only 1 industry

sample.

(**)

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

\1\ As found in EPA analysis of samples of all dye and pigment wastes from production of azo, TAM, and

anthraquinone dyes/pigments and FD& C colorants; ``ND'' means not detected; ``S'' denotes reported in industry

split samples.

\2\ From the Colour Index International, 3rd edition, 1996.

** Relevant data are not included at the present time for a number of constituents due to business

confidentiality concerns.

We believe that using analytical data from all dye and pigment

wastes sampled is clearly appropriate for filter aids. This is because

filter aids are used to treat and purify a wide variety of wastes

derived from all of the classes of dye and pigment products (azo,

triarylmethane, and anthraquinone). The shorter list for TAM sludges

also is appropriate, due to the more limited set of potential waste

constituents for this single dye and pigment class. We calculated

concentration limits for all constituents in Tables III-1 and III-2 for

both spent filter aids and TAM sludges, as we describe later in this

notice.

We are seeking comment on whether the constituents of concern we

selected are appropriate for the concentration-based listings for the

two wastes under consideration. We are interested in any information on

the potential for these, or any other constituents in Table III-2, to

be in these wastes at levels of concern. We believe that it is

reasonable to select constituents that we can link to the dye and

pigment processes under evaluation. To require testing for an extensive

list of constituents without adequate reason would lead to unnecessary

analysis by industry in evaluating if their wastes meet the listing

levels. After considering information provided in comments on today's

proposed rule, we may choose to add potential constituents from Table

III-2, or delete proposed constituents for the two wastes.

Analytical Issues

We found problems in our chemical analysis of dye and pigment waste

samples for some of the constituents in Table III-1. In a few cases,

our analyses could not distinguish between two compounds when we used

the usual EPA methods for semivolatile organic chemicals, GC/MS method

8270 in Test Methods for Evaluating Solid Wastes, Physical/Chemical

Methods; SW-846, hereafter called SW-846). We found problems for four

pairs of compounds: diphenylamine/N-nitrosodiphenylamine; 1,2-

diphenylhydrazine/azobenzene; o-toluidine/p-toluidine; and o-

phenylenediamine/p-phenylenediamine. We propose to deal with these

problems as outlined below.

N-Nitrosodiphenylamine breaks down to diphenylamine in the method

we used; therefore these two chemicals could not be distinguished. This

means

[[Page 40202]]

that detection by this method could be due to either compound being in

the waste. We found no reported use of the N-nitroso-derivative, but we

did find diphenylamine has some use in the production of azo and TAM

products. Therefore, for this pair we selected diphenylamine as the

likely constituent of concern. This means that, if we finalize

diphenylamine as a constituent in the concentration based listings,

generators would analyze for this constituent and assume any

concentration measured is diphenylamine.

Similarly, we could not distinguish the compounds 1,2-

diphenylhydrazine and azobenzene in the analytical method used, because

these chemicals interconvert readily under analytical conditions. Thus,

our data showed that one or both of these compounds were present in

waste samples, but we could not tell which one. In this case, we did

not find any reported use of either chemical in dye or pigment

production processes. However we believe that the presence of either

may be explained by oxidation of aniline from processes that use

aniline as a reactant. Thus, in this case we are proposing to include

the constituent with the lower concentration level (1,2-

diphenylhydrazine) to be protective. This means that generators would

analyze their waste for the total level of 1,2-diphenylhydrazine/

azobenzene, and assume that the amount detected is due only to the more

toxic 1,2-diphenylhydrazine. This is also reasonable because these

compounds may readily interconvert in wastes or the environment, thus

it is prudent to set the listing level for the more toxic component.

In our analysis we also could not separate two isomers of toluidine

(o-toluidine and p-toluidine) and phenylenediamine (o-phenylenediamine

and p-phenylenediamine). While it may be possible to distinguish these

isomers using other analytical methods, we have no data at this time to

indicate this. For the toluidine isomers, we are proposing to include

both isomers as constituents of concern. If generators cannot separate

these isomers, they could determine a total quantity for both. In the

absence of information on which isomer is expected in the waste,

generators would assume that the measured concentration is due to the

more toxic o-toluidine. Generators could use their knowledge of their

production processes, however, to definitively rule out the presence of

one of the isomers, and in this way identify which isomer is present.

For example, if generators know that only one isomer is used in any of

the relevant processes, they could document this and claim this as part

of their determination. Note that the risk-based concentration levels

we propose to set for these two chemicals are similar (i.e, they differ

by less than a factor of two for both wastes), thus the practical

distinction between these isomers is relatively unimportant, unless

generators measure them at levels approaching the listing levels.

For the o- and p-phenylenediamine isomers, we reviewed the

analytical data and now believe that o-phenylenediamine cannot be

reliably measured. We found that we could not reliably recover the

chemical from samples with known concentrations (spiked samples). In

addition, the reported usage of o-phenylenediamine in the production of

dyes and pigments is relatively limited compared to the use of p-

phenylenediamine (see Colour Index, vol. 4, page 4822). Furthermore, p-

phenylenediamine may also form from the degradation of a widely used

azo precursor, p-aminoacetoacetanilide. Therefore, because of these

analytical problems, and also because its use in dye or pigment

production is limited, we are proposing not to include o-

phenylenediamine in the list of constituents of concern for either

waste. Thus, if we finalize phenylenediamine as a constituent of

concern for filter aids, generators would be required only to determine

if p-phenylenediamine is present in their wastes below the listing

levels.

We seek comment on these analytical issues associated with the

potential constituents of concern. We are especially interested in any

information on methods that may reliably resolve the analytical

problems noted above. We also seek comment on the problematic chemicals

we identified, and whether EPA should adopt another approach. One

approach might be to simply avoid using any of these compounds on the

list of constituents of concern due to the analytical problems.

However, due to their potential importance, we believe at this time

that the above approach is a reasonable attempt to use these chemicals

in setting listing levels. Another approach would be to use the

approach described for the 1,2-diphenylhydrazine/azobenzene pair, i.e.,

if the generators cannot resolve the constituents in the chemical

analysis, they would always assume that the more toxic constituent was

in fact present. We believe this may be overly conservative in some

cases, but solicit comment on this and other possible approaches.

2. Choosing the Risk Assessment Scenarios To Evaluate

For both filter aids and TAM sludges, we evaluated the scenario of

disposal in unlined municipal landfills and assessed the impact of the

release of leachate from these landfills to the groundwater. In past

listings we have found that landfill disposal of wastewater treatment

sludges and similar solids is quite common (e.g., see EPA's recent

listing for petroleum refining wastes, 63 FR 42110; August 6, 1998).

The updated information we collected for both wastes showed that some

generators sent these wastes to municipal landfills. In both cases, EPA

chose to evaluate this scenario. However due to constraints on release

of information claimed as CBI, we cannot discuss in detail the

prevalence of this disposal practice or the extent of other practices.

We used the updated 1997 waste volumes (i.e., waste quantities)

reported by facilities in our modeling of potential releases from

municipal landfills. In the case of filter aids, we combined the filter

aids generated by each facility and arrayed these combined waste

volumes into a distribution that would represent quantities of filter

aids that go to municipal landfills. We then used this distribution of

waste volumes as a key input parameter into our modeling.

For TAM sludges (excluding sludges associated with TAM pigments

using aniline as a feedstock), the updated data showed few generators

of this waste. One facility sent 57 metric tons of sludge derived

solely from the production of TAM dyes or pigments to a municipal

landfill. This specific sludge was generated from wastewater that arose

from the production of TAM products, and did not include wastewaters

from other production processes. We cannot discuss the volumes or

management practices of the other facilities at this time due to CBI

constraints. We used the one volume associated with the dedicated

sludge in all modeling for TAM sludge disposal in municipal landfills.

Under Federal regulations, generators are free to send either waste

to any Subtitle D municipal landfill. We assumed that any municipal

landfill described in EPA's nation-wide distribution of municipal

landfills was possible, with some geographic limitations reflecting the

locations of the dye and pigment manufacturers (described further

below). Therefore, we used the distribution of data available for each

of the parameters needed to model potential risk associated with

disposal of dye and pigment waste

[[Page 40203]]

streams in municipal landfills. The primary source of data from which

we selected key modeling inputs (e.g., surface area, active life,

distance to well) is EPA's 1988 National Survey of Solid Waste

Municipal Landfill Facilities. These parameters are described in more

detail in the Risk Assessment Background Document (Section 4).

