[Federal Register Volume 63, Number 106 (Wednesday, June 3, 1998)]
[Proposed Rules]
[Pages 30302-30355]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-14736]
[[Page 30301]]
_______________________________________________________________________
Part III
Environmental Protection Agency
_______________________________________________________________________
40 CFR Part 745
Lead; Identification of Dangerous Levels of Lead; Proposed Rule
Federal Register / Vol. 63, No. 106 / Wednesday, June 3, 1998 /
Proposed Rules
[[Page 30302]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 745
[OPPTS-62156; FRL-5791-9]
RIN 2070-AC63
Lead; Identification of Dangerous Levels of Lead
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of proposed rulemaking.
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SUMMARY: In accordance with section 403 of the Toxic Substances Control
Act (TSCA), as amended by the Residential Lead-Based Paint Hazard
Reduction Act of 1992, also known as ``Title X,'' EPA is proposing a
regulation to establish standards for lead-based paint hazards in most
pre-1978 housing and child-occupied facilities. This proposed
regulation is a focal point of the Federal lead program and supports
the implementation of regulations already promulgated and others under
development which deal with worker training and certification, lead
hazard disclosure in real estate transactions, requirements for lead
cleanup under State authorities, lead hazard evaluation and control in
Federally-owned and Federally-assisted housing, and U.S. Department of
Housing and Urban Development (HUD) grants to assist in lead hazard
abatement. In addition, today's action also proposes, under the
authority of TSCA section 402, residential lead dust cleanup levels and
amendments to dust and soil sampling requirements and, under the
authority of TSCA section 404, amendments to State program
authorization requirements. By supporting the implementation of the
national lead program, this proposed regulation would help to prevent
lead poisoning in children under the age of 6.
DATES: Written comments in response to this proposed rule must be
received on or before September 1, 1998.
ADDRESSES: Each comment must bear the docket control number OPPTS-
62156. All comments should be sent in triplicate to: OPPT Document
Control Officer (7407), Office of Pollution Prevention and Toxics,
Environmental Protection Agency, 401 M St., SW., Rm. G099, East Tower,
Washington, DC 20460.
Comments and data may also be submitted electronically to:
[email protected]. Follow the instructions under Unit X. of
this document. No Confidential Business Information (CBI) should be
submitted through e-mail.
All comments which contain information claimed as CBI must be
clearly marked as such. Three copies, sanitized of any comments
containing information claimed as CBI, must also be submitted and will
be placed in the public record for this rulemaking. Persons submitting
information, any portion of which they believe is entitled to treatment
as CBI by EPA, must assert a business confidentiality claim in
accordance with 40 CFR 2.203(b) for each such portion. This claim must
be made at the time that the information is submitted to EPA. If a
submitter does not assert a confidentiality claim at the time of
submission, EPA will consider this as a waiver of any confidentiality
claim and the information may be made available to the public by EPA
without further notice to the submitter.
If requested, EPA will schedule public meetings where oral comments
will be heard. EPA will announce in the Federal Register the time and
place of any public meetings. Oral statements will be scheduled on a
first come first served basis by calling the telephone number listed in
the Federal Register notice that announces these meetings. All
statements will be made part of the public record and will be
considered in the development of the final rule.
FOR FURTHER INFORMATION CONTACT: For general information contact:
National Lead Information Center's Clearinghouse, 1-800-424-LEAD(5323).
For specific technical and policy questions contact: Jonathan Jacobson,
(202) 260-3779; [email protected].
SUPPLEMENTARY INFORMATION:
I. Overview
This overview identifies entities potentially affected by the rule,
summarizes the proposed rule, describes the uses and key limitations of
the proposal's scope, and provides a roadmap of the preamble.
A. Regulated Entities
The following table identifies the entities that would be involved
in the implementation of regulations that would be affected by today's
proposal and the effect of the proposal on implementation of those
regulations.
------------------------------------------------------------------------
Examples of
Category Entities Effect of Proposal
------------------------------------------------------------------------
Lead abatement professionals Workers, Provides standards
supervisors, that risk
inspectors, risk assessors would
assessors, and use to identify
project designers hazards and
engaged in lead- evaluate
based paint clearance tests;
activities helps determine
when certified
professionals
would be required
to perform
abatements
Training providers Firms providing Provides standards
training services that training
in lead-based providers would
paint activities have to teach in
their courses
HUD and other Federal agencies Proposed standards
that own residential property identify hazards
that Federal
agencies would
have to abate in
pre-1960 housing
prior to sale
Property owners who receive State and city Proposed standards
assistance through Federal public housing identify hazards
housing programs authorities, that property
owners of multi- owners would have
family rental to abate or
properties who reduce as
receive project- specified by
based assistance, regulations
owners of rental currently be
properties who developed by HUD
lease units under under authority
HUD's tenant- of Title X,
based assistance section 1012
program
Property owners Owner occupants, Proposed standards
rental property identify hazards
owners, public that would have
housing to be disclosed
authorities, under EPA/HUD
Federal agencies joint regulations
promulgated under
Title X, section
1018
------------------------------------------------------------------------
This table is not intended to be exhaustive, but rather provides a
guide for readers likely to be affected by this action through
implementation of the elements of the programs discussed in this
proposal. To determine whether
[[Page 30303]]
you, your business, or your agency is affected, you should carefully
examine the Requirements for Lead-Based Paint Activities at 40 CFR part
745, subpart L and subpart Q and Lead-Based Paint Disclosure at 40 CFR
part 745, subpart F and 24 CFR part 35, subpart H. The regulations
covering evaluation and control of lead-based paint hazards in HUD-
associated and Federally-owned housing are currently under development.
Proposed regulations were published in the Federal Register on June 7,
1996 (61 FR 29169). If you have any questions regarding the
applicability of this action to a particular entity, consult the person
listed in the ``FOR FURTHER INFORMATION CONTACT'' section.
B. Summary of the Proposed Rule
1. Lead-Based Paint Hazard Standards. EPA is proposing the
amendments in this document primarily under the authority of section
403 of TSCA. Section 403 requires EPA to promulgate regulations that
``identify . . . lead-based paint hazards, lead-contaminated dust and
lead-contaminated soil'' for purposes of the entire Title X which
includes Title IV of TSCA. Lead-based paint hazards, under TSCA section
401, 15 U.S.C. 2681, are defined as of conditions of lead-based paint
and lead-contaminated dust and soil that ``would result'' in adverse
human health effects (15 U.S.C. 2681(10)). Lead-based paint hazards
from all three sources apply to target housing (i.e., most pre-1978
housing) and child-occupied facilities.
The proposed standard for the paint component, called hazardous
lead-based paint, is lead-based paint in poor condition. Paint in poor
condition is defined as more than 10 square feet (ft2) of
deteriorated paint on exterior components with large surface areas,
more than 2 ft2 of deteriorated paint on interior components
with large surface areas (e.g., walls, ceilings, floors), or
deteriorated paint more than 10 percent of the total surface area of
exterior or interior components with small surface areas (e.g., trim,
baseboards). The proposed standards for dust-lead hazards are the
average levels of lead in dust that equals or exceeds 50 micrograms per
square foot (g/ft2) on uncarpeted floors and 250
g/ft2 on interior window sills. The proposed
standard for soil-lead hazards is the total lead that equals or exceeds
2,000 parts per million (ppm) based on a yard-wide average soil-lead
concentration rather than maximum or worst-case values.
Although the proposed regulation does not require property owners
to respond to the presence of lead-based paint hazards, EPA would
recommend that appropriate measures should be taken, commensurate with
the risk reduction achieved, to reduce or eliminate the hazards. Small
amounts of hazardous lead-based paint can be addressed by repairing
deteriorated paint. Larger amounts of hazardous lead-based paint should
be abated, meaning that the paint can be removed from the component,
the component can be replaced, or the paint can be enclosed.
Dust-lead hazards should be addressed through intensive cleaning.
If household surfaces are smooth and cleanable, regular household
cleaning can probably maintain acceptably low levels of lead in dust in
the absence of any event (e.g., remodeling project) that reintroduces
large amounts of dust contaminated with lead. Soil-lead hazards should
be eliminated. Currently available options include soil removal and
permanently covering the soil (i.e., paving).
In addition, this document proposes to identify a soil-lead level
of concern of 400 ppm based on a yard-wide average, which represents a
level at which risk should be communicated to the public as compared to
the more active risk reduction measures recommended for hazards. This
level will not be included in the regulation because it would impose no
legally recognizable requirements on any person or entities subject to
this regulation. Nevertheless, if a soil-lead hazard is not present,
but lead in soil exceeds the level of concern, EPA recommends that low
cost measures, which may be sufficient to reduce exposure, be
implemented. These measures include but are not limited to covering
bare soil, placement of washable doormats, more frequent washing of
hands and toys, and access restrictions. Access restrictions should
only be used if there are other parts of the yard that are available to
the residents.
EPA is planning to develop a guidance document to accompany the
final regulation that will explain these recommended responses to lead-
based paint hazards and the soil-lead level of concern in greater
detail.
It is important to note that the proposed standards are intended to
be used prospectively. That is, they should be used to identify
properties that present risks to children before children are harmed.
These standards would not be appropriate to use when identifying the
sources of exposure for a lead-poisoned child. When a property is being
evaluated in response to the identification of a lead-poisoned child,
the risk assessor in cooperation of a local public health official
should identify and consider all sources of lead exposure.
The proposed TSCA section 403 standards are based on the best data
and analytical tools currently available to the Agency. EPA expects
that the standards may need to be modified over time as better tools
and data become available. The Agency, however, believes that issuing
standards now, even in the face of considerable uncertainty, is
consistent both with the public's need for information from EPA and the
statutory intent to develop standards with currently available
information.
In this document, EPA is also proposing amendments to the existing
rules issued under TSCA sections 402 and 404, including: (1)
Requirements for interpreting the results of sampling of lead materials
for purposes of assessing risk; (2) clearance standards for cleaning up
hazardous lead dust of 50 g/ft2 for uncarpeted
floors, 250 g/ft2 for interior window sills, and
800 g/ft2 for window troughs; (3) amendments to the
dust and soil sampling locations in the risk assessment work practice
standards at 40 CFR 745.227; (4) work practice standards for the
management of soil removed during a soil abatement; and (5) amendments
to the State and Tribal program authorization requirements under 40 CFR
part 745, subpart Q.
C. Uses of the Standards
The TSCA section 403 standards support implementation of key
provisions of Title X which would require action with respect to lead-
based paint hazards by both private parties and the government,
principally for EPA and programs under the auspices of the Department
of Housing and Urban Development (HUD). These provisions include
eligibility criteria for the Department of Housing and Urban
Development's (HUD) lead hazard control grant program (section 1011 of
Title X), which authorizes grants to clean up lead-based paint hazards.
In addition, Title X imposes certain requirements on owners of HUD-
associated housing (section 1012 of Title X) and Federal agencies
selling residential properties they own to evaluate and control lead-
based paint hazards (section 1013 of Title X). Sellers and lessors of
housing built before 1978 have obligations to disclose known lead-based
paint and lead-based paint hazards prior to sale or rental (section
1018 of Title X). Regulations also impose requirements to use certified
workers for evaluation and cleanup of
[[Page 30304]]
lead-based paint hazards (section 402 of TSCA). These provisions are
described in more detail in Unit VIII. of this preamble.
EPA does note, however, that the regulations would not require
private property owners to undertake hazard control actions when
hazards are identified. Instead, EPA expects that concern about
children's health, liability exposure and other market forces will
provide incentive for property owners to take action voluntarily.
In addition to their applicability within Title X, EPA anticipates
that the TSCA section 403 regulations will have broader uses. The
proposed regulations will play a significant role in public education,
communicating the Agency's best judgment concerning the identification
of lead-based paint hazards to property owners, State and local
officials, tenants, and other decision-makers. EPA also expects that
public and private institutions may incorporate the standards into
State and local laws, housing codes, and lending and insurance
underwriting standards.
D. Limitations of the Proposed Rule
During the regulatory development process, it became clear that
significant confusion and uncertainty exists about the requirements and
purpose of the TSCA section 403 regulations. To address this confusion
and uncertainty, EPA wishes to highlight the major limitations and
other issues related to the scope and use of today's proposal.
First, this proposal does not establish a new definition for lead-
based paint, defined by statute as paint with lead levels equal to or
exceeding 1.0 milligrams per square centimeter (mg/cm2) or
0.5 percent by weight (see section 302(c) of the Lead-Poisoning
Prevention Act, 42 U.S.C. 4822(c) and TSCA section 401(9)). Under Title
X, only the Secretary of Housing and Urban Development has the
authority to change the standard for lead-based paint in target housing
(see TSCA section 401(9)). Title IV provides EPA the authority to
change the standard only for lead-based paint in non-residential
applications (e.g., public and commercial buildings, steel structures)
(see TSCA section 401(9)). This proposal does not include any changes
to this statutory definition.
Second, the proposed standards are intended to identify lead-based
paint hazards when the lead-based paint risk assessment is performed.
Because the conditions of lead-based paint and the levels of lead in
dust and soil are constantly changing, the results of the risk
assessment communicate conditions at the time the measurements are
taken and the observations made. The proposed standards do not address
the potential for hazards to develop. EPA recognizes, however, that
potential hazards (e.g., intact lead-based paint on a ceiling) may
become actual hazards as conditions change over time. Periodic
reevaluation of a property would enable a property owner to determine
whether potential hazards have become actual hazards. Recommendations
concerning reevaluation will be provided in a separate guidance
document that EPA is planning to issue.
Third, because the TSCA section 403 standards are established for
the purposes of Title X and TSCA Title IV, they do not apply to housing
and facilities occupied by children built during or after 1978, as well
as some pre-1978 housing that is not included in the definition of
target housing (e.g., 0-bedroom dwellings). EPA recognizes, however,
that property owners and other decision-makers may be concerned about
the presence of elevated levels of lead in dust and soil in housing and
facilities occupied by children not covered by the standards. In such
cases, EPA encourages these owners and decision-makers to use the
standards to help determine whether actions should be taken to reduce
risks to young children.
Fourth, the proposed regulations do not set standards that can be
used to identify housing that is free from risks associated with
exposure to lead. Such standards would be difficult to define,
unworkable in practice, and inconsistent with the intent of Title X.
Virtually all target housing has some lead present in paint, dust, and/
or soil, which, under certain circumstances, may present risk to
children. Furthermore, these risks often will depend on circumstances
that may change quickly, such as the physical condition of the
property. Thus, housing that presents minimal risks when examined may
present substantial risks later.
E. Preamble Overview
The remainder of this preamble consists of eleven units. Unit II.
provides background information, including: a description of the
residential lead-based paint problem; Title X as a legislative
response; key aspects of the regulatory development process; and the
Agency's general standard-setting approach. Unit III. is a section-by-
section review of the proposed regulatory provisions. Unit IV. presents
EPA's interpretation of the statutory authority for the proposed TSCA
section 403 standards, the Agency's policy basis for the proposed
standards, and EPA's decisions for the proposed TSCA section 403
standards. This unit includes a summary of the technical analyses
conducted by the Agency to support these decisions. Unit V. discusses a
range of issues that affected EPA's decision-making during the
regulatory development process. Unit VI. presents EPA's rationale and
decisions for requirements on comparing risk assessment sampling
results to the TSCA section 403 standards. Unit VII. describes the
Agency's rationale and decisions concerning clearance standards and
other amendments to the TSCA section 402 regulations related to work
practice standards and TSCA section 404 regulations concerning EPA
authorization of State and Tribal programs. Unit VIII. describes the
effect that today's proposal will have on other Title X regulations and
programs, and Unit IX. discusses the relationship between the proposed
regulations and other EPA programs. Unit X. provides information on the
public record supporting this regulation (``the docket''). Unit XI.
presents the bibliographic references cited in the preamble, which are
also part of the docket. Unit XII. presents a summary of the regulatory
assessment analyses and Agency determinations conducted in response to
various Federal laws and Executive orders concerning the public health
and economic impact of the proposed regulation.
II. Background
A. Nature of the Problem
Elemental lead is a heavy, soft, and malleable bluish metal that
has been used for thousands of years. Its favorable physical and
chemical properties account for its versatility and extensive use in
many common products including lead acid batteries, ammunition,
chemicals (e.g., plastic stabilizers, pigments, and ceramic glazes),
alloys (e.g., solder in piping and electronics), pipe/sheet lead, and
radiation and cable sheathing. Centuries of mining, smelting, and use
have released millions of tons of lead into the environment. With no
known or foreseeable technology to render anthropogenic sources of
environmental lead harmless, it remains ubiquitous in air, water, soil,
dust, and in older homes and commercial structures. As a result,
practically all people have some exposure to lead of anthropogenic
origin.
Lead affects virtually every system of the human body. Exposure to
high doses of lead can cause coma, convulsions,
[[Page 30305]]
and even death. Exposure to low levels of lead can cause harm gradually
and imperceptibly, with no obvious symptoms. In adults, chronic
exposure to low levels of lead may cause memory and concentration
problems, hypertension, cardiovascular disease, and damage to the male
reproductive system. Exposure to lead before or during pregnancy can
alter fetal development and cause miscarriages. A more detailed
description of the health effects of lead can be found in Chapter 2 of
the Risk Analysis to Support Standards for Lead in Paint, Dust, and
Soil, which can be found in the public record for this proposal (Ref.
1).
While potentially harmful to individuals of all ages, lead exposure
is especially harmful to children. Their rapidly developing nervous
systems are particularly sensitive to the effects of lead. In addition,
children absorb a greater portion of the lead to which they are exposed
than adults do. Excessive exposure to lead in children causes learning
disabilities, lower intelligence, behavioral problems, growth
impairment, permanent hearing and visual impairment, and other damage
to the brain and nervous system.
The concentration of lead in a child's blood is typically used as
an index of lead exposure. As recent studies have identified previously
unrecognized effects of exposure to lead at lower levels, there has
been increasing concern about blood-lead levels once thought to be
safe. Since 1975, the Centers for Disease Control and Prevention (CDC)
have lowered the blood-lead level considered elevated for children from
40 g/dl (micrograms per deciliter) to 10 g/dl (Ref.
2). Although the scientific community has not been able to identify a
threshold of exposure below which adverse health effects do not occur,
the evidence of health effects below 10 g/dl is not
sufficiently strong to warrant concern.
Ingestion of lead-contaminated dust and soil through normal hand-
to-mouth activity appears to be the primary pathway of lead exposure to
U.S. children under 6 years of age. (Refs. 3 and 4.), Dust is
contaminated by lead when: lead-based paint deteriorates; lead-based
paint is disturbed in the course of renovation, repair, or abatement
activity; or lead is tracked into, blown into, or otherwise enters the
home from soil in the yard or other external sources (e.g., workplace).
Soil contaminated with lead from deterioration of exterior lead-based
paint, industrial emissions, and/or deposition of lead from past use of
leaded gasoline may be ingested directly or contribute to indoor levels
of lead-contaminated dust when tracked into the home. Children may also
be exposed to lead through the ingestion of lead-based paint chips from
flaking walls, windows, and doors or from chewing on surfaces covered
with lead-based paint. Other sources of lead exposure include, but are
not limited to, lead-contaminated food and drinking water and
occupational exposure to dust and airborne lead particles.
Considerable progress has been made in reducing environmental lead
levels. Concrete steps taken by the Federal government to eliminate
sources of lead include the phase-out of leaded gasoline by EPA (40 CFR
part 80) and the ban by the Consumer Product Safety Commission (CPSC)
of the production and sale of lead-based paint for residential use in
1978 (16 CFR part 1303). The CPSC action placed a maximum limit on the
amount of lead in paint (0.06 percent by weight) for residential use,
as well as for furniture and toys. In addition, EPA has implemented
more stringent standards for lead in drinking water, and the domestic
canning industry voluntarily eliminated the use of lead in solder to
seal food cans (40 CFR parts 141 and 142).
Consistent with these improvements, the percentage of children with
elevated blood-lead levels has declined over the last 20 years. The
National Health and Nutrition Examination Survey (NHANES) conducted by
the National Center for Health Statistics indicates that over the past
2 decades the average child's blood-lead level has decreased from 12.8
micrograms/deciliters (g/dl) to 2.8 g/dl (Ref. 5).
According to NHANES III Phase 2, completed in 1994, approximately
900,000 U.S. children of ages 1 to 5 years had blood-lead levels equal
to or exceeding the 10 g/dl (Ref. 6).
Excessive exposure to lead affects children across all socio-
economic strata and in all regions of the country. Children in poor
inner-city families, however, are disproportionately affected because
lead-based paint hazards are more prevalent in older housing and the
overall ambient level of environmental lead from all sources tends to
be higher in inner cities (Ref. 7). Studies indicate that children
living in central cities are three to four times more likely to have
blood-lead levels equal to or exceeding 10 g/dl than those
outside central cities, with the highest prevalence in cities where
populations exceed 1 million (Ref. 7).
According to EPA's report on the HUD National Survey of Lead-Based
Paint in Housing, 83 percent of privately-owned, occupied homes built
before 1980, or 64.4 million homes, contain some lead-based paint (Ref.
8). The likelihood, extent, and concentration of lead-based paint vary
with the age of the building. Eighty-eight percent of privately-owned,
occupied housing units constructed before 1940, 92 percent of units
constructed between 1940 and 1959, and 76 percent of units constructed
between 1960 and 1979 contain some lead-based paint (Ref. 8). Over 12
million (or 19 percent) of these pre-1980 homes with some lead-based
paint have children aged 7 years or younger in residence (Ref. 8). (The
HUD National Survey presents results for children aged 7 years or
younger; Title X, which was enacted after the survey was conducted,
focuses upon children younger than 6 years.)
All homes containing lead-based paint pose a potential future
hazard to the occupants if the paint is not managed properly. Intact
lead-based paint may deteriorate over time to create a hazardous
condition. According to EPA's analysis of the HUD National Survey,
about 19 percent of pre-1980 privately-owned units contained non-intact
lead-based paint in 1989-90, which was defined at the time of the
survey as greater than 5 square feet of peeling, chipping, or otherwise
deteriorated paint (Ref. 8). Assuming that the percent of pre-1980
homes with non-intact lead-based paint that have young children is the
same as the percent of pre-1980 homes with some lead-based paint that
have young children (19 percent), about four percent of pre-1980 homes
in the United States contained both non-intact lead-based paint and
young children.
Based on the HUD National Survey, EPA estimates that 13 million or
17 percent of pre-1980 privately-owned homes have ``elevated'' lead
dust levels, which were defined at the time of the Survey as lead dust
exceeding 200 g/ft2 on floors, 500 g/
ft2 on window sills, or 800 g/ft2 on
window troughs (Ref. 8). Homes with non-intact lead-based paint were
five times more likely to have elevated lead dust levels than homes
with intact lead-based paint (Ref. 9).
EPA's analysis of the HUD National Survey also estimates that
approximately 16 million or 21 percent of privately-owned pre-1980
housing units have soil-lead concentrations exceeding 400 ppm (Ref. 8).
The prevalence of soil-lead levels exceeding 400 ppm varies greatly
with the age of housing. Sixty percent of pre-1940 units, but only
eight percent of 1940-1959 units and four percent of 1960-
[[Page 30306]]
1979 units have such soil-lead concentrations (Ref. 9).
B. Structure of Basic Legal Authorities
The Housing and Community Development Act of 1992 (Pub. L. 102-
550), enacted on October 29, 1992, contains 16 titles amending and
extending a number of laws relating to housing and community
development. Title X of this Act, entitled the ``Residential Lead-Based
Paint Hazard Reduction Act of 1992,'' contains five subtitles extending
and establishing programs for reducing exposure to lead, principally,
in paint and residential dust and soil. Provisions of Title X are
codified in the United States Code (U.S.C.) at volume 42, section 4851
and at various other sections of volume 42, as well as of volumes 12
and 15.
Subtitle A of Title X (codified at volume 42 U.S.C. 4852, and at
various other sections of volumes 42 and 12) applies primarily to
grants and other programs under the jurisdiction of the Secretary of
Housing and Urban Development (HUD). Subtitle B of Title X amends the
Toxic Substances Control Act (TSCA), 15 U.S.C. 2601, et. seq., by
adding Title IV, which requires EPA to establish requirements for
training and accreditation of contractors performing lead-based paint
related work, issue the standards being proposed today, sponsor public
education programs, establish programs for studying the effectiveness
of lead-based paint hazard evaluation and control products, and
establish a laboratory accreditation program. Subtitle C of Title X
deals with worker protection and training under jurisdiction of the
Occupational Safety and Health Administration (OSHA) and the National
Institute of Occupational Safety and Health (NIOSH). Subtitles D and E
provide for research and reporting on various aspects of lead-based
paint activities. These last three subtitles are codified at volume 42
U.S.C. 4853 to 4856.
An overview of the particular regulatory sections in the Subparts
of Title X that relate to this proposed rule follows.
1. EPA responsibilities. Under TSCA section 402 (15 U.S.C. 2682),
EPA has promulgated regulations governing the training and
certification of individuals and firms engaged in lead-based paint
activities, the accreditation of programs to train such individuals,
and work practice standards for conducting lead-based paint activities.
These regulations were published in the Federal Register of August 29,
1996 (61 FR 45778) (FRL-5389-9), and are codified at 40 CFR part 745,
subpart L. EPA will amend these regulations at a later date to address
deleading in public and commercial buildings, and other structures,
such as bridges.
In conjunction with these activities, EPA developed specific
guidelines under section 402(c)(1) for renovation and remodeling
activities that may create a risk of exposure to dangerous levels of
lead (Ref. 10). Under TSCA section 402(c)(3), EPA is required to revise
the certification and accreditation regulations under 40 CFR part 745,
subpart L, to address renovation and remodeling activities that create
lead-based paint hazards, after conducting a study of such activities.
In conjunction with the TSCA section 402 rule, EPA, under TSCA
section 404 (15 U.S.C. 2684), developed a Model State Program, which
States and Indian Tribes are encouraged to reference and use as
guidance to develop their own Federally-authorized lead-based paint
activities programs. The regulations in 40 CFR part 745, subpart Q,
include procedures for States and Indian Tribes to follow when applying
to EPA for authorization to administer and enforce a State or Tribal
training, accreditation, and certification program.
Under TSCA section 406(a) (15 U.S.C. 2686(a)), EPA, HUD, and CPSC
jointly released a lead hazard information pamphlet, Protect Your
Family from Lead in Your Home (60 FR 39167, August 1, 1995) (FRL-4966-
6). The pamphlet is designed to educate families about the potential
health risks associated with lead exposure and ways to avoid such
exposure.
Under TSCA section 406(b), EPA has promulgated a regulation to
require persons performing renovation work for compensation in
residential housing built before 1978 to provide owners and occupants
with a lead hazard information pamphlet before renovation begins.
Under Title X, section 1018 (42 U.S.C. 4852(d)), EPA and HUD have
jointly developed regulations requiring a seller or lessor of most pre-
1978 housing to disclose the presence of any known lead-based paint or
lead-based paint hazards to the purchaser or lessee (24 CFR part 35,
subpart H; 40 CFR part 745, subpart F). Under these rules, the seller
or lessor also must provide the purchaser or lessee any available
records or reports pertaining to such paint or hazards and a copy of
the lead hazard information pamphlet. Additionally, the seller must
allow the purchaser 10 days to conduct an inspection or risk assessment
for the presence of lead-based paint or lead-based paint hazards.
Finally, the sale or leasing contract must include certain disclosure
and acknowledgment provisions, and real estate agents must ensure
compliance with these standards.
2. HUD responsibilities. In addition, to the joint regulations
issued with EPA under section 1018 of Title X, HUD has a number of
programs under its own authorities that will be affected by the rule.
Under section 1011 of Title X (42 U.S.C. 4852), HUD provides grants
to State and local governments to evaluate and reduce lead-based paint
hazards in pre-1978 housing that qualifies as affordable housing and is
not Federally-assisted, Federally-owned, or public housing.
Under Title X sections 1012 and 1013, HUD is required to establish
lead-based paint hazard notification, evaluation, and reduction
requirements for HUD-associated housing and Federally-owned housing
under provisions codified at various parts of 42 U.S.C. These
regulations, which HUD proposed on June 7, 1996 (61 FR 29170), will
establish programmatic lead-based paint hazard notification,
evaluation, and reduction requirements and will describe how these
activities should be performed. The latter set of standards are based
on the detailed HUD Guidelines for the Evaluation and Control of Lead-
Based Paint Hazards in Housing (hereinafter HUD Guidelines) (Ref. 11),
which HUD developed under Title X section 1017 (42 U.S.C. 4852c), and
on EPA's TSCA section 402 standards described above. The HUD Guidelines
reflect input from housing, public health, and environmental
professionals with broad experience in lead-based paint hazard
identification and control.
3. Other agencies. The Department of Health and Human Services
(HHS), CPSC, the Department of Labor, and other Federal agencies have
contributed to the development of standards and other programs under
Title X, including through their consultation with EPA and HUD. EPA,
HUD, and CPSC jointly released the lead hazard information pamphlet in
consultation with CDC. Under section 1031 of Title X (subpart C), OSHA
promulgated interim final employee protection requirements for
construction workers exposed to lead, which apply to lead-based paint
activities in residential housing and other construction settings (29
CFR 1926.62).
C. Regulatory Development Process
EPA began development of the proposed rule immediately following
enactment of Title X. The Agency quickly encountered significant
challenges in its design and
[[Page 30307]]
implementation of the risk and economic analyses needed to guide
selection of the standards. Recognizing the growing need for advice on
this issue, EPA released an interim guidance document in July 1994 to
provide public and private decision-makers with guidance on identifying
and prioritizing lead-based paint hazards for control. The
recommendations in the guidance represented the Agency's best judgment
given the state of knowledge at the time. EPA subsequently published
the interim guidance document in the Federal Register of September 11,
1995 (60 FR 47248) (FRL-4969-6). The interim guidance will continue to
serve as EPA's official policy until EPA promulgates final standards
under TSCA section 403.
The TSCA section 403 regulations are a significant component of the
national lead-based paint hazard reduction program. As such, these
regulations will likely have a broad impact on public health and
housing. In light of these potential impacts as well as intense
interest in this proposed rule expressed by a large number of
stakeholders, EPA established a Dialogue Process to provide a forum
where EPA could obtain input early in the rulemaking process from
representatives of a range of groups that have an interest in the TSCA
section 403 regulations. Interested parties included lead-poisoning
prevention experts, environmental advocates, housing providers, the
lead industry, State and local governments, the banking and insurance
industries, and the lead risk assessment and abatement industry. EPA
did not use the Dialogue Process to develop a consensus among the
participants, but rather used the Process to gather individual points
of view. Meetings were open to the public and a summary of each meeting
was placed in the public record for this proposed rule (Refs. 12-16).
EPA held five meetings using the Dialogue Process: October 19,
1995; December 14, 1995; February 15, 1996; March 21, 1996; and
November 12, 1997. The first four meetings focused on a range of policy
and implementation issues for which EPA presented a range of potential
options. Participants commented on these options and sometimes
suggested options EPA had not previously considered. Dialogue Process
participants also identified issues EPA had not presented to the group.
The Dialogue Process did not address questions related to the risk
analysis or the technical basis for the rule. These are important and
difficult issues but were beyond the scope of the policy level input
EPA was seeking from the Dialogue. The Agency, instead, presented its
risk analysis document for an expedited peer review in August 1997.
Comments provided by the reviewers can be found in the public record
for this proposed rule. EPA will also ask its Science Advisory Board
(SAB) to review the risk analysis during the public comment period for
today's proposed rule. The SAB report will also be placed in the public
record, and EPA will consider this report in its development of the
final rule.
At the final meeting, EPA staff presented a draft of the options
for the proposed rule being recommended to senior Agency managers. This
meeting provided an opportunity for interested parties to express their
concerns about the current direction of the proposed rule and allowed
EPA to address these concerns by clarifying the Agency's rationale or
by seeking additional input. By addressing the concerns of interested
parties in the proposal, EPA hopes to facilitate the process of
finalizing the proposed regulations.
In addition to the Dialogue Process, EPA staff met with the public
in a variety of other forums to discuss issues related to the rule.
These forums included conferences sponsored by trade associations,
seminars sponsored by real estate groups (e.g., Owners and Managers
Group of the Mid-Atlantic Region, Real Estate Board of New York) and
legal publications (e.g., New York Law Journal), and meetings with
interested parties. In most of these settings, EPA staff provided an
update on the status of the rulemaking and responded to questions.
Occasionally, EPA met with interested parties to obtain information on
specific issues of concern. For example, Agency staff met with
representatives of rental property owners to gauge owner response to
the regulatory standards. In several instances, interested parties
requested meetings with EPA to provide their perspective on specific
regulatory and/or technical issues. EPA has placed a summary of all
meetings between its staff and interested parties in the public record
for this proposed rule (Ref. 17). EPA did not prepare summaries of
presentations delivered at conferences and seminars.
D. General Approach to Standard Setting
Before EPA could formulate and analyze options for the TSCA section
403 standards, the Agency had to develop an overall approach for the
rulemaking. EPA's standard-setting approach was based on the outcome of
two decisions. The first decision was whether the Agency should develop
uniform national standards or standards that are targeted (e.g., to
specific communities or populations). The second decision was whether
EPA should develop independent, media-specific standards or joint
standards. This unit presents EPA's analysis of these issues and its
decisions.
1. Uniform, national standards, or targeted standards. The
establishment of the standards in today's proposal required estimates
of the relationship between environmental lead levels (from paint,
dust, and soil) and their effects on the health of exposed children.
This relationship is extremely complex, and is dependent upon numerous
site-specific and child-specific factors. These estimates are more
accurate on a smaller (residence or community) scale, where more site-
specific factors can be considered.
A targeted approach to standard-setting (i.e., community- or
resident-specific standards) would result in numerically different
standards for each residence or community. Developing national
standards, on the other hand, would produce the same numerical standard
for all residences and communities, but with an attendant loss of
accuracy. That is, national standards would be more protective at some
locations and less protective at others because national standards
would not account for community- or residence-specific factors.
EPA decided, based on considerations of feasibility and ease of
implementation, that national standards are the most appropriate
regulatory approach. First, the data needed to establish standards at a
smaller scale are neither collected under the Title X program nor
available for communities nationwide. Much of the necessary residence-
specific data could be collected to establish residence-specific
standards, but lead-based paint risk assessments would have to be
broader in scope (i.e., include water sampling and sampling of other
ambient environmental levels) and more costly than currently
envisioned. Even then, residence-specific standards would not account
for variability in exposure influenced by child-specific factors (e.g.,
hand-to-mouth behavior, hygiene, nutrition). Community-specific data
would require new resource-intensive data collection efforts (e.g,
patterns of soil contamination, water lead levels). In contrast,
national data on lead in paint, dust, and soil are currently available.
Second, uniform national standards are easier to implement.
National standards provide a fixed basis of comparison for all homes.
National standards can also be used to compare
[[Page 30308]]
properties and establish priorities. In contrast, with residence-
specific standards, there would be millions of standards. Such a
regulation would be largely unworkable. Property owners and other
decision-makers would not know what standard would apply until a hazard
evaluation was conducted. Rental property owners who own multiple
properties would be working with a different standard for each
property. In addition, residence-specific standards would not help
establish priorities because it would be extremely difficult to compare
the relative needs of different properties.
In making this decision, the Agency was also mindful that certain
segments of the population have a higher incidence of elevated blood-
lead levels (e.g., some minority children in inner-city neighborhoods)
and a case could be made for proposing more stringent standards for
particular neighborhoods. However, estimates of the relationship
between environmental lead levels and children's health effects are not
sufficiently refined to distinguish relationships for particular
subsets of the general population of children.
In light of the recently released NHANES III, Phase 2 data, EPA
considered an alternative option under which uniform standards would
only be effective in higher risk communities. EPA, however, rejected
this option because there is insufficient data to definitively identify
these higher risk communities. In addition, the development of
standards for higher risk communities would introduce significant
complexities. First, EPA would have to establish criteria for
identifying these communities. Second, the Agency would have to develop
a set of standards for each category of community. Third, EPA would
have to develop an approach for addressing neighborhoods that border on
higher risk communities. As an alternative, the Agency believes that an
effective and simpler approach to address vulnerable communities is
through program implementation (e.g., training, education, and
environmental justice grants).
