Revising the National Ambient Air Quality Standard for Lead

Congressional research reportFeb 3, 2010

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Revising the National Ambient Air Quality

Standard for Lead

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February 3, 2010

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RL34479

CRS Report for Congress

Prepared for Members and Committees of Congress

Revising the National Ambient Air Quality Standard for Lead

Summary

The Administrator of the Environmental Protection Agency (EPA), under a court order to review

the National Ambient Air Quality Standard (NAAQS) for lead, announced his decision October

16, 2008, reducing the standard by 90%, from 1.5 micrograms per cubic meter (µg/m3) to 0.15

µg/m3. EPA also promulgated new monitoring requirements at that time, requiring monitors

downwind of any source emitting one ton or more of lead per year and in urban areas with

populations of 500,000 or more. In January 2009, the Natural Resources Defense Council and

three other groups petitioned EPA for a reconsideration of the monitoring requirements. EPA

granted the petition and, in December 2009, proposed changes in the monitoring requirements,

notably lowering the source-oriented emissions threshold from one ton to 0.50 tons per year.

NAAQS are standards for outdoor (ambient) air that are intended to protect public health and

welfare from harmful concentrations of pollution. In strengthening the lead standard, the

Administrator has concluded that protecting public health and welfare requires much lower

concentrations of lead pollution in ambient air than the level previously held to be safe. Lead

particles can be inhaled or ingested, and, once in the body, can cause lower IQ and effects on

learning, memory, and behavior in children. In adults, lead exposure is linked to increased blood

pressure, cardiovascular disease, and decreased kidney function.

Regulation of airborne lead is often described as one of the key successes of the Clean Air Act

and of the Environmental Protection Agency. In 1970, when lead was widely used as a gasoline

additive, emissions of lead nationwide totaled 224,100 tons. Lead was also present then in many

consumer products, and thus was emitted to the air from industrial processes and waste

incinerators. The phasing out of lead from gasoline, paint, and other products, as well as stricter

controls on industrial emissions, reduced lead emissions more than 99%, to 1,300 tons in 2007.

The reduction in lead emissions and ambient concentrations led some to suggest that there was no

longer a need for an ambient air quality standard for lead. Others, including the Clean Air

Scientific Advisory Committee (CASAC), an independent panel of scientists who advise the EPA

Administrator, concluded that the old NAAQS (established in 1978) was far too lenient, that lead

in ambient air still poses a threat to public health, and that the NAAQS needed to be significantly

strengthened. CASAC recommended that the standard be reduced from 1.5 µg/m3 to no higher

than 0.2 µg/m3. In promulgating a more stringent NAAQS, the Administrator agreed with the

scientists’ recommendation, rejecting the argument that the standard is no longer needed.

The Administrator’s decision followed a multi-year review of the science. To implement the new

standard, EPA and the states will first identify nonattainment areas (expected to occur no later

than January 2012), following which there will be a 5-10 year-long implementation process in

which states and local governments will identify and implement measures to reduce lead in the

air. As noted earlier, EPA also promulgated changes to the monitoring requirements for lead as

part of the NAAQS decision. As of 2008, at least 24 of the 50 states, including some with major

sources of lead emissions, had no lead monitors at all. Under the 2008 regulations, all 101

metropolitan areas with populations greater than 500,000 would be required to have monitors as

would the estimated 135 areas that have sources of lead emissions greater than or equal to one ton

per year. In December 2009, EPA proposed further changes, lowering the source-oriented

emissions threshold from one ton to 0.50 tons per year, while eliminating the urban area

monitoring requirement. In place of the latter, lead monitoring would be added to a national

network of 80 sites that will monitor multiple pollutants.

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Revising the National Ambient Air Quality Standard for Lead

Contents

Introduction ................................................................................................................................1

The Role of NAAQS in Improving Air Quality............................................................................1

What Are NAAQS?.........................................................................................................1

Implementing a NAAQS .................................................................................................2

Other Pollution Control Measures ...................................................................................2

The NAAQS Review Process......................................................................................................2

Schedule for Review .......................................................................................................2

How the Process Works...................................................................................................3

Adding or Deleting NAAQS Pollutants ...........................................................................3

Lead Emission Reduction: Success, but Not Generally Due to NAAQS.......................................4

EPA’s 2008 Lead NAAQS...........................................................................................................5

The Primary Standard .....................................................................................................5

The Secondary Standard..................................................................................................6

Expanding the Lead Monitoring Network........................................................................8

Issues Raised by the NAAQS Review ....................................................................................... 11

Costs and Benefits of the New Standard .................................................................................... 12

Costs............................................................................................................................. 13

Benefits ........................................................................................................................ 13

Issues for Congress ................................................................................................................... 14

Figures

Figure 1. Counties with Monitors Violating the 2008 Lead Standard of 0.15 micrograms

per cubic meter (µg/m3)............................................................................................................7

Figure 2. Locations of Current Ambient Lead Monitors, Largest Stationary Sources of

Lead Emissions, and Metropolitan Areas with Populations of 500,000 or More .......................9

Contacts

Author Contact Information ...................................................................................................... 14

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Revising the National Ambient Air Quality Standard for Lead

Introduction

On October 16, 2008, EPA Administrator Stephen Johnson announced his final approval of a

more stringent National Ambient Air Quality Standard (NAAQS) for lead. The publication of the

revised standard in the Federal Register, on November 12, 2008, was the final step in a multiyear review process.1

When the previous standard for lead was promulgated in 1978, lead was a widespread air

pollutant. Eighty to ninety percent of it was emitted by the nation’s automobiles and trucks, a

majority of which ran on leaded gasoline. Leaded gasoline was gradually phased out in the 1970s,

1980s, and early 1990s, and both emissions and concentrations of lead in the air plummeted.