EPA has promulgated regulations governing the design and operation

of municipal landfills (see 40 CFR Part 258), and our modeling

assumptions reflected some of these requirements when appropriate

(e.g., daily cover). We chose to model a landfill without the full

liner system described in the regulations, because it is reasonable to

assume that many landfills now and in the future may not have synthetic

liners. For example, the design criteria in 258.40 apply only to new

units or lateral expansions of existing units. Existing landfills

(i.e., those in existence prior to the effective date as defined in

Sec. 258.1(e)) do not have to meet the design requirements in

Sec. 258.40 (e.g., liner systems). Furthermore, the regulations allow

exemptions from the standards depending on the location and size of the

landfill (Section 258.1(f)), and States may approve alternative designs

for new units or lateral expansions based on performance standards

(Sec. 258.40(a)(1)). Finally, EPA is in the process of authorizing

States to implement the municipal landfill regulations, and States are

still working to issue permits and bring all landfills up to the

regulatory requirements. Given the existing exemptions in the

regulations, and the uncertainty in how many landfills have liner

systems, we believe it is prudent to base our modeling on landfills

without a liner.

Another reason the modeling of unlined landfills appears prudent is

because industrial wastes also can go to unlined landfills that do not

take municipal waste (i.e., industrial nonhazardous waste landfills),

and thus would not be subject to those standards. We are unaware of any

legal requirement that these wastes could not go to such non-municipal

waste landfills. Given the similarities in the disposal practices

(municipal and industrial nonhazardous waste landfills), we believe

that an unlined landfill scenario is reasonable.

EPA used the approximate geographic locations of the facilities

that generated spent filter aids and TAM sludges to estimate location

parameters needed to conduct the risk assessment. We used geographic

location to identify the soil, climate, and hydrogeologic parameters

used in the fate and transport modeling. Location related parameters

required for the risk assessment and specific inputs and data

distributions used to model risk from these units are described in

detail in the Risk Assessment Background Document (Section 4).

As noted above, there is uncertainty in how many landfills that

might receive these waste have liner systems in place. EPA acknowledges

that a liner system would serve to contain waste leachate, and would

lessen the risk while such a liner system was intact. We seek comment

as to whether an alternative regulatory approach should be taken for

wastes sent to landfills with liners or certain environmental controls.

3. The Receptors and Exposure Pathways Evaluated

The primary receptors we considered in this analysis are adults and

children exposed via ingestion (i.e., drinking water) and noningestion

(e.g. showering) exposure pathways to water from groundwater wells

contaminated by the leachate from the municipal landfill receiving

filter aid or TAM sludge wastes. We considered only receptors with

residential drinking water wells for the groundwater pathway. We

assumed all community wells and other municipal water supplies are

treated and, therefore, would not be contaminated with constituents

from the wastes of concern.

We also evaluated receptors from nongroundwater pathways in our

sensitivity analysis. We assumed the receptors for these pathways were

farmers and their children who live in close proximity to the municipal

landfill. We chose these receptors because their exposure results in

the highest potential risk for nongroundwater pathways, which was

appropriate for the initial sensitivity or screening analysis.

Nongroundwater exposure pathways for filter aids and TAM sludges

disposed in municipal landfills result from the emission of vapors from

these landfilled wastes. We evaluated exposure from both direct and

indirect nongroundwater pathways. The direct pathway consists of

dispersal of vapors from the landfill through the air pathway directly

to the receptor via the inhalation. Indirect pathways include

deposition to soil, transfer to fruits, vegetables, grain, and forage

(air-to-plant transfer and soil-to-plant transfer), and uptake by

grazing animals. The plant and animal products are then consumed by the

farm family.

E. How Did EPA Estimate Exposure Concentrations?

1. Risk Assessment Methods

To calculate listing levels for constituents of concern, we needed

to determine what concentrations at the point of exposure would be

associated with levels in the wastes. We conducted the risk assessment

in three stages: (1) the sensitivity analysis, (2) the deterministic

analysis, and (3) the probabilistic analysis for the groundwater

pathways. For the nongroundwater pathways, the Agency used results from

the sensitivity analysis to screen out nongroundwater risks, because

they were not significant relative to potential groundwater risks

associated with disposal of wastes in landfills.

a. Sensitivity Analysis. The purpose of our sensitivity analysis

was to identify the most sensitive or risk-driving parameters in the

risk assessment model and to determine high-end and central tendency

values for subsequent use in the deterministic analysis. A high-end

parameter corresponds to its 90th or 10th percentile value depending on

whether a high or low value of that parameter results in a higher

predicted risk. We conducted the sensitivity analysis by varying each

parameter or set of linked parameters to high ends one at a time, while

holding all other variables in the analysis at central tendency. We

then compared the risk results using a single high-end parameter to the

results obtained when all values are set at central tendency. Using

this method, we identified the two most sensitive high end parameters

that resulted in the highest risks. We then set these parameters to

their high-end values in the subsequent deterministic analysis. For the

groundwater pathway, we used the sensitivity analysis to identify high-

end parameters for use in the deterministic assessment of risk from

groundwater.

For the nongroundwater pathway, we were able to use the results

from the sensitivity analysis as a screening level analysis of

nongroundwater risks. Originally, we intended to use the nongroundwater

sensitivity analysis to identify the most sensitive parameters for use

in a deterministic analysis of nongroundwater risks from the dye and

pigment waste streams. However, we were able to use the results of the

nongroundwater sensitivity analysis to screen out or eliminate

nongroundwater risks as a primary concern for dye and pigment industry

wastes. We screened out nongroundwater risks by comparing the results

of the nongroundwater sensitivity analysis to the results of the

[[Page 40204]]

groundwater sensitivity analysis, which we performed using the same

inputs for common parameters. In all cases, the groundwater risk

analysis produced higher risk estimates for all constituents. Since the

purpose of this analysis was to set risk-based concentration limits, we

focused our analysis on the pathway of most concern (i.e., highest

risk) to determine protective concentrations. Because the groundwater

pathway presented the highest risk, we only evaluated the groundwater

pathway further using deterministic and Monte Carlo analyses. In other

words, risk-based concentrations set based on groundwater pathway risks

will also be protective of nongroundwater pathway risks. Based on this

finding, no further modeling of nongroundwater risks was conducted. The

Risk Assessment Background Document describes the sensitivity analysis

for both groundwater and nongroundwater pathways and presents the

results in Appendices A and H.

b. Deterministic Analysis. The ``deterministic'' method uses single

values for input parameters in the models to produce a point estimate

of risk or hazard. For this analysis, we used a double high-end risk

assessment. In this method, we set the two parameters identified to be

most sensitive at their high-end values and all other parameters are

set at central tendency. A central tendency risk estimate is the point

estimate in which all variables are set at central tendency values. We

presume the high-end risk estimate to be a plausible estimate of

individual risk for those persons at the upper end of the risk

distribution. By using these descriptors we intend to convey estimates

of exposure in the upper end of the distribution (i.e., above the 90th

percentile), while avoiding estimates that are beyond the true

distribution. (See the EPA guidance memo entitled, Guidance on Risk

Characterization for Risk Managers, 1992; hereafter known as the

Habicht memo, 1992). We applied the deterministic methodology to assess

groundwater pathway risks from disposal of spent filter aid and TAM

sludges in municipal landfills. The parameters that we found to be the

two key high-end parameters varied somewhat by chemical and waste.

However, these parameters were some combination of waste quantity, well

location, and duration of exposure.

c. Probabilistic Analysis (Monte Carlo Method). In the

probabilistic analysis, we vary sensitive parameters for which

distributions of data are available. Parameters varied for this

analysis include waste volumes, landfill size, parameters related to

the location of the landfill such as climate and hydrogeologic data,

location of the receptor, and exposure factors (e.g., drinking water

ingestion rates). The probabilistic analysis is conducted using a Monte

Carlo methodology. Monte Carlo analysis provides a means of quantifying

some variability and uncertainty in risk assessments by using

distributions that describe the full range of values that the various

input parameters may have. Some of the parameters in the probabilistic

analysis are set as constant values because (1) there are insufficient

data to develop a distribution, (2) simplifying assumptions are made,

(3) site specific constants are available, or (4) the analysis has not

been shown to be sensitive to the values of the parameter, that is,

even if the parameter is varied, the risk results do not vary

significantly.