EPA also wishes to note that Congress envisioned that important
elements of the Title X program would be delegated to the States.
Accordingly, the Agency preferred to establish a simple, minimal set of
standards that could easily be adopted by States and allow them to
tailor the standards (i.e., by considering more site-specific factors),
should they so choose. Consequently, States will have greater
flexibility in establishing and implementing their programs while a
national, baseline level of protection to children is maintained.
Because the decision to set uniform national standards has a
significant impact on the standard-setting process, EPA is interested
in obtaining comment on this issue. The Agency would like specific
input on how EPA should set standards that will ensure national
resources are targeted commensurate with risk.
2. Joint, media-specific standards vs. joint standards. The second
issue that shaped EPA's standard-setting approach involves the fact
that a child's total lead exposure is the sum of contributions from
numerous sources, including paint, dust, soil, and others.
Specifically, EPA had to decide whether to set separate, independent
standards for paint, dust, and soil or to integrate the standards.
Under the first option, EPA would establish the standard for each
medium without considering the conditions in the other media. For
example, the standard for soil would not be affected by the level of
lead in dust. The soil standard would remain constant, regardless of
whether dust lead levels were high or low. The chief advantage of this
option is that the standards are simple to understand and use. The main
disadvantage is that the standard for each medium may not correspond to
total exposure and risk.
[GRAPHIC] [TIFF OMITTED] TP03JN98.000
Under the second option, EPA would set standards to account for
total lead exposure from all media. Under a joint standard, the
standard for each medium would vary, depending on the conditions in the
other media. For example, the Agency could graphically represent
combinations of hazardous levels of lead in dust and soil with a
downward sloping line. In this graph, shown in Figure 1, the horizontal
axis could depict the level of lead in soil.
[[Page 30309]]
The vertical axis could depict the level of lead in dust. Any point on
this chart, therefore, would illustrate a combination of lead dust and
lead soil levels. The downward sloping line would intersect the
horizontal axis at the point representing the highest acceptable level
of lead in soil if there is no lead in dust. The line would intersect
the vertical axis at the point representing the highest acceptable
level of lead in dust if there were no lead in soil. All points above
the line would be defined as hazardous. To incorporate the condition of
paint into the joint dust and soil standards, the Agency, in theory,
could establish two downward sloping lines: one for homes with no
deteriorated lead-based paint and another for homes with deteriorated
lead-based paint. The major advantage of the joint standards is that
they better reflect the total exposure and risk. On the other hand,
joint standards are more difficult to explain, understand, and use.
Normally, EPA would tend to favor the approach that better reflects
risk to human health. Certainly the joint standard approach described
above would be the approach of choice in evaluating the environmental
risks to a child in a specific house. In the context of this proposed
rule, however, EPA has concluded that single, medium-specific standards
would be far more workable than joint standards for many of the same
reasons that national standards are more workable than targeted
standards. First, media-specific standards provide a fixed basis of
comparison for all homes and can be used to compare properties and
establish priorities. Second, EPA believes that fixed numerical
standards are more easily understood than standards that require an
understanding of mathematical relationships. In addition, the Agency
does not currently possess the analytical techniques necessary to
relate dust loadings to soil concentrations, the measurement basis for
the dust and soil standards. Consequently, EPA lacks a technical method
to establish joint standards.
III. Section-by-Section Review of the Proposed Rule
This unit of the preamble provides a section-by-section explanation
of the proposed regulations. The proposed regulations consist of five
components: the proposed section 403 standards for lead-based paint
hazards; amendments to the final section 402 regulations; amendments to
the final section 404 regulations; and definitions for specific terms.
The unit focuses on the proposed section 403 standards, the proposed
amendments to the final section 402 regulations, and the amendments to
the final section 404 regulation. The definitions are discussed in
relation to the relevant proposed regulatory provisions. Furthermore,
the definitions in proposed Sec. 745.63 that already exist in 40 CFR
745.223 are not subject to public comment.
A. Proposed Section 403 Standards
The TSCA section 403 standards consist of three parts: scope and
applicability; the standards for lead-based paint hazards; and
provisions for implementing the standards.
1. Scope and applicability. The scope and applicability part of the
standards, which is stated in proposed Sec. 745.61, would establish
that the proposed standards would apply to target housing (i.e., most
pre-1978 housing) and child-occupied facilities.
This part of the proposed rule also makes it clear that the TSCA
section 403 standards do not require the owner of properties covered by
this proposed rule to evaluate his/her properties for the presence of
lead-based paint hazards, or to take any action to control these
conditions if one or more of them is identified.
2. Standards for lead-based paint hazards. The proposed standards
for lead-based paint hazards are codified in proposed Sec. 745.65.
Proposed Sec. 745.65(a) states that hazardous lead-based paint includes
lead-based paint in poor condition. Proposed Sec. 745.63 defines paint
in poor condition as more than 10 square feet of deteriorated paint on
exterior components with large surface areas, more than 2 square feet
of deteriorated paint on interior components with large surface areas
(e.g., walls, ceilings, floors), or deteriorated paint on more than 10
percent of the total surface area of interior or exterior components
with small surface areas (e.g., trim, baseboards). EPA is not proposing
hazardous lead-based paint standards for accessible surfaces and
friction and impact surfaces. The Agency, instead, has presented a
range of options for these standards, which are discussed in Unit
IV.D.2 and IV.D.3. of this preamble. EPA is seeking public comment on
these options and will promulgate standards as part of the final rule
based on these options and consideration of public input.
Proposed Sec. 745.65(b) identifies dust-lead hazards in terms of
lead loading and location. Lead loading is the quantity of lead present
per unit of surface area (e.g., micrograms per square foot). The
proposed dust-lead hazard standard is 50 g/ft2 for
uncarpeted floors and 250 g/ft2 for interior window
sills. The proposed rule does not include a dust-lead hazard standard
for carpeted floors or for window troughs.
Proposed Sec. 745.65(c) identifies soil-lead hazards in terms of
lead concentration. Lead concentration is the relative content of lead
within the soil measured in parts per million by weight. The proposed
standard for soil-lead hazard is 2,000 ppm.
3. Proposed requirements for implementing the standards. This part
of the proposal describes the requirements for how a certified risk
assessor would compare on-site observations and sampling results to the
standards to determine whether lead-based paint hazards are present.
The general requirements are in Sec. 745.69. EPA has incorporated the
specific requirements, which are summarized in Table 1 below, into the
work practice standards for lead-based paint activities found at 40 CFR
745.227.
Proposed Sec. 745.69 would establish that the determination
requirements are applicable to the standards for lead-based paint
hazards. It also states that the determination would have to be made by
a certified risk assessor performing a risk assessment according to the
risk assessment work practice standards. Third, the proposed
regulations state that, for purposes of determining the presence of a
dust-lead hazard, the risk assessor must compare the weighted
arithmetic means of the samples to the applicable standard. For
purposes of determining the presence of soil-lead hazards, the risk
assessor must compare the arithmetic means of the samples to the
applicable standard.
Table 1.--Summary of Regulations for Determining the Presence of Lead-
Based Paint Hazards
------------------------------------------------------------------------
Type and Location of Hazard/Contamination Method
------------------------------------------------------------------------
Hazardous lead-based paint: lead-based Visual assessment for
paint in poor condition condition of paint; test
paint; assume all like
surfaces that have similar
painting history contain
lead-based paint if tested
component has lead-based
paint
[[Page 30310]]
Dust-lead hazard: uncarpeted floors Compare weighted arithmetic
(single-family and sampled units and mean lead loading of all
common areas in multi-family) samples for uncarpeted
floors to the hazard
standard for floors
Dust-lead hazard: interior window sills Compare weighted arithmetic
(single-family and sampled units and mean lead loading of all
common areas in multi-family) samples for interior window
sills to the hazard standard
for sills
Dust-lead hazard: uncarpeted floors Assumed to be hazard if
(unsampled units and common areas in hazard is present in any
multi-family) sampled unit or common area
of the same type
Dust-lead hazard: interior window sills Assumed to be hazard if
(unsampled units and common areas in hazard is present in any
multi-family) sampled unit or common area
of the same type
Soil-lead hazard Compare arithmetic mean of
dripline and mid-yard
samples to hazard standard
------------------------------------------------------------------------
Proposed Sec. 745.227(h) would establish the specific requirements
for how to determine whether lead-based paint hazards are present. To
determine whether hazardous lead-based paint is present, the risk
assessor must test paint that is in poor condition. The paint on all
surfaces with paint in poor condition need not be tested. The risk
assessor, however, must assume that untested surfaces contain lead-
based paint if tested surfaces that have a similar painting history
contain lead-based paint.
To determine whether a dust-lead hazard is present, the risk
assessor must compare the weighted mean (i.e., weighted average) of all
single surface samples or all composite samples to the appropriate
dust-lead hazard standard (i.e., uncarpeted floors, interior window
sills).
In multi-family housing, where risk assessors have the option not
to collect dust samples in every residential unit or common area, the
approach described in the previous paragraph applies to all sampled
residential units and common areas where samples were collected. For
residential units or common areas where samples are not collected, the
risk assessor would have to make assumptions based on the results of
sampled residential units and common areas. If at least one sampled
residential unit or common area exceeds the hazard standard for a
specific surface (i.e, floors, sills), then the risk assessor would
have to assume that hazards exist on that surface in all unsampled
residential units and common areas. It should be noted that risk
assessors always have the option to collect samples from all units and
common areas at a multi-family property.
Proposed Sec. 745.227(h) also would establish the requirements for
how to determine whether a soil-lead hazard is present. Under the
proposal, the risk assessor must compare the mean of a composite sample
from the dripline and a composite sample from the mid-yard for each
residential building to the standards to determine whether a hazard is
present. If the risk assessor collects more than one composite in
either the dripline or the mid-yard for a building, he or she should
compute the average of the composites from each area and use those
averages to compute the average concentration for the dripline and the
mid-yard.
Proposed Sec. 745.63 defines the dripline and mid-yard. The
dripline is the area within 3 feet surrounding the perimeter of a
building. The mid-yard is the part of yard that lies halfway between
the outermost edge of the dripline and property line or between the
outermost edge of the dripline and the outermost edge of the dripline
of another residential building on the same property. This approach
applies to both properties with a single residential building and to
those with more than one residential building.
B. Proposed Amendments to the Final Section 402 Regulations
Today's action includes proposed amendments to the final TSCA
section 402 work practice regulations for lead-based paint activities
at 40 CFR 745.227. The proposed amendments would establish clearance
standards for dust, limit reuse of abated soil, add a requirement for
interpreting composite dust clearance samples, and change risk
assessment and clearance sampling requirements to ensure compatibility
between sampling results and the TSCA section 403 standards and section
402 clearance standards. Unit IX. of this preamble discusses these
amendments and the Agency's rationale and supporting analyses for its
decisions.
Today's action proposes to amend the abatement work practice
standards at 40 CFR 745.227(e) by adding clearance standards for dust.
A risk assessor performs clearance testing to evaluate the adequacy of
post-abatement dust cleaning. The proposed clearance standards are 50
g/ft2 for uncarpeted floors, 250 g/
ft2 for interior window sills, and 800 g/ft2
for window troughs.
Second, today's action includes a proposed amendment to the
abatement work practice standards at 40 CFR 745.227(e) to prohibit the
reuse of soil removed during an abatement as top soil in another
residential yard or child-occupied facility. The current regulations do
not provide any management controls for the soil.
Third, today's proposal includes an amendment to the abatement work
practice standards at 40 CFR 745.227(e) to add a requirement for
interpreting composite dust samples for clearance. The current
regulation does not differentiate between single surface samples and
composite samples. The proposed amendment would require the risk
assessor to compare the composite sample to the clearance standard
divided by the number of subsamples in the composite. For example, if
the composite contains four subsamples, the risk assessor would compare
the composite to the clearance standard divided by four.
Fourth, the Agency is proposing that the risk assessment work
practice standards at 40 CFR 745.227 be amended to require that risk
assessor collect dust samples from uncarpeted floors and interior
window sills because EPA is proposing dust-lead hazard standards for
uncarpeted floors and window sills. Today's proposal also includes an
amendment to the abatement work practice standards at 40 CFR 745.227(e)
to require that a risk assessor collect dust clearance samples from
uncarpeted floors, window sills, and window troughs because EPA is
proposing clearance standards for all three surfaces. The current risk
assessment and abatement work practice standards require risk assessors
to collect dust samples from windows without specifying the part of the
window. The Agency is also proposing to amend the risk assessment work
practice standards to change the
[[Page 30311]]
location of soil samples from the dripline and ``play area'' to the
dripline and mid-yard.
C. Proposed Amendments to the Final Section 404 Regulations
Today's action includes proposed amendments to the final TSCA
section 404 States/Tribal program authorization regulations found at 40
CFR part 745, subpart Q. These proposed amendments would require
States/Tribes that are seeking program authorization and States/Tribes
that already have applied for authorization and wish to retain it to
incorporate lead-based paint hazard standards that are as protective as
the Federal standards no later than their first report to EPA after
years following the promulgation of the TSCA section 403 standards.
States/Tribes seeking authorization for the first time would
include their standards in their program application, the requirements
for which are described in 40 CFR 745.320 to 40 CFR 745.325. Proposed
amendments to Sec. 745.325, would explicitly clarify that lead-based
paint hazard standards and implementation requirements are necessary
components of the risk assessment work practice standards in
Sec. 745.325(d)(2). States/Tribes seeking to retain program
authorization would describe their standards in their regular report to
EPA in accordance with 40 CFR 745.324(h).
IV. Development of this Proposed Rule
This unit of the preamble presents EPA's analysis of its legal
authority, and describes the Agency's policy basis, technical analyses,
and decisions for the proposed section 403 standards. Section A
discusses EPA's legal authority and policy basis for the standards.
Section B discusses the technical analysis to support the development
of the proposed standards for dust and soil. Section C presents EPA's
analysis of the options for dust and soil standards and explains the
Agency's decisions. Section D presents the analysis of the options for
the paint hazard standard and explains the Agency's decisions. The
standard for lead-based paint, as further explained below, is defined
by statute and EPA is not modifying that standard in this proposed
rule.
A. Authority for Today's Action
1. Statutory mandate and related definitions. Section 403 of TSCA
is the key statutory provision for today's proposed regulation. It
requires EPA to identify three terms--lead-based paint hazards, lead-
contaminated dust, and lead-contaminated soil. For reasons explained
below, EPA needs to first define lead-contaminated dust and soil before
it may define lead-based paint hazards. These three terms and other
definitions that help define them are found in both TSCA section 401
(15 U.S.C. 2681) and in section 1004 of Title X (42 U.S.C. 4851b).
Because the definitions in both of these sections are identical for
practical purposes, the remainder of this preamble will cite the TSCA
definitions. Below, EPA explains how the definitions affect the
Agency's responsibilities in this proposed rule.
TSCA section 401(10) defines ``lead-based paint hazard'' to mean
any condition that causes exposure to lead from lead-contaminated dust,
lead-contaminated soil, lead-contaminated paint that is deteriorated or
present in accessible surfaces, friction surfaces, or impact surfaces
that would result in adverse human health effects . . . [emphasis
added].
Thus, there are three sources that may contribute to the existence of a
lead-based paint hazard--lead-contaminated paint, lead-contaminated
dust, and lead-contaminated soil.
EPA interprets lead-contaminated paint to mean the same as ``lead-
based paint,'' which is defined by TSCA section 401(9) to mean paint or
other surface coatings that contain lead in concentrations equaling or
exceeding limits established under section 302(c) of the Lead Based
Paint Poisoning Prevention Act (42 U.S.C. 4822(c)). Currently, this
limit is lead content that equals or exceeds 1.0 milligrams per square
centimeter (mg/cm2) or 0.5 percent by weight. EPA is not
taking any action in this proposed rule to redefine lead-based paint.
It must be emphasized that lead-based paint is not a risk-based
term. It is only a benchmark that identifies material subject to the
jurisdiction of various authorities of TSCA and Title X. Instead, the
term ``lead-based paint hazard'' will identify those conditions of
lead-based paint that would result in adverse health effects. The
statutory language makes it clear that not all lead-based paint is to
be considered a lead-based paint hazard. In fact, for lead paint to be
a hazard it must, at least, be deteriorated or be present on friction
or impact surfaces or on surfaces accessible for young children to
mouth or chew. Deteriorated paint is defined in TSCA 401(3). Friction,
impact, and accessible surfaces are defined in TSCA 401(2), (5) and
(6).
Lead-based paint hazards, furthermore, are not limited to the
hazards from paint, alone, because they include conditions that cause
exposure to residential lead-contaminated dust and soil, regardless of
the source of lead. EPA is responsible in this proposed rule for
identifying what constitutes lead-contaminated dust and soil. Both
terms are limited to dust and soil in residences, in contrast to lead
paint, which may be found in public and commercial buildings and in
other structures, such as bridges or superstructures (e.g., water
towers).
Lead-contaminated dust means surface dust in residential dwellings
that contains lead determined by EPA to pose a threat of adverse health
effects in pregnant women or young children [emphasis added] (TSCA
401(11)). Lead-contaminated soil means bare soil on residential
property that contains lead that is determined to be hazardous to human
health by EPA (TSCA 401(12)) [emphasis added].
The lead-based paint hazard definition contains the overarching
legal standard applicable to today's proposed regulation. In pertinent
part, the definition means any condition that causes exposure to lead-
contaminated dust, soil, or paint that would result in adverse human
health effects. To determine what constitutes lead-contaminated dust or
soil, on the other hand, EPA interprets the statute to require a less
rigorous level of certainty regarding the likelihood of adverse effects
occurring to establish the standards.
2. Statutory criteria for lead-contaminated dust and soil, and
lead-based paint hazards. Given the definitions of lead-based paint
hazards, lead-contaminated dust, and lead-contaminated soil in TSCA
section 401, EPA needs to establish standards for lead-contaminated
dust and soil separately from lead-based paint hazards. Put simply, not
all lead-contaminated dust or lead-contaminated soil (or lead-based
paint) needs to be considered hazardous. In fact, as explained below,
the definitions in TSCA section 401 support the Agency's adoption of a
weight of evidence approach for setting the varying standards.
To help differentiate between lead-contaminated dust and soil and
lead-contaminated dust and soil that are lead-based paint hazards, and
to alleviate the confusion created by this terminology, the Agency will
generally refer to lead-contaminated dust and soil that meet the lead-
based paint hazard criteria as dust-lead hazards and soil-lead hazards.
EPA will refer to the paint component of lead-based paint hazards as
hazardous lead-based paint.
a. Contamination standards. As indicated above, EPA believes that
the term ``poses a threat,'' used to define
[[Page 30312]]
lead-contaminated dust, connotes a lower level of certainty regarding
risk than the term ``would result in adverse effects,'' used to define
lead-based paint hazard, and indicates that the standard for lead-
contaminated dust requires a lesser weight of evidence of harm. The
level of certainty associated with the term ``hazardous to human
health,'' which is used to define lead-contaminated soil, is less
clear. The overall structure of the definitions in section 401,
however, indicates parallel treatment for lead-contaminated dust and
soil. EPA is, therefore, interpreting ``poses a threat'' and
``hazardous to human health'' to be associated with the same level of
evidence needed to determine risk.
The terms ``lead-contaminated'' dust and soil, therefore, describe
the universe of lead in soil and dust about which there may be some
level of concern. Within this universe are levels of lead-contaminated
dust and soil that result in lead-based paint hazards, which engender
greater concern because there is greater certainty of risk of adverse
human health effects. Identifying hazardous paint, dust, and soil,
therefore, requires a greater weight of evidence of harm.
The terms lead-contaminated dust and lead-contaminated soil, while
necessary components of the definition of lead-based paint hazards, do
not appear anywhere else in Title X. Thus, they have no direct effect
on any activities subject to regulation under Title X. For example, no
certification requirements are imposed for persons who remove lead-
contaminated soil, only soil associated with soil-lead hazards. EPA
concludes from this observation that the purpose for identifying lead-
contaminated dust and soil separately from hazardous dust and soil is
to identify levels of dust and soil contamination for which there are
lower levels of certainty regarding adverse effects and general
population concern, but about which owners and occupants of residential
property should be aware. Individual owners and occupants may wish to
make decisions based on the lesser level of certainty. To convey this
message, EPA has decided to call the standards for lead-contaminated
dust and soil, dust-lead and soil-lead ``levels of concern.'' EPA has
decided that the levels of concern should be based solely on their
potential to pose a threat to human health, without regard to whether
taking action on these levels could result in significant risk
reduction, or whether the resources that persons may choose to expend
on dealing with dust and soil at these levels are commensurate with any
potential risk reduction.
Because the level of concern does not affect other activities under
Title X or TSCA Title IV, EPA has decided not to include the levels of
concern in the proposed regulation. Nevertheless, because the level of
concern communicates important risk information to property owners and
occupants, the Agency believes that it is important to include the
levels of concern in the preamble and guidance that will accompany the
rule. At this point, the Agency is only proposing to adopt in guidance
a separate level of concern for lead in soil, which is discussed in
detail in Unit IV of this preamble. The Agency has decided that there
should not be a separate dust-lead level of concern, even in guidance,
because EPA's analysis shows that dust-lead level of concern should be
the same as the dust-lead hazard standard. The Agency believes,
therefore, that having a separate dust-lead level of concern would not
provide useful additional information to the public.
EPA is interested in public input with respect to the inclusion of
the levels of concern, particularly for soil, in the regulatory text of
the document. Specifically, EPA is seeking comment on whether the
absence of the soil-lead level of concern in the regulation would
diminish the visibility of the level and reduce its usefulness as a
risk communication tool, or whether the soil-lead level of concern
would be treated as the de facto hazard standard if it were included in
the regulation. EPA does not believe that the public should confuse the
soil-lead level of concern in the guidance, with the soil-lead hazard
standard in the regulation. As indicated above, the Agency is
specifically interested in comments on this issue.
b. Hazard standards. The determination of what constitutes lead-
based paint hazards--hazardous paint, dust, and soil--will require a
more elaborate analysis. Clearly, the statutory criterion for hazard,
``would result in adverse human health effects,'' means that lead-based
paint hazards are associated with a higher level of risk than levels of
concern. The challenge to the Agency is how to identify the higher
level of risk.
Based on the language of section 403, the purposes of Title X and
its legislative history, and basic policy discussions explained below,
EPA determined that it should identify this higher level of risk based
on consideration of the potential for risk reduction of any action
taken (considering uncertainties in the scientific evidence describing
the risks) and whether such risk reductions are commensurate with the
costs of those actions. This is commonly referred to as cost-benefit
balancing.
The use of the term ``would result'' in the statutory criteria --
``would result in adverse human health effects''--implies certainty of
adverse outcome. This interpretation is supported the by legislative
history discussed in the Senate Committee Report (National Affordable
Housing Act Amendments of 1992, Report of the Committee on Banking,
Housing and Urban Affairs, S. Rep. 102-332, 102d Cong., 2nd Sess., at
112 (hereinafter ``Senate Report'')). The Senate Report states that
Title X ``limits the definition of hazard, and thus the scope of the
bill to actual hazards--conditions that cause [ ] exposure to lead . .
. that would result in adverse human effects'' [emphasis added] (Senate
report, page 112).
Dealing with what would constitute an ``actual'' effect is the
dilemma posed by the statutory language. EPA's interpretation of the
broader Title X framework suggests that lead-based paint hazard
standards should not be based on absolute certainty. If the EPA were to
follow Congress' literal wording, available evidence would only allow
the Agency to set unreasonably high dust, soil, or paint hazard
standards. EPA does not believe that this is an appropriate formulation
of Congressional intent. As stated in section 1103(3), one purpose of
Title X is ``to encourage effective action to prevent childhood lead
poisoning'' (emphasis added). To follow this directive, EPA needs to
establish hazard standards that predict adverse health outcomes based
on their environmental observations and measurements. Due to the large
amount of variability in the relationship between environmental lead
levels and blood-lead concentrations, it is not possible to state with
certainty that a given set of environmental conditions would result in
an actual adverse outcome. EPA, therefore, has not used an absolute
certainty criterion but rather interprets the statute to require a
level of certainty regarding risk that is higher than that used for the
contamination standard--the ``level of concern.''
It is possible, however, to state that there is a relatively high
likelihood that an adverse outcome will occur. The dilemma the Agency
faces in this case would be that hazards would be identified only at
the very highest levels. Thus, for example, EPA could say that adverse
effects ``would result'' only when an individual child has a 100
percent probability of having a blood-
[[Page 30313]]
lead concentration equal to or exceeding 10 g/dl. Using this
100 percent probability criterion as the basis for setting hazard
standards, however, would contribute little, if anything, to the
statutory intent of preventing adverse effects. Moreover, the
environmental lead levels associated with this probability level would
be so high that they would likely apply to only a very small number of
situations--for example, soil levels well over 5,000 ppm or dust lead
levels well over 500 g/ft2. Children exposed to
significantly lower levels could be subject to substantial risk that
would be ignored in the national lead program. Therefore, EPA has
elected not to use such a formulation.
Accordingly, EPA examined the statute and its legislative history
for guidance on how to select appropriate parameters for identifying
lead-based paint hazards. Based on this analysis, the Agency concluded,
for the following reasons, that the hazard standards should be based on
a set of parameters identified by balancing the costs of reducing
exposures to lead-based paint hazards with the benefits of avoiding
adverse human health effects.
First, the identification of lead-based paint hazards is linked
with hazard reduction in many provisions of Title X, including sections
1011(e)(8) and (9), 1012(a) and (e), and TSCA section 401(8) and (13).
This linkage suggests that measures taken to reduce hazards should be
consistent with the risks presented. The Senate Report, recognizing
that many property owners would implement interim controls to respond
to lead-based paint hazards, states that ``interim measures should be
commensurate with the degrees of risk reported by the risk assessment''
(p. 115). The Report is most explicit in its discussion of lead-based
paint hazard reduction in Federally assisted and insured housing, where
it states that ``the response would correspond to the degree of danger
and the benefit to be achieved'' (p. 117). Cost-benefit balancing is a
reasonable method that can be used to assist EPA in setting hazard
standards that would promote control activities that are commensurate
with risk.
Second, cost-benefit balancing is a useful method to examine the
potential for adverse effects, the resource allocation that should be
associated with reducing that potential, and methods of public
protection when the available scientific evidence shows there is a wide
range of uncertainty in the risks that may be associated with any
particular levels. The Senate Report recognized that there is a wide
range of responses applicable to lead-based paint and paint hazards
depending on the degree of risk and the likelihood of risk reduction
that could occur from any particular action. In particular, property
owners can choose to reduce hazards through ``abatement'' (permanent
elimination of hazards) or ``interim measures'' (temporary exposure
reduction). See TSCA sections 401(1), (8), and (13). The Senate Report
at 113-115 specifically refers to this wide range of applicable
responses and the need to consider measures commensurate with the risk.
The Senate Report at 113 states that housing owners
will choose to abate or partially abate when they determine that
it is cost effective for them to permanently eliminate the source of
hazards.
Further, the Senate Report at 115 states that interim measures
should be commensurate with the degree of risk reported by the
risk assessment. Thus, where moderately elevated dust levels exist
but there is little deterioration in the paint, an appropriate
interim response might be limited to supercleaning leaded surfaces.
Where children are present and paint is peeling, interim controls
might require a more substantial effort and expense to prevent
exposure from paint chips and dust.
Given these standards, EPA believes that it is a reasonable
interpretation of TSCA section 403 to identify the conditions that
constitute lead-based paint hazards by considering the weight of
evidence on the range of environmental lead levels that would result in
particular blood lead levels, the adverse effects associated with those
blood-lead concentrations, and potential ranges of risk reduction
(reductions in blood-lead concentration) that would result from
eliminating or controlling the levels.
Several purposes of Title X also support the use of cost-benefit
balancing for establishing the hazard standards. According to section
1003(2) of Title X, one purpose of the statute is ``to implement, on a
priority basis, a broad program to evaluate and reduce lead-based paint
hazards in the Nation's housing stock.'' The concept of priority-
setting inherently recognizes that resources are scarce, and that
scarce resources are most effectively employed when decision-makers
apply them to the worst problems first. To develop standards that are
consistent with the need to set priorities, EPA factored in the
resources needed to reduce risks, the benefits of controlling lead-
based paint hazards, and data on the presence of lead in residential
paint, dust, and soil when selecting the proposed standards. Cost-
benefit analysis is a principal analytical tool available to the Agency
to measure the effectiveness of using resources to reduce human health
risks.
Section 1003(3) of Title X also states that a purpose of the
statute is ``to encourage effective action to prevent childhood lead
poisoning by establishing a workable framework for lead-based paint
hazard evaluation and reduction. . . .'' In developing today's
proposal, EPA interprets the term ``workable'' to mean practical,
usable, and realistic. First, a workable framework must be practical;
that is, it should promote priority-setting, focusing resources on the
most significant risks. Overly stringent standards that result in the
identification of lead-based paint hazards in large segments of the
housing stock would not be practical because they would not provide
guidance to decision-makers on where to focus resources.
Second, the standards must be usable by the intended audience. Risk
assessors must be able to use the standards as a tool to evaluate
properties quickly at a modest cost. The standards should not require
extensive and costly environmental measurement. The meaning of the
standards must be sufficiently simple for risk assessors to explain and
property owners, residents, and other decision-makers to understand the
significance of the findings of a risk assessment.
Third, for a framework to be workable, it needs to be based on
realistic goals, goals that are achievable with available resources and
feasible with available technology. The standards for identifying lead-
based paint hazards, therefore, need to recognize resource and
technological constraints. These standards, the primary function of
which is to provide guidance and advice, risk being ignored by their
intended audience and having no value if they are not practical,
usable, and realistic.
Section 1003(3) also refers to the Title X purpose of ``. . .
ending the current confusion over reasonable standards of care.'' EPA
interprets a ``reasonable'' standard to be one that requires exercise
of judgment to balance the probability that harm will occur, and the
magnitude and severity of that harm, against the adverse social and
economic impacts on society of the action taken to reduce the harm. The
reasonableness standard becomes more judgmental in the case of health
risks of lead where, as a practical matter, all the scientific evidence
is uncertain to some degree and EPA is forced to deal in probabilities
that can vary over extreme ranges. Therefore, in evaluating a
reasonable standard of care
[[Page 30314]]
under Title X, EPA will consider the various relationships among such
factors as toxicity, exposure, the effectiveness of interventions, and
the cost of interventions.
EPA, further, believes that consideration of cost is consistent
with the establishment of these lead standards. The purpose of the lead
hazard standards is to protect the public health. To do this within the
framework of Title X, however, requires the expenditure of scarce
public and private resources. Ensuring that these resources are used in
a manner that maximizes health protection means that EPA should
establish lead hazard standards that direct resources to where the
threats to public health are the greatest. EPA recognizes there are
different ways in which the TSCA section 403 standards may be
interpreted and, specifically, requests comment on whether it is
appropriate for the Agency to use the cost-benefit analysis to develop
the hazard standards for this rule.
3. Policy basis for the standards--a. Dust-lead and soil-lead
levels of concern. To implement its decision to treat the dust-lead and
soil-lead levels of concern as risk communication tools, EPA is
proposing that the soil and dust levels of concern should be associated
with a blood-lead concentration of concern and a child's probability of
exceeding that blood-lead concentration (exceedance probability). As
noted previously, EPA is proposing to establish a soil-lead level of
concern for use in guidance and not to include it in the proposed
regulation.
EPA used blood-lead concentration as the measure of human health
risk, because it is the most widely used index of human lead exposure
and risk. By exceedance probability, EPA means an individual child's
risk or probability of having a blood-lead concentration that equals or
exceeds a specified concentration. For example, if the blood-lead
concentration of concern is 10 g/dl, an exceedance probability
of one percent means that a child has a one percent chance of having a
blood-lead concentration that equals or exceeds 10 g/dl.
An exceedance probability is needed because the relationship
between lead in the environment and blood-lead concentration is
characterized by a great deal of variability due to several factors,
including differences among children in behavior and nutrition. The
measurement of lead in the environment and in blood is also subject to
a significant degree of variation. It is not possible, therefore, to
link a specific level of lead in the environment (e.g., soil) to a
specific blood-lead concentration with absolute certainty. Rather, a
specific level of lead in the environment is associated with a
distribution of blood-lead concentrations.
The distribution, which can be thought of as a curve drawn on a
graph, represents the range of blood-lead concentrations and the
relative probability that each blood-lead concentration would actually
occur. A distribution is described by three parameters: the form (i.e.,
shape) of the distribution (e.g., normal distribution or ``bell''
curve, log normal distribution); a measure of central tendency (e.g.,
mean or average); and a measure of variability or spread (e.g.,
standard deviation) around the measure of central tendency. With these
three parameters, the probability of exceeding any blood-lead
concentration can be calculated. For further discussion of standard
deviation, please see Matlack, Statistics for Public Policy and
Management (Ref. 18).
b. Dust-lead and soil-lead hazard standards. Having presented its
rationale, above, for using cost-benefit balancing to help develop the
proposed dust and soil-lead hazard standards, EPA now explains its
intent to use cost-benefit balancing in the hazard standard-setting
process.
It is important to note that the Agency's analyses for dust and
soil began with an examination of quantitative estimates based on
various modeling techniques. These techniques allow the Agency to
arrive at a range of options on which the Agency exercises its
administrative judgment. Thus, the quantitative modeling is used as a
tool to derive the boundaries of the Agency's inquiry, not as the sole
basis for decisions.
Furthermore, the Agency wishes to note that it employed a normative
analysis to support the selection of the dust-lead and soil-lead hazard
standards. A normative analysis estimates costs and benefits based on
the assumption that individuals will make perfectly rationale decisions
in response to the standards. That is, all individuals who should
conduct risk assessments will do so, and all individuals will undertake
appropriate interventions in response to hazards identified by the risk
assessment. This normative analysis also assumes that no action is
being taken in the absence of the standards. In reality, hazards will
not be identified in many homes because risk assessments will not be
performed. Even if hazards are identified, interventions may not be
performed or interventions different from those assumed in the analysis
may be performed. In addition, risk assessments and hazard control
interventions are currently being conducted.
EPA used a normative analysis for two reasons. First, as a
practical matter, it is difficult, if not impossible, to estimate
expected costs and benefits associated with the standards. Such
estimates would require data on the current level of risk assessment
and abatement, which is not available, and the Agency to predict how
property owners and other decision-makers will respond to the
standards. Second, the objective of the analysis is to provide
estimates that allow Agency decision-makers to compare costs and
benefits. Although the normative analysis is likely to overestimate
actual costs and benefits, EPA believes that the relative balance of
costs and benefits estimated by the analysis is unlikely to be very
different from the relative balance of actual costs and benefits.
Therefore, the Agency can use these estimates to evaluate various
options for the dust and soil standards.
With respect to the paint component of the proposed regulation,
data limitations prevented EPA from quantifying the costs and benefits
of the options considered in this proposal. Data that definitively
relate deteriorated paint to blood-lead concentration are not
available, preventing the Agency from estimating the benefits of these
options. EPA could not estimate the costs of these options because the
Agency's decision regarding deteriorated lead-based paint focused on
the area of deterioration on individual components whereas the
available data provide information on the amount of deteriorated paint
in an entire residence. Consequently, EPA's decisions with respect to
the options for the paint component involve a more qualitative judgment
on the part of the Agency.
As part of its economic analysis of the proposed rule, EPA
developed estimates of the costs and benefits of repairing or abating
deteriorated lead-based paint. The preamble presents these estimates in
Unit X. The data limitations identified above as well as other
analytical constraints described in Unit X, however, restrict the
usefulness and call into question the reliability of these estimates in
characterizing the proposed regulatory standards for paint.