Emissions fell more than 98% from 1980 to 2007. Ambient concentrations (the quantity of lead in

the air) fell by 94%.2 As of March 12, 2008, only two areas with a combined population of 4,664

people had air that remained in violation of the 1978 lead NAAQS.3

These developments led some to suggest that there was no longer a need for an ambient air

quality standard for lead. Others, including the independent scientific advisory panel that advises

EPA’s Administrator, concluded that the 1978 NAAQS was far too lenient, that lead in ambient

air still poses a threat to public health, and that the NAAQS needed to be significantly

strengthened as the result of the recent review. In promulgating a new standard, the Administrator

agreed with his scientific advisers, lowering the standard to 90% below the 1978 standard and

setting new requirements for monitoring.

This report provides background on NAAQS, the process used to establish them, the factors

leading to the reduction in lead emissions, the proposed and final changes to the lead standard and

related monitoring requirements, as well as information regarding the potential effects of the

revision.

The Role of NAAQS in Improving Air Quality

What Are NAAQS?

NAAQS are standards that apply to ambient (outdoor) air pollutants that exhibit two

characteristics: (1) they may reasonably be anticipated to endanger public health or welfare; and

(2) their presence in the air results from numerous or diverse mobile or stationary sources. 4 The

73 Federal Register 66964, November 12, 2008. The review was the result of a consent decree in Missouri Coalition

for the Environment v. U.S. EPA, 2005 Westlaw 2234579 (E.D. Mo. September 14, 2005).

Historical data on lead emissions come from various years of EPA’s National Air Quality and Emission Trends

Reports (titles vary somewhat from year to year), which can generally be found at http://www.epa.gov/air/airtrends/

reports.html; 2007 emissions data and ambient concentrations are from U.S. EPA, Office of Air Quality Planning and

Standards, “October 2008 Final National Ambient Air Quality Standards for Lead, General Overview,” pp. 6 and 8, at

http://www.epa.gov/air/lead/pdfs/20081015presentation.pdf.

The two areas were East Helena, Montana, and Herculaneum, Missouri, both of which have been the site of lead

smelters. The East Helena smelter closed in 2001. The Herculaneum smelter continues to operate. For additional

information, see U.S. EPA, Greenbook, at http://www.epa.gov/oar/oaqps/greenbk/lindex.html.

Authority to establish NAAQS comes from both Sections 108 and 109 of the act (42 U.S.C. 7408 and 7409); this

definition of criteria pollutants is found in Section 108. The authority and procedures for controlling the sources of

(continued...)

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Revising the National Ambient Air Quality Standard for Lead

Clean Air Act provides for two types of NAAQS: primary standards, “the attainment and

maintenance of which in the judgment of the [EPA] Administrator ... are requisite to protect the

public health,” with “an adequate margin of safety”; and secondary standards, necessary to

protect public welfare, a broad term that includes damage to crops, vegetation, property, building

materials, etc. 5

NAAQS are at the core of the Clean Air Act, even though they do not directly regulate emissions.

In essence, they are standards that define what EPA considers to be clean air.

Implementing a NAAQS

Once a NAAQS has been set, EPA uses monitoring data and other information submitted by the

states to identify areas that exceed the standard and must, therefore, reduce pollutant

concentrations to achieve it. After these “nonattainment” areas are identified (which EPA

estimates will occur by January 2012 at the latest for the new lead standard), state and local

governments must produce State Implementation Plans outlining the measures they will

implement to reduce pollution levels and attain the standards. Lead nonattainment areas will have

five years after their designation to actually attain the standard, with a possible extension of five

more years.

As will be noted in more detail later, most areas of the country do not monitor lead concentrations

in ambient air. Thus, in addition to strengthening the lead standard, the Administrator expanded

the requirements for lead monitoring. Installing the additional monitors and compiling up to three

years of data to determine compliance is the main reason that implementing the new standard is

likely to be a lengthy process.

Other Pollution Control Measures

In addition to requiring states to submit implementation plans, EPA also acts to control many of

the NAAQS pollutants wherever they are emitted, through national standards for products that

might emit them (particularly fuels) and through emission standards for new stationary sources

(e.g., lead smelters).

The NAAQS Review Process

Schedule for Review

The Clean Air Act requires the agency to review each NAAQS every five years. That schedule is

rarely met, but it often triggers lawsuits that force the agency to undertake a review. In the case of

lead, the last review of the NAAQS was completed in 1978.6 The Missouri Coalition for the

(...continued)

criteria pollutants are found throughout Titles I, II, and IV of the act. Pollutants that are less widely emitted are

generally classified as “hazardous air pollutants” and are regulated under a different section of the act (Section 112).

The Clean Air Act’s definition of welfare is found in Section 302(h) of the act (42 U.S.C. 7602(h)).