Monte Carlo simulation is a statistical technique that calculates

an individual risk value or hazard quotient for each category of

parameters that affect or determine risk. For each calculation, the

Monte Carlo simulation uses parameter values that are randomly selected

from the distribution of values available for each parameter. The range

of values selected for the input parameters reflects the distribution

of values corresponding to each input parameter. The repetitive

calculations take many randomly selected combinations of input

parameters to generate a range of risk results. Based on the

distribution of the output, we can determine a risk or hazard level

representing the high end (e.g., 90th or 95th percentile) or central

tendency (i.e., 50th percentile). Although the simulation is internally

complex, commercial software performs the calculations as a single

operation, presenting a distribution of risk results. From these

results, we can determine the percentile distribution of exposure point

concentrations and risks for the selected risk assessment scenario. We

assessed potential groundwater pathway risks from disposal of filter

aid and TAM wastes in municipal landfills using the probabilistic risk

assessment method.

Monte Carlo simulation can be used to simulate the effects of

natural variability and informational uncertainty that often accompany

many actual environmental conditions. Further, information on the range

and likelihood of possible values for these parameters is produced

using this technique. When compared with alternative approaches for

assessing parameter uncertainty or variability, the Monte Carlo

technique has the advantages of very general applicability, no inherent

restrictions on input distributions or input-output relationships, and

relatively straightforward computations. Also, Monte Carlo application

results can be used to satisfactorily calculate uncertainty, and to

quantify the degree of conservatism used. With deterministic analyses,

an alternative to Monte Carlo, it is often not possible to quantify the

level of protection represented by the results. However, some potential

limitations may exist when applying Monte Carlo techniques in modeling

efforts. Variability (inherent variation in a measure over time and

space) and uncertainty (lack of knowledge) are often difficult to

distinguish within applications. Also, one must account for

correlations among the various data parameters to avoid distorting

results. As explained in Section III.H, we relied on the Monte Carlo

approach to set listing levels for today's proposal.

2. Fate and Transport Modeling

The risk analysis employs several key fate and transport models.

The models include a landfill partitioning model based upon the

equations presented in a series of articles by Jury et al. We used this

model to estimate the concentration of leachate from the landfill and

the emission rate for volatile constituents from the landfill. We

applied EPA's Industrial Source Complex Short Term, version 3 (ISCST3)

to estimate the dispersion and deposition of vapors emitted from the

municipal landfill. For estimating the concentration of constituents of

concern at the residential drinking water well, we used the groundwater

model EPACMTP or EPA's Composite Model for Leachate Migration with

Transformation Products. Further details and references for these

models are presented in the Risk Assessment Background Document

(Section 5.2.2).

a. Landfill Partitioning Model. We used the Jury equations to

estimate fate and transport of constituents in the nongroundwater

pathways from the landfill to the receptor and to estimate leachate

from the landfill. Using a model based on the Jury equations, we

projected the contaminant loss from a landfill due to volatilization,

run-off, degradation, and leaching. The Jury equations partition the

waste in the landfill to waste, air, and pore water and calculate

potential losses from leaching, volatilization, and degradation. The

landfill partitioning model evaluates contaminant losses over both the

active waste disposal period and after the landfill is closed. We used

the landfill partitioning model to conduct the

[[Page 40205]]

sensitivity, deterministic, and Monte Carlo analyses.

b. Air Model. We used the ISCST3 air dispersion and deposition

model to estimate the vapor air concentrations and deposition rates

needed to develop relative risk estimates associated with vapor air

emissions from the municipal landfill. We estimated air pathway risks

using emissions estimates from the landfill partitioning model as

inputs to the ISCST3 air model, and using ISCST3 to estimate the air

concentration and deposition of vapor for each constituent at receptor

locations. This modeling step was only needed for the sensitivity

analysis to estimate risks from non-groundwater pathways.

c. Groundwater Model. We used the EPACMTP groundwater model to

estimate the concentration of constituents of concern at the

residential drinking water well. We conducted the groundwater modeling

using six surrogate compounds to represent the movement of all

constituents of concern through the groundwater pathway. Identification

of surrogate compounds provides a means of minimizing the modeling runs

required to model the large number of constituents evaluated for this

assessment. For this assessment, organic constituents are grouped into

six categories based on like chemical and physical properties. Sorption

potential and hydrolysis rate are the key parameters used to group

constituents; however, for the constituents of concern in today's

proposed rule, hydrolysis was not important. Therefore, the only

constituent-specific parameter of importance for transport of the

organic compounds of interest was the sorption potential (i.e., the

organic carbon partition coefficient, Koc; this is a measure

of the tendency for a chemical to adsorb to organic material in soils).

For computational efficiency, we only modeled the surrogate constituent

in each category, and then applied the modeling results for the

surrogate to each constituent in the category. We found that the

dilution and attenuation of the constituents we evaluated did not vary

significantly (i.e., less that a factor of 2), even with larger

differences in Koc. Thus, the use of surrogates did not

introduce any appreciable uncertainty into the final results. See

Appendix C of the Risk Assessment Background Document for details of

the designation of constituent categories and identification of

surrogate compounds.

We used the EPACMPT model to conduct the sensitivity analysis,

deterministic analysis, and Monte Carlo analysis for the groundwater

pathway. The groundwater pathway modeling yields the groundwater

exposure concentrations resulting from the release of waste

constituents from the landfill. Precipitation that percolates through

the waste unit generates leachate, which can infiltrate from the bottom

of the landfill into the subsurface. The waste constituents dissolved

in the leachate (as predicted by the partitioning model) are then

transported via aqueous phase migration through the vadose zone to the

underlying saturated zone and then down gradient to a ground water

receptor well. We project the concentration at the intake point of a

hypothetical groundwater drinking water well or receptor well, located

at a specified distance from the down gradient edge of the waste

management unit.

We located the residential wells down gradient from the landfill

and within the top ten meters of a plume of groundwater contaminated by

the leachate from the municipal landfill. As noted previously, we used

distances of receptor wells from waste management units from EPA's

National Survey of Municipal Landfills. The distance from the landfill

to the receptor well, and the location of the well in relation to the

plume of contaminated groundwater, are important parameters in the

groundwater model. This is because the projected concentrations of

constituents at the well, and the corresponding risks, increase as the

well location is moved closer to the source within the plume.

For the Monte Carlo analysis, we placed the receptor well

downgradient from the waste management unit at a radial distance of up

to 1,610 m; the distance for each simulation was taken from the

distribution of distances gathered by EPA in its survey noted above. We

assumed the lateral location of the well to be randomly distributed

within the estimated lateral extent of the plume. For the deterministic

analysis, the downgradient receptor well location was fixed within the

lateral extent of the plume (most often at the high end value of 102

meters from the landfill).

The objective of this ground-water modeling was to compute the

amount of dilution and attenuation a contaminant may undergo as it

migrates from a landfill to a ground-water well. The amount of dilution

and attenuation is expressed as a dilution/attenuation factor (DAF),

which represents the ratio of the initial leachate concentration

leaving the landfill to the ground-water receptor well concentration.

The high-end DAFs for the different constituents did not vary much for

the two wastes, i.e., the DAFs were in the range of 3 to 5.

The groundwater model accounts for the following processes

affecting contaminant fate and transport: advection, hydrodynamic

dispersion, linear or nonlinear equilibrium sorption, chained first-

order decay reactions, and dilution from recharge in the saturated

zone. EPACMTP was run in both deterministic mode and Monte Carlo mode.

In the deterministic mode, we set the two most sensitive variables to

their high end values, while keeping all other parameters set at

central tendency. In the probabilistic Monte Carlo mode, the model

randomly selected parameter values from their respective statistical

distributions. The Monte Carlo procedure allows assessment of the

uncertainty associated with ground-water well concentrations that

result from uncertainty and variability in climatic and hydrogeologic

characteristics of waste management units across the range of locations

associated with the Dyes and Pigments industry.

F. What Exposure Assumptions and Toxicity Levels Did EPA Use?

We used values from EPA's Exposure Factors Handbook (EPA, 1997) to

set the exposure assumptions for this analysis. We applied the

recommended values for the central tendency and high end intake rates

in the deterministic analysis, and we used a distribution of values

developed from the data presented in the Exposure Factors Handbook in

the Monte Carlo analysis. Section 6.0 of the Risk Assessment Background

Document discusses these values in detail.

The health benchmark data used in the analysis are based upon the

values presented in the Integrated Risk Information System (IRIS)

online database of verified health benchmarks or in the Health Effects

Assessment Summary Tables (HEAST) document. Appendix E of the Risk

Assessment Background Document contains toxicological profiles used in

our analysis. The studies used as the basis for these benchmarks have

been reviewed and summaries of these studies, along with references to

the complete studies, are presented in Appendix E of the Risk

Assessment Background Document.