While Title X provides no guidance on how to undertake cost-benefit
balancing, the legislative history of TSCA provides a useful and
pertinent explanation of the concept. The House Report on TSCA (H. Rep.
1341, 94th Cong., 2nd Sess. at 13-15, 32)
[[Page 30315]]
acknowledges that cost-benefit balancing for regulation is not precise
but, instead, requires the exercise of judgment by the decision-maker.
It involves the balancing of the probability that harm will occur, and
the magnitude and severity of that harm, against the cost of the
proposed action to reduce that harm. In other words, cost-benefit
balancing involves a weighing of the risks to be reduced by response
actions and the costs of these actions.
The TSCA House Report emphasizes that cost-benefit balancing does
not require a formal quantitative analysis under which a monetary value
is assigned to risks that may be reduced by regulation or the costs to
society. This is because precise values often cannot be assigned to
such risks and costs. Accordingly, cost-benefit balancing is
appropriately used to establish a range of options for the hazard
standards. Using this approach, the Agency then selects its preferred
options based on consideration of relevant factors, including the
weight of the evidence of harm, assumptions and tools that underlie
EPA's analysis, as well as other factors, including health
protectiveness and total costs.
Cost-benefit balancing involves a two-step process: evaluation of
risk and risk-reduction (i.e., benefit), followed by consideration of
the resources needed to achieve varying degrees of risk reduction.
Below, EPA explains first the concept of evaluating risk and risk
reduction, then the concept of evaluating how to balance risk reduction
(benefit) with costs.
With respect to risk, the TSCA House Report states that: ``. .
.risk is measured not solely by the probability of harm, but instead
includes elements both of probability of harm and severity of harm and
those elements may vary in relation to each other'' [emphasis added].
Determining risk becomes more judgmental in the case of health and
environmental risks covered by EPA in cases where the scientific
evidence on hazard and exposure contains a high degree of uncertainty
and variability encompassing numerous relationships among elements of
risk, including consideration of the severity and probability of harm
resulting from the different types of exposure that may occur. Because
of the uncertainty in all of these estimates, there are generally no
definitive answers as to what the risk may be. Therefore, in evaluating
risk, EPA considers various factors, including the strength of the
evidence on toxicity (for example, actual cases of harm from
epidemiology studies or results of high-dose animal tests), the type
and magnitude of effects that are predicted to occur (for example,
severe effects or more subtle ones), and estimates of the numbers of
individuals exposed and the levels of exposure based on mechanistic and
statistical models.
Once the risk is evaluated, with the attendant uncertainties in
hazard evaluation and the variations in exposure probability, the next
step is to consider the costs of the regulatory action. The probability
and severity of harm (in this case, a range of children's health
effects) are weighed against the impact of any action EPA proposes to
take to evaluate whether the costs are commensurate with risk
reduction. There is, however, no set way to apply EPA's chosen approach
for this rulemaking to balancing costs and risk reduction. To
illustrate this point, the Agency provides the following examples.
Where standards would require the high expenditure of resources, the
level of risk reduction (considering both the toxicity of lead and the
probabilities of exposure) and the strength of evidence should be
correspondingly high. On the other hand, if the costs of standards are
relatively low, the level of risk reduction and the strength of the
evidence could be less compelling.
Today's proposed rule takes this balancing into account in
proposing both soil and dust hazard standards. The determination on
soil standards considers the fact that relatively high costs would be
incurred to abate residential soils. Consequently, under a cost-benefit
balancing concept, before selecting an option associated with high
costs, EPA would want a greater measure of confidence that the standard
would result in a higher level of risk reduction. Because the cost of
reducing risk from residential dust is relatively low, EPA could select
a dust-lead hazard standard that would not result in as much risk
reduction.
Finally, EPA believes that this type of analysis is an appropriate
way to deal with the problems caused by lead in paint and residential
dust and soil. Lead is a substance for which there is no clear evidence
that there is a level of exposure below which there is no risk. It is
clear, however, that there is some level of lead where the use of
scarce resources to reduce exposure to lead is warranted. EPA
recognizes that resources needed to address risks from lead-based paint
hazards are limited and would like to set standards to target responses
to these hazards so that the highest risks will be addressed first. In
contrast, spending valuable resources engaging in cleanup activities to
achieve little or no reduction in risk would not be a reasonable
approach.
B. Technical Analyses
To support the development of dust and soil lead levels of concern,
as well as for the hazard standards, EPA requires a tool to relate lead
in the environment to blood-lead concentration. As will be further
explained below, EPA has chosen two types of models to be used for this
purpose: a mechanistic model and a statistical model based on empirical
data. A mechanistic model simulates the human body's response to lead
that is ingested or inhaled. Because biological processes that
mechanistic models are designed to simulate are not completely
understood, these models are typically limited in their predictive
capability. The components of the processes that are understood have to
be simplified and digested into a series of mathematical equations
resulting in another source of error. The data that are used as inputs
into these models may not be truly representative and may contain gaps.
Alternatively, EPA could use observational data to estimate the
relationship between environmental lead and blood lead. Two national
data sets are available to the Agency. EPA has national blood-lead data
from Phase 2 of the third National Health and Nutrition Examination
Survey (NHANES III) (Ref. 6) and national data on levels of lead in
dust and soil and condition of paint from the National Survey of Lead-
Based Paint in Housing, conducted from 1989-1990 by the U.S. Department
of Housing and Urban Development (Ref. 19). These data sets, however,
are not linked. That is, there is no direct observation between blood-
lead in NHANES and the environmental levels in the HUD survey.
Therefore, these data sets cannot be used in combination to estimate
the relationship between lead in dust and soil and blood-lead
concentration.
In light of limited data and imperfect models, the Agency cannot
rely on any single approach to specify the true relationship between
lead in dust and soil and blood lead. EPA, therefore, used several
tools to derive differing estimates of the relationship. The
mechanistic model used for the various analyses in this proposed rule
is the Agency's Integrated Environmental Uptake and Biokinetic (IEUBK)
model. EPA also conducted several analyses for this rule using data
from the Rochester Lead-in-Dust study, which contains data for
children's blood-lead concentrations and dust and soil-lead levels in
their environment (Ref. 20). These tools will be discussed further
below in the sections where they are used.
[[Page 30316]]
The Agency wishes to note that the differing estimates of the
relationship between environmental lead and blood-lead concentration do
not bound the range of options available to EPA for the proposed rule.
The true relationship between blood-lead and dust and soil-lead could
be stronger or weaker than the estimates used in this proposed rule.
1. Dust-lead and soil-lead levels of concern. This section of the
preamble presents the Agency's rationale for its choice of 10
g/dl as the blood-lead concentration of concern, and for its
choice of the appropriate exceedance probability of one to five
percent. EPA then explains how it identified the dust and soil-lead
levels at which the Agency reasonably expects an individual child would
have a probability of approximately one to five percent of having a
blood-lead concentration equal to or exceeding 10 g/dl.
a. Blood-lead concentration of concern. EPA has determined that the
weight of scientific evidence, as discussed below, shows that 10
g/dl is a reasonable level of concern for childhood blood lead
under the applicable statutory standard of ``poses a threat.'' EPA
disagrees that the term ``poses a threat'' suggests that the lead
levels of concern should be based on any non-zero risk (zero-risk
basis). Zero risk equates to a blood-lead concentration of zero because
there is no known health effects threshold for lead. EPA, however,
proposes to reject the zero risk basis for dust and soil-lead levels of
concern for several reasons. First, although some data suggest that
adverse health effects occur at the lowest observed levels, only a
small number of children with such low blood-lead concentrations have
been examined. Furthermore, the health effects at the lowest levels of
exposure are small and subtle, making it difficult to associate effects
with any single factor. Therefore, there is insufficient evidence at
these lowest levels to state that there is a level of risk that
warrants national public concern. Second, standards based on zero risk
would not serve as a useful communication tool because lead is
ubiquitous in the environment and there is no practical way to
eliminate exposure. Third, EPA believes that zero risk-based standards
were not the intent of Congress. If any level of lead in dust and soil
constitutes contamination or a hazard, there would be no need for EPA
to identify these conditions.
Having rejected zero as the blood-lead concentration basis for dust
and soil-lead levels of concern, EPA had to identify an alternative
blood-lead concentration. Numerous human epidemiological and clinical
studies, as well as animal toxicological and in vitro studies indicate
clear signs of toxicity across a wide range of exposures. While the
results of human studies are not uniform, and there is inevitably
uncertainty regarding the precise nature and persistence of effects at
low levels, these studies are predominately similar in their overall
findings. Furthermore, there is consensus within the expert medical
community that even low levels of lead exposure warrant public health
concern.
As listed below, numerous health effects, many of them
neurological, have been related to blood-lead concentrations down to
levels of at least 10-15 g/dl:
1. Altered synthesis of heme as indicated by inhibitions in the
enzymes delta-aminolevulinate dehydrase, pyrimidine-5-nucleotidase, and
red blood cell ATPase, and accumulations of the heme precursor,
erythrocyte protoporphyrin in red blood cells. (e.g., Refs. 21-29).
2. Reduction in vitamin D hormone synthesis in children (e.g., Ref.
30).
3. Alterations of brain electrical activity in children (e.g, Refs.
31-37).
4. Altered nerve conduction in auditory pathway and decreased
hearing acuity in children (e.g., Refs. 34 and 38).
5. Delays in cognitive development and slower sensory-motor
development during infancy (e.g., Refs. 39-41).
6. Other neurobehavioral impacts (e.g., IQ deficits) in children
(e.g., Refs. 42-48).
7. Decreased stature or growth in young children (e.g., Refs. 49-
51).
8. Decreased ability to maintain steady posture in children (e.g.,
Ref. 52).
9. Reduced gestational age and reduced weight at birth, associated
with maternal and cord blood-lead concentrations (e.g., Refs. 53 and
54).
10. Increased blood pressure in adults (e.g., Refs. 5 and 55).
While it is possible that some of these effects are reversible
(e.g., altered heme synthesis), or have unclear medical or functional
implications (e.g., altered brain electrical activity), the Agency
believes that the collective impact of these effects on diverse
physiological functions and organ systems of young children with blood-
lead concentrations as low as 10 g/dl are clearly adverse.
This conclusion is consistent with the findings of other EPA reports,
EPA's Clean Air Scientific Advisory Committee (CASAC), the Centers for
Disease Control and Prevention in their 1991 statement Preventing Lead
Poisoning in Young Children, and the National Academy of Sciences in
their 1993 report Measuring Lead Exposure in Infants, Children, and
Other Sensitive Populations.
U.S. EPA's 1986 Air Quality Criteria Document for Lead (Ref. 56)
concluded that for children: (1) The collective impact of the effects
at blood-lead concentrations above 15 g/dl represents a clear
pattern of adverse effects worthy of avoidance; (2) at levels of 10-15
g/dl there appears to be a convergence of evidence of lead-
induced interference with a diverse set of physiological functions and
processes, particularly evident in several independent studies showing
impaired neurobehavioral function and development; and (3) the
available data do not indicate a clear threshold at 10-15 g/
dl, but rather suggest a continuum of health risks approaching the
lowest levels measured. The health effects below this range are less
well substantiated.
In reviewing the information presented in the 1986 Air Quality
Criteria Document and Addendum, EPA's CASAC concluded various effects
starting at blood-lead concentrations around 10-15 g/dl or
even lower in young children ``may be argued as becoming biomedically
adverse'' (Ref. 57). After reviewing the 1990 Supplement to the
Addendum (Ref. 58), as well as a staff position paper of EPA's Office
of Air Quality Planning and Standards (Ref. 59), CASAC concluded that
blood-lead concentrations above 10 g/dl clearly warrant
avoidance, especially for the development of adverse human health
effects in sensitive populations. The Committee concluded ``that EPA
should seek to establish an air standard which minimizes the number of
children with blood-lead concentrations above a target value of 10
g/dl. In reaching this conclusion, the Committee recognizes
that there is no discernible threshold for several lead effects and
that biological changes can occur at lower levels'' (p. 1, Ref. 57).
In their 1991 Statement, CDC revised the action level for the lead
screening and intervention program from 25 g/dl set in 1985 to
10 g/dl and stated that ``the scientific evidence showing that
some adverse effects occur at blood-lead concentrations at least as low
as 10 g/dl in children has become so overwhelming and
compelling that it must be a major force in determining how we approach
childhood lead exposure'' (p. 1, Ref. 2). While CDC does not specify
which of the many effects associated with low-level lead exposure are
individually considered adverse, the following discussion indicates
that the collective impact of the different effects
[[Page 30317]]
poses risks that should be avoided (pp. 9-10, Ref. 2):
Blood-lead concentrations as low as 10 g/dl, which do not
cause distinctive symptoms, are associated with decreased intelligence
and impaired neurobehavioral development (Refs. 60-61). Many other
effects begin at these low blood-lead concentrations, including
decreased stature or growth (Refs. 49, 50, and 51), decreased hearing
acuity (Ref. 38), and decreased ability to maintain a steady posture
(Ref. 52). Lead's impairment of the synthesis of the active metabolite
1,25-(OH)2 vitamin D is detectable at blood-lead
concentrations of 10-15 g/dl. Maternal and cord blood-lead
concentrations of 10-15 g/dl appear to be associated with
reduced gestational age and reduced weight at birth (Ref. 62). Although
researchers have not yet completely defined the impact of blood-lead
concentrations <10 g/dl on central nervous system function, it
may be that even these levels are associated with adverse effects that
will be clearer with more refined research.
CDC recommends that community-wide interventions (e.g., outreach and
education, surveillance) should be considered by appropriate agencies
if many children have blood-lead concentrations that equal or exceed 10
g/dl (Ref. 2).
The National Academy of Sciences agreed with the CDC assessment of
the existing studies and data, noting that blood-lead concentrations
around 10 g/dl are associated with disturbances in early
physical and mental growth and in later intellectual functioning and
academic achievement (Ref. 63).
For purposes of this proposed rule, EPA is establishing 10
g/dl as the blood-lead concentration of concern. This decision
is based on EPA's review of the scientific evidence and earlier Agency
findings that a number of health effects begin to manifest themselves
at blood levels of 10-15 g/dl and that the collective impact
of these effects poses risks that should be avoided. EPA chose the
level at the lower end of this range to provide an adequate margin of
safety. EPA decided not to establish a level lower than 10 g/
dl because the evidence indicates that health effects at lower levels
of exposure are less well substantiated, based on a limited number of
studies, a limited number of children, and observation of subtle
molecular changes that are not currently thought to be sufficiently
significant to warrant national concern.
b. Exceedance probability. Unlike EPA's choice of the blood-lead
concentration, where there is a body of scientific literature to guide
the decision-making process, there is no scientific evidence to assist
the Agency in selecting the appropriate exceedance probability. EPA's
decision for this value is, instead, guided by judgment about levels of
risk that are achievable and consistent with the statutory criteria.
EPA looked at several options for an appropriate exceedance
probability. The Agency rejected the lowest possible probability, which
is zero, because it is unachievable. The Agency's risk analysis
demonstrated that a very small percentage of children would have blood-
lead concentrations equaling or exceeding 10 g/dl even if
there were no lead-based paint and lead-contaminated soil and dust,
because other sources of exposure (e.g., air, water, diet, and
background levels of lead) remain (Ref. 1).
At the other end of the range considered by EPA was an exceedance
probability of 10 percent. With this distribution of risk, a child
would have a 1.6 percent chance of having a blood-lead concentration
exceeding 15 g/dl and a less than one percent chance of having
a blood-lead concentration exceeding 20 g/dl, the level at
which CDC recommends medical intervention. The Agency rejected this
probability as presenting risks above the threshold that the dust and
soil-lead levels of concern are supposed to communicate.
Consequently, the Agency determined that the range of probabilities
between one and five percent would be consistent with the statutory
criterion for level of concern, ``pose a threat.'' Given the data and
analytical tools available to EPA, the Agency determined that, as a
practical matter, one percent is not distinguishable from five percent.
This overlap is due to the uncertainty and variability related to any
effort to associate levels of lead in the environment to blood-lead
concentrations and limited data.
As a result of exposure to levels of lead in dust and soil
associated with these probabilities, a child would have a relatively
small chance of having a blood-lead concentration equal to or exceeding
10 g/dl. The Agency considers this small chance of exceeding
the blood-lead concentration of concern to be consistent with ``pose a
threat.'' Consequently, EPA is proposing to include in guidance a level
of concern where the levels of lead in dust and soil are associated
with a one to five percent probability that a child would have a blood-
lead concentration equal to or exceeding 10 g/dl.
In seeking comment on this decision, EPA is interested in obtaining
any information that would provide additional support for its decision
or support the selection of another option.
c. Characterizing individual risk. EPA identified several
alternative tools to support the development of the dust and soil-lead
levels of concern: (1) The Agency's IEUBK model; (2) a ``multimedia''
model based on the data from the Rochester Lead-in-Dust study; and (3)
a performance characteristics analysis of the Rochester data. The IEUBK
model was not used to examine dust lead levels because the model uses
dust-lead concentration and, as explained in Unit V. of this preamble,
EPA has decided to propose a loading standard for dust. Conversely, the
multimedia model based on the Rochester data was used only for dust. It
uses dripline soil lead measurements rather than yard-wide average and,
therefore, EPA chose not to use it to examine the levels of concern for
lead in soil in this proposal. EPA used the performance characteristic
analysis of the Rochester data for both the dust and soil-lead levels
of concern.
d. Dust analyses. EPA conducted two analyses to support development
of the dust-lead level of concern: an analysis that used the multimedia
model based on the Rochester data and a performance characteristics
analysis of the Rochester data. The multimedia model was developed
specifically to support the development of options for this proposed
rule. It is a regression model that relates environmental lead levels
in dust and soil observed at a residence to the blood-lead
concentration measured for a child living at the residence. Regression
analysis is a statistical technique used to estimate the dependence of
one variable upon others, in this case the dependence of a child's
blood lead level on the environmental lead levels measured in and
around his or her home. For a detailed discussion of regression
analysis please see Matlack, Statistics for Public Policy and
Management (Ref. 18).
EPA decided to use the data from the Rochester Lead-in-Dust Study
as the basis for the multimedia model for the following reasons: (1)
Dust on all surfaces that are being considered for the TSCA section 403
standards were measured for lead in the Rochester Study; (2) the
Rochester Study includes dust-lead loadings from wipe sampling and the
TSCA section 403 dust standard is expected to be based on dust-lead
loading from wipe sampling; and, (3) the selection of homes and
children in the Rochester Study, although targeted, was more random and
more representative of a general population
[[Page 30318]]
than is the case with other recent epidemiological studies of lead
exposure in urban environments where lead-based paint is a significant
source of lead in dust and soil.
The multimedia model can be used to predict an average blood-lead
concentration for an individual child who is exposed to a given set of
environmental-lead levels. A constant empirical estimate of variability
is applied to this average to estimate a distribution of blood-lead
concentrations. In statistical terminology, this estimate of
variability is referred to as the geometric standard deviation (GSD), a
type of ``standard deviation'' that is used for log normal
distributions. The GSD in this case characterizes biological and
behavioral variability in blood lead for a given set of environmental
exposures. The predicted distribution can then be used to estimate the
probability of a child exceeding a specified blood-lead concentration
for a given level of environmental exposure.
Because, in this case, EPA was interested in determining the
environmental-lead levels that would result in a one to five percent
probability of an individual having a blood-lead concentration equal to
or exceeding 10 g/dl, the Agency started with the specified
range of probabilities of a child having a blood-lead concentration
equal to or exceeding 10 g/dl and calculated the level of lead
in dust needed to predict this distribution.
The Agency selected a GSD of 1.6 for use in the multimedia model,
consistent with the default value used in the IEUBK model. This value
was based upon the GSDs calculated for various sites after differences
in site-specific dust and soil-lead measurements were removed. In this
way, the GSD reflects the behavioral and biological variability in
children as well as repeat sampling variability, sample location
variability, and analytical error. Because EPA is using the multimedia
model to predict a blood lead distribution for a fixed level of lead in
the environment, it is appropriate to use a GSD that accounts for these
sources of variability but not differences in environmental lead
levels. Median GSDs, weighted by sample size within subgroups defined
by age, dust-lead concentration, and soil-lead concentration were
estimated as 1.69 for Midvale, Utah, 1.53 for the Baltimore data from
the Urban Soil Lead Demonstration Project, and 1.60 for Butte, Montana
(see section 4.2.2, Guidance Manual for the Integrated Exposure Uptake
Biokinetic Model for Lead in Children). Given these results, the Agency
believes that 1.6 is a reasonable value for the GSD in this
application.
EPA presents a more detailed description of the multimedia model in
the Risk Analysis to Support Standards for Lead in Paint, Dust, and
Soil, which can be found in the public record for this proposal (Ref.
1).
The multimedia model yielded the following results. The levels of
lead in dust on uncarpeted floors associated with an individual child
having from a one to five percent chance of having a blood-lead
concentration equal to or exceeding 10 g/dl range from near
zero to 6.7 g/ft2, depending on the dust-lead
loadings on window sills and the concentration of lead in soil. The
range for dust loadings on window sills is from near zero to 74
g/ft2 depending on dust-lead loadings on floors and
the concentration of lead in soil. The results of this analysis are
presented in Chapter 5 of the Agency's risk analysis document (Ref. 1).
These values are far below current clearance standards in both EPA
guidance and HUD Guidelines and some are near or below background
levels. These results depend on the model that has been fitted to the
Rochester data. If the model changes by including different variables
or selecting a different shape or form, the results could be higher or
lower. Therefore, an alternative approach that does not depend on a
model was also employed to estimate the levels of lead in dust
associated with a one to five percent probability of a child having a
blood-lead concentration equal to or exceeding 10 g/dl.
The non-modeling approach or performance characteristics analysis
of the Rochester data utilizes the concept of negative predictive value
(NPV), which, in this case, is defined as the probability of a child
having a blood-lead concentration below a specified level given that
the observed environmental lead level is below a hypothetical standard.
EPA used the performance characteristics analysis to estimate the dust
loading on uncarpeted floors and interior window sills that would yield
an NPV from 95 percent to 99 percent with a blood-lead concentration
equal to or exceeding 10 g/dl. This range of NPVs is
equivalent to a one to five percent chance of having a blood-lead
concentration equal to or exceeding 10 g/dl.
Table 2 below illustrates how NPV is computed. Homes in the
Rochester study are classified into four categories according to two
factors: (1) whether or not environmental-lead levels measured at the
home were below or above the example standard, and (2) whether or not
the home had a child with a blood-lead concentration above or below 10
g/dl. Using the notation presented in Table 2, the sum a + c
is the number of homes with environmental-lead levels below an example
option for the standards. The NPV is the ratio c/(a + c) and is the
portion of these homes that do not contain a child with a blood-lead
concentration at or above 10 g/dl. An NPV close to one
suggests that almost all of the children living in homes with
environmental-lead levels below the example standards have blood-lead
concentrations less than 10 g/dl. An NPV close to zero
suggests that very few of the children living in homes with
environmental-lead levels below the example standards have blood-lead
concentrations less than 10 g/dl.
The performance characteristics analysis yielded the following
results. For uncarpeted floors, dust-lead loadings ranged from 50
g/ft2 to 400 g/ft2 depending on
the dust-lead loading on interior window sills and the soil-lead
concentration. For interior window sills, dust-lead loadings ranged
from 100 g/ft2 to 800 g/ft2
depending on the dust-lead loading on uncarpeted floors and the soil-
lead concentration. These ranges are significantly higher than the
ranges yielded by the multimedia approach (Ref. 64).
Table 2.--Definition of Negative Predictive Value Based on Empirical
Data from Lead Exposure Studies*
------------------------------------------------------------------------
Media Standard
Blood-Lead Concentration Target ---------------------------------------
Level Below Media Above Media
Standard Standard
------------------------------------------------------------------------
At/Above 10 g/dl a b
Below 10 g/dl c d
------------------------------------------------------------------------
*In the table above, the letter ``a'' represents the number of children
who have a blood-lead concentration above a given blood-lead standard
and who live in a residence with an environmental lead level below a
standard for that environmental medium. Letters ``b,'' ``c,'' and
``d'' represent similar counts. From these counts the negative
predictive value (the probability of a resident child having a low
blood-lead concentration given that the observed levels of lead in the
environmental media are below the standard at the residence) is
calculated as c/(a + c).
There are also limitations in the use of the performance
characteristics model. Like the multimedia model, this approach is
based on data collected from a single city which may not be
representative of the nation and has not been subjected to rigorous
review. In addition, the NPVs associated with some options are based on
small sample sizes, which reduces the reliability of the estimate. It
is also important to note
[[Page 30319]]
that the NPV is purely descriptive and not based on any assumptions
about the true distribution of children's blood-lead concentrations. It
merely describes the characteristics of a given data set.
e. Soil analyses. EPA also used two analyses to support development
of the soil-lead level of concern: an analysis that used the IEUBK
model and one that used the performance characteristics analysis of the
Rochester data. The IEUBK model is a simulation model that estimates
the uptake pathways of environmental lead and the body's biological
response to environmental lead levels to predict a child's body burden
of lead. The model considers exposure (i.e., levels of lead in dust,
soil, air, water, and diet), intake (i.e., rates of ingestion and
inhalation), uptake (i.e., absorption in the lung and gut), and
biokinetics (i.e., movement through the blood and tissues and
elimination). The model predicts a geometric mean (i.e., a type of
average) blood-lead concentration for children exposed at the specified
environmental lead levels. An assumed geometric standard deviation
(GSD) is then applied to estimate the distribution of blood-lead
concentrations from which a probability of exceeding a specified blood-
lead concentration can be derived. As was the case with the multimedia
model analysis for dust, a GSD of 1.6 was assumed for this analysis.
EPA chose to use the IEUBK model to support this rule because it is
the Agency's most rigorously developed and thoroughly reviewed model
for childhood lead exposure. This model has historically been used in
other Agency programs and is the currently recommended tool for site-
specific evaluations in the CERCLA (Superfund) and RCRA corrective
action programs. Also, an earlier version of the model was peer-
reviewed and found acceptable as a tool for setting air lead standards
by EPA's Clean Air Science Advisory Committee of the Science Advisory
Board (Ref. 57). The IEUBK model was calibrated using environmental-
lead and blood-lead data from two western communities: Midvale, UT, a
suburb of Salt Lake City (Ref. 65), and East Helena, MT, a small town
outside of the State capitol at Helena (Ref. 66). Subsequent
evaluations have shown that the IEUBK model provides reasonable
descriptions of other sites, including urban sites (Ref. 67). The most
current version, Version 0.99d, of the IEUBK model was used in the TSCA
section 403 risk assessment.
The IEUBK model yielded the following results. Soil-lead
concentrations generally at or below 500 parts per million (ppm) will
result in a one to five percent probability that a child will have a
blood-lead concentration that equals or exceeds 10 g/dl
depending on the level of lead in dust. The results of this analysis
are presented in Chapter 5 of the Agency's risk analysis document (Ref.
1).
Of course, there are inherent uncertainties in any model that
simulates extremely complex relationships such as that between
environmental lead and blood lead. Not all of the relevant
physiological factors are thoroughly understood and others are
necessarily simplified. Also, there is child-to-child variability in
factors related to both exposure and biokinetic response (e.g., hand-
to-mouth activity, nutritional status). While the IEUBK model
application attempts to address these through selection of the GSD, it
is expected that deviations from the predicted blood-lead distributions
would most likely manifest themselves at the extremes, or ``tails,'' of
the distribution.
Recognizing that such uncertainties exist, the Agency choose to
also make use of a non-modeling approach with data from the Rochester
study. A performance characteristics analysis was conducted, as was
described earlier for dust. The analysis yielded the following results.
Soil-lead concentrations ranged from 200 ppm to 1,500 ppm depending on
dust-lead loadings on uncarpeted floors and interior window sills and
the exceedance probability. The wide range of soil-lead levels is
largely the result of a small number of data points.
2. Dust-lead and soil-lead hazard standards. As discussed in
section A of this unit, EPA believes it is reasonable to use cost-
benefit balancing to develop a range of viable options for the dust and
soil hazard standards. The risk reduction achieved as a result of
interventions designed to control or eliminate hazards constitutes the
benefits of the hazard standard. Dust interventions reduce risk by
reducing dust-lead levels. Soil interventions reduce risk both by
reducing soil-lead levels and by reducing lead contamination of
household dust.
To estimate benefits, the Agency built on the analysis used to
support development of the dust and soil-lead levels of concern. EPA
used the models that relate environmental lead to blood lead to
estimate the current or baseline distribution of blood-lead
concentrations for young children and the predicted blood-lead
distribution following hazard control interventions implemented in
response to the standards. Risk reduction, quantified in terms of
avoided health effects, is measured by looking at the change in blood-
lead distributions. EPA's normative economic analysis calculated
benefits by assigning a dollar value to the avoided adverse health
effects and compared these benefits to the costs of hazard control
interventions.
Before presenting the detailed description of the analysis, EPA
wishes to highlight two issues that the public should consider when
reviewing this proposed regulation. First, the Agency's analysis
estimates the benefits of primary prevention. Primary prevention is the
term used to characterize actions taken to protect people that have not
yet been exposed to a hazard. In this analysis, baseline risk is the
level of risk that the Agency would expect children to experience in
the absence of lead hazard control (i.e., risk associated with exposure
to current conditions). The post-intervention risk is the level of risk
that children, who have had no previous exposure to lead-based paint
hazards, are expected to experience with these controls in place. In
essence, the analysis estimates the level of risk prevented rather than
the level reduced. Where hazards are controlled, the exposure to lead-
based paint hazards never occurs.
The analysis does not estimate the benefits of secondary
prevention, the term used to characterize actions taken to protect
people already exposed to a hazard. Primary prevention is thought to be
more effective than secondary prevention because, with primary
prevention, children's risk remains at the pre-exposure level. With
secondary prevention, risk does not drop to pre-exposure levels because
lead that is stored in bone tissue continues to be released into blood
for some period of time even after environmental levels decline.
Many of the available exposure studies focus on the impacts of
secondary prevention, relating environmental lead to blood lead prior
to and after hazard control interventions. Because the subjects in
these studies have had prior exposure, the magnitude of the risk
reduction is smaller than estimated in EPA's analysis, which focuses on
children who have not had previous exposure.
Second, the majority of the benefits estimated by EPA are derived
from avoided IQ point loss resulting from prevented exposure to lead.
The dollar value placed on these benefits is a tool to assist EPA in
comparing costs and benefits for purposes of this proposed rule. It is
not in any sense a real value of the risk reduction or an Agency
standard for other actions. There are
[[Page 30320]]
plainly many benefits that are not measured in the analysis because EPA
lacks the tools and or data or because some benefits are subjective in
nature. On the other hand, EPA assigns risk reduction value to
fractional losses of an IQ point--tenths and even hundredths of a
point, and it is unclear the extent to which such small changes affect
quality of life of a single individual. By this combination of
underestimating and overestimating dollar values of potential risk
reduction benefits, EPA hopes to arrive at some reasonable range of
values that can be used to inform decision-making.
a. Estimating risk reduction. EPA's risk analysis that was
conducted to support this proposed rule provides a methodology for
measuring risk reduction (i.e., declines in blood-lead concentrations).
Under this methodology, EPA estimates the current national distribution
of blood-lead concentrations for the population of children ages one to
two. The Agency then uses this methodology to predict future changes in
the blood-lead distribution resulting from the implementation of hazard
interventions and expected changes in the nation's housing stock.
EPA used two models to estimate blood-lead concentrations: the
IEUBK model and an empirical model based on the Rochester data. The
empirical model is based on the multimedia model, which was described
earlier in this unit. In order for the multimedia model to be used for
national estimates, it was necessary to modify it to employ
environmental measures from the HUD National Survey (Refs. 8-9 and 19).
The resulting modified model is termed the empirical model. For a full
explanation of the differences between the multimedia model and the
empirical model, please see Chapter 5 of the Agency's risk analysis
document (Ref. 1). As noted above, the multimedia model could not be
used to support the development of the soil-lead of concern. The Agency
is requesting comment on the use of the empirical model to support
development of the soil-lead hazard standard.
To estimate the national distribution of blood-lead concentrations,
EPA had to run the empirical model with nationally representative data
on lead in dust and soil. The Agency used the HUD National Survey,
which is recognized as the leading source of data on environmental lead
levels in residential environments. The design and findings of the HUD
National Survey have been peer-reviewed and published in several
government reports.
For each house in the National Survey, EPA estimated the average
blood-lead concentration by using the HUD data on dust lead and soil
lead as inputs into the empirical and IEUBK models. EPA then applied
the GSD of 1.6 to estimate a geometric mean blood-lead concentration
for each home to derive a distribution of blood-lead concentrations for
each home. An estimate of the baseline national distribution of blood-
lead concentrations was constructed by aggregating the distributions
from each home using population weights based on the 1993 American
Housing Survey (Ref. 68), adjusted to the 1997 population of children
(aged 1 to 2 years). EPA then scaled the estimated national baseline
distribution using the blood-lead data from NHANES.
EPA used the following process to estimate the national blood-lead
distribution associated with each option for dust and soil hazard
standards. The soil and dust levels for each home in the survey were
compared to a set of hazard standard options for dust and soil. For
each set of options, the dust-lead level was adjusted down to reflect
implementation of a dust control intervention if the dust-lead level
exceeded the option for dust. If the soil-lead level exceeded the
option for soil, both the soil and dust lead levels were adjusted down
to reflect implementation of a soil control intervention. If a level
did not exceed an option, no adjustments to the data were made. Once
this comparison was made, the adjusted data were run through both
models to obtain an estimated blood-lead concentration predicted by the
model. The GSD of 1.6 was then applied to generate the blood-lead
distribution for each HUD survey home. The blood-lead distributions for
all homes in the survey were then aggregated using the same weights as
in the baseline analysis described previously.
The use of the IEUBK model to estimate the risk reduction
associated with various options for the dust-lead hazard standard
merits additional explanation. As noted earlier, the IEUBK model could
not be used to develop options for the dust-lead level of concern
because the dust standards are in terms of loading and the IEUBK model
uses dust concentration as its input. How, then, can the IEUBK model be
used to analyze options for the dust-lead hazard standard? In contrast
to the dust-lead level of concern, where a model that directly relates
a dust-loading value to a distribution of blood-lead concentrations is
needed, analysis of the options for the dust-lead hazard standard
requires a model to estimate changes in the blood-lead distribution for
the population of young children. EPA is able to do this with the IEUBK
model by using the model with the HUD National Survey data.
The HUD National Survey data contain both dust-lead loading and
concentration data for each home. To establish the baseline
distribution of blood-lead concentrations, EPA used the dust-lead
concentration value for each home as input for the IEUBK model. To
estimate the blood-lead distribution associated with a set of hazard
standard options for dust and soil, EPA identified the homes that would
exceed the paint, dust (loading), and/or soil standards. For these
homes, the analysis assigned a post-intervention dust-lead
concentration based upon the post-intervention soil concentration and
the presence or absence of deteriorated paint. The analysis then used
these assigned dust-lead concentrations as input to the IEUBK model to
generate post-intervention blood-lead distributions for each of the
homes. For the homes where no standard was exceeded, the measured dust-
lead concentration from the HUD survey was used. The details of the
procedure used to assign post-intervention dust-lead concentrations are
fully explained in Chapter 6 of the Agency's risk analysis document
(Ref. 1). The Agency is requesting comment on the use of this
application of the IEUBK model to support development of a dust-lead
loading hazard standard.
While all young children could be affected by exposure to lead, the
population of interest for this analysis was U.S. children aged 1 to 2
years. The selection of this age range as the population of interest
derived from the following general observations: the central nervous
system is rapidly developing in this age range, making it highly
susceptible to the effects of lead; synaptic density of the frontal
lobe of the brain peaks in a child's second year, and synaptic
development can be disrupted or delayed as a result of lead exposure;
the existence of a relationship between blood-lead concentration
measured at 1 to 2 years of age and IQ scores measured later in life;
blood-lead concentration tends to peak in this age range, due to an
increased ability to absorb lead; and, hand-to-mouth activity is high
in this age range, thereby increasing the potential for ingesting lead-
contaminated dust, soil, and paint.
b. Estimating costs and benefits. The normative economic impact
analysis estimates the benefits and costs associated with a broad range
of options for hazard standards. Benefits and costs are estimated over
a 50-year time frame.