43 Federal Register 46246, October 5, 1978.

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Revising the National Ambient Air Quality Standard for Lead

Environment and others filed suit against EPA over its failure to complete a review in 2004, and a

consent decree established the schedule EPA followed in reviewing the standard.7 The schedule

required EPA to propose any revision of the standard by May 1, 2008, and to promulgate a final

decision by October 15, 2008.

How the Process Works

Reviewing an existing NAAQS is a long process.8 As a first step, EPA scientists review the

scientific literature published since the last NAAQS revision, and summarize it in a report known

as a Criteria Document or Integrated Science Assessment. Generally, there are hundreds or

thousands of scientific documents reviewed, covering such subjects as environmental

concentrations, human exposure, toxicology, animal studies and animal-to-human extrapolation,

epidemiology, effects on vegetation and ecosystems, and effects on man-made materials. 9 A

second document that EPA prepares, the Staff Paper or Policy Assessment, summarizes the

information compiled in the Criteria Document and provides the Administrator with options

regarding the indicators, averaging times, statistical form, and numerical level (concentration) of

the NAAQS.

To ensure that these reviews meet the highest scientific standards, the 1977 amendments to the

Clean Air Act required the Administrator to appoint an independent Clean Air Scientific Advisory

Committee (CASAC). CASAC has seven members, largely from academia and from private

research institutions. In conducting NAAQS reviews, their expertise is supplemented by panels of

the nation’s leading experts on the health and environmental effects of the specific pollutant or

pollutants under review. These panels can be quite large. The 2005-2008 lead review panel had 15

members, in addition to the 7 statutory members of CASAC. CASAC and the public make

suggestions regarding the membership of the panels on specific pollutants, with the final

selections made by EPA. The panels review the agency’s work during NAAQS-setting and

NAAQS-revision, rather than conducting their own independent reviews.

Adding or Deleting NAAQS Pollutants

The pollutants to which NAAQS apply are generally referred to as “criteria” pollutants. Six

pollutants are currently identified as criteria pollutants: ozone, particulates, carbon monoxide,

sulfur dioxide, nitrogen oxides, and lead. The EPA Administrator can add to this list if she

determines that additional pollutants meet the act’s criteria (endangerment of public health or

welfare, and numerous or diverse sources); she can delete them if she concludes that they no

longer do so. Whether lead still met these criteria was one of the issues EPA considered in its

review of the standard.

As mentioned earlier, the schedule was set by the consent decree in Missouri Coalition for the Environment v. U.S.

EPA, 2005 Westlaw 2234579 (E.D. Mo. September 14, 2005).

For a discussion of the process, and of changes to the process that EPA is now implementing, see CRS Report

RL33807, Air Quality Standards and Sound Science: What Role for CASAC?, by (name redacted).

EPA indicates that more than 6,000 new studies on lead health effects, environmental effects, and lead in the air have

been published since 1990.

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Revising the National Ambient Air Quality Standard for Lead

Lead Emission Reduction: Success, but Not

Generally Due to NAAQS

The reduction of lead emissions is often described as one of the key successes of the Clean Air

Act and of the Environmental Protection Agency. In 1970, emissions of lead totaled 224,100 tons.

By 2007, emissions had been reduced more than 99%, to 1,300 tons.10

Little of that success is attributable to the setting of a NAAQS, however. The agency did not set a

NAAQS for lead until 1978 (by which time lead emissions had already declined about 40%), and

it established the NAAQS then only as a result of a lawsuit filed by the Natural Resources

Defense Council and others.11 After promulgating the NAAQS, the agency did not identify

nonattainment areas until 1991. The great bulk of the lead reductions “occurred prior to 1990,”

according to EPA.12 So, in general, the reduction of lead in ambient air did not come about as a

result of the 1978 NAAQS, or in the manner prescribed by Title I of the Clean Air Act, wherein

nonattainment areas are identified and the states or areas in which they are located submit to EPA

State Implementation Plans that identify local and national measures that will be implemented to

help such areas reach attainment.

Most of the reduction was a side-benefit of other Clean Air Act programs, especially the

regulation of emissions from new automobiles, beginning in the 1970s. In order to meet more

stringent requirements for emissions of hydrocarbons, nitrogen oxides, and carbon monoxide,

which took effect in 1975, the auto industry installed catalytic converters on new cars. Gasoline

with lead additives would have fouled the catalytic converters, rendering them useless; so, in

anticipation of the converters’ widespread adoption, EPA mandated the sale of unleaded fuel in

the early 1970s, and eventually banned the use of lead in gasoline entirely.

Being a metal, lead remains in the environment even though emissions have declined. Thus,

although human exposure to lead has declined, it has not done so by as much as the decrease in

emissions would suggest.13 Furthermore, research conducted since the 1970s suggests that lead

has significant health impacts at levels well below those previously considered safe.

Current sources of emissions include utility and other boilers, leaded fuel still used in some

general aviation airplanes, trace lead contaminants in diesel fuel and gasoline, lubricating oil, iron

and steel foundries, primary and secondary lead smelters, hazardous waste incinerators, and about

30 smaller categories of sources.14 In addition, there continues to be exposure from lead particles

U.S. EPA, National Air Quality and Emission Trends Reports, and October 2008 NAAQS General Overview, both

cited previously.