G. What Uncertainties Are Associated With The Risk Assessment?

Uncertainty is inherent in the risk assessment process. It occurs

because the risk assessment process is complex, and variability is

inherent in the environment. We may classify the sources of uncertainty

as parameter uncertainty and variability, exposure

[[Page 40206]]

scenario uncertainty, and model uncertainty. Parameter uncertainty

occurs when parameters appearing in equations cannot be measured

precisely and/or accurately. Variability refers to the normal

variations in physical and biological processes that we cannot reduce

with additional data. We have addressed variability in this risk

assessment by using a probabilistic analysis. Exposure scenario

uncertainty occurs because of the inability to measure exposure of

receptors to constituents of concern. Model uncertainty is associated

with all models used in risk assessment and occurs because computer

models require simplifications of reality, and thus exclude some

variables and interactions that influence fate and transport but cannot

be included in models due to complexity or lack of data. We discuss

each of these issues in detail in Section 8 of the Risk Assessment

Background Document.

One important area of uncertainty that we believe should be noted

is the uncertainty involving estimates of risks to children from

carcinogenic compounds. We used the same overall approach for

estimating cancer risks in both adults and children from the dye and

pigment waste streams evaluated. We modified the exposure factors for

children to account for differences between adult and child receptors

(e.g., body weight, exposure duration). However, we recognize that

significant uncertainties and unknowns exist regarding the estimation

of lifetime cancer risks in children. Methodologies for estimating

environmental threats to children's health are relatively new. They are

currently being debated within the scientific community, and will

continue to evolve. The analysis of cancer risks in children undertaken

for this assessment has not been externally peer reviewed.

H. What Risk Level Do the Concentration Levels Represent?

In calculating concentration limits for the two wastes, we assumed

the residential drinking water well concentration is equal to EPA

established protective or health-based level for each constituent for

the most sensitive receptor (adult or child). Protective concentrations

are those at which adverse health effects from any single constituent

present in contaminated drinking water and/or water used for bathing or

showering do not exceed a one in 100,000 (1 x 10-5)

individual lifetime cancer risk or a non-cancer hazard quotient of 1

(where the hazard quotient is the ratio of the concentration in the

water to the concentration at which no non-cancer effects are

expected). The use of these risk levels is consistent with the initial

cancer-risk and HQ ``levels of concern'' that we described in the

discussion on EPA's hazardous waste listing policy in the 1994 proposed

rule for dye pigment wastes (see 59 FR 66075). As noted previously, we

based the concentrations on the groundwater pathway, which is the

pathway of most concern for all constituents of concern for this

industry when disposed in municipal landfills. Section 5 of the Risk

Assessment Background Document provides the methodology we used to

derive risk limiting waste concentrations in greater detail.

I. What Are the Proposed Listing Levels?

Table III-3 presents the risk-based concentration levels for all

potential constituents of concern calculated for both spent Filter Aids

and TAM sludges based on our risk assessment. These levels represent

protective concentrations for constituents that may be present in the

wastes, and are based on the receptor that yielded the lowest allowable

waste concentration (i.e, adult or child). Using the partitioning model

described above, we calculated protective levels for constituents in

both the waste itself and for leachate that is released from the

landfill. We are proposing to set the concentration levels in the

listing at the levels calculated for the constituents in the two

wastes. If you generate either waste under consideration, your waste

concentrations would have to be below these levels, or else your waste

will be a listed hazardous waste. Therefore, under this proposal, you

would be assessing constituent concentrations in the waste itself.

1. Selection of Listing Levels in Wastes Versus Leachate

We considered using the landfill leachate levels in Table III-2

instead of the waste levels to define the listed waste. We could do

this if we require generators to evaluate their wastes using a test

designed to predict leaching from landfills. The Toxicity

Characteristic Leaching Procedure (TCLP) is one possible method

available. The Toxicity Characteristic (TC) regulation uses the TCLP to

decide whether wastes are hazardous under this characteristic (see 40

CFR 261.24). However, we decided not to use the TCLP approach for

several reasons. First, we did not perform TCLP analysis for these

constituents in any of the dye and pigment wastes examined. Thus, we

are uncertain how the method might perform for the wastes at issue. The

partitioning model also factors in the placement of the wastes into the

landfill and provides a leaching rate that reflects how the volumes of

wastes are assumed to be disposed over time. The TCLP approach is

appropriate for defining levels of concern under the TC for all wastes

on a nationwide basis, where we have no specific information on waste

quantities disposed. In today's proposed rule we have information on

the specific quantities of the two selected wastes in the dyes and

pigments industries. Finally, we believe that the analysis of the waste

itself is more straightforward to implement, and would not require

measuring levels in a derived leachate that are much lower than those

in the waste. Therefore, we chose to propose the concentration based

levels for the waste itself.

However, the TCLP does represent an actual measurement of leach

potential as opposed to a value generated by a model. Thus, the Agency

may still consider a final regulation based on the TCLP, depending on

comments received and additional information provided.

2. Selection of Probabilistic Versus Deterministic Modeling Results

The constituent concentrations in Table III-3 reflect the results

of the probabilistic modeling assessment. We chose to use the

probabilistic results, rather than rely on the deterministic results.

While the Agency has used the results of deterministic analyses for

past listing decisions, EPA has more recently used Monte Carlo analyses

for additional verification (see Petroleum Listing final rule, 63 FR

42110; August 6, 1998). As we have developed and refined the Monte

Carlo approach, we believe it provides some distinct advantages. As

noted earlier, when compared with alternative approaches for assessing

parameter uncertainty or variability, the probabilistic technique has

the advantages of general applicability and no inherent restrictions on

input distributions or input-output relationships.

An additional factor the Agency considered was the highly variable

nature of the data available. The constituents of concern, their

concentrations, and waste volumes can be highly variable across the

different industry processes, a factor which made the Agency reluctant

to rely on selected point estimates for its assessment. Also of

particular concern was the difficulty we found in choosing what set of

parameters would truly represent a ``high-end'' analysis for multiple

pathways, constituents, and locations. The issues associated with

choosing high-end parameters are discussed in the Risk Assessment

Background

[[Page 40207]]

Document, which presents the deterministic as well as the probabilistic

results.

The probabilistic simulations used in this proposed rulemaking

assessed the full distributions of critical input data (e.g., distance

to well, waste volumes, landfill area) to randomly generate receptor

well concentrations of key constituents for certain landfill

situations, and then combined the results from many runs to produce a

probability distribution of risks. We were then able to choose points

along the probability distribution of risk for comparison to the high-

end analysis. For example, a risk that corresponds to the 90th

percentile for a specific waste constituent in a landfill means that

the risk would be below this level in 90 percent of the runs.

The concentration levels in Table III-3 represent the probabilistic

modeling results at the 90th percentile. As discussed previously, we

are attempting to calculate estimates of exposure in the upper end of

the distribution (i.e., above the 90th percentile), while avoiding

estimates that are beyond the true distribution. (See Habicht memo,

1992.) The Agency's policies do not indicate that there is any

particular point on a Monte Carlo distribution that should be the point

at which the Agency regulates or does not regulate. This conceptual

range is not meant to precisely define the limits of this descriptor,

but should be used by the assessor as a target range for characterizing

``high-end risk.'' Therefore, a high-end estimate that falls within the

range (above the 90th percentile but still realistically on the

distribution) is a reasonable basis for a decision.

We believe that the 90th percentile levels calculated for the waste

concentrations in today's proposed rule are protective. For filter

aids, the high-end deterministic results gave concentrations that were

somewhat higher than the 90th percentile levels from the probabilistic

analysis (by a factor of 2-4 fold). Therefore, we believe that using

the 90th percentile values (as opposed to higher percentile values)

provides results that are more consistent with previous listing

determinations based on high-end deterministic assessments. For TAM

sludges, the 90th percentile probabilistic levels are also close to the

deterministic results, although for this waste the probabilistic levels

for most constituents are slightly above the deterministic values

(approximately two-fold). Thus, the 90th percentile results appear to

agree reasonably well overall with the deterministic results.

Furthermore, the probabilistic DAFs predicted for transport of landfill

leachate from the landfill to the receptor well were already quite low

at the 90th percentile (i.e., 2-5), also suggesting that the 90th

percentile is adequately protective.

We are soliciting comments on both the use of the probabilistic

modeling results, rather than the deterministic analyses, and also our

use of the 90th percentile risk level, rather than any other level. For

example, the 95th percentile probabilistic results yields

concentrations that are about two-fold lower. Details of the

deterministic modeling results, and levels calculated using other

percentiles from the probabilistic analysis, are given in the Risk

Assessment Background Document (Appendix F). We also seek comment on

the setting of the regulatory levels for the waste itself, rather than

the option of using the TCLP values.