[[Page 30321]]
Net benefits are computed by subtracting the costs from the benefits
for each option and discounting each to the present using a three
percent rate.
The benefits include a value for each of three health outcomes
associated with declines in blood-lead concentration: avoided IQ points
lost; avoided incidence of IQ below 70; and avoided incidence of blood-
lead concentrations exceeding 20 g/dl. The costs include the
expenditures on the hazard control interventions implemented by
property owners and other decision-makers in response to the standards.
Interventions include dust cleaning, interior and exterior paint repair
and abatement, and soil abatement.
The underlying engine of the normative economic analysis is the
``birth trigger'' model. The chief feature of this model is the
assumption that property owners do not undertake hazard control actions
until a young child who could be harmed by the hazard is present. The
timing of testing and intervention, therefore, is governed by the birth
rate. In the first year of a model run, the model randomly assigns the
arrival of a child to some of the 284 homes in the HUD National Survey
data set. In homes where a child's arrival is predicted to occur, the
model uses the risk analysis methodology to estimate a post-
intervention blood-lead distribution for that home. In the other homes,
interventions are not undertaken, regardless of the environmental
conditions, and there is no change from the baseline blood-lead
distribution. Using the risk analysis methodology, the blood-lead
distributions for each home in the survey are aggregated to develop a
new national blood-lead distribution after the first year. The Agency
compares the post-intervention blood-lead distribution in each year to
the baseline blood-lead distribution to compute the reduction in blood-
lead concentrations associated with the option being evaluated. The
analysis is then repeated for each of the following years through year
50.
The operation of the model in each of the subsequent years differs
from the initial year in two respects. First, the analysis determines
whether interventions need to be repeated. For example, paint repairs
are assumed to last 4 years, and therefore need to be repeated to
maintain their effectiveness. Second, the weights assigned to each home
in the survey, which reflect the proportion of the national housing
stock represented by that sample home, change to reflect ongoing
changes in the housing stock. With each passing year, new homes are
built and old homes are destroyed. In fact, the modernization of the
housing stock results in ``natural'' interventions as older homes that
have lead-based paint are replaced by new homes that do not.
The analysis then converts the change in blood-lead concentrations
into the three health endpoints: avoided lost IQ points, avoided
incidence of IQ below 70, and avoided incidence of blood-lead
concentrations above 20 g/dl. The term ``avoided'' is the
difference in health measures between the baseline scenario which
assumes no intervention activity and post-intervention scenarios, each
of which assumes a different combination of lead hazard standard
options and hence intervention activities.
To estimate the economic value of avoiding lost IQ points, the
analysis must first convert changes in blood-lead concentration to
changes in IQ. The analysis then assigns a monetary value to the IQ
point loss by using an estimate of the foregone lifetime income due to
IQ point loss. The computation of IQ point loss is based on an average
decrease of 0.257 IQ points per increase of one g/dl in blood-
lead concentration (Ref. 48).
IQ affects income through ability, education, and labor force
participation. The estimation procedure, therefore, has two major
steps. First the present value of the earnings stream of an average
newborn is estimated. Second, available economic literature was used to
estimate the percentage increase in lifetime earnings one would expect
from a one point increase in IQ. Based on this procedure, the analysis
assigns a value of $8,346 per IQ point lost (1995 dollars) (Refs. 48,
69-71).
EPA's estimate of the incidence of IQ score less than 70 is based
on results in a paper by Wallsten and Whitfield (1986) on the
relationship between reduced IQ scores and blood-lead concentration
(Ref. 72). The economic value of avoiding cases of IQ less than 70 is
approximated by using avoided special education costs. As defined,
these education costs are incurred from age 7 through age 18.
Avoided cases of blood-lead concentration exceeding 20 g/
dl is obtained directly by comparing the distribution of post-
intervention blood-lead concentrations with the baseline distribution
of blood-lead concentrations. The monetary value was approximated by
using avoided compensatory education costs. In this case, the education
costs are assumed to be incurred from age 7 through age 9. In addition,
there are medical monitoring and intervention costs associated with
children who have blood-lead concentrations that exceed 20 g/
dl (Refs. 2, 73, and 74).
Benefits accrue over time as hazard control interventions are
conducted, reducing children's exposure to lead in paint, dust, and
soil. All benefit estimates are discounted to the present using an
annual rate of three percent. Total benefits are the sum of benefits
calculated for each year or cohort of children protected and represent
the present value of the stream of benefits from the hazard controls.
The costs in this normative analysis are principally the costs of
conducting interventions designed to control lead-based paint hazards.
Interventions assumed to be are conducted only in those media (i.e.,
paint, dust, soil) where hazards are identified. For example, if lead
levels in the soil exceed the hazard standards, then the soil will be
removed and replaced with ``clean'' soil, but there will not be an
interior paint intervention in response to elevated levels of lead in
soil. Some interventions, however, include dust cleaning even if no
dust hazard has been identified initially because the intervention may
increase levels of lead in dust.
For purposes of this normative analysis, EPA identified six hazard
control interventions. These interventions include paint repair or
abatement of interior paint and exterior paint and a single
intervention each for soil and dust. It was assumed that abatement of
interior and exterior paint hazards occur when deteriorated lead-based
paint is extensive. Paint repair occurs when deteriorated lead-based
paint is present but not extensive. Soil intervention activities occur
when the soil-lead concentration exceeds the soil standard. Dust hazard
control occurs when the floor dust-lead loading exceeds the floor dust-
lead standard, the window sill-lead loading exceeds the window sill
dust-lead standard, or when it is required to accompany another
intervention type, such as abatement of interior paint or soil removal.
Some of the intervention actions result in permanent control of lead
hazards; others need to be repeated periodically to maintain their
effectiveness. According to the methodology, non-permanent
interventions are repeated as necessary in a home until the child is 6
years of age.
Drawing on a variety of sources, EPA obtained unit cost estimates,
that is cost per intervention per home, for the six hazard control
interventions identified for the analysis (Refs. 75-79). EPA also
obtained cost estimates for hazard evaluation activities (Refs. 80-83).
The Agency developed separate cost
[[Page 30322]]
estimates for single- and multi-family housing units, by adjusting the
single-family unit cost estimates to reflect the smaller size of multi-
family units and the smaller yards (per unit) of multi-family units.
Table 3 below summarizes these costs for single-family and multi-family
housing.
Table 3.--Hazard Evaluation and Control Costs
(Per activity in 1995 dollars)
------------------------------------------------------------------------
Multi-family (per
Activity Single-Family unit)
------------------------------------------------------------------------
Risk assessment 456 235
Interior paint repair 437 437
Interior paint abatement 6,587 4,687
Exterior paint repair 807 182
Exterior paint abatement 45,706 12,275
Dust cleaning 391 262
Soil removal (dripline; 2,046 399
nonhazardous waste)
Soil removal (mid-yard; 7,878 777
nonhazardous waste)
Soil removal (both areas; 9,008 901
nonhazardous waste)
Soil removal (dripline; 3,443 541
hazardous waste)
Soil removal (mid-yard; 16,486 1,351
hazardous waste)
Soil removal (both areas; 19,013 1,617
hazardous waste)
------------------------------------------------------------------------
The costs of intervention for a specific residence are a function
of when a residence is evaluated, the environmental lead conditions in
the residence, and the length of time that an intervention is effective
(duration). The arrival of a child determines when a hazard evaluation
will be conducted. The choice of intervention activities depends on the
environmental lead conditions in each medium. The frequency with which
interventions need to be repeated depends on the duration of the
intervention. Costs for a residence accrue over time as interventions
are repeated.
For example, paint abatement is assumed to have a duration of 20
years. Therefore, if post-intervention conditions are to be maintained
because a child under age 6 is present, paint abatement is assumed to
be repeated 20 years after the initial intervention, and again 40 years
after the initial paint abatement. Costs incurred after the first year
are discounted back to the present using an annual discount rate of
three percent. The total cost estimate is the sum of the discounted
cost of hazard controls conducted each year.
In estimating costs of each hazard standard option, the model
assumes that either a lead hazard screen (for single-family units
without deteriorated lead-based paint) or a risk assessment (all other
units) is performed. Testing is done at the time the arrival of a child
is expected and testing is not repeated for a unit.
The analysis' computation of net benefits is the difference between
the total benefits estimate and the total cost estimate. Net benefits
are an indicator of the societal gains from hazard controls.
When interpreting the results of EPA's analysis, it is important to
consider a number of limitations, qualifications, and uncertainties
which affect both the estimates of benefits and costs.
With respect to benefits, issues are associated with the
methodology used to estimate baseline and post-intervention blood-lead
concentrations and with efforts to place a monetary value on IQ points
lost. There are important concerns with respect to the cost analysis as
well.
There are four areas of concern with respect to the methodology
used to estimate blood-lead distributions. The first area is associated
with the HUD National Survey data. These include limited numbers of
environmental samples taken at each housing unit, the sampling of only
284 houses to represent the nation's pre-1978 housing stock, the age of
the study, and use of a dust collection device other than the wipe
collection method being adopted by the TSCA section 403 proposal.
The limited number of environmental samples can result in the
mischaracterization of dust and soil-lead levels at a home in the
survey. Combined with the small number of homes sampled,
mischaracterization of dust and soil-lead levels can result in large
errors in EPA's estimates. The age of the study can also introduce
error because environmental-lead levels have most likely changed since
the data were collected in 1989-1990. The use of a dust collection
device other than wipe samples required the development of an equation
to convert these values to wipe-equivalent values which introduces
additional error into the estimates. The introduction of error into the
estimates contributes to overall uncertainty in the analytical results.
A second and significant source of uncertainty is the paucity of
data with respect to the effectiveness of hazard control activities at
reducing exposures to lead in paint, dust, and soil. For example, EPA's
estimate of the effectiveness of interventions on dust-lead loading is
based on a limited number of studies. The Agency's estimate of
effectiveness of interventions on dust-lead concentrations is, in part,
based on limited data and, in part, based on the best judgment of
Agency scientists. Due to the lack of data about the effectiveness of
interim controls to reduce exposure to lead in soil, the Agency did not
include these interventions in its analysis. The Agency would, however,
be interested in any data the public may have concerning the
effectiveness of interim controls that address exposure to lead in
soil.
Third, uncertainty is introduced by using NHANES III, Phase 2 data
to calibrate the national distribution of baseline blood-lead
concentrations. While the national representation of NHANES III results
is widely accepted, some possible limitations in using these data
include ignoring any seasonality effects on blood-lead concentrations
and any further decline in concentrations that may have occurred since
1994.
Fourth, the two models are sources of uncertainty. The limitations
of the IEUBK model were discussed previously in this preamble. The
empirical model shares the limitations of the multimedia model
discussed previously.
Questions regarding the value of IQ points fall into two
categories: the relationship between blood-lead changes and IQ point
changes and the monetary value assigned to IQ point losses.
There are two significant limitations involved in assigning a
monetary value to IQ point losses. The first concerns the
[[Page 30323]]
ability to assign value to fractional losses of an IQ point. The
analysis assigns value to tenths and even hundredths of an IQ point
which may not be of much significance at the individual level. The
second concerns the value of IQ points across the range. The analysis
assigns equal value to any IQ point change; the value of an IQ dropping
from 140 to 135 is treated the same as an IQ dropping from 80 to 75. In
contrast, it is possible that the value of a point may vary depending
where in the range the point is lost.
On the other hand, the Agency notes that there are a range of other
health effects (e.g., neurological, developmental, and others) that are
not considered in its economic analysis (see Appendix B of the Risk
Analysis to Support Standards for Lead in Paint, Dust, and Soil) (Ref.
1). Declines in children's lead exposures will also reduce the
incidence of these effects. In addition, the economic analysis does not
include the benefits of secondary prevention (benefits obtained by
reducing environmental and blood-lead levels in a child already living
in a contaminated environment). Consequently, the value associated with
avoided IQ losses in the economic analysis can reasonably be considered
to serve as a surrogate for benefits associated with these other
effects. Therefore, to the extent that IQ-related benefits may be
overestimated due to the two limitations discussed above, the non-
valued benefits associated with these other effects would tend to
mitigate such overestimates.
With respect to the estimate of costs, there are several sources of
uncertainty. EPA's analysis identifies only a few of the dozens of
responses that property owners and other decision-makers could
undertake. The costs for these activities are based on current data and
could change as competition among providers increases or new
technologies are developed. The frequency with which temporary measures
need to be repeated, which also affects costs, depends on assumptions
the Agency made about the duration of the measures' effectiveness.
These assumptions, in turn, are based upon judgments and extrapolations
from limited data.
c. Results. This section of the preamble discusses the results of
EPA's normative economic analysis of the options for dust and soil-lead
hazard standards. Before presenting the results, however, the Agency
believes that it is important to consider two issues when interpreting
these results.
First, undue emphasis should not be placed on the estimates for
total costs and benefits. As noted earlier, the costs and benefits
estimated by the normative analysis are likely to overstate the actual
costs and benefits associated with the standards. The Agency's analysis
also assumes that technologies and costs will remain unchanged over the
50-year modeling horizon. Over time, as new technologies develop, costs
may decline. In addition, many health benefits were not included in the
analysis because either the relationship between exposure and the
magnitude of health effects is unknown or because the benefits cannot
be monetized.
Estimates of costs and benefits associated with the standards are
also heavily influenced by the number of homes estimated to exceed any
standard option. The estimated number of homes is based on the HUD
National Survey. Although this Survey is the best nationally
representative data on residential lead, it is characterized by several
shortcomings that were described earlier. Among the most significant of
these is the small sample size, which, as was noted, can introduce
errors into EPA's estimates. For example, only seven homes in the
Survey have soil that exceeds 2,000 ppm. Based on the age, location,
and other characteristics of these homes, EPA estimates that these
seven homes represent 2.5 million homes nationally which yields $9
billion in soil intervention costs over the 50-year model period. If
HUD conducted another survey, it is possible that only three homes in
the survey, representing 1 million homes nationally, exceed 2,000 ppm,
reducing costs by 60 percent. Benefits would also be lower because
fewer children would be protected. It is also possible that 10 homes in
the survey, representing 3 million homes nationally, exceed 2,000 ppm,
resulting in higher costs and benefits.
By providing these explanations, EPA does not intend to dismiss the
costs associated with this proposed rule. Although the expected costs
associated with the standards are likely to be significantly less than
costs estimated by the normative analysis, these costs would probably
still be substantial. That is why the Agency considered costs in
evaluating options for the hazard standards and in selecting a
preferred option. It should be remembered, however, that these
activities will protect millions of children who will live in abated
homes over the next 50 years. As was noted earlier, EPA's analysis did
not focus on children already exposed to excessive levels of lead but
on children who have not been born. In the absence of the standards and
assuming other exposures to lead remain unchanged, approximately 10
million children are estimated to have elevated blood-lead levels over
the next 50 years. Of these, one million are estimated to have levels
that require medical attention (Chapter 5, Ref. 83).
Second, the results obtained using each model should be evaluated
individually to compare performance of the options. Options should not
be compared across models. The models represent two fundamentally
different approaches to estimating the relationship between dust and
soil-lead and blood-lead which are not comparable: one is mechanistic
and the other empirical. As explained above, the two models also use
different data for input. The IEUBK model uses dust-concentration data
from the HUD survey to estimate baseline blood-lead and assumed dust-
concentrations to estimate post-intervention blood-lead concentrations.
The empirical model uses dust-loading data from the HUD survey to
estimate baseline blood-lead and assumed dust-loadings to estimate
post-intervention blood-lead. This difference is one reason why the
IEUBK model-based analysis estimates greater risk reduction than the
empirical model-based analysis.
The objective of the analyses is to provide EPA with a tool to
compare options in terms of relative costs and benefits of each option,
not to develop precise absolute estimates of costs and benefits.
Despite the limitations and uncertainties noted here and in previous
sections of this unit, EPA believes that the results for options within
each model can be compared. The limitations may affect the estimates of
absolute costs and benefits, but these limitations should have similar
effects on the estimates for each option. Therefore, the impact of the
limitation and uncertainties on the relative performance of each
option, in terms of net benefits, estimated by each model should be
small, except where noted in the discussion below.
Tables 4 and 5 below present the results of the IEUBK-based
analysis for a range of dust and soil hazard standard options. Table 4
presents the costs, benefits, and net benefits for actions taken in
response to the specified options for dust standards; it does not
include any soil interventions. Because the IEUBK model does not
include a parameter for sill dust, it was used only to analyze floor
dust options. Table 5 presents figures relating to soil standards; it
does not include any dust interventions. Neither table includes any
testing or risk assessment costs, nor costs or benefits of paint
interventions.
[[Page 30324]]
Table 4.--Estimated Costs, Benefits, and Net Benefits for Dust-Lead Hazard Standard Alone (Using the IEUBK
Model)*
----------------------------------------------------------------------------------------------------------------
Number of Homes IEUBK Model Results (50-years; $Billion)
Floor Dust Options (g/ Exceeding Option -----------------------------------------------------------
ft2) (Millions) Costs Benefit Net Benefit
----------------------------------------------------------------------------------------------------------------
50 21 12 73 61
100 19 10 59 48
----------------------------------------------------------------------------------------------------------------
*Note: Rows may not add due to rounding. This table does not include estimated costs or benefits of paint and
soil interventions, or any risk assessment costs.
Table 5.--Estimated Costs, Benefits, and Net Benefits for Soil-Lead Hazard Standard Alone (Using the IEUBK
Model)*
----------------------------------------------------------------------------------------------------------------
Number of Homes IEUBK Model Results (50-years; $Billion)
Soil Option (ppm) Exceeding Soil -----------------------------------------------------------
Option (Millions) Costs Benefit Net Benefit
----------------------------------------------------------------------------------------------------------------
500 11.8 42 149 107
1,000 5.8 28 92 65
1,200 4.7 25 82 57
1,500 3.2 16 63 47
2,000 2.5 9 45 36
2,500 1.5 6 30 24
3,000 0.7 4 19 15
3,500 0.7 4 19 15
4,000 0.7 4 19 15
4,500 0.3 1 6 6
5,000 0.2 0.4 4 4
----------------------------------------------------------------------------------------------------------------
*Note: Rows may not add due to rounding. This table does not include estimated costs or benefits of paint and
dust interventions, or any risk assessment costs.
Total benefits increase as options become increasingly stringent,
ranging from $59 billion to $73 billion for dust and from $4 billion to
$149 billion for soil. Total benefits are a function of the number of
children (which is directly related to the number of homes) affected by
an option and the amount of risk reduction predicted for each child.
Furthermore benefits increase at an increasing rate because, as dust
and soil-lead levels decline, the number of homes at given
environmental lead levels increases more quickly. For example, moving
from a soil standard of 5,000 ppm to 4,500 ppm increases the number of
homes exceeding the standard from about 200,000 to about 300,000 (an
increase of about 100,000 housing units), while moving from 1,000 ppm
to 500 ppm increases the number of homes exceeding the standard from
about 5.8 million to 11.8 million (an increase of about 6 million
housing units).
The rate also increases because the changes in blood-lead
concentration predicted by the IEUBK model are greater for a given
change in dust and soil-lead levels at lower dust and soil-lead levels.
The increasing strength of this relationship between environmental lead
and blood lead is sufficient to overcome the smaller changes between
baseline and post-intervention dust and soil-lead levels that occur as
the standard options become more stringent. For example, the assumed
change in soil-lead level for a home that has a soil-lead concentration
of 2,500 ppm is 2,350 ppm (the assumed post-intervention concentration
is 150 ppm). The assumed change for a home that has a soil-lead
concentration of 500 ppm is only 350 ppm.
Total costs also increase as options become increasingly stringent,
ranging from $10 billion to $12 billion for dust and $400 million to
$42 billion for soil. Total costs are mainly a function of unit costs
(costs for a single intervention) and the number of homes affected. For
dust, unit costs ($391 for single-family homes and $262 for multi-
family units) are the same regardless of the standard being evaluated.
For soil, unit costs vary depending on the part of the yard (e.g.,
dripline, mid-yard) being addressed by the abatement and on whether the
removed soil has to be managed as hazardous waste under regulations
found at 40 CFR part 260 to 40 CFR part 270. The unit cost is lower for
lower soil-lead levels (below 2,000 ppm) because the removed soil does
not have to be managed as hazardous waste. Table 3 above presents the
complete range of unit costs for soil removal. As is the case for
benefits, total costs increase as the standard options become more
stringent because more homes exceed each optional standard.
Unit cost should not be confused with average cost per residence.
Unit cost is the cost per intervention per residence. Average cost is
the cost per residence over the entire 50-year modeling horizon and
takes into account factors such as the need to repeat interventions
(dust), averaging a range of unit costs (soil), and discounting (both
dust and soil). Because the duration of dust intervention effectiveness
is limited if the underlying source of lead is not eliminated, dust
cleaning may have to be repeated, raising the average cost per
residence. Average cost for soil abatement per residence will reflect a
mix of soil intervention costs which vary depending on the area of the
yard addressed and the type of disposal required. Interventions
performed in the future are discounted back to the present. For
example, the present value of a dust cleaning performed in a single-
family house 40 years from now would be approximately $120 assuming a
three percent discount rate.
Because total benefits increase at a faster rate than total costs,
net benefits also increase as options become increasingly stringent,
ranging from $41 billion to $61 billion for dust and $4 billion to $107
billion for soil. The increase in net benefits is relatively constant
as the dust standards become more stringent. For soil, net benefits
increase slowly from 5,000 ppm to 3,000
[[Page 30325]]
ppm and increase more quickly from 3,000 ppm to 500 ppm. Net benefits
increase because total benefits are increasing at a faster rate than
total costs. This result is primarily explained by the relationship
between lead in dust and soil and blood-lead which strengthens as dust
and soil-lead levels decline under the IEUBK model.
Given the large number of residences at the lower baseline dust and
soil-lead levels and the small changes in these levels that would
result from interventions, the results of the analysis for the more
stringent options are extremely sensitive to the assumed relationship
between dust and soil-lead and blood lead. If the true relationship is
slightly weaker, total and net benefits could be significantly lower.
Tables 6 and 7 below present the results of the empirical model-
based normative analysis for a range of possible dust and soil hazard
standard options. Table 6 presents the costs, benefits, and net
benefits for actions taken in response to the specified options for
dust standards; it does not include any soil interventions. Table 7
presents figures relating to soil standards; it does not include any
dust interventions. Neither table includes any testing or risk
assessment costs, nor costs or benefits of paint interventions.
Total benefits increase as options become increasingly stringent,
ranging from $25 billion to $36 billion for dust and $1 billion to $36
billion for soil. As is the case in the IEUBK model-based analysis, the
rate at which benefits increase rises as the stringency of the options
increase, because more homes are affected (and more children are
protected). The rate at which benefits increase, however, is tempered
somewhat because the relationship between dust and soil-lead and blood-
lead remains relatively constant across the range of options
considered. The increasing number of children protected by more
stringent standards is counterbalanced by decreasing risk reduction
predicted for children living in homes with low dust and soil-lead
levels because the smaller changes between baseline dust and soil-lead
levels and post-intervention levels at lower baseline levels equate to
smaller changes in blood-lead concentration. Costs are the same as in
the IEUBK-based analysis because the models are used only to calculate
benefits.
Table 6.--Estimated Costs, Benefits, and Net Benefits for Dust-Lead Hazard Standard Alone (Using the Empirical Model)*
--------------------------------------------------------------------------------------------------------------------------------------------------------
Option (g/ft2) Number of Homes Empirical Model Results (50-years; $Billion)
------------------------------------------------------------ Exceeding Option --------------------------------------------------------------------
Floor Dust Sill Dust (Millions) Costs Benefit Net Benefit
--------------------------------------------------------------------------------------------------------------------------------------------------------
50 100 34 19 36 17
50 250 21 12 34 22
100 250 19 10 32 22
50 500 16 9 31 22
100 500 14 8 28 21
100 1,000 11 6 25 19
--------------------------------------------------------------------------------------------------------------------------------------------------------
*Note: Rows may not add due to rounding. This table does not include estimated costs or benefits of paint and soil interventions, or any risk assessment
costs.
Table 7.--Estimated Costs, Benefits, and Net Benefits for Soil-Lead Hazard Standard Alone (Using the Empirical
Model)*
----------------------------------------------------------------------------------------------------------------
Number of Homes Empirical Model Results (50-years; $Billion)
Soil Option (ppm) Exceeding Soil -----------------------------------------------------------
Option (Millions) Costs Benefit Net Benefit
----------------------------------------------------------------------------------------------------------------
500 11.8 42 36 -6
1,000 5.8 28 22 -6
1,200 4.7 25 19 -7
1,500 3.2 16 14 -1
2,000 2.5 9 10 2
2,500 1.5 6 5 -0.2
3,000 0.7 4 3 -1
3,500 0.7 4 3 -1
4,000 0.7 4 3 -1
4,500 0.3 1 1 1
5,000 0.2 0.4 1 0.5
----------------------------------------------------------------------------------------------------------------
*Note: Rows may not add due to rounding. This table does not include estimated costs or benefits of paint and
dust interventions, or any risk assessment costs.
Net benefits for dust range from $17 billion to $22 billion. Of the
six combinations of dust standard options evaluated, net benefits are
relatively constant for all the combinations except the most and least
stringent. For the four other options, benefits and costs increase at
approximately the same rate, resulting in little change in net
benefits. Net benefits for soil range from $-7 billion to $2 billion,
approaching maximum levels near 5,000 ppm and 2,000 ppm. Below 2,000
ppm, net benefits decrease because total benefits increase at a slower
rate than total costs. The increased number of children protected at
more stringent standards is offset by a smaller predicted reduction in
risk at lower environmental levels.
As stated above, the results presented in this section show the
estimated costs, benefits, and net benefits associated with a range of
dust standards resulting from dust interventions only and with a range
of soil standards resulting from soil interventions only. These are the
estimates EPA used in its decision-making process when selecting the
preferred options for the proposed dust-lead and soil-lead hazard
standards. These single-medium estimates enable the Agency to attribute
costs, benefits, and net benefits to the interventions in
[[Page 30326]]
a specific medium and allowed EPA to compare options when developing
the media-specific standards.
The Agency, however, believes that it would be useful for the
public to examine the estimates of costs, benefits, and net benefits
for dust and soil interventions combined. Table 8 presents the
estimates developed by the IEUBK model-based approach for a range of
floor dust standards assuming a sill dust standard of 250 g/
ft2 and a soil standard of 2,000 ppm. Table 9 presents the
estimates developed by the IEUBK model-based approach for a range of
soil standards assuming a floor dust standard of 50 g/ft2
and a sill dust standard of 250 g/ft2. Table 10
presents the estimates developed by the empirical model-based approach
for a range of floor and window sill dust standards assuming a soil
standard of 2,000 ppm. Table 11 presents the estimates developed by the
empirical model-based approach for a range of soil standards assuming a
floor dust standard of 50 g/ft2 and a sill dust
standard of 250 g/ft2. The estimates presented in
these tables are based on the Agency's economic analysis.
It is important to note that the costs and benefits for the
combined dust and soil standards in tables 8 through 11 are less than
the sum of the costs and benefits for the corresponding media-specific
dust and soil standards presented in tables 4 through 7. This
difference occurs because soil abatements are assumed to include dust
cleaning. Therefore, the estimate of benefits derived from addressing
soil hazards alone includes some benefit from dust cleaning, which is
also included in the estimate of dust benefits alone. When EPA
estimates the benefits for the combined dust and soil standards, dust
cleaning that would be triggered by either proposed standard is only
counted once. The overlapping dust benefit, however, accounts for only
a small part of the overall benefit of the proposed dust standard. Many
homes that exceed the proposed dust standard do not exceed the proposed
soil standard; therefore, only a dust cleaning would be performed in
these homes and benefits derived from establishing a dust hazard
standard would not be double counted.
EPA wishes to reiterate that the estimates presented in Tables 8
through 11 are presented for informational purposes only and were not
used to guide Agency decision-making for this proposal. The Agency
requests comments on this alternate approach for presenting benefits,
costs, and net benefits.
Table 8.--Estimated Costs, Benefits, and Net Benefits for Dust-Lead Hazard Standard Options (Using the IEUBK
Model)*
(assumes a soil-lead hazard standard of 2,000 ppm)
----------------------------------------------------------------------------------------------------------------
Number of Homes IEUBK Model Results (50 years; $Billion)
Floor Dust Options (g/ Exceeding Dust or -----------------------------------------------------------
ft2) Soil Option
(Millions) Costs Benefit Net Benefit
----------------------------------------------------------------------------------------------------------------
50 18 19 108 89
100 16 18 95 77
----------------------------------------------------------------------------------------------------------------
*Note: Rows may not add due to rounding. This table does not include estimated costs or benefits of paint
interventions, or any risk assessment costs.
Table 9.--Estimated Costs, Benefits, and Net Benefits for Soil-Lead Hazard Standard Options (Using the IEUBK
Model)*
(assumes dust-lead hazard standards of 50 g/ft2 for floors and 250 g/ft2 for window sills)
----------------------------------------------------------------------------------------------------------------
Number of Homes IEUBK Model Results (50 years; $Billion)
Exceeding Dust or -----------------------------------------------------------
Soil Option (ppm) Soil Options
(Millions) Costs Benefit Net Benefit
----------------------------------------------------------------------------------------------------------------
500 22 50 193 143
1,000 19 38 150 112
1,200 19 35 142 106
1,500 18 26 124 98
2,000 18 19 108 89
2,500 18 17 95 78
3,000 18 16 86 70
3,500 18 16 86 70
4,000 18 16 86 70
4,500 17 12 75 62
5,000 17 12 73 61
----------------------------------------------------------------------------------------------------------------
*Note: Rows may not add due to rounding. This table does not include estimated costs or benefits of paint
interventions, or any risk assessment costs.
Table 10.--Estimated Costs, Benefits, and Net Benefits for Dust-Lead Hazard Standard Options (Using the Empirical Model)*
(assumes a soil-lead hazard standard of 2,000 ppm)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Option (g/ft2) Number of Homes Empirical Model Results (50 years; $Billion)
------------------------------------------------------------ Exceeding Dust or Soil --------------------------------------------------------------------
Floor Dust Sill Dust Options (Millions) Costs Benefit Net Benefit
--------------------------------------------------------------------------------------------------------------------------------------------------------
50 100 28 27 43 16
[[Page 30327]]
50 250 18 19 39 19
100 250 16 18 37 19
50 500 14 17 36 19
100 500 12 15 33 18
100 1,000 10 14 30 16
--------------------------------------------------------------------------------------------------------------------------------------------------------
*Note: Rows may not add due to rounding. This table does not include estimated costs or benefits of paint interventions, or any risk assessment costs.
Table 11.--Estimated Costs, Benefits, and Net Benefits for Soil-Lead Hazard Standard Options (Using the
Empirical Model)*
(assumes dust-lead hazard standards of 50 g/ft2 for floors and 250 g/ft2 for window sills)
----------------------------------------------------------------------------------------------------------------
Number of Homes Empirical Model Results (50 years; $Billion)
Exceeding Dust or -----------------------------------------------------------
Soil Option (ppm) Soil Options
(Millions) Costs Benefit Net Benefit
----------------------------------------------------------------------------------------------------------------
500 22 50 55 5
1,000 19 38 47 9
1,200 19 35 45 10
1,500 18 26 42 16
2,000 18 19 39 19
2,500 18 17 36 19
3,000 18 16 35 19
3,500 18 16 35 19
4,000 18 16 35 19
4,500 17 12 33 21
5,000 17 12 33 21
----------------------------------------------------------------------------------------------------------------
*Note: Rows may not add due to rounding. This table does not include estimated costs or benefits of paint
interventions, or any risk assessment costs.
C. Agency Decisions for Dust and Soil Standards
This section of the preamble presents EPA's decisions regarding the
dust and soil standards. These decisions are based on the
interpretation of, and the conclusions drawn from, the results of the
normative analysis presented in the previous section of the preamble.
The interpretations and conclusions are discussed in the context of the
explanations for the specific decisions made by the Agency. The public
should refer back to the previous section for a more complete treatment
of the analytical results.
When considering the impacts of the proposed standards for dust and
soil, the public should understand that properties will be evaluated by
comparing these standards to average dust and soil-lead levels measured
by a risk assessor, not worst-case or maximum values. As noted in Unit
VI. of this preamble, the use of the average value is the most
reasonable approach in the absence of specific detailed information
about exposure.
1. Dust-lead hazard. EPA has decided to propose 50 g/
ft2 as the dust-lead hazard standard for uncarpeted floors
and 250 g/ft2 for interior window sills. According
to the empirical model-based analysis, the results of which are
summarized in Table 6, four of six combinations of options for floor
and window sill standards have net benefits in the maximum range (i.e.,
$21 to $22 billion). One combination (100 g/ft2 for
floors, 1,000 g/ft2 for sills) provides
significantly less risk reduction relative to cost; and one combination
(50 g/ft2 for floors, 100 g/ft2
for sills) provides little additional benefit but costs increase
significantly. Incremental benefits are less than one third the
incremental costs and an additional 11 million homes would fall under
the standard. EPA, therefore, considers that this lower standard for
sills is associated with increased costs without commensurate attendant
benefits.
Of the four combinations where net benefits are in the maximum
range, the proposed option is the most protective in terms of the
amount of risk reduction yielded. The other three options, though less
costly, also provide less risk reduction. The decrease in both costs
and benefits as the combination of floor and sill options become less
stringent are roughly the same (between $5 billion and $6 billion),
resulting in little change in net benefits.
EPA decided to propose the 50 g/ft2 and 250
g/ft2 standards respectively for floors and sills
because the Agency prefers to select the most protective of the four
combinations where net benefits are in the maximum range. Selecting the
most protective combination of dust-lead hazard standards is especially
important when considered in combination with the soil and paint
standards being proposed or considered today. It will help protect
children who are exposed to lead in soil at concentrations between the
level of concern and the hazard level by mitigating exposure in one of
the pathways by which children are exposed to lead in soil.
The Agency did not consider a floor standard option less than 50
g/ft2 because, in its risk analysis, EPA's best
estimate is that the post intervention-
[[Page 30328]]
dust lead loading is the lower of the pre-intervention dust-loading or
40 g/ft2. This is the Agency's best estimate of
dust levels that would remain after controlling sources of lead and
thoroughly cleaning the residence. It is based on an analysis of data
from several abatement studies which is more fully discussed in Chapter
6 of the Agency's risk analysis. In light of this estimate, it would be
impractical to set the standard for floors lower than 40 g/
ft2 because little or no risk reduction is likely to be
achieved for homes that had dust-lead loadings at or below 40
g/ft2. If new data become available before
promulgation of the final rule that show that even lower post-
intervention dust-lead loadings can be achieved, EPA would consider
establishing a more stringent dust-lead hazard standard.
EPA's decision on the floor standard is further supported by the
results of the IEUBK model-based normative analysis, summarized in
Table 4, which show that the net benefits for the proposed floor
standard are greater than those for a less stringent standard; net
benefits estimated by this analysis increase from $48 billion for 100
g/ft2 to $61 billion for the proposed 50
g/ft2 standard. The IEUBK model was not used to
analyze sill options because the model does not contain a sill
parameter.
EPA reiterates that this normative cost-benefit analysis has been
undertaken for comparative purposes only and does not mean to imply
that billions of dollars will be spent on lead dust cleanup. These
costs are put into better perspective when it is understood that the
cost per residence of dust cleaning is less than $600 per affected
residence over a 50-year period in 1995 dollars. In making this
decision, EPA recognizes that the proposed standard could result in
dust hazard interventions in perhaps as many as 20 million homes.
Although this is a very large number of homes, the cost of intensive
dust cleaning is relatively low for individual residences.