NRDC v. Train, 411 F. Supp. 864 (S.D.N.Y. 1976) aff’d., 545 F. 2d 320 (2d Cir. 1976). EPA was ordered to list lead

as a criteria pollutant and to develop NAAQS. The agency listed lead March 31, 1976, and on October 5, 1978,

established a NAAQS for lead.

U.S. EPA, Review of the National Ambient Air Quality Standard for Lead: Policy Assessment of Scientific and

Technical Information, OAQPS Staff Paper, November 2007, p. 2-5, at http://www.epa.gov/ttnnaaqs/standards/pb/data/

20071101_pb_staff.pdf.

The supporting documentation for the new standard states that the median concentration of lead in children’s blood

dropped 89%, from 15 micrograms per deciliter (µg/dL) in the late 1970s to 1.6 µg/dL in 2003-2004. See October 2008

NAAQS General Overview, previously cited, p. 7.

OAQPS Staff Paper, previously cited, Table 2-2, p. 2-7.

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Revising the National Ambient Air Quality Standard for Lead

in soil or dust re-suspended in the atmosphere as a result of vehicular traffic, construction,

agricultural operations, and the wind. 15

EPA’s 2008 Lead NAAQS

As a result of the review it completed in 2008, EPA decided to deal with the remaining issue of

lead in ambient air by both strengthening the lead NAAQS and by expanding the network of

monitors that are used to measure attainment.

The Primary Standard

The primary (health-based) standard, promulgated in 1978, was 1.5 micrograms per cubic meter

(µg/m3) averaged over three months. With the exception of two small areas (one in Montana, one

in Missouri), the United States has attained this standard, but the NAAQS review found evidence

of health effects at the levels of exposure currently experienced by much of the U.S. population.

The Staff Paper reported “significant associations between Pb [lead] exposures and a broad range

of health effects,” including, in children, neurological effects, notably intellectual attainment,

attention, and school performance, with “long-term consequences over a lifetime.”16 The Staff

Paper also reported effects on the immune system, with “increased risk for autoimmunity and

asthma.”17 In adults, the Staff Paper found associations between lead exposure and “increased risk

of adverse cardiovascular outcomes, including increased blood pressure and incidence of

hypertension, as well as cardiovascular mortality.”18 Lead exposure also was associated with

reduced kidney function, with adverse impacts enhanced in those with diabetes, hypertension, and

chronic renal insufficiency.

As a result, both EPA staff and the CASAC recommended strengthening the NAAQS. According

to the Staff Paper:

Staff concludes that it is appropriate for the Administrator to consider an appreciable

reduction in the level of the standard, reflecting our judgment that a standard appreciably

lower than the current standard could provide an appropriate degree of public health

protection and would likely result in important improvements in protecting the health of

sensitive groups. We recommend that consideration be given to a range of standard levels

from approximately 0.1-0.2 µg/m3 (particularly in conjunction with a monthly averaging

time) down to the lower levels included in the exposure and risk assessment, 0.02 to 0.05

µg/m3.19

CASAC concurred, stating in a January 22, 2008 letter that it “... unanimously affirms EPA staff’s

recognition of the need to substantially lower the level of the primary NAAQS for Lead, to an

upper bound of no higher than 0.2 µg/m3 ....”20

Ibid., p. 2-10.

Ibid., p. 3-22.

Ibid.

Ibid., pp. 5-44 to 5-45.

“Clean Air Scientific Advisory Committee’s Review of the Advance Notice of Proposed Rulemaking (ANPR) for the

NAAQS for Lead,” Letter of Dr. Rogene Henderson, Chair, CASAC, to Hon. Stephen L. Johnson, Administrator, U.S.

(continued...)

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Revising the National Ambient Air Quality Standard for Lead

The Administrator agreed that the primary NAAQS should be substantially lowered, choosing a

level of 0.15 µg/m3.

The Administrator also proposed two options for revising the averaging time and form used to

determine whether an area meets the standard. Instead of the former not-to-be-exceeded form,

based on quarterly (3-month) averages of lead concentrations, the proposal would have either

revised the current averaging form to clarify that it applies across a three-year span (i.e., to

demonstrate attainment, an area would need to show quarterly readings lower than the standard

for 12 consecutive quarters); or the proposal would revise the measure to the second highest

monthly average in a three-year span. According to agency staff, this latter form would better

capture short-term increases in lead exposure, while allowing the average from one bad month

(perhaps resulting from unusual meteorological conditions) to be disregarded. The agency noted

that “control programs to reduce quarterly mean concentrations may not have the same protective

effect as control programs aimed at reducing concentrations in every individual month.”21

CASAC also recommended that consideration be given to changing from the calendar quarter to

the monthly averaging time. In making that recommendation, CASAC emphasized support from

studies suggesting that blood lead concentrations respond at shorter time scales than would be

captured completely by quarterly values.

The Administrator chose neither of these options. Instead, the agency will use a rolling threemonth average, evaluated over a three-year period: any three-month average exceeding the

standard will be considered a violation of the NAAQS. For a nonattainment area to be

subsequently redesignated to “attainment,” the area would have to have three years of rolling

three-month averages that met the standard. This is somewhat more stringent than the previous

averaging time (calendar quarters), but not as protective as the second highest monthly average

would have been.