Table III-3.--Calculated Risk-Based Concentration Levels for Possible Constituents of Concern for Dye and

Pigment Wastes\1\

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

Concentration levels for Concentration levels for TAM

filter aids ** sludges

Constituents ---------------------------------------------------------------

Leachate (mg/ Leachate (mg/

Waste (mg/kg) ml) Waste (mg/kg) ml)

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

Aniline......................................... .............. .............. 17 0.03

Benzaldehyde.................................... .............. .............. 5000 5.6

Benzene......................................... .............. .............. 370 0.11

Benzidine....................................... .............. .............. 0.027 0.000023

Chloroaniline, p-............................... .............. .............. 250 0.25

Chlorobenzene................................... .............. .............. 36 0.0036

Chloroform...................................... .............. .............. 100 0.042

Cresol, p-...................................... .............. .............. 330 0.33

Dichlorobenzene, 1,2-........................... .............. .............. 1100 0.043

Dimethoxybenzidine, 3,3'-....................... .............. .............. 520 0.38

Dimethylaniline, N,N-........................... .............. .............. 300 0.11

Diphenylamine................................... .............. .............. 27,000 1.1

N-Nitrosodiphenylamine.......................... .............. .............. 7,400 0.62

Diphenylhydrazine, 1,2-......................... .............. .............. 31 0.0042

Azobenzene...................................... .............. .............. 720 0.013

Formaldehyde.................................... .............. .............. 7000 11

Naphthalene..................................... .............. .............. 17 0.0028

Phenol.......................................... .............. .............. 28,000 34

Phenylenediamine, o-(2-aminoaniline)............ .............. .............. 61 0.11

Phenylenediamine, p-(4-aminoaniline)............ .............. .............. 5,000 10

Toluidine, o-(2-aminotoluene)................... .............. .............. 13 0.022

Toluidine, p-(4-aminotoluene)................... .............. .............. 23 0.029

Toluidine, 5-nitro-o-(2-Methyl-5-nitroaniline).. .............. .............. 220 0.15

(**)

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

\1\ Levels represent the 90th percentile risk derived from the probabilistic analysis.

** Relevant data are not included at the present time for a number of constituents due to business

confidentiality concerns.

[[Page 40208]]

IV. Proposed Listing Determinations and Regulations

A. What Are the Proposed Regulations for the Two Wastes?

We are proposing that, if you generate either of the two categories

of dye and pigment wastes at issue, you must either determine whether

or not your waste is a listed hazardous waste within a specified time,

or assume that it is hazardous as generated. Your waste would become a

listed hazardous waste if it contains any of the constituents of

concern at a concentration equal to or greater than the hazardous

concentration identified for that constituent. You must make a

determination that all of the constituents of concern in your waste are

below the hazardous concentrations to claim that your wastes remain

nonhazardous. We are proposing the following specific regulatory

language for the two wastes:

K167 Spent filter aids, diatomaceous earth, or adsorbents used

in the production of azo, anthraquinone, or triarylmethane dyes,

pigments, or FD&C colorants, unless these wastes do not contain any

of the constituents identified in Sec. 261.32(b)(3)(iii) at a

concentration equal to or greater than the hazardous level set for

that constituent as demonstrated by the procedures specified in

Sec. 261.32(b).

K168 Wastewater treatment sludges from the production of

triarylmethane dyes and pigments (excluding triarylmethane pigments

using aniline as a feedstock), unless these wastes do not contain

any of the constituents identified in Sec. 261.32(b)(3)(iii) at a

concentration equal to or greater than the hazardous level set for

that constituent as demonstrated by the procedures specified in

Sec. 261.32(b).

The constituents and levels in these listing descriptions would be

those given in Tables IV-1 for Filter Aids and Table IV-2 for TAM

sludges. Section V describes the steps you must follow to implement the

concentration-based listing.

We solicit comment on the proposed list of constituents and their

levels. Specifically, based on the rather high levels set for some

constituents (e.g., diphenylamine, formaldehyde for TAM sludges), EPA

is considering removing these. These levels may be unlikely in these

wastes, and may not merit analysis. We seek any information that may

assist us in deciding on whether we should retain all of these

constituents. We also solicit comment as to whether any other

constituents (e.g., any others in Table III-3) should be added to the

regulatory lists in Tables IV-1 or IV-2.

Table IV-1.--Concentration Levels for Spent Filter Aids

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

Concentration

Constituents levels (mg/

kg)**

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

Aniline

Benzaldehyde

Chloroaniline, p-

Cresol, p-

Dimethylaniline, N,N-

Dimethoxybenzidine, 3,3'-

Diphenylamine

Diphenylhydrazine, 1,2-

Formaldehyde

Naphthalene

Phenol

Phenylenediamine, p-

Toluidine, o-

Toluidine, p-

(**)

(**)

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

** Relevant data are not included at the present time due to business

confidentiality concerns.

Table IV-2.--Concentration Levels for TAM Sludges

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

Concentration

Constituent levels (mg/

kg)

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

Benzaldehyde............................................. 5000

Dimethylamine, N,N-...................................... 300

Diphenylamine............................................ 27,000

Formaldehyde............................................. 7000

Toluidine, o-............................................ 13

Toluidine, p-............................................ 23

(**) (** )

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

**Relevant data are not included at the present time due to business

confidentiality concerns.

As required under Sec. 261.30(b), we are adding those constituents

that are the bases for listings to Appendix VII of Part 261, ``Basis

for Listing Hazardous Waste.'' Thus, we are proposing to add the

constituents in Table IV-1 for K167 (filter aids), and the constituents

in Table IV-2 for K168 (TAM sludges) to Appendix VII. In addition,

several constituents in Tables IV-1 and IV-2 are not currently listed

on Appendix VIII to Part 261, ``Hazardous Constituents.'' EPA places

constituents on Appendix VIII if they have been shown in scientific

studies to have toxic, carcinogenic, mutagenic, or teratogenic effects

on humans or other life forms (see 261.11(a)(3)). The Risk Assessment

Background Document contains the detailed toxicological data for all

constituents we evaluated, including the specific chemicals that we are

proposing to add to Appendix VIII in today's rule: benzaldehyde, N,N-

dimethylaniline, p-cresol, and p-phenylenediamine, and another

chemical, the identity of which is not given due to business

confidentiality concerns. While cresol and phenylenediamine are

currently listed on Appendix VIII, the precise isomers are not

specified. Therefore, we are proposing to add these specific isomers.

If, in response to comment, we decide to add any additional

constituents to the chemicals of concern in either concentration-based

listing, then we would also add those constituents to Appendix VII, and

to Appendix VIII, if necessary.

In proposing to promulgate a concentration-based listing for filter

aids and TAM sludges under 40 CFR 261.11(a)(3), we considered the

factors given under 40 CFR 261.11(a)(3) and believe that these wastes

pose a substantial present or potential hazard to human health or the

environment at the proposed listing levels. We considered nearly all of

these factors as part of the risk assessment described in today's rule.

Specifically, we considered the constituents' toxicity/concentration,

mobility, persistence, and bioaccumulation potential in setting the

concentration-based levels (corresponding to factors (I) through (vi)

given in Sec. 261.11(a)(3)). As described in the risk assessment

section, we considered municipal landfills as the ``plausible''

management practice (factor (vii)), and evaluated the waste quantities

generated by facilities (factor viii). Concerning factor (ix), we

examined damage cases for the dye and pigment industries for the 1994

proposed rule (see Risk Assessment Support for Dye and Pigment Listing

Determination, November 29 1994; document number S0333, EPA Docket No.

F-94-DPLP-FFFFF). However none of those cases provide any information

on the possible damages associated with the two wastes at issue in

today's proposal. Finally, we considered other regulatory programs

(factor (x)), when appropriate. No other regulatory program EPA

identified adequately addressed the risks posed by the wastes. However,

as noted in Section IV.C, we considered the protection afforded by the

Clean Water Act, and the regulations being considered for leachate from

landfills. As a result of this consideration, we are proposing to

temporarily defer any regulation of landfill leachate that may be

derived from the wastes proposed for listing, provided certain

conditions are met.