2. Dust-lead level of concern. As noted earlier, EPA has decided
not to include a level of concern in the proposed regulations. The
Agency has further decided not to include a dust-lead level of concern
that is distinct from the dust-lead hazard standard in accompanying
guidance. This decision is based on the fact that there is significant
overlap between the results of the analysis for the level of concern
and the dust-lead hazard standards. According to the performance
characteristics analysis, the range for the level of concern is 50 to
400 g/ft2 for uncarpeted floors and 100 to 800
g/ft2 for interior window sills. The hazard
standards of 50 g/ft2 for floors and 250
g/ft2 for sills are within these ranges. Because it
would make no sense for the level of concern to be higher than the
hazard standard according to the Agency's policy framework, the level
of concern for floors could not be higher than 50 g/
ft2, the lowest level of concern shown by the Agency's
analyses. EPA's analysis therefore suggests that the dust-lead level of
concern and the dust-lead hazard level for floors should be the same.
In light of this result, the Agency has decided that including a dust-
lead level of concern in guidance would serve no practical purpose.
For window sills, it is possible to have a level of concern as low
as 100 g/ft2, which is lower than the hazard level.
For several reasons, however, EPA has decided not to use this level in
guidance. First, the performance characteristics analysis of the
Rochester data show that there is no difference in risk between 100
g/ft2 and 250 g/ft2. Due to the
high correlation between lead in dust on window sills and lead in dust
on floors and a small sample size, risk does not change as sill dust-
lead levels vary when accounting for floor dust-lead levels (Ref. 64).
Second, there is a high degree of variability in dust-lead loading
measurements, varying from day-to-day and from location-to-location on
the same surface. In light of the small difference in risk and the high
degree of variability in measuring dust levels, having a level of
concern for window sills in accompanying guidance would introduce
unnecessary complexity into EPA's program.
3. Soil-lead level of concern. EPA is proposing not to include a
soil-lead level of concern in the regulation. The Agency, instead, is
requesting comment on including 400 ppm as the soil-lead level of
concern. As discussed above, the IEUBK model indicates that soil-lead
concentrations associated with the risk level of concern are generally
at or below 500 ppm and the performance characteristics analysis
yielded a range of 200 ppm to 1,500 ppm. Thus, the range of soil-lead
levels from 200 ppm to 500 ppm is supported by the results of both
analyses. Lacking technical criteria to select one level from this
range as the proposed soil-lead level of concern in accompanying
guidance, the Agency determined that it should choose 400 ppm because
it is both within this range and consistent with the soil screening
level used by EPA's Superfund and RCRA corrective action programs (Ref.
84) and EPA's current guidance on lead-based paint hazards (60 FR
47248). It is clear from all the evidence that this level ``poses a
threat of adverse health effects.'' The analysis, above, shows there is
a one to five percent chance that individual children exposed to this
soil level could have a blood-lead level equal to or exceeding 10
g/dl, although the Agency could not say that adverse health
effects ``would result'' from these levels.
4. Soil-lead hazard. As explained in Unit II. of this preamble,
this public health decision requires consideration of the potential
risks to children that may occur at levels equal to or lower than the
chosen hazard level. At the same time, EPA believes that consideration
of costs is necessary to ensure that the hazard standard promotes
priority-setting and supports the establishment of a workable national
hazard evaluation and control program. To arrive at a proposed soil-
lead hazard level, EPA sought a level at which the Agency had
sufficient confidence in the likelihood of harm (i.e., greater than the
level of concern) and that the cost of abatement seemed warranted to
achieve the associated level of risk reduction.
Based on the Agency's analysis and judgment, EPA has decided to
propose 2,000 ppm as the soil-lead hazard standard. This decision is
based on the following reasons. First, the results of the empirical
model-based normative analysis (summarized in Table 7) show that net
benefits are positive and near the maximum level at 2,000 ppm. The
IEUBK normative model-based analysis (summarized in Table 4b) shows
positive and significantly higher net benefits at concentrations up to
2,000 ppm than for soil-lead concentrations above 2,000 ppm. Positive
net benefits indicate that the cost of soil abatement at this
concentration is less than the benefits associated with risk reduction
for the population as a whole. Because both analyses show positive net
benefits at 2,000 ppm, EPA is confident that this level represents a
reasonable public health policy choice for today's proposal.
As stated previously, EPA conducted the normative cost-benefit
analysis for purposes of comparing options. Undue emphasis should not
be placed on the total costs and benefits estimated by each analysis.
It is probably more useful, therefore, to consider what the Agency's
analysis and decision implies for the average property. According to
EPA's analysis, the average cost of soil abatement for a residence at
2,000 ppm is about $3,600. The analyses show that cost is commensurate
with risk reduction at this concentration because the value of risk
reduction in terms of avoided adverse health effects is greater than
the cost. It is important to recognize, however, that the benefits
[[Page 30329]]
account not only for the child immediately protected when the abatement
is performed but also for children who may reside in that residence in
the future. The comparison of estimated costs and benefits for an
individual property is also an average. For some homes, costs could be
higher than benefits. EPA's decision, however, is based on the overall
benefit to society which accounts for benefits for future generations
of children and for the average child.
Second, outside of its use in the economics model, the IEUBK model
predicts significant risk to children at this soil-lead concentration
under virtually all exposure scenarios. At 2,000 ppm in soil, the model
estimates a mean blood lead level in the range of 11-16 g/dl,
depending upon the assumed concentration of lead in house dust (100-
1,400 ppm in this case). This range corresponds to approximately 55 to
80 percent equal to or exceeding 10 g/dl and 9 to 30 percent
exceeding 20 g/dl.
Third, data from a number of epidemiological studies show that
between 40 and 50 percent of the children living in certain communities
with soil-lead concentrations at the 2,000 ppm level have blood-lead
concentrations equal to or exceeding 10 g/dl and that 10
percent of children have blood-lead concentrations equal to or
exceeding 20 g/dl (Ref. 85).
In reaching its decision, EPA rejected more stringent options for
several reasons. First, although the IEUBK model-based analysis shows
higher net benefits for more stringent standards, the results of the
IEUBK model-based analysis at relatively low soil-lead concentrations
(e.g., 500 ppm) are very sensitive to assumptions in both the analysis
and the model. As noted above, a significant proportion of these
benefits are associated with changes in dust concentration which are
affected by both the HUD National Survey data and EPA's assumptions
about post-intervention dust concentrations. The results are also very
sensitive to the assumed relationship between soil-lead and blood-lead
concentrations in the IEUBK model. Because of the larger number of
homes at lower soil-lead concentrations (e.g., 11.8 million
500 ppm versus 2.5 million 2,000 ppm) and the smaller
reductions in environmental lead levels that can be achieved at the
lower concentrations, a slight change in the relationship between soil-
lead and blood-lead concentrations can produce significantly different
net benefits. Consequently, it is questionable whether risk reduction
would be commensurate with costs and lower soil-lead concentrations.
Second, the Agency's analysis did not consider the role that
interim controls can play in reducing risks at lower soil-lead
concentrations. Interim controls were not considered because EPA lacks
data to estimate the effectiveness of these controls. The Agency
believes that at lower soil-lead concentrations, interim measures can
interfere with exposure pathways and reduce risk and that these
measures may be more cost effective than abatement at lower
concentrations.
Third, EPA is concerned that more stringent standards would not
meet the priority-setting goals the Agency believes are appropriate for
the Title X program. Based on the soil-lead data in the HUD National
Survey, EPA estimates that 4.7 million homes would exceed 1,200 ppm and
nearly 12 million homes would exceed 500 ppm, two options considered by
the Agency. Scarce resources potentially would have to be allocated
across more communities and would be diverted away from interventions
needed to respond to both deteriorated interior and exterior lead-based
paint. The proposed 2,000 ppm standard will help focus resources for
soil abatement on significantly fewer properties (i.e., 2.5 million).
In proposing 2,000 ppm as the soil-lead hazard standard, EPA does
not wish to communicate a lack of concern about risks that exists below
this soil-lead concentration. In fact, the Agency recognizes that there
could be substantial risk below 2,000 ppm. The IEUBK model predicts
risk to children under a variety of exposure scenarios. At 1,200 ppm in
soil, the model estimates a mean blood lead level in the range of 8 to
11 g/dl, depending upon the assumed concentration of lead in
house dust (100 to 850 ppm in this case). This range of mean blood-lead
concentrations corresponds to a range of approximately 30 to 60 percent
exceeding 10 g/dl and 2 to 10 percent exceeding 20 g/
dl. As noted above, however, the Agency believes that it is not
appropriate to set a more stringent uniform national soil-lead hazard
standard because costs may not be commensurate with risk reduction and
resources would not be adequately focused. The Agency further thinks
that measures undertaken in response to the proposed soil-lead level of
concern in the accompanying guidance and dust hazard standards will
help protect children exposed to soil-lead concentrations between 400
ppm and 2,000 ppm. It should be noted that abatement at levels below
2,000 ppm may be appropriate on a case-by-case basis depending on local
conditions.
EPA also considered a less stringent standard of 5,000 ppm. This
option has several advantages. First, consistent with the priority-
setting concept of Title X and the need to apply scarce resources
effectively, as noted in Unit IV.A.2.b, this option would focus on
properties that present the greatest risk to young children. Second, it
would affect relatively few homes (i.e., an estimated 200,000 units
based on data from the HUD National Survey). Because fewer homes would
be affected, the estimated cost associated with this option, as shown
in Tables 5 and 7, is significantly lower than the cost of the
preferred option ($0.4 billion for 5,000 ppm vs. $9 billion for 2,000
ppm), thus reducing the impact of the rule on properties and
communities. In fact, according to the empirical model-based approach,
the net benefits are about the same for 5,000 ppm and 2,000 ppm. Third,
this level would be consistent with EPA's interim guidance document on
lead-based paint hazards (60 FR 47248). Some argue that the adoption of
a more stringent soil hazard standard -- given the substantial costs of
soil abatement -- may influence the decisions or actions of owners of
target housing in unintended ways. The Agency is interested in
receiving comments on how the hazard standard may influence owners, the
number of clean-ups or interventions, and whether the hazard standard
would influence housing availability. In discussions at EPA's dialogue
process, many interested parties stated that the guidance was a
workable approach that should be adopted in the regulation.
This option, however, is characterized by several important
disadvantages. First, the IEUBK model predicts, and the epidemiological
data show, that a substantial number of children who are exposed to
soil with lead levels between 2,000 ppm and 5,000 ppm have moderately
to highly elevated blood lead levels. Furthermore, interim controls
would be relied upon to address risks from soil-lead concentrations up
to 5,000 ppm under this option. It is important to consider that
interim controls, which may successfully mitigate risks at lower soil
lead concentrations, do not eliminate the lead source. Rather, they
serve to reduce exposure by limiting the accessibility of the soil and
the consequent inadvertent ingestion or tracking of the soil into a
home (where it can contribute lead to interior dust). As the soil lead
concentration increases, however, it is more likely that even if
accessibility of the soil were reduced,
[[Page 30330]]
significant risk would remain. In the case of track-in, the Agency is
concerned that even a relatively small amount of high-lead-
concentration soil can re-contaminate interior dust and reintroduce a
dust-lead hazard. Second, although, as stated above, costs may be lower
at 5,000 ppm, the IEUBK model-based approach shows that net benefits
also decrease by $32 billion when increasing the standard from 2,000
ppm to 5,000 ppm. Furthermore, the empirical model-based approach shows
that, while net benefits are about the same for both options, benefits
decline by $9 billion when the standard increases from 2,000 ppm to
5,000 ppm.
In light of the results of EPA's formal cost-benefit analysis, the
risk predictions of the IEUBK model, and the risk to young children
documented by the epidemiological data, EPA decided that 2,000 ppm was
a more appropriate option for today's proposal. In reaching this
decision, EPA was mindful of the impacts that the costs of soil
abatement could have on individual properties and communities.
Consideration of costs and their impacts was the primary reason why EPA
selected 2,000 ppm rather than a more stringent option (e.g., 1,200
ppm). Moreover, EPA would have selected 2,000 ppm as its preferred
option even if the Agency had relied only on the empirical model and
epidemiological data as some stakeholders have suggested. The results
of the empirical model-based analysis show that both the 2,000 ppm
option and the 5,000 ppm option are equivalent in terms of net
benefits. The benefits at 2,000 ppm, however, are substantially higher
because, as the epidemiological data shows, there is substantial risk
to children exposed to lead in soil at concentrations between 2,000 ppm
and 5,000 ppm.
EPA notes that it does not anticipate that setting the soil-lead
hazard standard at 2,000 ppm would adversely impact individuals who
previously relied voluntarily on the guidance. First, EPA has no
information to suggest that many property owners have performed soil
abatements. Second, it is very likely that properties where soil
abatements were performed would now have soil-lead concentrations well
below 2,000 ppm and even below 400 ppm, the soil-lead level of concern.
This conclusion is based on the fact that when soil is removed, it is
replaced by ``clean'' soil--soil that has a very low lead
concentration.
D. Hazardous Lead-Based Paint
This section of the preamble presents EPA's proposed standard for
deteriorated lead-based paint. It also presents options for addressing
lead-based paint on friction and impact surfaces and lead-based paint
on surfaces accessible for chewing and mouthing by young children. The
Agency, however, is not proposing standards for lead-based paint on
friction, impact, and accessible surfaces, but is, instead, asking for
public comments on the options presented below.
For any type of hazardous lead-based paint, the paint must be lead-
based according to the statutory definition (i.e., 1 mg/
cm2 or 0.5 percent by weight). Determination of whether the
paint is lead-based is made by a certified inspector or risk assessor
based on testing results. EPA is developing a separate guidance
document that will address paint sampling.
1. Deteriorated lead-based paint. To meet the statutory requirement
to identify hazardous lead-based paint, EPA must determine those
conditions of deteriorated lead-based paint which would result in
adverse human health effects.
Exposure to deteriorated lead-based paint can result in adverse
human health effects, based on the fact that children can be exposed to
lead through several pathways when lead-based paint is deteriorated and
that studies document an association between children's blood-lead
concentrations and the presence of deteriorated lead-based paint. EPA,
however, is unaware of any data that would allow the Agency to more
specifically relate conditions of deterioration (e.g., levels of lead
in paint, minimum area of deteriorated lead-based paint) to blood-lead
concentration. The Agency, therefore, has chosen to propose a standard
for deteriorated paint using the criteria for paint condition in Table
5.3 of the HUD Guidelines (Ref. 11) for the reasons discussed below.
Exposure to lead from deteriorated lead-based paint can occur in
three ways. First, children who exhibit pica, a hunger for substances
not fit for food, may eat paint chips (Ref. 86). Second, deteriorated
interior lead-based paint can contaminate household dust which may be
inadvertently ingested by children through normal hand-to-mouth
behavior. Third, deteriorated exterior lead-based paint can contaminate
residential soil which can also be inadvertently ingested by children.
Soil, in turn, can be tracked into a residence, contaminating the
household dust.
These three scenarios have been demonstrated in various studies
that used stable isotopes of lead as tracers (see, e.g., Refs. 87 and
89). Basically, this technique relies upon the fact that the isotope
ratios of lead ores vary by deposit. Consequently, lead-containing
products, such as lead-based paints and leaded gasolines, can have
unique ratios of the stable isotopes in the lead. Comparison of the
isotope ratios in these products to those of environmental media and
blood can in some cases identify categories of products as the source
of lead in the environmental media and/or lead in the blood.
Rabinowitz (1987) reports use of this technique to investigate the
specific sources and pathways of lead exposure in three cases of
chronic, high-level lead poisoning (blood-lead concentrations of 120,
83, and 66 g/dl) (Ref. 90). In each case, blood, feces, and
the child's home environment (paint, dust, and soil) were sampled and
analyzed. All of the children had deteriorated paint present in their
homes. Additionally, a series of environmental samples were collected
and analyzed to characterize background lead throughout the city.
In the first two cases, the isotopic composition of the blood
(indicative of chronic exposure) and the feces (indicative of exposure
during the preceding day) were nearly identical. In the first case,
they resembled the paint sample from the child's bedroom wall (which
was similar to the exterior soil). In the second case, they closely
matched the lead in window sill paint, but not the kitchen wall or
garden soil. In the third case, the blood lead was close to that of the
paint in the child's bedroom, which was believed to be the source of
his chronic exposure, whereas the fecal lead appeared to be similar to
fallout from current automobile emissions in the area. While such data
do present some ambiguities, they are consistent with paint being the
proximate or remote source of the child's lead exposure and the
author's conclusion that, in cases of severe lead poisoning, the lead
in the child's blood and feces closely resembles lead in paint on an
accessible surface. Additionally, based upon isotopic comparisons
between household dust and urban soils, the study also concluded that:
(1) In the absence of lead-based paint, the leads in urban soils and
household dust have nearly the same isotopic composition, and (2) lead-
based paint, when present, can be responsible for 20 to 70 percent of
lead in household dust and much of the lead in yard soil.
Yaffe, et al. presented two cases which also included measurement
of the isotopic ratios of lead in blood, paint, dust, and soil (Ref.
89) . In both cases, it was unlikely that direct ingestion of paint
chips was the cause of the elevated blood-lead
[[Page 30331]]
concentrations. This was based on the facts that: (1) There was no
indication that the children were pica-prone based upon interviews with
the children and their parents, and (2) higher than exhibited blood-
lead concentrations would be expected if paint chips were being
ingested, given the very high lead levels in the paint.
The first case involved 10 children with blood-lead concentrations
from 28 to 43 g/dl. The isotopic ratios of the children's
blood lead were similar, suggesting a common set of lead exposures.
These ratios were quite similar to those of soil samples collected
around the house and interior dust samples. The close agreement between
the average isotopic ratios of exterior paint samples and the soils
near the house suggested that the soil was contaminated by the exterior
paint, which was badly deteriorated.
The second case involved twin 2-year old males with blood-lead
concentrations of 37 and 43 g/dl. The isotopic ratios of the
twins' blood lead were similar to the soil in their side yard and in
the back yard of a nearby house where they often played. These soils
had similar ratios to adjacent exterior walls. This suggests that the
lead in the soils was primarily derived from the weathering of nearby
painted surfaces and that the contaminated soil was a significant
source of the twins' exposure. The interior dust sample lead was not
similar to the exterior soil or the twins' blood lead. Such cases,
where soil or dust becomes contaminated by deteriorating paint,
demonstrate the need for a paint standard as well as soil and dust
standards. Lacking a paint standard, the paint can continue to re-
contaminate soil and dust, rendering abatement and control measures
directed at those two media ineffective.
The scientific literature also includes several studies that have
identified a statistically significant relationship between
deteriorated paint and children's blood-lead concentrations. One study
suggests that infant blood-lead concentrations are a function of paint
deterioration and lack of maintenance of the residence (Ref. 91). In
this study, housing was classified as deteriorated if the exterior was
not well maintained or had peeling paint, as observed from the street.
For infants at 12 to 18 months old, geometric mean blood-lead
concentrations were twice as high in deteriorated housing (33
g/dl) than in housing graded as satisfactory (15 g/
dl).
Another study identified statistically significant correlations
between the presence of both deteriorated interior and exterior lead-
based paint and children's blood-lead concentrations (Ref. 92).
Presence of peeling exterior paint was among the most influential
factors explaining the blood-lead concentrations of 2-year olds. It
should be noted, however, that lead levels in paint were not reported
in the paper. Therefore, it is not certain that the results of this
study actually represent deteriorated lead-based paint.
Analysis of data from the Rochester Lead-in-Dust Study performed to
support this rule's comprehensive risk analysis also shows a
relationship between deteriorated lead-based paint and children's
blood-lead concentrations. The empirical model, which explicitly
incorporated pica behavior, yielded a significant positive relationship
between deteriorated paint and children's blood-lead concentrations
(Ref. 1).
Analysis of the HUD National Survey data suggests that deteriorated
lead-based paint is indirectly linked to elevated blood-lead
concentrations in young children through lead in household dust and
residential soil (Refs. 8-9, and 19). Of those homes with interior
lead-based paint, 34 percent with non-intact paint had elevated dust
lead levels (i.e., elevated in comparison to HUD's dust clearance
levels at the time the survey was conducted) compared to 18 percent of
homes with intact paint. Of those homes with exterior lead-based paint,
53 percent of homes with non-intact paint had elevated dust lead levels
compared to 12 percent with intact paint. Although correlation analysis
cannot be used to prove causation, EPA believes that it is reasonable
to conclude that the lead in the deteriorating paint is a significant
source of the lead in the dust and soil.
Based on its analysis of existing studies and data, EPA believes
that deteriorated paint is a significant source of lead exposure for
young children through direct ingestion and through contamination of
dust and soil. To promote priority setting and the establishment of a
workable program, EPA thinks that the standard for deteriorated lead-
based paint should exclude small amounts of deterioration. From a
common sense perspective, it seems that there should be lower exposure
and risk from lead-based paint where there are lesser amounts of
deteriorated lead-based paint. There would be fewer paint chips to
contribute lead to dust and fewer paint chips available for direct
ingestion.
Because there are no data to directly relate the degree of
deterioration to blood-lead, EPA was unable to perform an analysis to
specify a minimal area of deterioration that would be considered a
hazard. The Agency therefore has decided to propose the conditions of
deterioration used currently in the 1995 HUD Guidelines. The HUD
Guidelines define lead-based paint in poor condition as more than 2
square feet of deteriorated lead-based paint on any large interior
architectural component (e.g., floors, walls, ceilings, doors, etc.),
more than 10 square feet of deteriorated lead-based paint on any large
exterior architectural component (e.g., siding), or deteriorated lead-
based paint on more than 10 percent of the surface area of any small
architectural component constitutes hazardous lead-based paint.
The Agency decided to use the criteria in the HUD Guidelines for
two reasons. First, these criteria are becoming the de facto industry
standard. They are being considered for incorporation into model
housing and building codes and by State officials for adoption as State
standards. Second, EPA decided that relatively small thresholds are
needed to be protective, because the area of deterioration has the
potential to increase over time and because the presence of even small
amounts of deterioration can present a significant risk to children who
exhibit pica for paint. The Agency wishes to emphasize that while areas
of deteriorated paint that fall below the threshold would not be
considered a hazard, property owners should try to keep paint intact,
especially paint known to be lead-based, because of the risk to some
children.
EPA cannot quantify the cost savings of including a minimum area of
deteriorated lead-based paint. The Agency presumes, however, based on
the available data, the minimum area threshold would reduce the number
of paint interventions that may be undertaken while still providing
protection to populations of concern. For example, according to the HUD
National Survey, of the estimated 15 million homes currently in the
housing stock that have deteriorated lead-based paint, 11 percent have
less than 5 square feet of deteriorated paint and 36 percent have less
than 10 square feet of deterioration (Ref. 93). With a de minimis level
in place, millions of homes would not be identified as having hazardous
deteriorated paint. It is important to note, however, that the
presentation of these data is only intended to provide a frame of
reference. They are not comparable to the criteria in the HUD
Guidelines because these criteria are component-based and the data in
the HUD National Survey apply to the aggregate area of deteriorated
paint in the entire residence.
[[Page 30332]]
EPA considered two other options for identifying the conditions
where deteriorated lead-based paint would be defined as a hazard. One
alternative involved combining surface area with the levels of lead in
paint. This approach is based on the assumption that the hazard
presented by an area of highly concentrated deteriorated lead-based
paint is greater than the hazard presented by an equal area of
deteriorated paint with a lower concentration of lead. Although this
assumption is technically appealing, EPA has no basis for establishing
the appropriate combinations of area and lead loadings. Furthermore,
the Agency believes that this approach would be overly complex and
costly to implement because it would require significantly more paint
testing.
The second alternative involved measuring the aggregate amount of
deteriorated lead-based paint at an entire residence, as was measured
in the HUD National Survey, rather than on individual architectural
components, as is provided for in the HUD Guidelines. The advantage of
this approach would be that the aggregate amount of deteriorated lead-
based paint at an entire residence may be a better indicator of risk
than the amount of deteriorated paint on individual components. EPA,
however, has no data to support this assumption or to select a minimum
area. In addition, this approach may be more expensive to implement
because it could require the risk assessor to test all deteriorated
paint on all individual components to determine whether the aggregate
area of deteriorated lead-based paint exceeds the threshold. In
contrast, the component-based approach would be less expensive because
it would require the risk assessor to test deteriorated paint on only
those components where the deterioration exceeds the area threshold.
Furthermore, the component-based approach is consistent with paint
abatement activities, which addresses hazards on individual components.
In light of the uncertainty associated with EPA's decision, the
Agency is seeking comment on several issues related to the deteriorated
lead-based paint hazard standard. First, EPA is interested in any data
the public may have that would enable the Agency to better characterize
the relationship between the amount of deteriorated lead-based paint
and health risk. Second, EPA requests comments on the surface area
hazard thresholds included in the proposed standard. Third, the Agency
is seeking comment on whether the proposed component-based area
threshold is better than an aggregate residence-based threshold.
2. Friction and impact surfaces. Title IV of TSCA specifically
identifies lead-based paint on friction and impact surfaces as a
potential type of hazardous lead-based paint because the repeated
rubbing and impacts may generate fine particles of lead-containing
paint that can contaminate household dust. TSCA section 401 defines
friction surfaces as surfaces that are subject to abrasion or friction
including certain window, floor, and stair surfaces. Impact surfaces
are surfaces subject to damage by repeated impacts such as certain
parts of a door frame.
The data linking lead-based paint on friction and impact surfaces
with lead in dust, however, are limited and inconclusive. Analysis of
the HUD grantee data shows that there are many instances where lead-
based paint on friction and impact surfaces and low dust-lead levels
may be found in the same residence (Ref. 94). These data were collected
from homes undergoing hazard evaluation and control under lead hazard
control grants awarded by HUD under authority of section 1011 of Title
X. In fact, of the windows with lead-based paint in good condition, 65
percent had dust-lead levels below the HUD clearance level. These data
suggest, contrary to the conventional wisdom, that lead-based paint on
friction and impact surfaces does not necessarily result in elevated
levels of lead in household dust. Even if elevated levels of lead in
dust are identified, it is not clear that lead-based paint on friction
and impact surfaces is the source of the lead. In light of the
uncertainties and contradictory evidence, EPA considered several
alternatives for addressing these surfaces.
When reviewing these alternatives, the public should be mindful
that the options for lead-based paint on friction and impact surfaces
are designed to address exposure through ingestion of dust contaminated
with lead. Lead-based paint is always a hazard when it is in poor
condition, regardless of its location in a residence. The paint in poor
condition critierion is designed to address exposure through direct
ingestion of paint chips.
Option 1. Under this alternative, EPA considered identifying any
lead-based paint on a friction or impact surfaces as a lead-based paint
hazard. The Agency considered this option because it is the approach
taken in EPA's July 1994 guidance. The major advantage of this option
is that it is designed to address a source of dust contamination.
On the other hand, the data show that surfaces that have lead-based
paint in good condition do not necessarily generate elevated levels of
lead in dust (Ref. 94). This option is also inconsistent with several
of the statutory precepts (i.e., priority-setting, establishing a
workable framework) because it would result in widespread paint testing
and/or costly responses even where dust-lead hazards are not present.
Option 2. Under the second option, EPA considered identifying
abraded lead-based paint on friction and impact surfaces as hazardous
lead-based paint. The point of this option is that it identifies a
condition, abrasion, associated with the generation of leaded dust,
thus overcoming the chief deficiency of the first option. It shares the
advantage of option one in that it is designed to address a source of
dust contamination.
On the other hand, this option is characterized by several
disadvantages. It would identify friction or impact surfaces as a
hazard regardless of the dust-lead levels present in the residence.
Without a dust-lead hazard, there appears to be no pathway of exposure.
Even if a dust-lead hazard is present, there is no certainty that the
friction and impact surfaces are the source of the lead. As with option
one, this option would result in paint testing and/or costly responses
in many older homes because of the high prevalence of abraded paint,
even if there is no evidence that these surfaces are contributing to
elevated levels of lead in dust.
Option 3. Under the third option, EPA would not identify lead-based
paint on friction and impact surface as hazardous lead-based paint. A
risk assessor should evaluate the levels of lead in dust and determine
whether a dust-lead hazard is present in the residence. If so, the
property owner or other decision-maker has the option to clean dust,
which may provide only short-term control of the hazard, or to address
the sources of lead in the dust, including friction and impact
surfaces, which would provide long-term control. The purpose of this
option is to address the immediate exposure source for children, which
is lead in the dust, and to provide flexibility to property owners
regarding how to control hazards.
This option has several disadvantages. First, this option is not
designed to address the source of lead but rather the exposure pathway.
A second disadvantage is that this option depends on dust-lead
measurements, which are highly variable, to determine whether there is
a problem. If a risk assessor
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obtains an atypically low dust measurement, he/she might not identify
friction and impact surfaces as a potential source of contamination.
Third, it fails to address directly a component that was specifically
identified in the statute.
For today's proposal, EPA has decided not to include a standard for
friction and impact surfaces. None of the three options is clearly
preferable. The first two options are designed to address sources of
lead. The primary pathway of exposure, however, is lead dust, and, it
makes little sense to burden a system with potential replacement of
components if there is no serious dust exposure.
The third option overcomes these disadvantages, providing an
incremental and flexible approach that indicates response actions where
there is an exposure pathway (i.e., presence of dust) and allows
decision-makers to choose the most cost-effective response (i.e,
repeated dust cleaning or component replacement). On the other hand,
this option fails to set a separate standard for surfaces of concern
that were specifically identified in the statute. Because this option
relies exclusively on dust loading measurements, which are highly
variable, it may fail to identify sources of hazards and may not be
adequately protective.
In light of the concern about friction and impact surfaces and the
uncertainties and contradictory data, EPA requests comment on the three
options presented above. EPA would also be interested in other
approaches for addressing lead-based paint on friction and impact
surfaces.
3. Surfaces accessible for chewing or mouthing. TSCA section 403
also requires EPA to identify the conditions under which exposure to
intact lead-based paint on surfaces accessible for chewing or mouthing
by young children would result in adverse human health effects. Chewing
on surfaces covered by lead-based paint can result in the ingestion of
a relatively large amount of lead, leading to an acutely high exposure.
Unlike pica, which is not considered normal behavior and occurs in a
relatively small percentage of the population, the chewing or mouthing
of hard surfaces is a normal part of a child's teething process.
The available data with respect to prevalence of mouthing or
chewing of accessible surfaces are mixed. Radiological examinations of
the children with high blood-lead concentrations (mean blood-lead
concentration was 56 g/dl) showed that 13 of 90 children (14
percent) had evidence of paint chip ingestion (Ref. 95). The study
notes, however, that the transit time of ingested material through a
child's digestive system ranges from several hours to several days.
Because the half-life of lead in blood is 30 days, radiographs will
reveal only a small percentage of children who have elevated blood-lead
concentrations due to the ingestion of a single paint chip.
On the other hand, data from HUD's lead hazard control grant
recipients show that the prevalence of chewing accessible surfaces is
extremely low. In the nearly 1,900 homes assessed, evidence of chewing
on accessible surfaces was found in 21 residences (1.1 percent). The
number of homes with accessible surfaces, however, was not determined.
Window sills were the most frequently chewed component. The data show,
however, that tooth marks were found on window sills in only 18
residences (one percent) (Ref. 96).
In developing today's proposal, EPA considered several options for
addressing intact lead-based paint on accessible surfaces.
Option 1. Under the first option, EPA considered identifying
characteristics of a component's accessibility. These characteristics
would include the dimensions of a component as well as its orientation
(e.g., horizontal components such as sills, vertical components such as
rail spindles) and location (e.g., height of component). This approach
would limit the number of surfaces which might be considered hazards to
those which could potentially be chewed or mouthed. This approach,
however, would significantly change the scope of risk assessments as
currently defined at 40 CFR 745.227(d). In addition, the Agency lacks
data to support the choice of specific criteria. Therefore, the Agency
does not consider this an appropriate option.
Option 2. Under the second option, EPA considered not adopting a
separate standard for surfaces accessible for chewing or mouthing.
Hazardous lead-based paint would exist only if lead-based paint on the
component were determined to be in poor condition. This approach would
avoid requiring property owners to expend resources to address
accessible surfaces when, in the vast majority of situations, these
surfaces are not likely to be chewed or mouthed. This approach,
however, would do nothing to address the infrequent, but often serious
problem of children chewing or mouthing accessible surfaces, unless and
until that actively resulted in significant deterioration of the
surface.
Option 3. Under the third option, EPA would identify lead-based
paint on accessible interior window sills because these are the
surfaces most likely to be chewed according to the available data. EPA
would propose to define accessible interior window sills as interior
window sills that are no higher than 5 feet from the floor, a height
that can be reached by a child when standing on the floor or on a chair
or sofa. By targeting these surfaces, hazard intervention (e.g.,
covering or replacing the component) would be more cost-effective than
an approach that identified lead-based paint on any accessible surface
as a hazard. This option also has the advantage of being easy to
implement, because specific surfaces (e.g., window sills) are easy to
identify. On the other hand, it would result in interventions where, in
the vast majority of cases, children do not need to be protected.
EPA's decision requires the Agency to balance an event (i.e.,
chewing of interior window sills) that has a low probability of
occurring with the high probability of serious harm when the event does
occur. By not establishing a hazard standard for accessible surfaces,
option two gives greater weight to the event's low probability. In
contrast, option three is more focused on the adverse outcome
associated with chewing of paint on these surfaces. Because neither of
these two options is clearly preferable, EPA is not selecting a
preferred option for today's proposal. Instead the Agency is seeking
comment on options two and three. In particular, the Agency would be
interested in input on three issues: (1) How to balance the low
probability of chewing with the high probability of serious harm if
chewing occurs; (2) low cost alternatives to sill replacement (e.g.,
paint removal); and (3) the effectiveness of guidance to property
owners to temporarily cover sills when a child who demonstrates a
propensity to chew resides in the unit. EPA also invites the public to
submit data on the prevalence of chewing on accessible surfaces.
V. Other Issues Affecting Standards Development and Selection
During the regulatory development process, EPA encountered a range
of issues that affect the scope and structure of today's proposal and
the implementation of the standards.
A. Applicability of the Standards
Two factors affect the applicability of the proposed standards for
lead-based paint hazards: the statutory language and the scope of the
Agency's supporting analyses. With respect to the statutory language,
the term ``lead-based paint hazards'' refers to target housing in most
sections of Title X and TSCA
[[Page 30334]]
Title IV. TSCA section 402 also uses the term in reference to public
and commercial buildings and structures (e.g, water towers, bridges).
The statutory definitions of lead-contaminated dust and soil, however,
refer only to residential property, showing that the applicability of
the dust and soil standards differs from the applicability of the paint
standards. The Agency's analyses are based on data for residential
exposure, thereby raising questions regarding whether the standards
being proposed today would be appropriate for non-residential
environments. This section of the preamble explores the applicability
issue and the Agency's decision, first, with respect to the paint
component of the standards and second, with respect to the dust and
soil standards.
1. Paint. The definitions in TSCA section 401 do not explicitly
identify the applicability of hazardous lead-based paint. The
definition of lead-based paint hazard refers to deteriorated lead-based
paint and lead-based paint on friction, impact, and accessible
surfaces. The reference to deteriorated lead-based paint does not
identify specific types of properties, nor do the definitions of
friction, impact, and chewable surfaces. As noted above, however, the
term ``lead-based paint hazard'' is used in context of target housing.
The definition of deleading in TSCA refers to lead-based paint and
lead-based paint hazards and, in doing so, extends the scope of lead-
based paint hazards to non-residential properties as well. The
statutory language, therefore, shows that the paint standard should be
applicable to target housing, public and commercial buildings, and
structures.
EPA, however, has no data on children's exposure to lead in paint
in non-residential environments. The Agency, therefore, believes that
the paint standards being proposed today should apply to target
housing. The Agency has also decided to propose that the paint
standards apply to child-occupied facilities. Although EPA lacks data
on exposure in child-occupied facilities, the Agency believes that
children face potentially equivalent risks from lead-based paint
hazards in schools and day-care centers as they do at home. EPA based
its decision to apply the same training, certification and work
practice standards to both target housing and child-occupied facilities
in the final TSCA section 402 regulation on the same argument.