As shown in Figure 1, 17 counties have monitors showing nonattainment using the new standard.

(By comparison, only portions of two counties violated the old standard.) As will be discussed in

more detail below, less than 3% of the nation’s counties have active lead monitors. Thus, more

counties may be found in nonattainment once the monitoring network is expanded.

The Secondary Standard

As part of its current review, EPA also assessed the secondary (public welfare) NAAQS for lead.

The secondary standard has been identical to the primary standard. The agency concluded that:

A significant number of new studies have been conducted since 1978 that associate lead

pollution with adverse effects on organisms and ecosystems. However, there is a lack of

evidence linking various effects to specific levels of lead in the air.22

(...continued)

EPA, January 22, 2008, p. 5, at http://yosemite.epa.gov/sab/sabproduct.nsf/

427DE71C7D43AFDC852573D8006FB5BC/$File/EPA-CASAC-08-007-unsigned.pdf.

U.S. EPA, National Ambient Air Quality Standards for Lead, Proposed Rule, 73 Federal Register 29236, May 20,

2008.

U.S. EPA, “Fact Sheet: Proposed Revisions to the National Ambient Air Quality Standards for Lead,” p. 3 at

http://www.epa.gov/air/lead/pdfs/20080501_factsheet.pdf.

Congressional Research Service

Figure 1. Counties with Monitors Violating the 2008 Lead Standard of 0.15 micrograms per cubic meter (µg/m3)

Source: U.S. EPA.

Notes:

1. 18 of 111 monitored counties violate the 2008 lead standard of 0.15 micrograms per cubic meter (μg/m3) measured as total suspended particulate matter (TSP).

2. These estimates are based on the most recent air quality data available (2005–2007). EPA will not designate areas based on these data, but likely on data from

2007-2009 or 2008-2010.

3. The existing monitoring network for lead is not sufficient to determine whether many areas of the country would meet the revised standards of 0.15 μg/m3. EPA

is re-designing the national lead monitoring network to allow assessment of compliance with the revised standards.

4. Monitored air quality data is available from the Air Quality System at http://www.epa.gov/ttn/airs/airsaqs/

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Revising the National Ambient Air Quality Standard for Lead

Lacking such evidence, the Administrator continued the practice of making the secondary

standard identical to the primary standard.

Expanding the Lead Monitoring Network

Besides finding that the 1978 NAAQS was inadequate to protect public health and welfare, EPA’s

review concluded that “[t]he current monitoring network is inadequate to assess national

compliance with the proposed revised lead standards.”23 Only 70 of the roughly 3,000 counties in

the United States (2.3%) had active lead monitors in 2008, leaving many areas of the country

without any means of determining whether they were in violation of the lead NAAQS.24 Twentyfour entire states, including some with major sources of lead emissions, had no lead monitors.25

Under the old (1978) standard, this was not much of an issue. There were, at one time, about 900

lead monitors in operation; but, as lead emissions decreased and as the monitors showed

consistent attainment of the standards, many of the monitors were shut down or removed. With a

substantially more stringent standard, however, it cannot be assumed that areas without monitors

are still in attainment.

The locations of monitors and of the major sources of lead emissions are shown in Figure 2. The

figure shows that large sources of emissions in Alaska, Arizona, Arkansas, Florida, Illinois,

Indiana, Iowa, Kansas, Michigan, Mississippi, Nebraska, New York, Oklahoma, Tennessee,

Texas, Utah, Virginia, Wisconsin, and other states appear to be located more than 100 miles from

the nearest ambient monitor.

U.S. EPA, “May 2008 Proposal, National Ambient Air Quality Standards for Lead, General Overview,” Text Slides,

at http://www.epa.gov/air/lead/pdfs/20080501_text1.pdf, p. 17.

In the support documents for the proposed and final NAAQS, EPA provided several different estimates of the

number of counties with active monitors, ranging from 86 to 111. Further communication with the Office of Air

Quality Planning and Standards produced a final estimate of 70 counties with a total of 133 active monitors. The reason

for the discrepancies is that there are a number of counties that have (or had) monitors that were switched off after

years of showing attainment with the 1978 NAAQS. In these cases, there may be data for older time periods, but the

agency does not know with certainty whether the areas would be in attainment of the new standard. Personal

communication, October 23, 2008.

In support of the lead NAAQS proposal, EPA produced a map of the United States showing the locations of lead

monitors and of sources emitting more than 5 tons of lead per year. The map showed that several of the states without

monitors have large sources of lead emissions. Arkansas, for example, has two of the 12 largest stationary sources of

lead in the United States (those with lead emissions exceeding 5 tons per year), but no ambient lead monitors. Montana,

which has one of the two nonattainment areas for the 1978 lead standard, also has no ambient lead monitors. Similarly,

large sources in Oklahoma, the Texas panhandle, and other locations appear to be located more than 100 miles from the

nearest ambient monitor. Additional data on monitor locations, confirming that 24 states have no monitors, was

provided by EPA’s Office of Air Quality Planning and Standards, May 6, 2008. See also “EPA to Seek Comment on

Increasing Air Monitors as Part of Lead Rulemaking,” Daily Environment Report, November 29, 2007, p. A-10.

Congressional Research Service

Figure 2. Locations of Current Ambient Lead Monitors, Largest Stationary Sources of Lead Emissions,

and Metropolitan Areas with Populations of 500,000 or More

Source: U.S. EPA.