B. What Are We Proposing for Anthraquinone Sludges?

We are proposing not to list wastewater treatment sludges from the

production of anthraquinone dyes and pigments. As described earlier in

this notice, the only constituents that were

[[Page 40209]]

found in wastes that could be attributed to anthraquinone production (

the identities are not given due to business confidentiality concerns)

do not have health-based benchmarks. We did not receive any data in

comments on the 1994 proposed rule that would allow us to estimate such

benchmarks.

Discussion of the details of waste generation and management for

this waste cannot be released at this time due to business

confidentiality concerns.

Therefore, we are proposing not to list anthraquinone sludges

because we cannot identify any health threat from these wastes. Further

discussion on the generation of this waste cannot be released at this

time due to CBI constraints. We do not find any demonstrated risk from

the constituents that we can attribute to anthraquinone production. We

seek comment on this decision not to list this waste.

C. What Is the Status of Landfill Leachate From Previously Disposed

Wastes?

Leachate derived from the treatment, storage, or disposal of listed

hazardous wastes is classified as a hazardous waste by virtue of the

``derived-from'' rule in 40 CFR 261.3(c)(2). The Agency has been clear

in the past that hazardous waste listings apply to wastes disposed of

prior to the effective date of a listing, even if the landfill ceases

disposal of the waste when the waste becomes hazardous (see 53 FR

31147; August 17, 1988). We also have a well-established interpretation

that listings likewise apply to leachate derived from the disposal of

listed hazardous wastes, including leachate derived from wastes

disposed before a listing effective date which meet the listing

description. We are not reopening any of these issues by the present

notice.

Of course, as set out in detail in the August 1988 notice, this

does not mean that landfills holding wastes which are subsequently

listed as hazardous become subject to Subtitle C regulation. However,

previously disposed wastes now meeting a listing description, including

residues such as leachate which are derived from such wastes, which are

``actively managed'' do become subject to Subtitle C regulation (id.).

In many, indeed most circumstances, active management of leachate would

be exempt from Subtitle C regulation because the usual management

practice is discharge either to POTWs via the sewer system, where

leachate mixes with domestic sewage and is excluded from RCRA

jurisdiction (see RCRA Section 1004(27) and 40 CFR 261.4(a)(1)), or to

navigable waters, also excluded from RCRA jurisdiction (see RCRA

Section 1004(27) and 40 CFR 261.4(a)(2)). In addition, management of

leachate in wastewater treatment tanks prior to discharge under the CWA

is also exempt from RCRA regulation (40 CFR 264.1(g)(6)).

However, we believe, because the proposed listings for the two

categories of dye and pigment wastes (K167-K168) are concentration-

based listings, it would be difficult to know whether the previously

disposed wastes that meet the narrative description of K167-K168 are in

fact K167-K168 hazardous wastes that exceed the listing levels. We

don't anticipate that records documenting the concentrations of

proposed constituents of concern for these wastes exist for previously

disposed wastes. Therefore, absent a finding that the wastes, when

disposed, would have met the listing being proposed today, the

previously disposed wastes (including landfill leachate and gas

condensate derived from these wastes that are actively managed) could

not be classified as K167-K168.

However, if actively managed landfill leachate and gas condensate

derived from the two categories of dye and pigment wastes proposed to

be listed in today's rule could be classified as K167-K168, we are

concerned about the potential disruption in current leachate management

that could occur and the possibility for redundant regulation.

Recently, this issue was raised to the Agency in the context of the

petroleum refinery waste listings (see 63 FR 42173; August 6, 1998). A

commenter expressed concern that, because some of their nonhazardous

waste landfills received petroleum wastes which are now listed, the

leachate that is collected and managed from these landfills would be

classified as hazardous. The commenter argued that this could lead to

increased treatment and disposal costs without necessarily any

environmental benefit. After examining and seeking comment on this

issue, we published a final rule that temporarily defers regulation of

landfill leachate and gas condensate derived from certain listed

petroleum refining wastes (K169-K172) that were disposed before, but

not after, the new listings became effective, provided certain

conditions are met (see 64 FR 6806; February 11, 1999).

At the time this issue was brought to the Agency's attention in the

context of the petroleum refinery waste listings, EPA's Office of Water

had recently proposed national effluent limitations guidelines and

pretreatment standards for wastewater discharges--most notably,

leachate--from certain types of landfills (see 63 FR 6426; February 6,

1998). In support of this proposal, EPA conducted a study of the volume

and chemical composition of wastewaters generated by both Subtitle C

(hazardous waste) and Subtitle D (nonhazardous waste) landfills,

including treatment technologies and management practices currently in

use. EPA proposed effluent limitations (for nine pollutants in the

Nonhazardous Subcategory) for direct dischargers (see 63 FR 6463). Most

pertinent to finalizing the temporary deferral for the petroleum

refining wastes, EPA did not propose pretreatment standards for

Subtitle D landfill wastewaters sent to POTWs because the Agency's

information indicated that such standards were not required.

The conditions included in the temporary deferral published on

February 11, 1999 are that the leachate is subject to regulation under

the Clean Water Act, and the leachate is not stored in surface

impoundments after February 13, 2001. See 40 CFR 261.4(b)(15). We

believed that it was appropriate to temporarily defer the application

of the new waste codes to such leachate in order to avoid disruption of

ongoing leachate management activities while the Agency decides how to

integrate the RCRA and CWA regulations consistent with RCRA section

1006(b)(1). As discussed above, we do not anticipate that this

situation is likely to occur because the nature of the concentration-

based listing makes it difficult to determine whether the wastes

previously disposed met the concentrations at the time of disposal.

However, to the extent previously disposed of dye and pigment wastes

could be determined to meet the listing description and levels, we

believe that the same rationale fully discussed in the February 11,

1999 rulemaking applies in this situation as well. As such, we would be

concerned about forcing pretreatment of leachate even though

pretreatment is neither required by the CWA nor needed. Therefore, we

are proposing to temporarily defer landfill leachate and gas condensate

derived from the two categories of dye and pigment wastes, with the

same conditions as described in 40 CFR 261.4(b)(15) for petroleum

wastes. We believe the issue of whether disruptions can be minimized

through integration of CWA and RCRA rules will be more amenable to

resolution once the CWA rulemaking is completed.

We request any available information on whether or not the two

categories of dye and pigment wastes previously disposed in

nonhazardous landfills contained constituents of concern identified for

these wastes at

[[Page 40210]]

concentrations equal to or greater than the proposed listing levels.

Even if we don't receive any information that previously disposed dye

and pigment wastes will result in generation of hazardous landfill

leachate and gas condensate, we nonetheless intend to finalize the

temporary deferral for landfill leachate and gas condensate from these

wastes. This is because someone may discover this problem later (after

the effective date of the listing), so, by having a temporary deferral

in place, it would be possible to avoid disruption of ongoing leachate

management activities while we further examine this issue and await the

CWA final rule.

V. Generator Requirements for Implementation of Concentration-Based

Listings

We are proposing that the concentration-based listings be self-

implementing. This requires that you (the waste generator) meet the

necessary conditions to determine whether or not your waste is

hazardous based on the procedures we describe below. We have identified

the constituents of concern for the two categories of dye and pigment

wastes in Tables IV-1 and IV-2. We have also identified the listing

level for each of these constituents in the same tables. We are

proposing that you use this information, in conjunction with waste

analysis results, to determine if your waste is a listed hazardous

waste.

Unless you make a determination that your waste is nonhazardous

using the specified procedures, you are subject to the existing

requirements under RCRA for persons who generate hazardous waste. Thus,

if you are not already a hazardous waste generator, you must notify the

EPA, according to section 3010 of RCRA, that you generate a hazardous

waste. You are also subject to all applicable requirements for

hazardous waste generators in 40 CFR 262.

If you determine that your waste is nonhazardous, we are proposing

to require, under the authority of sections 2002 and 3007 of RCRA, that

you keep certain records of your waste and submit a notification and

certification to the EPA claiming you have a nonhazardous waste.

Following a nonhazardous claim, you would have a continuing obligation

to ensure that your waste meets all of the proposed conditions and

requirements for the waste to be deemed nonhazardous.

A. Do I Have to Determine Whether or Not My Waste Is Hazardous?

If you want to assume that your waste is hazardous as-generated or

you don't want to analyze it to make a hazardous waste determination,

you may do that. In such a case, we are proposing your waste would be

considered hazardous as-generated and subject to all applicable RCRA

Subtitle C hazardous waste requirements, effective as of the effective

date of the final rule or initial generation of the waste. However, if

you want your waste to be nonhazardous as-generated, you must perform

the waste analysis steps in V.C and determine your waste to be

nonhazardous. If your waste is determined to be nonhazardous and

claimed to be nonhazardous within 60 days (see V.D) following the

effective date of the final rule or initial generation of the waste, we

are proposing that none of the waste generated following the effective

date of the rule or initial generation is hazardous as-generated.