In the absence of environmental and exposure data for other types
of properties, the Agency has decided not to propose paint standards
that are applicable to other types of public buildings, commercial
buildings, and structures at this time. EPA believes, however, that
this limitation should not have any meaningful impact on the regulation
and its ability to protect human health. Lead-based paint encompasses
lead-based paint hazards and lead-based paint is defined. Because the
applicability of the proposed standard for hazardous lead-based paint
is more limited than that required in the statutory language, the
Agency is specifically requesting comment on this decision.
2. Dust and soil. In contrast to paint, the statutory language is
more limited in defining the applicability of the dust and soil
standards. In TSCA section 401, the statute specifically identifies
lead-contaminated dust and soil in terms of ``dust in residential
dwellings'' and ``bare soil on residential real property.'' TSCA
section 403 states that EPA should identify lead-based paint hazards
for purposes of Title X and TSCA Title IV which focus on a specific
subset of residential property, namely target housing which includes
most pre-1978 housing. The statutory language shows that the dust and
soil standards should apply to target housing.
EPA has decided, however, to interpret residential more broadly and
to propose that the dust and soil standards should apply to child-
occupied facilities as well as to target housing. This decision is
based on the same rationale for applying the paint standards to child-
occupied facilities. As argued in the preamble to the final TSCA
section 402 regulation, the Agency believes that children face
potentially equivalent risks from lead-based paint hazards in schools
and day-care centers as they do at home. In fact, some children spend
more time in a particular classroom, day-care room, or outdoor ``play
area'' then they might spend in a single room or yard at home.
Failure to apply the dust and soil standards to child-occupied
facilities would leave a significant gap in the work practice standards
for risk assessments and abatements at child-occupied facilities.
Without dust and soil standards for child-occupied facilities, risk
assessors would not be able to determine whether dust-lead and soil-
lead hazards are present at these facilities. Because abatements are
defined as actions designed to permanently eliminate lead-based paint
hazards, owners of these facilities would be unable to determine what
activities constitute abatement and when certified firms and
individuals are required to perform these activities.
In light of EPA's decision to propose applying the dust and soil
standards more broadly than a literal reading of the statute would
suggest, the Agency is seeking comment on this aspect of the
regulation. Specifically, EPA would be interested in any disadvantages
associated with this decision and in alternative approaches that would
provide as much protection to children.
3. Child-occupied facilities. Because child-occupied facilities are
often located within larger facilities where children would have
limited or no access, the applicability of the hazard standards to
these facilities requires further explanation. The definition of child-
occupied facilities found at 40 CFR 745.227 helps clarify the
applicability of the hazard standards to child-occupied facilities.
First, a child-occupied facility must have been constructed prior to
1978. Second, a child-occupied facility is a building or portion of a
building visited regularly by children age 6 and under. The definition
provides several examples including day care centers, pre-schools, and
kindergarten classrooms. By limiting the meaning of a child-occupied
facility to the portion of a building where a child regularly visits,
the definition limits the applicability of the paint, dust, and soil-
lead hazard standards to the same portion of a building. For example,
the soil standard would apply only to that portion of the area outside
the building designated for use by children age 6 and under.
Several examples may help illustrate how the hazard standards apply
to child-occupied facilities. The first example is a day care center at
a manufacturing facility. There is a separate entrance to the center
and a fenced playground area adjoining the center. In this case, the
center (interior rooms and outside area making up the center), not the
entire plant is the child-occupied facility. Paint and dust samples
would be taken from the rooms in the day care center, and soil samples
would be taken from within the fenced playground. Hazard interventions
should be limited to those areas. The second example is a stand-alone
pre-school (i.e., the pre-school occupies the entire structure). In
this case, the standards would apply to the entire property. The third
example is a kindergarten at a public or private school which has a
yard for recess designated for use by children age 6 and under. In this
case, the paint and dust standards would apply to the kindergarten
classrooms and the soil standard would apply to the school yard
designated for use by the kindergarten children (i.e., except for the
portions of
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the property such as the front lawn of the school that are not
designated for use by children age 6 and under). As a final example, a
day care center is located within a public or private high school. The
school has several outside recreational areas, none of which are
designated for regular use by children who attend the day care center.
The day care consists of a class room, which is now divided into two
main rooms. In this scenario, the hazard standards only apply to the
interior area because the outside areas would not be defined as part of
the child-occupied facility.
B. Dust Issues
1. Loading vs. concentration. Title X provides the legal basis for
selecting the levels of lead that constitute dust-lead hazards. The
statute, however, does not stipulate the measurement basis for the dust
standards. Two different measures are commonly used to characterize the
lead level in dust: loading and concentration. Lead concentration (or
mass concentration) is a measure of how much lead is present in a given
amount of dust and can be expressed in either micrograms of lead per
gram of dust (g/g) or, equivalently, in parts per million
(ppm) by weight. Lead loading or area concentration, a measure of how
much lead is present on a surface of given area, is expressed in mass
of lead per area of surface sampled (typically, g/ft2
or g/m2).
The two measures also differ in the way environmental sampling is
conducted. Dust-lead loading data can be obtained through either wipe
sampling or vacuum sampling. Concentration data are usually obtained
through vacuum sampling. In wipe sampling, a wet wipe (e.g., baby wipe)
is used to collect dust from a surface with known area. Through
laboratory analysis, the total lead picked up by the wipe is measured
and compared to the surface area to calculate the dust-lead loading.
Because the wipe sampling only measures the mass of the lead and not
the total mass of the dust, the concentration of lead in the dust
cannot be determined. In a wipe test, the mass of the dust is combined
with the mass of the wipe which is typically unknown. Therefore, it is
not possible to isolate the mass of the dust and compute the
concentration.
In vacuum sampling, a specialized vacuum cleaner is used to collect
dust from a surface with known area. Through laboratory analysis, the
amount of lead picked up by the vacuum can be measured and compared to
the surface area to calculate loading. Laboratory analysis also can
yield the concentration measure because the only material in the sample
is the dust (including the lead). It is, therefore, possible to obtain
both the total mass of the dust (including the lead), and the mass of
the lead alone. Concentration is calculated by dividing the mass of the
lead by the total mass of the dust.
Ideally, EPA would favor the use of both loading and concentration
data to characterize hazards and to identify appropriate response
actions. Two examples help illustrate the value of using two measures.
In the first example, a risk assessor finds high dust-lead loadings
both in house A and in house B. Dust-lead concentration is high in
house A, but low in house B. Without the concentration data, the risk
assessor would treat both houses the same. With the concentration data,
the risk assessor would be able to conclude that house A, with the high
dust-lead concentration, has an on-going source of lead that needs to
be identified and controlled. In house B, high loading combined with
low concentration may indicate the presence of excessive dust that
could be addressed through routine housecleaning. This example shows
how the additional information provided by the concentration data
allows the risk assessor to differentiate between two residences that
have similar dust-lead loadings.
In the second example, a risk assessor finds high dust
concentrations in both house X and house Y; the dust-lead loadings are
high in X and low in Y. The concentration data suggest the presence of
an on-going source of lead that should be identified and addressed. The
loading data, however, indicate that only house X currently has a dust-
lead hazard. Cleaning, the recommended control measure for dust-lead
hazards, would likely be an effective risk reduction intervention in
house X but probably would not be necessary at present in house Y. This
example shows how the additional information provided by dust-lead
loading data allows the risk assessor to differentiate between two
houses that have similar dust-lead concentrations.
Although EPA acknowledges that both loading and concentration data
would be valuable to a risk assessor, the Agency recognizes that
setting standards based on both measures might impede implementation of
hazard evaluation on a large scale (i.e., in the nation's housing).
Currently, wipe sampling is the method that most risk assessors use. In
contrast, few risk assessors are skilled in vacuum sampling (the method
required for obtaining concentration data). Furthermore, vacuum samples
require significantly more time to collect because the equipment needs
to be cleaned between samples, resulting in higher costs for risk
assessments. EPA, therefore, believes that a standard based on loading
alone is more workable than a standard that uses both measures. For
those risk assessors that use vacuum sampling or other methods of dust
sampling, the Agency is planning to provide guidance on the use and
interpretation of concentration data.
2. Surfaces. To date, Federal, State, and local agencies have
traditionally tested for the presence of lead in dust on three
horizontal surfaces: uncarpeted floors, interior window sills, and
window troughs. The HUD Guidelines provide clearance levels for these
three surfaces to evaluate post-abatement cleanup. EPA included these
clearance levels in its 1994 guidance on lead-based paint hazards. In
addition, 25 States currently have, are revising, or are promulgating
standards for floors, sills, and troughs. The State standards are
largely based on the HUD Guidelines and EPA's guidance (Ref. 97).
Although Title IV does not explicitly require it as part of the
TSCA section 403 rule, EPA had to determine for which surfaces it would
propose dust-lead hazard standards. EPA considered several factors in
its decision. First, the Agency wanted to include surfaces that would
enable risk assessors to adequately characterize risk. Second, it
wanted to minimize the amount and complexity of sampling required in
order to reduce the cost of risk assessments. Third, EPA did not want
to deviate significantly from current approaches unless there was
adequate justification.
Analyses performed by the Agency show that the dust on floors,
sills, and troughs are highly correlated (Refs. 98 and 99). Of the
three surfaces, however, the scientific literature suggests that floor
dust-lead loadings are the dust-lead measure most relevant to childhood
lead exposure. The child plays on the floor, thereby coming in contact
with any settled dust containing lead. Lead dust loadings on sills and
troughs are also significant measures but explain less of the variation
in blood-lead concentrations (Ref. 100). For some data sets, lead dust
loadings on sills are a better predictor of blood-lead concentrations
than lead-dust loadings in troughs, while the opposite is true for
other data sets (Ref. 101). In addition, sills and troughs are
themselves highly correlated (Ref. 102).
Based on these data and analyses, the Agency has determined that
standards should be proposed for floors and either sills or troughs.
Proposing standards both for sills and troughs does not improve a risk
assessor's ability to
[[Page 30336]]
characterize risk sufficiently to justify the additional expense for
sampling and analysis of both surfaces. EPA has decided to propose dust
standards for sills but not troughs for two reasons. First, sills are
easier to sample than troughs. Second, lead in troughs may be caused by
direct deposits from exterior sources and therefore be less
representative of typical interior levels than lead on sills. The
Agency wishes to note that this approach is not intended to imply
indifference to dust-lead levels in troughs. In fact, EPA is including
a dust-lead clearance standard for troughs (discussed in Unit VIII. of
this preamble) to ensure that troughs are adequately cleaned as part of
a dust cleaning intervention.
EPA recognizes that its proposal not to establish dust levels for
window troughs represents a departure from the interim guidance. That
guidance, however, did not attempt to identify risk-based dust-lead
levels. Rather, it adopted the HUD clearance levels for floors, window
sills, and window troughs and suggested that they be used to identify
``hazards'' until the Agency was able to assess the risks from dust-
lead on the various surfaces. Today's proposal is based upon these new
analyses and presents standards for those surfaces that appear to
adequately characterize a child's exposure to dust, namely floors and
interior window sills.
The EPA requests comment on this difference. In particular, EPA
requests comments on the impact of not having window trough dust levels
on the accuracy, complexity, and cost of risk assessments. EPA also
requests any new data or analysis concerning the relationships between
dust on floors, sills, and troughs and childhood blood-lead
concentrations that could help the Agency in setting hazard standards
for window troughs.
3. Carpeted floors. Today's proposal does not include dust
standards (contamination, hazard, or clearance) for carpeted floors.
EPA made this decision because the Agency is unaware of adequate data
that could be used to establish a statistical relationship between dust
lead on carpeted floors and children's blood-lead concentrations. In
the absence of a statistical relationship between children's blood-lead
concentrations and dust lead on carpeted floors, EPA cannot estimate
the level of risk and risk reduction that would be associated with
various levels of dust-lead in carpeted floors. The Agency, therefore,
is unable to select hazard standards that meet the statutory and policy
criteria. Furthermore, EPA does not have adequate data on the
effectiveness of carpet cleaning that would be needed to establish a
dust clearance level for carpeted floors. When the data necessary to
establish dust standards on carpeted floors become available, EPA plans
to analyze them expeditiously and amend the regulations being proposed
today to add standards for carpeted floors.
Because many residences built prior to 1978 have carpeted floors,
EPA recognizes that the lack of standard for carpeted floors is a
significant limitation on today's proposal. The Agency is therefore
requesting comment on the impact of not including standards for
carpeted floors. EPA would also be interested in any information or
data that would help it establish such standards.
4. Emergency dust level. During the regulatory development process,
several interested parties urged EPA to establish an emergency dust
level as part of the TSCA section 403 rule (Ref. 13). Two purposes for
an emergency level have been articulated. First, this level could be
used to help property owners and other decision-makers set priorities
for implementing hazard control interventions. Second, an emergency
dust level could be used by local public health authorities to
recommend or require specific drastic and immediate actions, such as
removal of a child or immediate environmental intervention where dust
levels exceeded the emergency threshold.
EPA believes that, while these goals are worthwhile, an emergency
dust level is not needed either for priority-setting or for mandating
specific actions. Priorities for intervention should be based on the
``worst-first'' approach where residences with the highest levels of
lead are targeted for earliest response action. Furthermore, because
response actions should be taken in all houses with hazards, EPA does
not believe that its national program should establish a further
priority for action. Such priorities should vary by location,
occupants, housing availability, and other local factors.
With respect to mandating specific drastic and immediate actions,
EPA believes that such a response to a lead-based paint hazard would be
appropriate if exposure to very high levels of lead in dust presents an
acute health risk, and drastic and immediate action is the only way to
prevent further harm to the health of resident children. Although EPA
is concerned about continuous exposure to very high levels of lead in
dust, health threats in the United States today usually occur due to
chronic rather than acute exposure to dust. In addition, drastic action
should be taken in response to other important findings, such as an
elevated child blood-lead concentration. The dust hazard standard
should be sufficient for inducing prompt action by property owners or
other decision-makers and providing adequate protection to child
occupants.
In the event that EPA obtains information justifying the need for
an emergency standard, the Agency has explored several approaches for
setting an emergency dust standard. Under one approach, EPA would
derive an emergency standard by applying a multiplier (e.g., 10) to the
dust-lead hazard level. Although this approach is easy to understand,
there is no direct link to severe human health risk. The second
approach bases the emergency standard on dust levels found in the homes
of children who have received medical treatment for lead poisoning. EPA
believes that the second approach would be preferable because the level
would be associated with exposure and risk. It has, however, several
disadvantages. Many cases of severe lead poisoning result from
ingestion of paint chips and not necessarily from dust ingestion (Ref.
95). In addition, dust measurements may have been obtained weeks or
months after the blood-lead concentration was measured and may not
reflect dust-lead levels that were present when the exposure occurred.
For these reasons, the Agency's attempts to develop emergency dust
levels using the second approach have not been successful. Thus, EPA
lacks sufficient data to associate levels of lead in dust with specific
cases of medically-managed lead poisoning. Nevertheless, EPA believes
that this approach is the best currently available for setting an
emergency dust-lead level.
The Agency is seeking comment on the issue of an emergency dust
standard. The Agency is interested in comments concerning the need for
an emergency dust standard, given the ready availability of blood-lead
data. The Agency also seeks comments on whether and how an emergency
standard would be used, including whether immediate responses are
needed because lead from dust usually causes harm through chronic
rather than acute exposures. In addition, EPA requests any data,
analysis, or approach that would help the Agency set an appropriate
emergency standard if the need for such a standard could be justified.
C. Soil Issues
1. Dual standards for soil-lead level of concern. During the
Dialogue Process,
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several interested parties suggested that EPA should establish two
standards for soil-lead level of concern: a more stringent standard for
``play areas'' and a less stringent standard for other areas in a
residential yard (Ref. 15). This suggestion was based on the hypothesis
that there is less contact between children and the soil in ``non-play
areas,'' resulting in lower exposure and risk. Proponents of this
suggestion also cited EPA's July 14, 1994 guidance which established a
separate advisory level for soils on non-residential property and where
use by children is less likely. EPA wishes to note that the separate
advisory level (2,000 ppm) presented in the 1994 guidance is intended
for use at non-residential property and that the more stringent level
(400 ppm) applies to all residential property, including ``non-play
areas.''
The parties that proposed this option expressed two concerns about
a single, more stringent standard for soil-lead level of concern
applying to the whole yard. First, response costs would increase
because interim controls (i.e., soil cover), the recommended response
for the lower tier soil level in the guidance, would have to be applied
to larger areas. Second, because it may not be feasible to install and
maintain soil cover, property owners would have to perform full soil
abatement, the response recommended for soil-lead hazards in order to
provide adequate protection.
EPA rejected proposing separate soil-lead levels of concern for
``play areas'' and ``non-play areas'' on residential property for two
reasons. First, the cost concern is based on this option because it is
based on an incorrect interpretation of soil-lead level of concern. As
noted in Unit II. of this preamble, the presence of a soil-lead level
of concern does not trigger any regulatory requirements or legal
obligation. The soil-lead level of concern is a risk communication
tool. It is, therefore, appropriate that owners and occupants be aware
of any soil on property where the lead concentration exceeds this level
regardless of its location. If owners and occupants are aware of the
presence of soil-lead level of concern, they can take actions to reduce
exposure to children. Such actions can include applying soil cover and
preventing children from playing in areas of a yard where lead levels
equal or exceed the level of concern.
Second, EPA believes that it is infeasible to distinguish between
``play areas'' and ``non-play areas'' in many yards. Indicators of
where children play, such as playground equipment, are not always
present. In the Rochester study, ``play areas'' could not be identified
at more than half the residences in the data set (Ref. 20). Even when
such equipment is present, children's outdoor activity is not
necessarily limited to that location. In addition, play patterns may
change when a new family assumes occupancy following turnover of a
residence. Nevertheless, the Agency recognizes that, at some
residences, direct exposure to soil occurs mainly around play
equipment. EPA believes, however, that it is more appropriate to
address this issue in its sampling guidance by providing advice to risk
assessors on where to collect soil samples. This issue is discussed
further in Unit VII. of this preamble.
In light of the interest expressed by some stakeholders in a
separate level of concern for ``play areas,'' EPA is seeking public
comment on this issue. In particular, the Agency would like input on
(1) a workable approach for identifying ``play areas'' that addresses
the problems discussed above and (2) the technical basis for
establishing a separate soil-lead level of concern. The available data
and analytical tools enable the Agency to assess risk from soil on
residential property but not in specific parts of a yard. EPA would
also like the public to comment on whether a separate level of concern
for ``play areas'' would be necessary if the soil-lead level of concern
appears only in guidance and not in the regulation.
Another interested party suggested that the standard for soil-lead
level of concern should apply to all ``play areas'' and to ``non-play
areas'' only where lead levels in household dust continuously exceed
the dust hazard standard (Ref. 17). This option is predicated on the
assumption that the exposure pathway for ``non-play areas'' is track-in
lead which would be measured through interior dust sampling. If there
is no dust hazard, this party reasoned, then the lead in the ``non-play
area'' soil does not present a health threat.
EPA rejected proposing this option for three reasons. First, EPA is
not aware of any data that link exposure pathways to location of soil.
Therefore, the Agency cannot assume that track-in contamination of
household dust is the only pathway associated with ``non-play area''
soil. Second, as noted above, EPA believes that it is infeasible to
distinguish between ``play areas'' and ``non-play areas'' in many
yards. Third, the proposed dust standards are lead loading standards,
which reflect a combination of the amount of dust present and the
concentration of lead in that dust. The amount of dust on an interior
surface at any particular time can be extremely variable and can depend
upon cleaning procedures used in a residence and the length of time
between cleaning and the collection of the dust sample. Also, the rate
of soil entry into the home can vary depending upon such factors as the
use of doormats and residents' preferences regarding leaving windows
open. Given these variables, the Agency does not believe that a low
interior dust-lead loading measurement at the time of a risk assessment
could reasonably ensure that soil in any specific area of a yard
(including ``non-play areas'') does not present a risk of concern to
children.
2. De minimis area of bare soil. The definition of lead-
contaminated soil in section 401 refers to bare soil which is not
defined by the statute. Bare soil, as defined by HUD in its proposed
regulations under sections 1012/1013 of Title X (61 FR 29206, June 7,
1996) is ``soil not covered by grass, sod, or other live ground covers,
or by wood chips, gravel, artificial turf, or similar covering. Bare
soil includes sand.'' EPA considered whether this definition is
sufficient for the TSCA section 403 rule. Specifically, the Agency
considered whether the rule should include a minimum (i.e., de minimis)
area of bare soil as part of the lead hazard criteria.
The inclusion of a de minimis area of bare soil is based on two
assumptions. First, there is a relationship between the amount of soil
cover and exposure to lead in the soil. In yards with very small
amounts of bare soil, it is presumed that exposure would be low.
Second, a de minimis value would help target resources by eliminating
the need to evaluate soil or respond to contamination or hazards for
properties where there is only a small amount of bare soil. For
example, the HUD Guidelines instruct risk assessors to sample yards
that have at least 9 square feet of bare soil, with no de minimis in
the ``play area'' (Ref. 11).
EPA considered three options for a bare soil de minimis area. Under
the first option, EPA would adopt the de minimis area from the HUD
Guidelines. Although, this approach is consistent with existing
guidance, it would require risk assessors to measure the size of
individual patches of bare soil. It also does not account for
differences in lot size. Under the second approach, EPA would define
the de minimis in terms of bare soil as a percent of the whole yard.
The risk assessor would measure the percentage of bare soil using a
specified technique (e.g., the line transect method used by soil
conservationists to assess the erosion potential of cropland soil)
(Ref. 103). This option was designed to simplify the process of
measuring the area of bareness and to account for differences in yard
size. Under the third
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option, EPA would not include a de minimis area of bare soil in the
proposed regulations.
EPA decided not to include a de minimis area for bare soil because
the disadvantages of each of the two approaches for establishing a de
minimis outweighed the advantages. The de minimis used in the HUD
Guidelines does not account for differences in yard size; 9 ft2
outside of the ``play area'' may be insignificant in a suburban yard
but large for the back yard of an urban row house. Although a
percentage-based de minimis would account for different yard sizes, EPA
has no analysis or data that relate the amount of bare soil to risk
and, therefore, no basis upon which to select the de minimis.
Furthermore, there is no existing government or consensus percentage-
based standard that EPA could adopt.
EPA also believes that a de minimis area of bare soil provides
little benefit. First, information provided by an experienced risk
assessor suggests that very few properties would be excluded using the
de minimis in the HUD Guidelines (Ref. 104). Second, the incremental
cost of including soil testing in a risk assessment is small. Third, if
a soil-lead hazard is present, the property owner or other decision-
maker should take action to control the hazard and this action should
address all soil where lead levels exceed the hazard standard whether
or not it is bare.
3. Covered soil. Although Title IV of TSCA restricts the standard
for soil-lead hazards to bare soil, EPA is concerned that the presence
of soil cover, such as grass, may not reduce exposure to lead
sufficiently. Consequently, it may be prudent to test covered soil to
determine whether a soil-lead hazard exists.
The Agency, therefore, recommends that covered soil be tested in
cases where the risk assessor has reason to believe that the level of
lead in soil may constitute a soil-lead hazard. Factors that the risk
assessor should consider include high soil-lead levels in bare sections
of the yard where soil sampling was conducted, the presence of high
dust-lead levels in a home that has no lead-based paint, the presence
of children with elevated blood-lead levels in the community, high
soil-lead levels in neighboring yards, the presence of nearby
industrial sources, the presence of a nearby steel structure such as a
bridge or highway overpass, and the past use of the property. It is
important to note that testing of covered soil is only a
recommendation. The standards being proposed under TSCA section 403 do
not apply to covered soil, and the testing of covered soil is not
required by the regulations promulgated under authority of TSCA section
402 at 40 CFR 745.227(d) as amended by today's proposal.
4. Soil-lead level of concern standard becoming de facto hazard
standard. Interested parties expressed concern about the potential
confusion over the two standards for soil. Specifically, some parties
feared that the standard for soil-lead level of concern could become
the de facto hazard standard for soil, leading to soil abatement at
millions of homes.
EPA believes, however, that there is no basis for this concern.
First, as proposed in today's action, the level of concern will appear
only in guidance, not in the rule.
Second, the Agency will clearly explain the differences between the
two levels in its public outreach documents and education efforts. The
two standards are based on different criteria and have different
purposes. The level of concern is a tool to communicate risk and is
based on an individual child having a one to five percent probability
of equaling or exceeding a blood-lead concentration of 10 g/
dl. Thus, EPA believes that soils with lead levels that exceed the
level of concern present a level of risk to children of sufficient
concern that a variety of actions should be considered to reduce
exposure (e.g., soil cover, door mats, hand and toy washing). The
standard for a soil-lead hazard, in contrast, is based on greater
certainty regarding probability of harm. The presence of a hazard
indicates that the cost of intensive controls (e.g., soil removal) is
commensurate with the level of risk reduction that could be achieved.
Third, EPA's 1994 guidance on lead-based paint hazards contains
multiple levels for soil, and yet there is no evidence that the public
thinks that abatement is the recommended action at 400 ppm, the lower
level in the guidance.
D. Sample Collection and Analysis
Numerical standards for lead in paint, dust, and soil have little
significance in the absence of information about how the samples were
collected and analyzed. In order for the sampling results to be useful,
they must be reliable. Several conditions have to be met to consider
sampling results reliable. First, assurances are needed that the
individual who collected the samples has the appropriate training and
expertise. These individuals must be familiar with specific
requirements regarding sample collection and handling. They also must
be skilled in sampling techniques and able to make critical subjective
judgments about the number and location of samples to collect. For
example, if a risk assessor fails to measure the area of a dust wipe
sample accurately, the results will be invalid. Sample handling is also
important because contamination of samples can invalidate results.
Second, reliability of sampling results is dependent upon the
quality of laboratory analysis. Laboratories must adhere to strict
quality assurance and quality control procedures to ensure that samples
are analyzed properly. These procedures address, among other things,
contamination of samples and the calibration of laboratory instruments.
Contamination of samples can have a significant effect on sampling
results and invalidate them. Similarly, laboratory instruments that are
out of calibration can yield erroneous results.
EPA has several options for ensuring that the sampling results are
reliable and are comparable to standards. Under the first option, the
Agency could tie the standards to specific methods. This approach has
the advantage that it uses methods known to EPA to be reliable and
effective. The major disadvantage is that it references specific
technologies. As technologies change, the Agency would have to amend
the rule to reflect these changes. Referencing specific technologies in
a regulation could also stifle technological innovation.
Alternatively, under a second option, EPA could adopt an approach
that relies on the performance of its training and certification
program for workers and contractors and its accreditation program for
laboratories and only specify the type of samples to be collected and
analyzed. Under this approach, EPA would assume that compliance with
applicable (i.e., Federal, State, Tribal) certification standards for
workers and contractors and laboratory accreditation through the
National Lead Laboratory Accreditation Program (NLLAP) ensures that
samples are being collected, handled, and analyzed in a manner that the
results can be reliably compared to the TSCA section 403 standards.
EPA has decided to propose tying the TSCA section 403 standards to
risk assessments conducted according to the risk assessment work
practice standards found at 40 CFR 745.227. This approach assures that
samples can be reliably compared to the TSCA section 403 standards
while more easily accommodating technological change than an approach
that references specific technologies.
Accordingly, EPA is proposing that the determination of whether in-
situ
[[Page 30339]]
paint on a specific component is lead-based shall be made by a
certified risk assessor. If confirmatory laboratory analysis is
necessary, paint chip samples must be analyzed by a laboratory
recognized by EPA as proficient for paint analysis. A certified risk
assessor shall determine whether the paint is in poor condition based
on visual observation. Dust-lead loadings shall be determined from wipe
samples collected from uncarpeted floors, interior window sills, and
window troughs by a certified risk assessor and analyzed by a
recognized laboratory. Soil-lead concentrations shall be determined
from samples collected by a certified risk assessor and analyzed by a
recognized laboratory.
VI. Requirements for Interpreting Sampling Results
Under this proposal, to determine whether lead-based paint hazards
are present at a residence, a risk assessor would have to compare his/
her measurements and observations to the hazard and level of concern
standards in this proposed rule. Unit IV. of this preamble presented
the proposed lead-based paint hazard standards. Regulations promulgated
by EPA as part of the TSCA section 402 training and certification rule,
at 40 CFR 745.227, establish work practice standards for risk
assessments. Neither the proposed lead-based paint hazard standards nor
the work practice standards, however, prescribe how a risk assessor
should compare his/her measurements and observations with the proposed
standards. Therefore, under authority of TSCA section 403, EPA is
proposing implementation requirements that will prescribe how a risk
assessor should compare his/her measurements and observations to the
proposed standards. This unit of the preamble presents these proposed
requirements and the Agency's rationale for its decisions.
A. Paint
According to the regulations at 40 CFR 745.227(d), the risk
assessor identifies and tests all painted surfaces that are in poor
condition (i.e., where deteriorated paint exceeds the proposed minimum
surface area requirements) and are determined to have a distinct
painting history to determine whether the paint is lead-based. EPA is
proposing that results of this sampling be interpreted in the following
manner. If the testing confirms that the paint is lead-based, then
lead-based paint in poor condition on that component and other like
components with a similar painting history is considered hazardous
lead-based paint. This approach for interpreting the paint sampling is
based on inductive logic; if the tested component is covered with lead-
based paint, then other like components with similar painting histories
are covered with lead-based paint. This approach is consistent with the
HUD Guidelines (Ref. 11).
Risk assessors have the option of using composite samples rather
than single surface samples. Because composite samples provide an
average level of lead, low values on some surfaces may mask the
presence of lead-based paint on other surfaces. EPA is, therefore,
proposing to adopt the approach recommended in the HUD Guidelines that
the standard for lead-based paint (1 mg/cm2 or 0.5 percent
by weight) be divided by the number of subsamples in the composite
(Ref. 11). For example, if a composite sample contains five subsamples,
the risk assessor would compare the results to a standard of 0.2 mg/
cm2 or 0.1 percent by weight. Using this approach, it is
mathematically impossible for the composite to pass when any single
subsample exceeds the 1 mg/cm2 or 0.5 percent by weight
standard for lead-based paint.
It is important to note the composite paint sampling is essentially
a negative screen. It can be used to demonstrate that lead-based paint
is not present, but cannot be used to identify which component has
lead-based paint if the results indicate that lead-based paint is
present. If a composite sample shows that lead-based paint is present,
the risk assessor would need to take single surface samples to identify
the specific component(s) that contains lead-based paint.
B. Dust
1. Single-family housing. Risk assessors can take two kinds of dust
samples: single surface samples which yield a result for the specific
surface that was sampled; or composite samples which yield an average
result that applies to all the surfaces that were sampled. The
interpretation of the composite sample is straightforward. The risk
assessor compares the result of the composite sample to the standard
for dust-lead hazards. For single surface samples and multiple
composite samples, EPA is proposing that the risk assessor should
compare the average, weighted by the number of subsamples in each
sample, to the standard for dust-lead hazard. Under this approach each
single surface sample would have a weight of one.
The Agency is proposing this approach because, in the absence of
information on the amount of exposure that occurs in each location, the
average of single surface samples reasonably reflects a child's typical
exposure to lead in dust. This same rationale was used to design the
methodology for the Agency's risk analysis. Because average exposure
was used to estimate risk and choose the standard, it is appropriate to
adopt a consistent approach for interpretation of dust samples. Using a
weighted average gives the subsamples in a composite the same weight as
single surface samples and better reflects average exposure to lead in
dust.
EPA recognizes that averaging single surface samples yields the
same numerical result as a composite sample, and that this might serve
as a disincentive to conduct single surface sampling. The Agency
believes, however, that single surface sampling can yield valuable
information that can help a risk assessor identify sources of
contamination and/or recommend hazard control strategies that target
particular parts of a home. For example, single surface sampling may
show that dust-lead levels are well above the hazard standard in the
entry hall of a home but below the standard elsewhere. Using the
averaging approach, if the entry hall levels are sufficiently high, the
risk assessor would determine that there is a dust-lead hazard. By
interpreting the results of the single surface samples, however, the
risk assessor may be able to determine the source of the dust
contamination is exterior soil or dust tracked-into the entry hall and
not interior paint. In addition, the risk assessor may recommend that
dust cleaning be focused on the entry hall, rather than the whole
house. Whether the information provided by single surface samples
justifies the cost will be a site-specific decision.
2. Multi-family housing--a. Dwelling units. In multi-family
housing, a risk assessor would use the approach for single-family homes
to interpret the results of sampling in each unit where samples were
collected. There is an additional issue that must be addressed in
multi-family housing because the sampling guidance, which is based on
the HUD Guidelines, will provide several approaches to the risk
assessor for collecting dust samples from a limited number of units.
Because no dust samples would be collected from many units under these
approaches, the risk assessor would have to make assumptions about dust
levels in units that are not sampled. This issue does not apply to
buildings that contain from two to four units because the risk assessor
would have to collect samples in all units.
[[Page 30340]]
EPA considered three alternatives for identifying dust-lead hazards
in units that are not sampled in multi-family housing.
Option 1. Under option one, the risk assessor would assume that
dust-lead hazards are present in all unsampled units if dust-lead
hazards are identified in at least one sampled unit. The risk assessor
would assume that unsampled units do not contain lead-based paint
hazards only if no dust-lead hazards are identified in the sampled
units. In other words, a sampled unit where dust-lead hazards is
present would represent all unsampled units.
Option 2. Under this option, the risk assessor could refine
assumptions about unsampled units if he/she could establish a pattern
for units that have dust-lead hazards. For example, testing results may
show that only first floor units have dust-lead hazards and soil-lead
exceeds the level of concern on the property. The risk assessor could
conclude from this information that the dust is being contaminated by
the soil and that this pathway of contamination applies only to first
floor units. Therefore, only unsampled first floor units should be
assumed to have dust-lead hazards.
Option 3. This option applies only to risk assessors who use random
sampling to select units for testing. The random sampling protocol is
based on the specification that the number of sampled units provides 95
percent confidence that fewer than 5 percent of all units in the
building(s) (or 50 units, whichever is less) contain dust-lead hazards
if no sampled units have hazards. Under this option, the risk assessor
could randomly test a sufficient number of additional units to achieve
the same specification when some units originally tested have hazards.
The Agency selected the first option for the proposed rule.
Although EPA recognizes that some unsampled units would be identified
as having dust-lead hazards even if dust levels in those units are
below the proposed standards, it is not possible to determine which
unsampled units would have hazards in the absence of additional data.
The only protective approach, therefore, is to assume that all
unsampled units have hazards.
Because this approach may identify some units that do not have
dust-lead hazards as having hazards, EPA would encourage property
owners, who are faced with this situation, to test the dust in units
that were not initially sampled. This additional information would
allow the risk assessor to determine whether dust hazards are actually
present in these units. In light of the cost of testing and possible
cleaning in a large number of units, the property owner may consider
focusing attention first on units where young children are present.
Dust testing and cleaning at other units could wait until unit
turnover.
EPA is not proposing the two other options because they are
unlikely to be practical or useful. Option 2 would not be beneficial
because, given the variability of dust loading levels, risk assessors
would probably not be able to identify patterns of hazard. Option 3
offers little value because there is a high probability that an
additional unit would fail requiring the risk assessor to conduct dust
testing in even more units. In the end, the risk assessor would likely
test dust in nearly all the units.
Because the proposed approach for interpreting the results of dust
testing in multi-family housing is not optimal (i.e., it may falsely
identify some units as having dust-lead hazards), the Agency is seeking
comment on this issue. Specifically, EPA would be interested in an
alternative approach and the data and rationale used to support an
alternative. The Agency is also interested in comment on the two
options it considered but rejected.
b. Common areas. The same approach for interpreting dust samples
would apply to common areas. For common areas that can be grouped
together such as hallways, the risk assessor could test dust from a
random, targeted, or worst-case sample if there are a sufficient number
of areas. The risk assessor would assume that dust-lead hazards are
present in the unsampled common areas if a dust-lead hazard is present
in at least one of the sampled common areas. For common areas that
cannot be grouped together (e.g., entry lobbies, basement laundry
rooms), the risk assessors would treat each area as a separate dwelling
unit and collect dust samples from all such areas. The risk assessor
would interpret the dust sample results for each area according to the
requirements for single-family homes described above.