Notes:

1. Ambient lead monitoring sites measure lead in total suspended particulate (Pb-TSP). The 133 monitoring sites shown are those operating in 2008.

2. The current monitoring network for lead is not sufficient to determine whether many areas of the country would meet the 2008 lead standards. EPA is redesigning the nation’s lead monitoring network to allow assessment of compliance with the revised standard. EPA is requiring Pb-TSP monitors in areas near lead

sources with emissions greater than or equal to 1.0 ton per year, and a monitor in every urban area with population of 500,000 or greater.

3. The emissions estimates used to develop this map are based on EPA’s 2002 National Emission Inventory (NEI) with modifications documented in Tom Pace’s

05/01/08 memorandum and Marion Hoyer’s 05/12/08 and 05/14/08 memoranda to the docket.

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Revising the National Ambient Air Quality Standard for Lead

To address this shortfall, EPA proposed—in addition to the revised lead NAAQS—to require

monitors near all sources of lead that exceed a threshold of between 200 and 600 kilograms (441

to 1,323 pounds) of emissions per year. The agency also proposed to require a small network of

monitors to be placed in urban areas with populations greater than one million to gather

information on the general population’s exposure to lead in the air.

In the final rule, the Administrator chose thresholds different than proposed: he set the source

threshold at one ton of emissions rather than 200-600 kilograms, and required monitors in urban

areas with populations of 500,000 or more rather than one million. The final choice appeared to

have reflected concerns by industry groups, including the Battery Council International, who

argued that emphasis should be placed more on exposure-oriented monitoring than on specific

sources of emissions. 26

The monitoring decision was challenged by the Natural Resources Defense Council, Missouri

Coalition for the Environment Foundation, and two other groups: they petitioned the agency for

reconsideration of the monitoring requirements, in January 2009. EPA agreed to a reconsideration

in July and proposed changes to the monitoring rule on December 23.27 In the December

proposal, EPA reverted to a 0.5 ton threshold for source-oriented monitors. The agency also

proposed eliminating the required monitoring in areas with populations of 500,000 or more, in

favor of a network of approximately 80 multi-pollutant monitoring sites known as NCore. The

NCore network would include 60 sites located in urban areas and about 20 sites located in rural

areas. In all, EPA estimates that the proposal would increase the number of monitors by about

140.28

The states remain free to install more monitors than EPA requires, but finding the money to do so

might be difficult at a time when many of the states are experiencing a shortage of revenues. EPA

estimated the initial cost of the network (as required by the 2008 rule) at $4.5 million, and the

operational costs at $3.5 million annually. The agency estimated that the December 2009 rule

would increase ambient air monitoring costs by an additional $1.8 million. To address these costs

(and the costs of new monitoring requirements for other NAAQS pollutants), EPA has requested

an additional $15 million in its FY2011 budget. The agency is also requesting an $82.5 million

(36%) increase in total budget authority for state and tribal assistance grants in FY2011, in part to

support activities related to the implementation of new NAAQS.

See, for example, “Industry Says Urban Monitoring Key to Final EPA Lead NAAQS Decision,” Inside EPA Clean

Air Report, October 2, 2008. According to OMB Watch, the requirement was changed at the last minute at the request

of the Office of Management and Budget. A draft of the rule attached to an October 13, 2008 e-mail from EPA to OMB

stated that the emissions threshold would be set at 0.5 tons per year and the urban area cutoff at one million. (The draft

is available at http://www.ombwatch.org/files/regs/PDFs/half-ton_excerpt.pdf.) In changing the emissions threshold to

1 ton per year, as many as 124 areas with sources emitting between 0.5 tons and 1 ton per year were exempted from

required monitoring. In changing the urban area threshold, on the other hand, 49 areas were added. Thus, overall, 75

fewer areas were required to monitor as a result of the changes. See “EPA to Reduce Airborne Lead, but OMB

Bedevils the Details,” OMB Watch, October 21, 2008, at http://www.ombwatch.org/node/3817.

The proposed changes appeared in the Federal Register December 30, 2009, at 74 FR 69050.

U.S. EPA, “Fact Sheet – Revisions to Lead Ambient Air Monitoring Requirements,” at http://epa.gov/air/lead/

fs20091223.html.

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Revising the National Ambient Air Quality Standard for Lead

Issues Raised by the NAAQS Review

Perhaps the two largest issues raised during the lead NAAQS review process—whether a

NAAQS was still needed, and whether the Administrator’s proposed range of standards reflected

the scientific advice he received—have been resolved, with little remaining controversy. CASAC

and EPA staff both concluded that airborne lead still meets the NAAQS criteria (endangerment of

public health or welfare, and numerous or diverse sources). Rather than support the deletion of

lead from the list of criteria pollutants, they concluded that lead in ambient air still poses a threat

to public health, that the old NAAQS (established in 1978) was far too lenient, and that the 1978

NAAQS needed to be significantly strengthened.29 The Administrator agreed.