If you elect not to make this determination by the 60th day, or

alternatively determine that your waste is hazardous, you may use the

same waste analysis procedures (see V.C) to make a nonhazardous

determination for your waste at anytime after the 60th day. If this

determination shows your waste as-generated is nonhazardous, it can be

claimed to be nonhazardous (see V.D). We are proposing that the

nonhazardous claim for waste as-generated, if submitted more than 60

days after the effective date of the rule or initial generation, would

only become effective on the date when you receive a written receipt or

confirmation that your notification and certification has been

delivered to the EPA. After you have received this receipt or

confirmation, any waste generated on or after the generation date of

the waste that was analyzed for the nonhazardous determination may be

claimed a nonhazardous waste that is not subject to Subtitle C,

including LDR requirements. Any waste generated prior to that

generation date remains hazardous.

We request comment on whether the 60 day time limit for making a

hazardous or nonhazardous waste listing determination and nonhazardous

waste claim should be longer (e.g., 90 days) to allow adequate time for

sampling and analyses.

B. How Do I Manage My Waste During the Period Between the Effective

Date of the Final Rule and Initial Hazardous Waste Determination for My

Waste?

You cannot dispose of your waste as nonhazardous until you complete

an initial determination to show that your waste is nonhazardous.

Because the potential hazard from your waste is due to its placement on

land, we are proposing that, as a condition of the waste being

nonhazardous, you must store your waste in containers, or in another

manner that does not involve land placement.

Because the interim storage period for the waste prior to a

hazardous waste determination is relatively short (60 days), we request

comment on whether it is necessary to impose such a condition. Given

that the generator would be subject to enforcement for improper storage

if the waste turns out to be hazardous, generators may have adequate

incentives to store the waste in compliance with Subtitle C

requirements during the interim period.

Alternatively, we could condition the waste being nonhazardous on

the generator's storing the waste in accordance with the requirements

described in 40 CFR 262.34. This would be an appropriate precaution in

case the waste turns out to be hazardous. We also request comment on

this approach.

C. What Are the Steps I Must Follow To Determine Whether or Not My

Waste Is Hazardous?

We are proposing the following waste analysis steps for making a

determination that your waste is nonhazardous as-generated:

1. You must collect a minimum of four representative samples of

your waste and analyze each for the constituents of concern identified

in Tables IV-1 or IV-2. These samples must be adequate to determine the

maximum levels of constituents that may be in your waste. Instead of

analyzing for a constituent, you may also apply process knowledge

(knowledge of the constituents in your waste based on the materials,

degradation products, and manufacturing processes used) to document

that a constituent could not be present in the waste. You should note,

however, that process knowledge cannot be used to determine a level of

constituent in your waste.

2. Compare the sampling and analyses results or process knowledge

information (documentation that a constituent could not be present in

the waste) for the constituents of concern in your waste to the

hazardous

[[Page 40211]]

concentration levels set for these constituents.

3. If none of your waste samples contain any of the constituents of

concern at concentrations equal to or greater than the hazardous

concentration levels set for these constituents, you can determine that

your waste is nonhazardous. However, if any of your waste samples

contains any of the constituents of concern at a concentration equal to

or greater than the hazardous concentration level set for that

constituent, your waste is a listed hazardous waste and subject to all

applicable RCRA Subtitle C hazardous waste requirements.

We would consider requiring less than four representative samples

of the waste for the initial hazardous waste determination if this

could be supported. We request comment on whether generators can

reliably determine the maximum concentration of constituents in the

waste with less than four samples. We also request comment on whether

the generators should be allowed to use process knowledge information,

in lieu of testing, to support claims that constituents of concern

could not be present in their wastes. Alternatively, we could require

testing for all constituents of concern in the initial testing.

We are proposing that the maximum concentration of any constituent

detected in any sample must be below the established listing level in

order for you to determine that the waste is nonhazardous. We are

proposing this approach because we believe it is the most protective,

and because it does not rely on any statistical manipulation of waste

analysis data to determine constituent concentrations in the waste.

However, we request comment on whether the generator should be allowed

to average constituent levels in multiple waste samples. Under that

approach, the generator would calculate concentrations using an upper

confidence limit on the mean (e.g., 95th percent) and compare this

limit to the listing levels established for the constituents.

D. What Are the Requirements for a Waste Determined To Be Nonhazardous,

and How Do I Claim My Waste To Be Nonhazardous?

We are proposing that after you have determined your waste is

nonhazardous, but prior to disposing the waste as nonhazardous, you

must claim your waste to be nonhazardous as follows:

1. You must submit a one-time notification to the EPA. The

notification must include the facility name, address, and telephone

number of an authorized representative, description of the waste and

potential waste code, and an estimate of the average annual volume of

waste claimed to be nonhazardous. The notification must also include a

certification that none of your waste samples contain any of the

constituents of concern identified for your waste at concentrations

equal to or greater than the hazardous concentration levels set for

these constituents, and these levels were determined without dilution

of the waste. By dilution, we mean addition of other waste or media to

your waste after generation, which do not meet the narrative listing

description for your waste, in order to reduce the concentration of the

constituents of concern in your waste to below listing levels.

2. The notification and certification must be sent by certified

mail return receipt, or by written confirmation of delivery from a

commercial delivery service.

3. The certification must be signed by a responsible corporate

official and must state as follows: ``I certify under penalty of law

that none of the waste samples contain any of the constituents of

concern identified for this waste at concentrations equal to or greater

than the hazardous concentration levels set for these constituents, and

that these levels were determined without dilution of the waste. Based

on information and belief formed after reasonable inquiry, the

statements and information in the document are true, accurate, and

complete. I am aware that there are significant penalties for

submitting a false certification, including the possibility of fine and

imprisonment.''

We are proposing to require the notification and certification

under the authority of Sections 2002 and 3007 of RCRA. The notification

and certification will provide confirmation that certain wastes that

meet the narrative description for the two categories of dye and

pigment wastes are not RCRA hazardous wastes. We are not proposing to

require submission of waste analysis data to the EPA for review or

approval. Instead, we propose to require, also under the authority of

sections 2002 and 3007 of RCRA, that certain records be kept on-site

(see below). We request comment on whether generators should be

required to submit waste analyses data along with the notification.

E. What Records am I Required To Keep On-Site To Support a Nonhazardous

Claim for My Waste?

We are proposing that you must, at a minimum, keep the following

information on-site:

1. A copy of the notification and certification sent to the EPA and

documentation that it was received.

2. The sampling and analysis plan used for collecting and analyzing

representative samples of your waste.

3. The initial sampling and analyses data and process knowledge

information (if used) that support a nonhazardous claim for your waste.

4. All follow-up sampling and analyses data and process knowledge

information (if used) for the most recent three years.

F. What Happens if I Do Not Meet the Notification and Recordkeeping

Requirements for a Waste That I Have Determined To Be Nonhazardous?

We are requiring notification and recordkeeping under the authority

of sections 2002 and 3007 of RCRA. These provisions are requirements,

not conditions of the waste being nonhazardous. Failure to comply with

these requirements may result in an enforcement action under Section

3008 of RCRA. This section of the statute permits the imposition of

civil penalties in an amount up to $27,500 for each day of

noncompliance.

G. What Are the Follow-Up Waste Analysis Requirements for My

Nonhazardous Waste?

You must analyze a minimum of one representative sample of the

nonhazardous waste every calendar year it is generated. You must also

analyze a minimum of one representative sample of the nonhazardous

waste anytime, after the initial waste analysis, there is a process

change that may increase the concentrations of hazardous constituents

of concern in the waste. If process change has not occurred, you may

use the results of the initial waste analysis to create a more tailored

list of the constituents of concern in your waste and test just for

those constituents. If your waste is in fact hazardous (i.e., if it

contains any constituent of concern at or above the regulatory level),

you are liable for compliance with Subtitle C requirements.

We request comment on whether a minimum of four representative

samples should be required for follow-up waste analysis and whether

follow-up waste analysis required every calendar year should be

terminated after three consecutive years of verification that the waste

remains nonhazardous. This would be based on the waste generator

performing the required follow-up analysis on the waste and finding

that none of the waste samples contain any of the constituents of

concern at

[[Page 40212]]

concentrations at or above the hazardous concentration levels set for

these constituents for three consecutive years.