C. Soil
EPA is proposing that the interpretation of soil samples would use
techniques similar to those employed for the interpretation of dust
samples. The risk assessor would compare the average concentration of
the dripline and mid-yard composites to the soil-lead hazard standard.
If the risk assessor collects more than one dripline or mid-yard
composite sample, he/she would first compute the average concentration
in the dripline and/or in the mid-yard and then compute the average of
the dripline and mid-yard concentrations. The approach of using the
average concentration is based on the rationale stated above for the
interpretation of dust samples. Risk assessors would use the above
approach for each building in a multi-family housing development and
compare the average for all buildings to the soil-lead hazard standard.
The use of sampling data, however, should not be limited to
determining whether a hazard exists. Soil samples can provide valuable
information to the risk assessor about the location and extent of soil
contamination, which can help the assessor design a targeted control
strategy. For example, a risk assessor may determine, based on the
average of the dripline composite sample and mid-yard composite sample,
that a yard exceeds the soil-lead hazard standard. The individual
composite samples may show, however, that the soil in the dripline is
above the hazard standard but the mid-yard soil is not. This
information enables the risk assessor to design a strategy that focuses
controls for soil solely in the dripline. Examining the results of
individual composite samples would be especially valuable in a multi-
family housing development where focusing soil intervention on
relatively small areas can reduce the costs of intervention
significantly.
In addition, as EPA will detail in the guidance document on using
the hazard standards, the Agency recommends that when the remediation
strategy is developed, that areas with highest lead levels be addressed
first. For example, if dripline soil is 3,500 ppm and mid-yard soil is
500 ppm (i.e., yard-wide average of 2,000 ppm), the strategy to reduce
average levels below 2,000 ppm should rely first on removing the highly
contaminated soil at the dripline rather than on covering the
moderately contaminated soil at the mid-yard.
VII. Amendments to TSCA Section 402 Regulations
This unit of the preamble presents proposed amendments to the work
practice standards for risk assessments and abatements promulgated
under the authority of TSCA section 402 at 40 CFR 745.227 along with
EPA's rationale for its decisions. These amendments would include the
establishment of dust clearance standards, management controls for soil
removed during an abatement, and changes to existing dust and soil
sampling provisions. EPA did not include clearance standards as part of
the original TSCA section 402 rule because the Agency thought that it
was more appropriate to establish these
[[Page 30341]]
standards together with the TSCA section 403 hazard standards.
Amendments to the sampling provisions are necessary because the work
practice standards were developed prior to the TSCA section 403
regulations. Therefore several previously developed sampling provisions
are not compatible with the hazard standards proposed in this rule. EPA
is proposing management controls for soil removed during an abatement
because of concern that soil removed from one yard could be disposed of
in the yard of another residential property or child-occupied facility.
When EPA finalizes the regulations being proposed today, the Agency
will also issue conforming amendments to the section 402 regulations to
ensure consistency in terminology between the regulations. These
conforming amendments will most likely focus on references to the terms
lead-contaminated dust and lead-contaminated soil which are not
included in today's proposal.
A. Clearance Standards
Under the authority of section 402 of TSCA, EPA is proposing
clearance standards for dust in today's proposed rule. Clearance
standards are used by certified individuals to evaluate the adequacy of
the cleanup performed in residences at the completion of abatement.
According to the practices prescribed at 40 CFR 745.227, a certified
risk assessor or inspector must collect dust samples and have them
analyzed by an accredited laboratory following the cleanup to assure
that the cleanup reduced dust-lead levels to the levels prescribed in
today's proposal. If the clearance levels are not met, the cleanup and
testing process must be repeated until the clearance standards are met.
Although clearance testing is not required following implementation of
interim controls (e.g., paint repair), the Agency strongly recommends
such testing to ensure that the residence has been adequately cleaned.
TSCA section 402 establishes three criteria for performing lead-
based paint activities: reliability, effectiveness, and safety. EPA is
reluctant to propose an approach that mandates a specific technology.
In fact, the Agency wants to promote technological innovation that
could result in less costly products and practices that are equally or
more effective.
Consequently, EPA is proposing that these criteria should apply to
numerical dust lead clearance levels. Under this approach, the Agency
would be establishing standards that are achievable using products and
methods known to be reliable and effective. Specifically, EPA has
decided to base the clearance standards on the performance of the
cleanup method recommended in the HUD Guidelines which is currently
considered state of the art. This method involves a combination of a
wet wash with an all-purpose or lead-specific cleaner and HEPA
vacuuming. Although clearance standards are based on dust-lead levels
achievable using this method, the standard does not require this
method. Any cleanup method would be satisfactory as long as the
clearance standard is met. This approach ensures that the cleanup was
reliable and effective while providing an incentive for entrepreneurs
to develop less costly technologies that can meet the standard.
EPA considers safety, for purposes of clearance, to be a level of
lead in dust that is a associated with the risk level of concern (i.e.,
a one to five percent probability that a child will have a blood-lead
concentration equal to or exceeding 10 g/dl). As is the case
with a clearance standard that is effective and reliable, a safe
clearance standard would not prescribe a specific cleaning technology;
any technology would be acceptable as long as it is able to reduce
dust-lead loadings to ``safe'' levels.
The clearance standards must also be evaluated within the broader
context of Title X and its purposes. In particular, EPA must select
clearance standards that are compatible with the development of a
workable framework for lead-based paint hazard evaluation and
reduction.
1. Clearance standard for floors and sills. The available field
data documenting experience with the cleaning protocol recommended in
the HUD Guidelines do not identify obvious candidates for clearance
standards (Ref. 105). Instead, use of the protocol yields a range of
dust loadings. It should be noted that these data were collected under
the controlled conditions associated with field studies. In practice,
higher post-cleanup dust-lead levels should be expected.
EPA's analysis of data from HUD demonstration projects and five
State and local programs shows that the median dust-lead loading for
floors after the first clearance test was 25 g/ft2
with a 90th percentile loading of 187 g/ft2. The
median dust-lead loading for interior window sills was 33 g/
ft2 and the 90th percentile was 475 g/
ft2. These data show that there is significant overlap among
the dust-lead loadings achievable using the HUD cleaning protocol and
the levels of lead in dust associated with the risk level of concern
and the dust-lead hazard level.
EPA has decided, therefore, to propose clearance standards that are
the same as the dust-lead hazard standard, 50 g/ft2
for uncarpeted floors and 250 g/ft2 interior window
sills. This decision as based primarily on choosing standards that are
consistent with the available data and that are as easy as possible to
understand and implement. The other option considered was to select a
clearance standard that is lower than the hazard standard.
EPA is concerned that separate clearance and hazard standards would
be difficult for property owners and other decision-makers to
understand. Especially troublesome are post-cleanup dust loadings that
exceed clearance standard but not the hazard standard. Recleaning would
be required in response to the clearance test, but no action would be
indicated if the same loading was measured prior to intervention.
Although this situation would be technically justifiable because hazard
and clearance standards serve different purposes (indicator of risk vs.
indicator of cleaning adequacy), it may seem to be inconsistent to
owners and other decision-makers and make the standards difficult to
understand. This situation is avoided by having both the hazard and
clearance standards set at the same dust-lead loading.
Another argument that has been made to support separate hazard and
clearance standards is to provide a margin that allows for
reaccumulation of lead in dust following the cleanup. In the absence of
this margin, there is a concern that a residence could have a dust-lead
hazard soon after hazard control interventions were performed. The
field data show, however, that in most circumstances reaccumulation
will not result in the immediate reappearance of a dust-lead hazard
because the majority of residences would be cleaned to levels well
below clearance (Ref. 105).
2. Clearance standard for window troughs. The Agency considered two
alternatives for window trough clearance standards: 800 g/
ft2, the standard in the HUD Guidelines; and a ``no-
visible'' dust standard. The first option has the advantage that it is
consistent with existing practice, ensures that troughs will be
adequately cleaned, and meets the statutory criteria. The ``no-
visible'' clearance standard does not require follow-up dust testing of
the trough. Although, data suggest that troughs have been adequately
cleaned if there is no visible dust and debris in the window troughs
and the clearance standards for uncarpeted floors and interior window
sills are met, these data were collected when there
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was a trough clearance standard that had to be met (Ref. 105). In the
absence of a clearance standard, there is no assurance that troughs
would be cleaned as well. EPA, therefore, has decided to propose
adopting the existing HUD clearance level for troughs. Although this
option would require trough sampling, it is expected that the
incremental cost for clearance sampling would be $5 to $10 depending on
the number of composite samples taken.
3. Interpretation of dust clearance samples. The work practice
standards at 40 CFR 745.227 already include a provision for
interpreting dust clearance samples, which states that if a clearance
sample fails, all components represented by the failed sample shall be
recleaned. This provision, however, does not differentiate between
single surface samples and composite samples. Because composite samples
provide an average level of lead, low values on some surfaces may mask
the presence of lead levels that exceed clearance standards on other
surfaces. In fact, EPA's analysis of empirical clearance testing data
shows that there is a 57 percent chance that a composite sample would
pass clearance even if any individual subsample would have failed the
clearance test using the clearance standard (i.e., false passing) (Ref.
105). False passing introduces the possibility that a post-abatement
cleanup would be judged to be adequate when, in fact, it was not. There
are no ``false failures'' for composite samples under this approach
(Ref. 105). Consequently, EPA developed and analyzed two options for
amending the requirements at 40 CFR 745.227(e)(8) to include separate
provisions for interpreting the results of composite dust clearance
samples.
Option 1. The first option is the most stringent. Under this
option, the risk assessor would divide the clearance standard by the
number of subsamples in the composite. For example, if a composite
floor sample contained four subsamples, the risk assessor would compare
the loading from the composite sample to 12.5 g/ft2
(i.e., the floor clearance standard divided by four). This approach is
analogous to that being proposed above for interpretation of composite
paint samples. Using this approach, it is mathematically impossible for
the composite to pass when any single subsample exceeds the 1 mg/
cm2 or 0.5 percent by weight standard for lead-based paint.
It would, however, introduce the possibility of a composite sample
failing clearance even if all the subsamples would have passed
clearance individually (i.e., false failure), leading to additional
clean up activities that may not be necessary. EPA's analysis of the
empirical data shows that there is an 18 percent chance of having a
false failure (Ref. 105).
Option 2. The second option is a middle ground approach between
using the clearance standard for single surfaces samples and option
one. Under this option, the risk assessor would compare the result of
composite dust clearance samples to twice the value of the clearance
level calculated in option one. That is, the risk assessor would
compare the composite sample lead loading to 2CS/n, where CS is the
clearance standard for single surface samples and n is the number of
sub-samples in the composite. EPA's analysis of the empirical data
shows that under this option there is a 5 percent chance of failing
clearance when all subsamples pass individually and a 22 percent chance
of passing clearance when at least one of the subsamples would have
failed clearance.
EPA selected option one for the proposed amendment because it
provides the best balance of safety, effectiveness, and reliability.
The false failure error probability for option one, 18 percent, is
lower than the false passing probability (57 percent) using single
surface clearance standards. Moving from option one to option two, the
improvement in false failure probability, which declines from 18
percent to 5 percent, is smaller than the decline in false passing
probability, which increases from zero percent under option one to 22
percent under option 2. The Agency specifically asks for comment on
this approach.
B. Amendments to Sampling Requirements
1. Risk assessment and clearance dust sampling. As stated above, 40
CFR 745.227(d) requires risk assessors to collect dust samples from
windows without specifying whether the samples should be collected from
window sills, window troughs, or other surfaces. EPA adopted this
general approach when promulgating the 402 regulation because the TSCA
section 403 standards, which would specify hazard standards for only
certain surfaces, were not yet in place. In the absence of standards,
the decision on where to collect samples was left to risk assessors,
based on their experience and training.
Because EPA is now proposing dust-lead hazard standards for window
sills but not for troughs, risk assessors would only need to collect
dust samples from window sills; dust samples for windows troughs would
not be necessary. EPA, therefore, is proposing to amend 40 CFR
745.227(d)(5) and 40 CFR 745.227(d)(6) to specify that dust samples be
collected from window sills for risk assessment.
Because EPA is proposing clearance standards for window sills and
troughs, risk assessors would need to collect dust samples from both
surfaces. EPA, therefore, is proposing to amend 40 CFR
745.227(e)(8)(v)(A) and 40 CFR 745.227(e)(8)(v)(B) to specify that dust
samples be collected from both interior window sills and window troughs
for clearance sampling.
2. Soil sampling. A third sampling provision that requires amendent
is the location of soil sampling. Currently, 40 CFR 745.227(d) requires
the risk assessor to collect soil samples from the dripline and the
``play area.'' The rationale for specifying these two locations was
that the ``play area'' was most representative of a child's exposure to
lead in soil and the dripline represents the worst-case exposure to
lead in soil. Additional review of this issue during development of
today's proposal, however, suggests that these sampling locations
should be changed to the dripline and the middle of the yard.
EPA is proposing this amendment, because the Agency believes that,
in the absence of site-specific information about a child's play
pattern, a child's exposure to lead in soil is best reflected by the
average soil-lead level in a yard. First, it is the Agency's judgment
that it is not feasible for risk assessors to improve on this average
exposure assumption for many properties. Indicators of where children
play, such as playground equipment, are not always present. Even when
such equipment is present, children's outdoor activity is not
necessarily limited to that location. Additionally, play patterns may
change when a new family assumes occupancy following sale of a
residence, a time when many risk assessments may occur, due to the
opportunity provided to buyers under section 1018 of Title X.
Second, the data show that the average of composite samples taken
from the dripline and the mid-yard provides a reasonable estimate of
yard-wide soil-lead levels. Lead concentrations are often distributed
in predictable patterns, with the largest differences in lead levels
found between the soil around the building perimeter (i.e., the
dripline) and the mid-yard soil. For example, the median concentration
in the dripline in the HUD National Survey is 448 ppm while the mean
mid-yard concentration is 204 ppm (Ref. 8).
Two factors explain this pattern. Dripline soil may be contaminated
by deteriorating exterior lead-based paint. For properties that do not
have exterior
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lead-based paint, it has been suggested that exterior wall surfaces
capture lead aerosol particles (from the past combustion of leaded
gasoline), which in turn wash off and accumulate in the soils around
buildings (Ref. 106).
C. Management Controls for Soil
Under the abatement work practice standards, there are no
management controls for soil that is removed during an abatement. At
the final Dialogue Process meeting, stakeholders expressed concern that
this soil could be reused improperly (e.g., as topsoil at another
residential property) (Ref. 16). EPA agrees that the lack of management
controls for abated soil is a significant gap in the regulatory
framework. To respond to this issue, the Agency identified two options.
Under the first option, EPA would propose that the reuse of removed
soil as topsoil at another residential property or child-occupied
facility be prohibited. This option addresses the most egregious misuse
of removed soil but may not adequately deal with other potential
abuses. The second option would involve the development of
comprehensive management controls. Comprehensive controls would ensure
that soil removals are safe, reliable, and effective. Development of
such controls, however, could further delay the rule.
EPA chose the first option. It addresses the worst abuse and can be
done without further delaying the rule. The Agency will examine this
issue further and determine whether more comprehensive controls are
required. If so, these controls would be proposed as a separate
amendment to the soil abatement work practice standards. To assist EPA
in its examination of this issue, EPA is interested in obtaining
comment on the types of practices that should be prohibited and on the
types of controls that should be considered.
VIII. Effect of TSCA Section 403 Standards on Other Title X
Regulations and Programs
The term ``lead-based paint hazard'' is used throughout Title X. As
a result, TSCA section 403 standards will affect the implementation of
other Title X programs. This unit of the preamble describes the impact
of the proposed standards on the other Title X programs.
A. HUD Programs
1. HUD grants. Under section 1011 of Title X, HUD issues grants for
the evaluation and reduction of lead-based paint hazards in privately
owned, low-income housing. Once today's proposal has been promulgated,
clearance testing would have to be conducted following abatements
performed with grant funding.
2. Requirements for Federally-assisted or Federally-owned housing.
Under sections 1012 and 1013 of Title X, HUD is establishing lead-based
paint hazard notification, evaluation, and reduction requirements for
certain pre-1978 HUD-associated and Federally-owned (prior to sale to
the public) housing. The programs covered by these requirements range
from HUD-owned housing to single-family insured housing. For programs
where hazard evaluation is required, the TSCA section 403 standards,
when finalized, will provide criteria to risk assessors for identifying
lead-based paint hazards in residences covered by these programs. For
programs that require abatement of lead-based paint hazards, the TSCA
section 403 standards shall be used to identify residences that contain
lead-based paint hazards to determine where abatement will be
necessary.
HUD proposed regulations under 1012 and 1013 on June 7, 1996 (61 FR
29170) that reflected EPA's lead-based paint hazard guidance. HUD is
required to incorporate the TSCA section 403 standards, or more
stringent standards, directly into its final rule or to cross-reference
the standards.
3. HUD Guidelines The HUD Guidelines for the Evaluation and Control
of Lead-Based Paint Hazards in Housing were developed in 1995 under
section 1017 of Title X. They provide detailed, comprehensive,
technical information on how to identify lead-based paint hazards posed
by paint, dust, and soil in residential housing and how to control such
hazards safely and efficiently. Although the TSCA section 403 standards
will have no regulatory impact on the Guidelines, the Guidelines will
be revised periodically to incorporate new information, technological
advances, and new Federal regulations, including EPA's lead-based paint
hazard standards.
Chapter 5 of the Guidelines on risk assessment would need to be
updated to incorporate the standards for lead-based paint hazards. For
example, the discussion of the following topics would need to be
revised: hazard levels for deteriorated paint, dust (for both risk
assessment and screening of dwellings in good condition), and bare
soil; and interpretation of sampling results. The clearance standards
in Chapter 15 also would need to be revised to be consistent with the
TSCA section 403 standards.
4. Real estate disclosure requirements. On March 6, 1996 (61 FR
9064) (FRL-5347-9), pursuant to section 1018 of Title X, HUD and EPA
jointly issued regulations requiring sellers or lessors of most pre-
1978 housing to disclose the presence of known lead-based paint and
lead-based paint hazards and provide the potential purchaser or lessee
with a copy of the pamphlet, Protect Your Family from Lead in Your
Home. In addition, sellers must provide a 10-day period to buyers to
conduct a risk assessment or inspection for the presence of lead-based
paint and lead-based paint hazards. Sellers and lessors must also
include warning language in sales contracts (24 CFR part 35, subpart H;
40 CFR part 745, subpart F).
To date, owners have relied on EPA's guidance for advice about
conditions that may be considered lead-based paint hazards. By
establishing regulatory standards for lead-based paint hazards, the
TSCA section 403 rule will provide criteria for triggering certain
disclosure by property owners. Furthermore, because the TSCA section
403 standards will be based on a comprehensive analysis of the most
recent data and research available, they will offer buyers and lessees
a better tool for interpreting risk assessment reports provided by
property owners. As part of EPA's outreach efforts in this area, the
Agency is planning to provide guidance on how to use the TSCA section
403 standards to interpret sampling results in risk assessment reports.
Disclosure of the presence of lead-based paint is unaffected by the
TSCA section 403 standards.
B. EPA Programs
1. Training, accreditation, and certification requirements and work
practice standards. Under TSCA section 402(a), EPA issued a regulation
on August 29, 1996 (61 FR 45778), at 40 CFR part 745 requiring
individuals engaged in lead-based paint activities in target housing
and child-occupied facilities to be trained; these individuals and
contractors engaged in the same activities to be certified; and
training programs to be accredited. These regulations also contain work
practice standards for performing lead-based paint activities,
including risk assessments, taking into account reliability,
effectiveness, and safety.
The most significant impact of the TSCA section 403 standards on
the training and certification programs concerns the determination of
when certified workers and contractors are required to perform
abatements. According to the training and certification regulations at
40 CFR 745.223, abatement is defined as the permanent elimination of
lead-based paint hazards, and must be performed by certified
individuals and contractors
[[Page 30344]]
unless it is performed by the property owner in an owner-occupied
residence (40 CFR 745.220(b)). By identifying lead-based paint hazards,
the TSCA section 403 regulations help owners determine when work needs
to be performed by certified individuals and contractors.
Today's action also contains proposed changes to the TSCA section
402 regulations. These changes include: the establishment of clearance
standards for dust; amendments related to risk assessment and clearance
sampling for dust, and sampling for soil; management controls for
abated soil; and amendments changing the references to the lead-based
paint hazard guidance to the TSCA section 403 regulations when final.
The final TSCA section 403 regulations and the accompanying amendments
to TSCA section 402 will necessitate changes to EPA's model training
curricula in the areas of hazard standards, related underlying advances
in scientific and technical information, risk assessment sampling,
interpretation of sampling results, approaches for hazard control, and
clearance standards.
2. State Programs. In conjunction with the TSCA section 402
regulations described above, EPA adopted procedures for States and
Indian Tribes to follow when applying to EPA for authorization to
administer and enforce a State or Tribal lead-based paint program (40
CFR 745.324). EPA considers standards for lead-based paint hazards and
soil-lead level of concern, dust-lead clearance standards, and
associated requirements for sampling and interpreting sampling results
to be an integral part of the work practice standards for risk
assessments and abatements. Therefore, EPA is proposing amendments to
subpart Q that would require States and Tribes to establish standards
and requirements that are as protective as the Federal standards being
proposed today.
States and Tribes that apply for authorization following the date
that is 2 years after promulgation of the rule would have to
demonstrate, as part of their application for program authorization,
that their standards are as protective as the Federal standards.
Today's proposed amendment would require all other States and Tribes
that wish to retain authorization to demonstrate to EPA's satisfaction
that their standards are as protective as the Federal standards within
2 years of the promulgation of the rule. To minimize the reporting
burden, these States and Tribes would apply to retain authorization as
part of their reports to EPA in accordance with 40 CFR 745.324(h).
As a general matter, States and Tribes that apply to obtain or
retain authorization that incorporate the same standards or standards
that are more stringent than the Federal standards will meet the ``as
protective as'' criteria. States and Indian Tribes that incorporate
less stringent standards would have to provide analytical support and
other documentation demonstrating that their standards are ``as
protective as'' the Federal standards. For example, a State or Tribe
may demonstrate that a higher soil-lead hazard standard could be ``as
protective as'' the Federal standard because most of the lead found in
the soil is less bioavailable than lead considered by the Agency. EPA
plans to develop specific guidance on the types of analysis and
documentation that a State or Tribe would need to provide to make such
a demonstration.
3. Real estate disclosure requirements. EPA and HUD jointly
developed these requirements. The effects of the TSCA section 403 lead
hazard standards on real estate disclosure requirements were discussed
previously in reference to the HUD programs.
4. Public outreach programs. EPA, in conjunction with HUD and other
Federal agencies, has developed various public education programs, such
as the National Lead Information Center and outreach campaigns
targeting housing providers, health care professionals, the media,
persons involved in real estate transactions, and the general public.
When promulgated, the TSCA section 403 standards will play a
significant role in this public education. Information regarding these
standards will communicate the Agency's best judgment concerning the
identification of lead-based paint hazards to property owners, State
and local officials, tenants, and other decision-makers. To assist in
this education, the Agency will be developing materials specifically
addressing the TSCA section 403 standards, including a fact sheet and
questions and answers bulletin. In addition, some existing outreach
materials will be modified to discuss the TSCA section 403 standards or
to reference materials with such discussion.
IX. Relationship of TSCA Section 403 Standards to Other EPA
Programs
Because lead exposures occur through all media, a variety of EPA
programs, in addition to the TSCA Title IV program, address residential
lead contamination and lead in soil. The Resource Conservation and
Recovery Act (RCRA) regulates as hazardous certain wastes containing
lead, including some wastes that may be generated during lead-based
paint activities. The Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA or Superfund) and the RCRA
corrective action programs clean up lead released into the environment.
EPA's Indoor Air program also seeks to reduce contamination of the
indoor environment by substances including lead. This unit describes
the relationships between the proposed TSCA section 403 standards and
each of these EPA programs.
A. RCRA Hazardous Waste Requirements
Wastes generated by lead-based paint hazard reduction activities
may be regulated as ``hazardous wastes'' under RCRA Subtitle C. Wastes
may be considered hazardous waste by virtue of being specifically
listed as hazardous or by exhibiting a characteristic of hazardous
waste. Lead-bearing wastes from lead-based paint activities are not
listed wastes. Such wastes, however, may exhibit the hazardous
characteristics of toxicity (40 CFR 261.24), corrosivity (40 CFR
261.22), or ignitability (40 CFR 261.21). They are unlikely, due to
lead content, to exhibit the other hazardous characteristic of
reactivity (that is, be capable of easily generating explosive or toxic
gas, especially when mixed with water, or be unstable and undergo
violent change without detonating).
Under the toxicity characteristic, wastes or media (e.g., soil)
contaminated with wastes are hazardous for lead if, after applying the
toxicity characteristic leaching procedure (TCLP) to a sample, the
waste produces an extract with a concentration of lead equal to or
exceeding 5 milligrams per liter (5 ppm). Corrosive hazardous waste is
waste that has a pH less than or equal to 2 (highly acidic) or greater
than or equal to 12.5 (highly basic), or that can corrode steel at a
certain rate. Unneutralized waste from the use of caustic or acidic
paint strippers may be corrosive hazardous waste. Ignitable hazardous
waste generally includes liquids with flash points less than 140 deg.F
(60 deg.C), flammable solids, compressed gases, and oxidizers. Wastes
generated by the use of certain solvents for paint stripping may be
ignitable hazardous waste.
When promulgated, TSCA section 403 standards will not affect the
determination of whether wastes or soil containing lead are hazardous
under RCRA. Moreover, there is no direct relationship between the
approaches used to identify a TSCA section 403 lead-based paint hazard
and a RCRA
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characteristic hazardous waste. The TSCA section 403 standards are
based on an exposure scenario involving the ingestion of lead-
contaminated dust or soil by young children. In contrast, the level at
which wastes contaminated with lead are considered hazardous under the
RCRA toxicity characteristic is based upon an analysis using a scenario
involving the consumption of ground water contaminated by waste
constituents leaching from a landfill receiving municipal waste.
The potential applicability of RCRA hazardous waste regulations and
the associated compliance costs, however, have informed the development
of the proposed TSCA section 403 soil-lead hazard standard. As
discussed in Unit IV. of this preamble, when developing TSCA
regulations, EPA considered both risk reduction and cost in selecting
the proposed soil-lead hazard standard. Because the costs of managing
excavated lead-contaminated soil as hazardous waste are significantly
higher than the cost of managing this material as non-hazardous waste,
identifying this material as hazardous waste would approximately double
the cost of abatement and was a factor in the selection of the proposed
standard.
B. CERCLA Response Actions and RCRA Corrective Actions
Under CERCLA, the Federal government may undertake or compel
responsible parties to cleanup hazardous substance releases. Because
lead is a CERCLA hazardous substance, these response actions may
address lead contamination in soil and other environmental media.
Likewise, soil, sediment, or other media contaminated with lead may be
considered a RCRA hazardous waste (as described above) and RCRA
hazardous waste management facilities undergoing corrective action may
be required to remediate such contamination. The CERCLA and RCRA
cleanup programs have similar purposes, but address different types of
sites: whereas RCRA regulates permitted hazardous waste treatment,
storage, and disposal facilities, CERCLA generally governs abandoned or
uncontrolled industrial sites (but may also be applied to residential
or commercial properties).
To assist the regulators responsible for CERCLA responses and RCRA
corrective actions, EPA has developed soil screening levels (SSLs) for
various hazardous constituents, including lead. The SSL for lead is 400
ppm, based on risk analysis using the IEUBK model with a residential
scenario (Ref. 84). The SSL is not a cleanup standard. It neither
triggers the need for response actions nor defines unacceptable levels
of soil contamination. Instead, it helps Federal and State regulators
identify and define lead-contaminated areas that require further study.
Where soil-lead concentrations at CERCLA sites or RCRA corrective
action facilities are below the SSL, no further response action or
study of such contamination is generally warranted. Where contaminant
concentrations equal or exceed the SSL, however, further investigation,
but not necessarily cleanup, is warranted. These further investigations
often involve site characterization and the application of the IEUBK
model using site-specific data for sites that include residential
property. Federal and State regulators use the results of these
investigations to determine the need for remediation and, if necessary,
to analyze remedial options and establish site-specific preliminary
remediation goals (PRGs) at CERCLA sites and at RCRA corrective action
facilities.
The TSCA section 403 standards are defined for largely different
purposes and audiences. Unlike CERCLA responses and RCRA corrective
actions, residential lead hazard reduction activities often occur
without government oversight. The TSCA section 403 standards are
intended for use by any person involved in identifying and addressing
lead-based paint hazards, including homeowners, rental property owners,
tenants, contractors, government housing programs, and Federal, State,
and local regulators. The proposed TSCA section 403 standards are
designed to provide practical advice widely applicable to residential
property. Expensive, residence-specific investigations would not be
required. Rather, when promulgated, the standards could be used for
millions of homes throughout the nation to evaluate properties quickly
at modest cost.
In addition, the criteria used to select hazard control methods
differ under TSCA section 403, RCRA, and CERCLA. Under CERCLA, for
example, preference is given to ``treatment [methods] which permanently
and significantly reduce the volume, toxicity or mobility'' of the
hazardous constituents regardless of risk (CERCLA section 121(b)).
Likewise, under RCRA, hazardous waste must be treated to meet stringent
standards prior to land disposal. TSCA does not have any similar
preferences for permanent treatment. Furthermore, Title X recognizes
the important role of temporary control measures (i.e, interim
controls).
In summary, the TSCA section 403 standards should not affect the
selection of cleanup remedies at CERCLA response actions or RCRA
corrective action facilities. The TSCA section 403 standards are being
developed for different purposes and audiences. They will provide
generic guidance that can be used at millions of widely varying sites
throughout the nation. Owners of properties with lead-based paint
hazards should undertake permanent or interim measures to control these
hazards. In contrast, the site-specific investigations that occur under
CERCLA and RCRA allow risk and cleanup levels to be narrowly tailored
to the individual site with a preference for permanent solutions. Thus,
the action levels, cleanup goals, and remedies selected at CERCLA and
RCRA sites may differ from those being proposed in today's action.
C. Indoor Air Activities
The Indoor Environment Division of EPA's Office of Air and
Radiation seeks to reduce indoor air pollution through a variety of
educational and other non-regulatory means. The Indoor Air Program
incorporates lead-based paint concerns in its outreach to owners and
occupants of residential, public, and commercial buildings, even though
lead-based paint concerns are not its primary focus and the inhalation
of air containing lead-contaminated dust is not the major pathway of
childhood lead exposure. The Indoor Air Program will reference and
discuss section 403 standards in its efforts to help building owners
and occupants properly identify and respond to lead-based paint hazards
and other indoor air problems.
X. Public Record and Electronic Submissions
The official record for this proposed rule has been established
under docket control number OPPTS-62156 (including comments and data
submitted electronically as described below). A public version of this
record, including printed, paper versions of electronic comments, which
does not include any information claimed as CBI, is available for
inspection from 12 noon to 4 p.m., Monday through Friday, excluding
legal holidays. The official record is located in the TSCA
Nonconfidential Information Center, Rm. NE-B607, 401 M St., SW.,
Washington, DC. The record now includes:
1. ``Risk Analysis to Support Standards for Lead in Paint, Dust,
and Soil,'' Office of Pollution Prevention and Toxics.
2. The economic analysis.
3. Materials related to the Dialogue Process and other public
meetings
[[Page 30346]]
(contained in Dockets OPPTS-62148, OPPTS-62151, OPPTS-62151A, and
OPPTS-62151B).
4. Support documents, reports, and published literature cited in
this report, including all the references listed in Unit XI. of this
preamble.
5. Published literature and all other references cited in all
relevant documents.
Electronic comments can be sent directly to EPA at
[email protected]. Electronic comments must be submitted as an
ASCII file avoiding the use of special characters and any form of
encryption. Comments and data will also be accepted on disks in
WordPerfect 5.1/6.1 or ASCII file format. All comments and data in
electronic form must be identified by the docket control number OPPTS-
62156. Electronic comments on this proposed rule may be filed online at
many Federal Depository Libraries.
XI. References
1. U.S. Environmental Protection Agency. December 1997. Risk
Analysis to Support Standards for Lead in Paint, Dust, and Soil.
Volumes I and II. EPA 747-R-97-006.
2. U.S. Centers for Disease Control and Prevention. October 1991.
Preventing Lead Poisoning in Young Children: A Statement by the Centers
for Disease Control.
3. Lepow, M.L., et al. 1975. ``Investigations into Sources of Lead
in the Environment of Urban Children.'' Environmental Research. 10:415-
426.
4. Rabinowitz M., A. Leviton, H. Needleman; D. Bellinger, and C.
Waternaux. 1985. ``Environmental correlates of infant blood lead levels
in Boston.'' Environmental Research. 38(1):96-107.
5. Pirkle, J.L., D.J. Brody, E.W. Gunter, R.A. Kramer, D.C.
Paschal, K.M. Flegal, and T.D. Matte. 1994. ``The Decline in Blood Lead
Levels in the United States: The National Health and Nutrition
Examination Surveys (NHANES).'' Journal of the American Medical
Association. 272(4):284-291.
6. U.S. Centers for Disease Control and Prevention. February 21,
1997. ``Update: Blood Lead Levels-U.S., 1991-1994.'' Morbidity and
Mortality Weekly Report. 46(7):141-145.
7. Brody, D.J., J.L. Pirkle, R.A. Kramer, K.M. Flegal, T.D. Matte,
E.W. Gutiter, and D.C. Paschal. 1994. ``Blood Lead Levels in the U.S.
Population: Phase I of the Third National Health and Nutrition
Examination Survey (NHANES III, 1988 to 1991).'' Journal of the
American Medical Association. 272(4):277-283.
8. U.S. Environmental Protection Agency, Office of Pollution
Prevention and Toxics. April 1995. Report on the National Survey of
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[[Page 30349]]
Planning and Evaluation, Draft Final Report.
XII. Regulatory Assessment Requirements
A. Executive Order 12866
The Agency submitted this proposed action to the Office of
Management and Budget (OMB) for review under Executive Order 12866,
entitled Regulatory Planning and Review (58 FR 51735, October 4, 1993),
and any changes made during that review have been documented in the
public record. OMB has determined that this proposed action is
``economically significant,'' because this proposed rule may result in
behavioral changes that involve increased expenditures by owners of
target housing and child-occupied facilities, with a potential annual
effect on the economy of $100 million or more. Although the
establishment of the standards contained in this proposed rule do not,
in and of themselves, mandate any action, the Agency recognizes that
the existence of the hazard standards may influence the decisions or
actions of owners of target housing.
The Agency believes that, in establishing the standards, it is
appropriate to consider the potential costs and benefits associated
with the possible actions that an owner could or might take based on
the hazard standard. The Agency has therefore prepared an economic
analysis which assumes that a risk assessment would be conducted in all
target housing at the time a newborn enters the home, that the owners
of the target housing would respond to all identified hazards, and that
no activities would occur in the absence of the 403 standards.
The Agency recognizes, however, that risk assessments will not be
conducted in all target housing, nor will all the owners of target
housing respond to all identified hazards. In addition, intervention
activities are occurring and will continue to occur, even in the
absence of the 403 standards. Consequently, EPA believes that this
analysis overestimates the potential costs and benefits associated with
the non-mandatory intervention activities related to the establishment
of the proposed standards. Furthermore, EPA used other assumptions in
the analysis (e.g., the use of a birth trigger for testing and hazard
intervention activities, and the use of a 3 percent discount rate),
that can potentially affect the relative balance of costs and benefits.