A second major issue was whether the proposed range of standards (as opposed to the final,

promulgated version) was supported by the available science. The range proposed by the

Administrator, while substantially stronger than the 1978 standard, would have allowed him to set

a final NAAQS 50% higher (i.e., less stringent) than the least stringent level recommended by

both EPA’s scientific staff and by the independent CASAC panel. Given uncertainties in the

science (particularly the estimated correlation between airborne lead and blood lead levels and the

uncertainties in the concentration-response functions—i.e., the effect that changes in blood lead

levels have on IQ), the Administrator stated in the May 2008 proposal that his decision would be

supported by the science at any point in the proposed range of 0.10 to 0.30 µg/m3.30

His final choice (0.15 µg/m3) fell within the range recommended by EPA staff and CASAC, and,

thus, did not provoke controversy. At that level, the standard was supported by the staff’s

conclusions, which were themselves based on the review of more than 6,000 scientific studies,

and by the unanimous conclusions of the 22-member CASAC review panel.

There are, of course, some who wanted weaker or stronger standards. In comments on the

proposed range, some commenters expressed disappointment that the Administrator did not

consider the potential economic impacts in making his choice. 31 These comments were echoed by

the Association of Battery Recyclers (ABR), following the Administrator’s decision: in press

reports, an ABR representative stated that the new standard “potentially threatens the viability of

the lead recycling industry.”32 The Clean Air Act does not allow the consideration of costs or

economic impacts in the setting of NAAQS, however—a point underlined by the Supreme Court

in a unanimous 2001 decision, 33 and repeated by the agency in announcing the final decision.

Thus, the Administrator appears to have been on firm ground in rejecting economic arguments.

EPA staff conclusions are found in the Office of Air Quality Planning and Standards Staff Paper at

http://www.epa.gov/ttn/naaqs/standards/pb/data/20071101_pb_staff.pdf. See especially pp. 5-43 to 5-45. CASAC’s

conclusions can be found in a March 27, 2007 letter from its Chair, Dr. Rogene Henderson, to Administrator Johnson,

at http://yosemite.epa.gov/sab/sabproduct.nsf/989B57DCD436111B852572AC0079DA8A/$File/casac-07-003.pdf.

U.S. EPA, National Ambient Air Quality Standards for Lead, Proposed Rule, 73 Federal

See, for example, “Environmentalists Push New Lead Standard; Industry Warns of Consequences for Business,”

Daily Environment Report, August 28, 2008.

Robert N. Steinwurtzel, a lawyer for the Association of Battery Recyclers, as cited in a “E.P.A. Toughens Standard

on Lead Emissions; Change Is the First in 3 Decades,” New York Times, October 17, 2008.

Whitman v. American Trucking Associations, 121 S. Ct. 903 (2001).

Congressional Research Service

Revising the National Ambient Air Quality Standard for Lead

Others, including EPA’s Children’s Health Protection Advisory Committee (CHPAC), argued for

a stronger standard.34 CHPAC cited evidence that lead exposure at low levels poses even greater

harm per unit of lead than does exposure at higher levels, and argued that the standard should be

set at 0.02 µg/m3, almost an order of magnitude below the Administrator’s final choice.35

Despite that recommendation, criticism was muted in the wake of the Administrator’s decision,

with most environmental groups expressing support. A typical reaction was that of Dr. John

Balbus, a member of CHPAC and the Chief Health Scientist on the staff of the Environmental

Defense Fund: “While EPA’s own analysis justifies an even lower lead standard, this tenfold

reduction will go a long way to protecting children most at risk from airborne lead.... It’s

refreshing to see the agency follow the science and the advice of its experts in making this

decision.”36

Costs and Benefits of the New Standard

Although the Administrator is prohibited from taking costs or economic factors into consideration

in setting a NAAQS,37 the agency generally does prepare a Regulatory Impact Analysis (RIA) for

information purposes, and to comply with an executive order. 38 The RIA analyzes in detail the

costs and benefits of new or revised NAAQS standards. The agency released an RIA for the final

lead standard as part of the final regulatory package, October 16, 2008.

The RIA presented a range of both costs and benefits from the new standard, assuming full

implementation of control measures in 2016. Both the cost and benefit ranges were large, and

EPA stressed that “there are important overall data limitations and uncertainties in these

estimates.”39 In general, costs and benefits may be understated, because the study developed

estimates only for the 17 counties that currently have monitors showing nonattainment. Until new

monitors are installed, the agency has no way of estimating how many additional areas will be

affected by the standard, but the RIA emphasizes that “... there may be many more potential

nonattainment areas than have been analyzed in this RIA.”40

EPA’s Children’s Health Protection Advisory Committee (CHPAC) is a body of researchers, academicians, health

care providers, environmentalists, children’s advocates, professionals, government employees, and members of the

public who advise EPA on regulations, research, and communication issues relevant to children.

Letter of Melanie A. Marty, Chair, Children’s Health Protection Advisory Committee, to EPA Administrator

Johnson, June 16, 2008, re Proposed Rulemaking for the NAAQS for Lead, at http://yosemite.epa.gov/ochp/

ochpweb.nsf/content/61608.htm/$file/61608.pdf.

Environmental Defense Fund, “New EPA Lead Standard Significantly Improved to Protect Kids’ Health,” Press

Release, October 16, 2008, at http://www.edf.org/pressrelease.cfm?contentID=8688.

Although costs can’t be considered in setting the NAAQS, costs can be considered by the states in developing their

State Implementation Plans, i.e., the regulations by which they will bring nonattainment areas into attainment.