H. What Happens if My Waste Constituent Concentration Are No Longer

Below the Listing Concentrations?

If follow-up waste analysis (or any analysis of your waste after

the initial waste analysis) finds your waste contains one or more

constituents of concern at concentrations at or above their hazardous

concentrations, your waste is a listed hazardous waste and subject to

all applicable RCRA Subtitle C hazardous waste requirements. To claim

the waste nonhazardous again, you must repeat the initial waste

analysis and show that none of the waste samples contain any of the

constituents of concern at or above their hazardous concentrations. You

must also submit a new notification and certification for your waste.

I. Can I Treat My Waste to Below Listing Concentrations and Then Claim

My Waste To Be Nonhazardous?

If your waste is hazardous as-generated, you can treat the waste to

make it nonhazardous. However, if your waste is hazardous as-generated,

it is subject to all applicable RCRA Subtitle C hazardous waste

requirements and would be required to be treated in any case to meet

the proposed LDR treatment standards before any placement in a land-

based unit. Under the proposed LDR treatment standards (see Section

VI), the wastes must be treated using specified technologies

(``technology standards''). We believe that compliance with LDR

treatment standards is likely to result in nonhazardous concentrations

of constituents in the waste. However, based on the mixture and

derived-from rules, the treated waste would still carry the hazardous

waste code. Therefore, you may choose to use the initial waste

determination procedures for waste as-generated (see V.C above) to

determine if your treated waste is nonhazardous. If your treated waste

is determined to be nonhazardous and you want to claim it as

nonhazardous, you must follow the same procedures as those required to

claim ``as-generated'' waste nonhazardous (see V.D above). We are

proposing that the non-hazardous claims for treated waste would only

become effective on the date when you receive a written receipt or

confirmation that your notification and certification has been

delivered to the EPA. Thus, prior to the effective date, your waste

still remains a listed hazardous waste and must meet all applicable

RCRA Subtitle C hazardous waste requirements.

J. Alternative Implementation Approach

As an alternative to the implementation approach proposed in

today's rule, we may adopt a more streamlined approach for waste

generators to use in self-implementing the concentration-based listings

for these wastes. Under a streamlined approach, we would not require

the waste generator to perform sampling and analysis procedures as

conditions to determine that its waste (which meets the narrative

description of K167 or K168) is nonhazardous. We would also not have

notification and recordkeeping requirements for a waste determined to

be nonhazardous. However, the levels for the constituents of concern in

the waste would have to be below the listing levels, if the waste

generated after the effective date of the rule is to be handled as

nonhazardous waste. Therefore, after the effective date of the rule, if

the waste is in fact hazardous (i.e., if it contains any constituent of

concern at or above the regulatory level), the waste would be subject

to Subtitle C requirements. We may also adopt an approach somewhere in

the middle that includes some minimal waste characterization

requirements.

The streamlined implementation approach discussed above for the

concentration-based listings would be similar to the existing program

for determining whether a waste exhibits a hazardous characteristic. At

this time, EPA believes the approach presented earlier in today's

proposal (see V. A-I) is the more appropriate approach for this listing

since, in contrast to the situation with characteristic wastes, we have

performed analyses specific to this industry and have determined that

the constituents of concern are likely to be present in the industry's

waste. However, we will give careful consideration to any arguments

presented or relevant waste analysis data submitted in response to

today's proposal (e.g., data showing that only a small portion of the

wastestreams in the industry exceed the listing levels) in order to

decide whether a more streamlined approach is warranted. We request

comment on possibly allowing the waste generators to use a more

streamlined approach for self-implementing the concentration-based

listings proposed in today's rule.

VI. Proposed Treatment Standards Under RCRA's Land Disposal

Restrictions

A. What Are EPA's Land Disposal Restrictions (LDRs)?

The statute requires EPA to establish treatment standards for all

hazardous wastes that are land disposed. These are the so called ``land

disposal restrictions'' or LDRs. For any hazardous waste identified or

listed after November 8, 1984, EPA must promulgate these LDR treatment

standards within six months of the date of identification or final

listing (RCRA Section 3004(g)(4), 42 U.S.C. 6924(g)(4)). The statute

also requires EPA to set as these treatment standards ``* * * levels or

methods of treatment, if any, which substantially diminish the toxicity

of the waste or substantially reduce the likelihood of migration of

hazardous constituents from the waste so that short-term and long-term

threats to human health and the environment are minimized.'' (RCRA

Section 3004(m)(1), 42 U.S.C. 6924(m)(1)).

Wastes that meet treatment standards established by EPA may be land

disposed. Wastes that do not meet these standards are prohibited from

land disposal (except in units meeting a stringent no-migration test).

Each waste proposed for listing as hazardous in this rule will be

subject to all the land disposal restrictions on the same day their

respective listing becomes effective.

B. How Does EPA Develop LDR Treatment Standards?

To establish LDR treatment standards, EPA first identifies the best

demonstrated available technology (BDAT) for the hazardous constituents

present in the hazardous waste, and then determines what constituent

concentrations can be achieved by the technology or technologies

identified as BDAT.

EPA typically has established treatment standards based on

performance data from the treatment of the waste at issue, if such data

are available, and also from the treatment of wastes with similar

chemical and physical characteristics or similar concentrations of

hazardous constituents. Treatment standards typically cover both

wastewater and nonwastewater waste forms on a constituent-specific

basis. The constituents selected for regulation under the LDR program

are not necessarily limited to those present in a proposed listing ,

but also may include those constituents or parameters that will ensure

that treatment technologies

[[Page 40213]]

are operated properly. For listed waste EPA identifies these as

``regulated constituents'' and they appear individually in the Table at

40 CFR 268.40, along with their respective treatment standards.

EPA may either designate a method of treatment as the treatment

standard or develop a numerical treatment standard, which could be

satisfied by use of any treatment technology (that doesn't entail

impermissible dilution). On the other hand, if the treatment standard

is a designated method, that is the only permissible means of treating

the waste.

After developing the LDR treatment standards, we must also

determine if treatment capacity is available to treat the expected

volumes of wastes. If so, the LDR treatment standards become effective

essentially at the same time a listing does. If not, EPA may grant up

to a two-year national capacity variance (NCV) during which time the

LDR treatment standards are not effective.

For a more detailed overview of the Agency's approach for

developing treatment standards for hazardous wastes, see the final rule

on solvents and dioxins (51 FR 40572, November 7, 1986) and section

III.A.1 of the preamble to the final rule that set land disposal

restrictions for the ``Third Third'' wastes (55 FR 22535, June 1,

1990). EPA also has explained its BDAT procedures in ``Best

Demonstrated Available Technology (BDAT) Background Document for

Quality Assurance/Quality Control Procedures and Methodology (EPA/OSW,

October 23, 1991)''. This document is available in the docket

supporting this proposed rulemaking.

C. What Treatment Standards Are Proposed?

The Agency has previously promulgated technology-specific

standards--i.e., in the words of the statute, ``methods of

treatment''--for the following K167 core constituents of concern: 3,3'-

dimethoxybenzidine (U091), 1,2-diphenylhydrazine (U099), formaldehyde

(U121), o-toluidine (U328), p-toluidine (U353), and other chemical(s),

the identities of which are not included due to business

confidentiality concerns. We also promulgated technology-specific

standards for K168 core constituents of concern: formaldehyde, o-

toluidine, and p-toluidine. Analytical complications formed the basis

of the Agency's decision to promulgate technology-based BDAT treatment

standards (see 55 FR 22611, June 1, 1990).

These pre-existing technology-specific standards provide the

starting point for our analysis. We also assessed the potential of

developing numerical standards for these and the other constituents of

concern in K167 and K168. We found that numerical treatment standards

based on performance of BDAT (combustion) would nonetheless potentially

result in situations where threats to human health and the environment

are not minimized, as required by section 3004(m). This seeming anomaly

is explained by the fact that numerical treatment standards based on

performance of combustion consist of an analytical detection limit

times a variability factor. In this instance, this numerical value

would be significantly above the risk-based model levels of concern

which justify the listing, largely due to high analytical detection

limits for some constituents. Thus, the numerical treatment standards

calculated in the accepted manner would arguably not meet the

``minimize threat'' language governing LDR treatment standards in RCRA

section 3004(m).1 As a result, we are not inclined to pursue

the use of numerical treatment standards for K167 and K168.

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\1\ This is not to say that the listing levels necessarily

represent ``minimize threat'' levels for these constituents. EPA is

pursuing these questions in the HWIR rulemaking. Our point here is

that t

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