Executive Order 12866 and OMB Circular A-4 require regulatory agencies to assess the benefits and costs of

selected regulatory options, as well as one less stringent and one more stringent option. OMB Circular A-4 also

requires both a benefit-cost, and a cost-effectiveness analysis for rules where health is the primary effect. The RIA for

the Lead NAAQS can be found at http://www.epa.gov/ttn/ecas/regdata/RIAs/finalpbria.pdf.

U.S. EPA, Office of Air Quality Planning and Standards, Regulatory Impact Analysis of the Proposed Revisions to

the National Ambient Air Quality Standards for Lead (hereafter, “RIA”), at http://www.epa.gov/ttn/ecas/regdata/RIAs/

finalpbria.pdf, p. ES-1.

RIA, p. 7-1.

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Revising the National Ambient Air Quality Standard for Lead

Costs

The cost estimates ranged from $150 million annually in 2016 to as much as $2.8 billion, 19

times as much. The difference is attributable to EPA’s inability to demonstrate attainment of the

standard in all areas through the application of identified control technologies. The RIA states:

For the selected standard of 0.15 µg/m3, over 94% of the estimated emission reductions

needed for attainment are achieved through application of identified controls, and less than

6% through unspecified emission reductions. Identified point source controls include known

measures for known sources that may be implemented to attain the selected standard,

whereas the achievement of unspecified emission reductions requires implementation of

hypothetical additional measures in areas that would not attain the selected standard

following the implementation of identified controls to known sources.41

The known controls are estimated to cost $130 million to $150 million annually, depending on the

discount rate chosen. But the unspecified emission controls are estimated at from $20 million to

$3.1 billion annually depending on the methodology used.

A key feature of EPA’s analysis is that it assumed all emission reductions would come from

controls on point source emissions (e.g., smelters, foundries, incinerators, etc.). But, according to

the agency, 45% of emissions come from aviation fuel. In October 2006, EPA received a petition

from Friends of the Earth to reduce or eliminate lead from aviation gasoline. 42 The agency, in

coordination with the Federal Aviation Administration (FAA), is analyzing the petition. The RIA

does not address the costs or benefits of such a step.

In addition, the agency notes:

...in this RIA we have not accounted for the effect of improvements that tend to occur, such

as technology improvement, process changes, efficiency improvements, materials

substitution, etc. We believe these typical improvements will tend to result in more cost

effective approaches than simply adding extremely expensive pollution controls in many

areas by the attainment date of 2016. Many industrial sources of lead emissions emit very

small quantities of lead in absolute terms. Our cost modeling shows that some could face

significant costs to reduce these low levels of lead, costs which could be prohibitively

expensive. Rather than applying additional controls, it may be possible for firms emitting

small amounts of Pb [lead] to modify their production processes or other operational

parameters, including pollution prevention techniques, which would be more cost effective

than adding additional control technology. Such measures might include increasing the

enclosure of buildings, increasing air flow in hoods, modifying operation and maintenance

procedures, changing feed materials to lower Pb content, measures to suppress dust from

tailings piles, etc.43

Benefits

The RIA estimates that benefits of the NAAQS will range from $3.7 billion to $6.9 billion

annually in 2016—and, thus, that benefits will outweigh costs at all points in the estimated range.

The benefits mostly represent the expected increase in lifetime earnings that would result from

RIA, p. 6-1.

For the petition, and additional information, see http://www.epa.gov/otaq/aviation.htm.

RIA, p. ES-4.

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Revising the National Ambient Air Quality Standard for Lead

children under seven years of age avoiding IQ loss due to exposure to lead. The RIA focuses

primarily on children’s health effects. It does not attempt to estimate the changes in lead-related

health effects among adults. Unquantified health effects include:

•

Hypertension

•

Non-fatal coronary heart disease

•

Non-fatal strokes

•

Premature mortality

•

Other cardiovascular diseases

•

Neurobehavioral function

•

Renal effects

•

Reproductive effects

•

Fetal effects from maternal exposure (including diminished IQ). 44

It is beyond the agency’s capability, at present, to quantify these effects. Thus, the benefits, just

like the costs, are subject to substantial uncertainty.

Issues for Congress

The lead NAAQS was less controversial than the recent NAAQS decisions on ozone and

particulate matter, both of which were challenged in the D.C. Circuit Court of Appeals;45 but,

given the importance of its potential health benefits and the uncertainties regarding both the

number of areas affected and the means by which areas will reach attainment, implementation of

the NAAQS may continue to be of interest to the Congress.

An immediate issue is the need for additional funds for monitoring and implementation of the

NAAQS. EPA has requested a substantial increase in its FY2011 budget for state and tribal

assistance grants, in order to fund both new monitors and the increased state workload involved in

implementing the revised NAAQS for lead and other pollutants.

Author Contact Information

(name redacted)

Specialist in Environmental Policy

[redacted]@crs.loc.gov, 7-....

RIA, Chapter 5, pp. 1-14.

For additional information on those rules, see CRS Report R41062, Ozone Air Quality Standards: EPA’s Proposed

January 2010 Revisions, and CRS Report RL34762, The National Ambient Air Quality Standards (NAAQS) for

Particulate Matter (PM): EPA’s 2006 Revisions and Associated Issues.

Congressional Research Service

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