These assumptions are summarized below in the discussion of the
Agency's sensitivity analyses, which are presented in Chapter 7 of the
Agency's economic analysis.
This analysis is contained in a document entitled Economic Analysis
of Proposed Lead Hazard Standards (Ref. 83), and is available as a part
of the public record for this action. The analysis was used by the
decision-makers to help in the selection of the hazard standards
proposed in this document. The following summary of the economic
analysis presents the benefits, costs, and net benefits for those
activities that could be potentially related to the establishment of
the lead hazard standards (i.e., related to lead-based paint hazard
interventions, as well as the costs of conducting risk assessments to
evaluate homes for lead-based paint hazards). The Agency presents costs
and benefits for paint interventions separately because they did not
affect the Agency's evaluations and decisions regarding dust and soil.
As discussed in Unit IV. of this preamble, EPA did not use the economic
analysis of the paint component of the proposed regulation in selecting
the preferred option for the paint standard due to data limitations.
EPA presents the costs of conducting risk assessments separately
because these costs are the same for all dust and soil standard options
and, therefore, did not affect the Agency's decision-making on the
standards.
In general, the economic analysis is designed to provide
comparisons of different standards, and does not attempt to predict
precisely how much remediation of residential lead-based paint hazards
will occur as a result of promulgating these standards. The economic
analysis compares alternative standard options in terms of their net
benefits. Net benefits are based on the benefits of risk reduction
minus the costs of control activities needed to achieve the reduction
in risk. The benefit categories all measure health effects resulting
from childhood lead exposure. The analysis calculates net benefits for
a wide range of alternative standards, including the proposed section
403 hazard levels.
The total costs (estimated over a 50-year span, and discounted at 3
percent) for setting the proposed dust and soil standards, which are
based on the proposed standard of 50 g/ft2 for
floor dust, 250 g/ft2 for window sill dust and
2,000 ppm for soil, are estimated to be $19 billion, while the total
estimated benefits are $108 billion using the IEUBK model and $39
billion using the empirical model, resulting in estimated net benefits
of $89 billion using the IEUBK model and $19 billion using the
empirical model. For paint interventions, the estimated total cost is
$20 billion, with total estimated benefits of $59 billion using the
IEUBK model and $5 billion using the empirical model, resulting in
estimated net benefits of $39 billion using the IEUBK model and -$15
billion using the empirical model. The total estimated costs for
testing are $14 billion, and the Agency did not estimate any benefits
for potential testing activities. About 25.4 million homes are
projected to exceed one or more of the standards, and the Agency
projected approximately 43.8 million children would experience reduced
exposure to household lead in soil, dust, and paint.
1. Dust and soil analysis. The monetized benefits estimated over
the 50-year modeling period for the proposed TSCA section 403 standards
of 50 g/ft2 floor dust, 250 g/ft2
window sill dust, and 2,000 ppm soil are $39 billion from the empirical
model and $108 billion from the IEUBK model. These estimates are based
on the following assumptions: that all owners of target housing will
conduct a risk assessment to identify lead hazards at the time when a
newborn child enters the home; that these owners will respond to all
identified lead hazards; and that no intervention activities will occur
in the absence of the 403 standards.
As would be expected, alternative dust and soil standards that are
more stringent than these are estimated to produce additional benefits.
Changes in stringency affect the benefits differently depending upon
the model used. For the empirical model, benefits fall within a fairly
tight range of $30 to $47 billion, when options range from 1,000 to
5,000 ppm for soil, from 50 to 200 g/ft2 for floor
dust, and 100 to 500 g/ft2 for window sill dust.
For the IEUBK model, the range of benefits over these alternative
options is wider, from approximately $73 billion to $150 billion.
The costs for the proposed TSCA section 403 standards of 50
g/ft2 floor dust, 250 g/ft2
window sill dust, and 2,000 ppm soil (estimated over the 50-year
modeling period and discounted at 3 percent) are $19 billion. This
represents the costs of interventions to reduce soil and dust-lead
levels in response to these standards. EPA estimates costs
independently of the two models (i.e., IEUBK, empirical). Costs,
therefore, are the same for both analytical approaches. Alternative
dust and soil options that are more stringent than the proposed
standards are estimated to have higher costs. Changes in stringency
ranging from 1,000 to 5,000 ppm for soil, 40 to 200 g/ft2
for
[[Page 30350]]
floor dust, and 100 to 500 g/ft2 for window sill
dust, produce a range of costs from about $12 billion to about $38
billion.
The net benefits of the proposed TSCA section 403 standards for
dust and soil are shown in Table 12 below. Net benefits have been used
to evaluate alternative lead hazard levels. The estimated net benefits
for the proposed standards of 50 g/ft2 for floor
dust, 250 g/ft2 for window sill dust, and 2,000 ppm
for soil are $19 billion (using the empirical model for blood lead) or
$89 billion (using the IEUBK model).
Table 12 also provides an indication of the net benefits
corresponding to a range of options for the proposed lead hazard
standards. Using the empirical model, the net benefits appear to be
near the maximum at 2,000 ppm and 5,000 ppm. At the same time, net
benefits decrease (in fact become negative) with more stringent soil
options under the empirical model.
Table 12.--Net Benefits from Hazard Options Varying around the Proposed Standard: Point Estimates and Ranges*
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hazard Standard Net Benefits ($Billions)
--------------------------------------------------------------------------------------------------------------------
Floor Dust (g/ Window Sill Dust
ft2) (g/ft2) Soil (ppm) IEUBK Model Empirical Model
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range of Soil Options 50 250 500 143 5
50 250 2,000 89 19
50 250 5,000 61 21
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range of Floor Dust Options 50 250 2,000 89 19
100 250 2,000 77 19
--------------------------------------------------------------------------------------------------------------------------------------------------------
Range of Sill Dust Options 50 100 2,000 N/A 16
50 250 2,000 N/A 19
50 500 2,000 N/A 19
--------------------------------------------------------------------------------------------------------------------------------------------------------
*Net Benefits do not include the costs and benefits of paint interventions, nor testing costs. The models paint intervention costs (over 50 years
discounted at 3 percent) are $20 billion. Paint intervention benefits (over 50 years discounted at 3 percent) are $59 billion with the IEUBK Model and
$5 billion with the empirical model. Testing costs (over 50 years discounted at 3 percent) are approximately $14 billion. As explained in Unit IV. of
this preamble, the net benefit estimates generated by the IEUBK model-based approach and the empirical model-based approach are not comparable.
The IEUBK model, on the other hand, suggests that maximum net benefits
occur at more stringent options, and decline with less stringent ones.
Net benefits do not vary substantially under either model across the
range of dust options evaluated.
Given overall modeling uncertainties, and the fact that both models
suggest that net benefits are positive in the 2,000 ppm soil range, the
proposed soil and dust standards appear to provide a reasonable
combination of national values that will tend to maximize the net
benefits of performing interventions to protect children from exposure
to lead from these sources. In addition to the relative net benefits,
each hazard standard was evaluated in terms of number of children
protected. Under the proposed option, it is estimated that the number
of children with blood-lead concentrations equal to or exceeding 10
g/dl would decline by 2 to 6 million over 50 years and the
number of children with blood-lead concentrations equal to or exceeding
20 g/dl would decline by 300,000 to 700,000 in the same
timeframe (estimated by the empirical-model based analysis and the
IEUBK-model based analysis respectively) (Ref. 83).
2. Paint analysis. EPA used the available data on deterioration
from the HUD National Survey to estimate costs and benefits associated
with repairing or abating deteriorated paint. The Survey reports only
the total deterioration in each residence, whereas the proposed hazard
standard for paint is based on the amount of deterioration per
component in a residence. Because of this difference, as noted in Unit
IV. of this preamble, the Agency was unable to use this analysis in
selecting a preferred option. In summary, the empirical model-based
analysis estimates benefits of $5 billion and the IEUBK model-based
analysis estimates benefits of $59 billion. The costs for paint
interventions are estimated to be $20 billion yielding net benefits for
paint of $-15 billion using the empirical model-based analysis and $39
billion using the IEUBK model-based analysis. For the following
reasons, however, the reliability and usefulness of these estimates for
characterizing the economic impacts of the proposed standard for
deteriorated lead-based paint is significantly limited due to
differences in approach and data used. It is also inappropriate to
compare the results of each analytical approach.
First, as previously noted, the determination of where paint
interventions occur is based on the HUD National Survey, which reports
deterioration for an entire residence. The proposed standard, however,
is based on the amount of deterioration per component. There is no way
to relate the two measurements.
Second, the lack of data to relate quantitatively deteriorated
paint to blood-lead concentration limits EPA's ability to measure
benefits associated with direct ingestion of lead-based paint. Both
modeling approaches (i.e., IEUBK-based and empirical-based) predict
benefits based only on the presence or absence of deteriorated paint.
Thus, each model's estimate of benefits remains unchanged regardless of
the amount of deterioration present.
Third, under the empirical model-based analysis, only interior
paint abatement, which is accompanied by dust cleaning, yields dust-
related benefits. The analysis does not predict any dust-related
benefit for interior paint repair or exterior paint repair or
abatement. As discussed in Chapter 4 of the Agency's risk analysis, EPA
used data from several abatement studies to estimate the impact of dust
cleaning on dust-lead loading when sources of dust-lead contamination
were abated. In contrast, the Agency has no basis for estimating the
impact of source control alone on dust-lead loading. It is likely,
however, that other paint interventions would reduce dust-lead loading.
Thus, the empirical model-based analysis probably underestimates the
dust-related benefits of paint intervention.
[[Page 30351]]
3. Testing costs. EPA estimates that the costs of conducting risk
assessment to test target housing for the presence of lead-based paint
hazards is $14 billion. The analysis assumes that each target housing
unit will be tested at the time a newborn enters the home. Testing
costs are the same for all hazard standard options. Likewise, the
testing costs cannot be assigned to one medium or another because
testing costs assume that each of the three media (paint, dust, and
soil) are addressed.
4. Sensitivity and uncertainty analyses. The economic analysis
addresses the robustness of results by reporting model outcomes when
each of several different parameters or assumptions are changed. The
parameters considered are the discount rate and the value of an IQ
point. In addition, the assumption that avoiding small losses of IQ
(i.e., less than one point) provides an economic benefit was examined.
The first parameter analyzed is discount rate. In the base model, a
rate of 3 percent is used. In the sensitivity analysis, 7 percent is
used because this is the value recommended in the January 11, 1996 OMB
Guidance entitled Economic Analysis of Federal Regulations Under
Executive Order No. 12866. When the discount rate is 7 percent, model
results at each possible standard option change from the base model in
the following way: costs decrease, benefits decrease substantially
more, and net benefits decrease. Following from these changes, the
options at which net benefit would be maximized are less stringent in a
7 percent discount regime than in a 3 percent discount regime. Benefits
decrease more than costs because they would be realized over a much
longer time horizon, the economically productive lifetime of affected
individuals. Costs for actions to protect a given individual would be
incurred before the sixth birthday.
The second parameter tested is the value of an IQ point. The base
model uses an IQ point value of $8,346, based on recently published
analyses (Ref. 69). As an alternative, benefits were calculated using
an IQ point value of $6,847, from earlier EPA analyses (Refs. 109 and
110). The total cost calculated would be the same under each
assumption, because this parameter does not affect costs. The benefits
and net benefits, however, for all options would be lower when the
alternative, smaller IQ value is used, because over 95 percent of total
benefits are due to changes in IQ. The effect on benefits is small
enough, however, that there is no effect on which the standard would
maximize net benefits in the IEUBK model, and the empirical model-based
analysis predicts only a small decrease of stringency of the window
sill dust standard. Thus, the choice of standard is not sensitive to
the use of this revised value of an IQ point.
The third issue EPA examined in the sensitivity analysis was the
effect of the value of small IQ point differences. The Agency's
analysis assumes that a difference in average blood-lead levels between
two populations, no matter how small that difference is and regardless
of the magnitude of blood-lead levels involved, is associated with a
corresponding difference in average IQ scores. In the cost-benefit
analysis performed for these standards, the Agency is essentially
comparing the blood-lead distributions that would occur between two
populations: one with the TSCA section 403 standards versus one without
the 403 standards. Furthermore, the analysis relies on the empirical
finding that a difference in average IQ scores between two populations,
again no matter how small, is associated with a difference in average
lifetime earnings. Note that it is not possible to say that for any
pair of individuals that a difference in blood-lead will necessarily
reflect a difference in IQ scores or lifetime earnings. The available
research, however, does demonstrate that such differences do occur on
the average for groups of individuals.
Notwithstanding the fact that the risk assessment and benefit-cost
analysis were constrained to address population average changes, it was
recognized that there might be an interest in considering the
contribution to those population average changes made by subgroups in
the population whose particular blood-lead and IQ point improvements
might be considered small. An analysis was therefore performed and
presented in section 7.3.1 of the Economic Analysis to try to
characterize the portion of the total benefits from IQ improvements
that were contributed by that portion of the population having
improvements of less than 1 IQ point. The computational considerations
involved in doing that analysis were discussed in detail there. That
special analysis showed that, at the proposed standards (window sill
dust at 250 g/ft2; floor dust at 50 g/
ft2; soil at 2,000 ppm), the contribution of these small IQ
point improvements in the population, contributed 30 percent of the
value of the IQ point benefits under the IEUBK model and 90 percent of
the IQ point benefits under the empirical model.
The Agency, however, recognizes that the methodology used for this
sensitivity analysis is preliminary in nature and should not be relied
upon for decision-making purposes. More importantly, the Agency is not
aware of any technical basis or rationale for not including the
benefits associated with small IQ changes.
B. Regulatory Flexibility Act (RFA)
Pursuant to section 605(b) of the Regulatory Flexibility Act (5
U.S.C. 601 et seq.), the Agency hereby certifies that this proposed
action will not have a significant economic impact on a substantial
number of small entities. As previously discussed, this proposed rule
does not, in and of itself, mandate any action, or directly impose any
costs. The Agency does, however, recognize that the existence of the
hazard standards may influence the decisions or actions of owners of
target housing, and has therefore considered the potential costs and
benefits associated with the possible actions that an owner could or
might take based on the hazard standard. The Agency also involved
potentially affected entities, including representatives of small
businesses (e.g., owners of multi-housing and rental properties), and
State/Tribal and local governmental agencies, in an extensive
``dialogue'' process, which is discussed in more detail in Unit II. of
this preamble, as well as other mechanisms of communication.
In addition, although other regulations implementing other sections
of Title X will use or reference the hazard standards that are proposed
in this document, the impacts of those regulations on small entities
are evaluated in the context of those regulations. To date, EPA has
promulgated regulations under sections 402, 404, 406, and 1018. For
each of these regulations, EPA evaluated the potential impacts on small
entities in compliance with the RFA.
Information relating to this determination will be provided to the
Chief Counsel for Advocacy of the Small Business Administration upon
request, and is included in the docket for this proposal. Any comments
regarding the economic impacts that this proposed regulatory action may
impose on small entities should be submitted to the Agency at the
address listed above.
C. Unfunded Mandates Reform Act (UMRA) and Executive Order 12875
Although the requirements of Title II of the Unfunded Mandates
Reform Act of 1995 (UMRA) (Pub. L. 104-4) and Executive Order 12875,
Enhancing the Intergovernmental Partnership (58 FR 58093, October 28,
1993), do not apply to this proposed rule, the Agency believes that its
consideration of the
[[Page 30352]]
potential costs and benefits of those non-mandatory activities that
could be potentially related to the establishment of the lead hazard
standards, i.e., activities related to lead-based paint hazard
interventions and risk assessments, as well as its discussions with
State and Tribal governments, address these requirements. The UMRA
requirements in sections 202 and 205 do not apply to this proposed
rule, because this action does not contain any ``Federal mandates'' or
impose any ``enforceable duty'' on State/Tribal, or local governments
or on the private sector. The requirements in section 203 do not apply
because this proposed rule does not contain any regulatory requirements
that might significantly or uniquely affect small governments. In
addition, since this is not a discretionary act containing an unfunded
mandate, no consultation is required under the Executive Order.
Nevertheless, the Agency recognizes that the existence of the
hazard standards may influence the decisions or actions regarding the
intervention activities undertaken by State/Tribal or local governments
as potential owners of child-occupied facilities, even if those actions
are not mandated by this or any other EPA regulation. The Agency
therefore believes that it is important to consider the potential
impacts of this proposed rule on State/Tribal or local governments. It
is, of course, difficult to predict whether or what intervention
activities might be undertaken by State/Tribal or local governments as
a result of the establishment or existence of the proposed hazard
standards, but the Agency does not believe that the analysis needs to
differentiate between ownership in considering the potential costs
related to the possible intervention activities. Therefore, since the
Agency considered the potential costs and benefits associated with
possible intervention activities in selecting the proposed hazard
standards, the Agency has also considered the potential costs that
might be experienced by State/Tribal or local governments. Intervention
activities in child-occupied facilities, because a much larger number
of children are involved, will naturally result in greater benefits,
increasing the ratio between costs and benefits significantly.
D. Paperwork Reduction Act (PRA)
This proposed regulatory action does not contain any information
collection requirements that require additional approval by the Office
of Management and Budget (OMB) under the Paperwork Reduction Act (PRA),
44 U.S.C. 3501 et seq. Specifically, States and Tribes with authorized
programs under 40 CFR part 745, subpart L will still need to
demonstrate their standards for identifying lead-based paint hazards
and soil-lead level of concern, and clearance standards for dust, in
the reports that they submit to EPA under 40 CFR 745.324(h). This
reporting requirement is contained in the regulations implementing TSCA
sections 402(a) and 404, for which the Information Collection Request
(ICR) has already been approved by OMB under control number 2070-0155
(EPA ICR No. 1715). As a part of the economic analysis, EPA also re-
examined this ICR and determined that the burden estimates provided in
the ICR would not change as a result of the promulgation of the
standards proposed. Because there are no new information collection
requirements to consider, or any changes to the existing requirements
that might impact the existing burden estimates, additional OMB review
and approval under the PRA is not necessary.
Under the PRA, ``burden'' means the total time, effort, or
financial resources expended by persons to generate, maintain, retain,
or disclose or provide information to or for a Federal agency. This
includes the time needed to review instructions; develop, acquire,
install, and utilize technology and systems for the purposes of
collecting, validating, and verifying information, processing and
maintaining information, and disclosing and providing information;
adjust the existing ways to comply with any previously applicable
instructions and requirements; train personnel to be able to respond to
a collection of information; search data sources; complete and review
the collection of information; and transmit or otherwise disclose the
information.
An Agency may not conduct or sponsor, and a person is not required
to respond to a collection of information subject to OMB approval under
the PRA unless it displays a currently valid OMB control number. The
OMB control numbers for EPA's regulations, after initial publication in
the Federal Register, are maintained in a list at 40 CFR part 9.
Comments are requested on the Agency's need for this information,
the accuracy of the provided burden estimates, and any suggested
methods for minimizing respondent burden, including through the use of
automated collection techniques. Send comments on the ICR to EPA at the
address provided in the ``ADDRESSES'' section, with a copy to the
Office of Information and Regulatory Affairs, Office of Management and
Budget, 725 17th St., NW., Washington, DC 20503, marked ``Attention:
Desk Officer for EPA.'' Please remember to include the ICR number in
any correspondence. The final rule will respond to any comments on the
information collection requirements contained in this proposal.
E. Executive Order 12898
Pursuant to Executive Order 12898, entitled Federal Actions to
Address Environmental Justice in Minority Populations and Low-Income
Populations (59 FR 7629, February 16, 1994), the Agency has considered
environmental justice-related issues with regard to the potential
impacts of this proposed action on the environmental and health
conditions in low-income and minority communities. The Agency's
analysis found that non-white households are more likely to live in
housing with lead-based paint hazards, and their children are expected
to realize greater reductions in blood-lead levels if these hazards are
mitigated. As a result, non-white households are expected to bear more
of the costs of responding to the section 403 standards but also
receive more of the benefits. Lower- and upper-income households face
roughly the same response costs and are expected to receive the same
blood-lead reductions. Lower-income households would have to forego a
larger share of their income to respond to the section 403 standards
(Ref. 83).
F. Executive Order 13045
This proposed rule is subject to Executive Order 13045, entitled
Protection of Children from Environmental Health Risks and Safety Risks
(62 FR 19885, April 23, 1997), because OMB has determined that this is
an economically significant regulatory action as defined by Executive
Order 12866 (see section A. of this unit), and the Agency has reason to
believe that the environmental health or safety risk addressed by this
action may have a disproportionate affect on children. In accordance
with section 5(501) of Executive Order 13045, the Agency has evaluated
the environmental health or safety effects of lead-based paint on
children in the selection of the hazard standards contained in this
proposed rule. The results of this evaluation are contained in the
``Risk Analysis to Support Standards for Lead in Paint, Dust and Soil''
(Ref. 1), which is summarized and discussed in Unit IV. of this
preamble; a copy has been placed in the docket for this action.
Futhermore, the proposed regulation would help to prevent lead
poisoning
[[Page 30353]]
among young children by supporting the implementation of the national
lead program. Because exposure to lead in paint, dust, and soil is
mostly limited to children under the age of 6, young children are, in
fact, the primary beneficiaries of this proposed rule, as well as the
program.
G. National Technology Transfer and Advancement Act
This proposed regulatory action does not involve any technical
standards that would require Agency consideration of voluntary
consensus standards pursuant to section 12(d) of the National
Technology Transfer and Advancement Act of 1995 (NTTAA), Pub. L. 104-
113, section 12(d) (15 U.S.C. 272 note). Section 12(d) directs EPA to
use voluntary consensus standards in its regulatory activities unless
to do so would be inconsistent with applicable law or otherwise
impractical. Voluntary consensus standards are technical standards
(e.g., materials specifications, test methods, sampling procedures,
business practices, etc.) that are developed or adopted by voluntary
consensus standards bodies. The NTTAA requires EPA to provide Congress,
through OMB, explanations when the Agency decides not to use available
and applicable voluntary consensus standards. EPA invites public
comment on this conclusion.
List of Subjects in Part 745
Environmental protection, Hazardous substances, Lead-based paint,
Lead poisoning, Reporting and recordkeeping requirements.
Dated: May 26, 1998.
Carol M. Browner,
Administrator.
Therefore, it is proposed that 40 CFR part 745 be amended as
follows:
PART 745--[AMENDED]
1. The authority citation for part 745 continues to read as
follows:
Authority: 15 U.S.C. 2605, 2607, 2615, 2681-2692 and U.S.C.
4852d.
2. By adding new subpart D to read as follows:
Subpart D--Lead-Based Paint Hazards
Sec.
745.61 Scope and applicability.
745.63 Definitions.
745.65 Lead-based paint hazards.
745.69 Determining whether lead-based paint hazards are present.
Subpart D--Lead-Based Paint Hazards
Sec. 745.61 Scope and applicability.
(a) This subpart identifies lead-based paint hazards.
(b) The standards for lead-based paint hazards apply to target
housing and child-occupied facilities.
(c) Nothing in this subpart requires any person to evaluate the
property(ies) for the presence of lead-based paint hazards or to take
any action to control these conditions if one or more of them is
identified.
Sec. 745.63 Definitions.
The following definitions apply to this subpart.
Arithmetic mean means the algebraic sum of data values divided by
the number of data values (e.g., the sum of the concentration of lead
in several soil samples divided by the number of samples).
Certified risk assessor means an individual who has been trained by
an accredited training program, as defined by Sec. 745.223, and
certified by EPA pursuant to Sec. 745.226 or by an authorized State or
Tribal program to conduct risk assessments. A certified risk assessor
also samples for the presence of lead in dust and soil for the purposes
of abatement clearance testing.
Child-occupied facility means a building, or portion of a building,
constructed prior to 1978, visited regularly by the same child, 6 years
of age or under, on at least two different days within any week (Sunday
through Saturday period), provided that each day's visit lasts at least
3 hours and the combined weekly visit lasts at least 6 hours, and the
combined annual visits last at least 60 hours. Child-occupied
facilities may include, but are not limited to, day-care centers,
preschools, and kindergarten classrooms.
Deteriorated paint means paint that is cracking, flaking, chipping,
peeling, or otherwise separating from the substrate of a building
component.
Interior window sill means the portion of the horizontal window
ledge that protrudes into the interior of the room.
Lead-based paint means paint or other surface coatings that contain
lead equal to or exceeding 1.0 milligram per square centimeter or 0.5
percent by weight.
Lead-based paint hazard means hazardous lead-based paint, a dust-
lead hazard, or a soil-lead hazard as described in Sec. 745.65.
Paint in poor condition means more than 10 square feet of
deteriorated paint on exterior components with large surface areas; or
more than 2 square feet of deteriorated paint on interior components
with large surface areas (e.g., walls, ceilings, floors, doors); or
more than 10 percent of the total surface area of the component is
deteriorated on interior or exterior components with small surface
areas (e.g., window sills, baseboards, soffits, trim).
Risk assessment means an on-site investigation to determine the
existence, nature, severity, and location of lead-based paint hazards,
and the provision of a report by the individual or the firm conducting
the risk assessment, explaining the results of the investigation and
options for reducing lead-based paint hazards.
Target housing means any housing constructed prior to 1978, except
housing for the elderly or persons with disabilities (unless any one or
more children age 6 years or under resides or is expected to reside in
such housing for the elderly or persons with disabilities) or any 0-
bedroom dwelling.
Weighted arithmetic mean means the arithmetic mean of sample
results weighted by the number of subsamples in each sample. Its
purpose is to give influence to a sample relative to the number of
subsamples it contains. A single surface sample is comprised of a
single subsample. A composite sample may contain from two to four
subsamples. The weighted arithmetic mean is obtained by summing for all
samples, the product of the sample's result multiplied by the number of
subsamples in the sample, and dividing the sum by the total number of
subsamples contained in all samples. For example, the weighted
arithmetic mean of a single surface sample containing 60 g/
ft2, a composite sample (3 subsamples) containing 100
g/ft2, and a composite sample (4 subsamples)
containing 110 g/ft2 is 100 g/
ft2. This result is based on the equation
[60+(3*100)+(4*110)]/8.
Wipe sample means a sample collected by wiping a representative
surface of known area with an acceptable wipe material (e.g., moist
towelette).
Sec. 745.65 Lead-based paint hazards.
(a) Hazardous lead-based paint. Hazardous lead-based paint is lead-
based paint in poor condition.
(b) Dust-lead hazard. A dust-lead hazard is dust that contains lead
equal to or exceeding 50 g/ft2 on uncarpeted floors
or 250 g/ft2 on interior window sills based on wipe
samples.
(c) Soil-lead hazard. A soil-lead hazard is bare soil that contains
total lead equal to or exceeding 2,000 parts per million.
[[Page 30354]]
Sec. 745.69 Determining whether lead-based paint hazards or a soil-
lead level of concern are present.
(a) Applicability. This section applies to the following:
(1) Determining whether hazardous lead-based paint is present.
(2) Determining whether a dust-lead hazard is present on:
(i) Uncarpeted floors.
(ii) Interior window sills.
(3) Determining whether a soil-lead hazard is present.
(b) Work practice standards. Determinations of the presence of
lead-based paint hazards or a soil-lead level of concern must be made
by a certified risk assessor conducting a risk assessment according to
the applicable work practice standards at Sec. 745.227(d) and (h).
(c) Use of standards. (1) To determine whether a dust-lead hazard
is present, a certified risk assessor must compare the weighted
arithmetic means of uncarpeted floor dust samples and interior window
sill samples to the applicable standards in Sec. 745.65.
(2) To determine whether a soil-lead hazard is present, a certified
risk assessor must compare the arithmetic mean of soil samples to the
applicable standard in Sec. 745.65.
3. In Sec. 745.223, by alphabetically adding the following
definitions to read as follows:
Sec. 745.223 Definitions.
* * * * *
Arithmetic mean means the algebraic sum of data values divided by
the number of data values (e.g., the sum of the concentration of lead
in several soil samples divided by the number of samples).
* * * * *
Common area group means a group of common areas that are similar in
design, construction, and function. Common area groups include, but are
not limited to hallways, stairwells, and laundry rooms.
* * * * *
Concentration means the relative content of a specific substance
contained within a larger mass, such as the amount of lead (in
micrograms per gram or parts per million by weight) in a sample of dust
or soil.
* * * * *
Dripline means the area within 3 feet surrounding the perimeter of
a building.
* * * * *
Interior window sill means the portion of the horizontal window
ledge that protrudes into the interior of the room.
* * * * *
Loading means the quantity of a specific substance present per unit
of surface area, such as the amount of lead in micrograms contained in
the dust collected from a certain surface area divided by the surface
area in square feet or square meters.
* * * * *
Mid-yard means an area of a residential yard approximately midway
between the outermost edge of the dripline of a residential building
and the nearest property boundary or between the outermost edges of the
driplines of a residential building and another building on the same
property.
* * * * *
Residential building means a building containing one or more
residential dwellings.
* * * * *
Weighted arithmetic mean means the arithmetic mean of sample
results weighted by the number of subsamples in each sample. Its
purpose is to give influence to a sample relative to the number of
subsamples it contains. A single surface sample is comprised of a
single subsample. A composite sample may contain from two to four
subsamples. The weighted arithmetic mean is obtained by summing for all
samples, the product of the sample's result multiplied by the number of
subsamples in the sample, and dividing the sum by the total number of
subsamples contained in all samples. For example, the weighted
arithmetic mean of a single surface sample containing 60 g/
ft2, a composite sample (3 subsamples) containing 100
g/ft2, and a composite sample (4 subsamples)
containing 110 g/ft2 is 100 g/
ft2. This result is based on the equation
[60+(3*100)+(4*110)]/8.
Window trough means, for a typical double-hung window, the portion
of the exterior window sill between the interior window well (or stool)
and the frame of the storm window. If there is no storm window, the
window trough is the area that receives both the upper and lower window
sashes when they are both lowered. The window trough is sometimes
referred to inaccurately as the window ``well.''
Wipe sample means a sample collected by wiping a representative
surface of known area with an acceptable wipe material (e.g., moist
towelette).
4. In Sec. 745.227, by revising paragraphs (d)(4), (d)(5), (d)(6)
introductory text, (d)(7), (d)(8)(i), (e)(7)(i), (e)(8)(v)(A),
(e)(8)(v)(B), and (e)(8)(vii), by redesignating paragraphs (d)(11) as
paragraph (d)(12) and paragraph (h) as paragraph (i), and by adding
paragraphs (d)(11), (e)(8)(viii) and (h) to read as follows:
Sec. 745.227 Work practice standards for conducting lead-based paint
activities: target housing and child-occupied facilities.
* * * * *
(d) * * *
(4) Each surface with deteriorated paint, which is determined,
using documented methodologies, to be in poor condition and to have a
distinct painting history shall be tested for the presence of lead.
Each interior window sill determined, using documented methodologies,
to have a distinct painting history, shall also be tested for the
presence of lead in paint.
(5) In residential dwellings, dust samples (either composite or
single-surface samples) from the interior window sill(s) and floor
shall be collected in all living areas where one or more children, age
6 and under, are most likely to come into contact with dust.
(6) For multi-family dwellings and child-occupied facilities, the
samples required in paragraph (d)(4) of this section shall be taken. In
addition, interior window sill and floor dust samples (either composite
or single-surface samples) shall be collected in the following
locations:
* * * * *
(7) For child-occupied facilities, interior window sill and floor
dust samples (either composite or single-surface samples) shall be
collected in each room, hallway, or stairwell utilized by one or more
children, age 6 and under, and in other common areas in the child-
occupied facility where the certified risk assessor determines one or
more children, age 6 and under, are likely to come into contact with
dust.
(8) * * *
(i) Mid-yard areas where bare soil is present; and
* * * * *
(11) The certified risk assessor shall determine whether lead-based
paint hazards are present according to paragraph (h) of this section.
* * * * *
(e) * * *
(7) * * *
(i) If the soil is removed: (A) The soil shall be replaced by soil
that has a level of lead less than 400 ppm.
(B) The soil that is removed shall not be used as top soil at
another residential property or child-occupied facility.
[[Page 30355]]
* * * * *
(8) * * *
(v) * * *
(A) After conducting an abatement with containment between abated
and unabated areas, one dust sample shall be taken from one interior
window sill and window trough (if available) and one dust sample shall
be taken from the floors of no less than four rooms, hallways, or
stairwells within the containment area. In addition, one dust sample
shall be taken from the floor outside the containment area. If there
are less than four rooms, hallways, or stairwells within the
containment area, then all rooms, hallways, or stairwells shall be
sampled.
(B) After conducting an abatement with no containment, two dust
samples shall be taken from no less than four rooms, hallways, or
stairwells in the residential dwelling or child-occupied facility. One
dust sample shall be taken from one interior window sill and window
trough (if available) and one dust sample shall be taken from the floor
of each room, hallway, or stairwell selected. If there are less than
four rooms, hallways, or stairwells within the residential dwelling or
child-occupied facility, then all rooms, hallways, or stairwells shall
be sampled.
* * * * *
(vii) The certified inspector or risk assessor shall compare the
residual lead level (as determined by the laboratory analysis) from
each single surface dust sample with applicable clearance levels for
lead in dust on floors, interior window sills, and window troughs or
from each composite dust sample with the applicable clearance levels
for lead in dust on floors, interior window sills, and window troughs
divided by the number of subsamples in the composite sample. If the
residual lead level in a single surface dust sample equals or exceeds
the applicable clearance level or if the residual lead level in a
composite dust sample equals or exceeds the applicable clearance level
divided by the number of subsamples in the composite sample, all the
components represented by the failed sample shall be recleaned and
retested.
(viii) The clearance levels are 50 g/ft2 for
uncarpeted floors, 250 g/ft2 for interior window
sills, and 800 g/ft2 for window troughs.
* * * * *
(h) Determinations. (1) Hazardous lead-based paint is present on:
(i) All components that have paint in poor condition and that are
determined to contain lead-based paint.
(ii) All components that have paint in poor condition and that are
similar to and have a similar painting history to a tested component
that contains lead-based paint.
(2) A dust-lead hazard is present on:
(i) Uncarpeted floors and interior window sills when the weighted
arithmetic mean lead loading for all single surface or composite
samples of uncarpeted floors and interior window sills are equal to or
greater than 50 g/ft2 for uncarpeted floors and 250
g/ft2 for interior window sills;
(ii) Uncarpeted floors or interior window sills in an unsampled
residential dwelling unit in a multi-family dwelling, if a dust-lead
hazard is present on uncarpeted floors or interior window sills,
respectively, in at least one sampled residential unit on the property.
(iii) uncarpeted floors or interior window sills in an unsampled
common area in a multi-family dwelling, if a dust-lead hazard is
present on uncarpeted floors or interior window sills, respectively, in
at least one sampled common area in the same common area group on the
property.
(3) A soil-lead hazard is present when the arithmetic mean lead
concentration from a composite sample (or arithmetic mean of composite
samples) from the dripline and a composite sample (or arithmetic mean
of composite samples) from the mid-yard for each residential building
on a property is equal to or greater than 2,000 parts per million.
5. In Sec. 745.325, by revising paragraphs (d)(2)(iii), by
redesignating (d)(2)(iv) and (d)(2)(v) as (d)(2)(v) and (d)(2)(vi),
respectively, and by adding paragraphs (d)(2)(iv) and (e), to read as
follows:
Sec. 745.325 Lead-based paint activities: State and Tribal program
requirements.
* * * * *
(d) * * *
(2) * * *
(iii) Risk assessments consist of at least:
(A) An assessment, including a visual inspection, of the physical
characteristics of the residential dwelling or child-occupied facility;
(B) Environmental sampling for lead in paint, dust, and soil;
(C) Environmental sampling requirements for lead in paint, dust,
and soil that allow for comparison to the lead-based paint hazard
standards established or revised by the State or Indian Tribe pursuant
to paragraph (e) of this section; and
(D) A determination of the presence of lead-based paint hazards
made by comparing the results of visual inspection and environmental
sampling to the lead-based paint hazard standards established or
revised by the State or Indian Tribe pursuant to paragraph (e) of this
section.
(iv) The program elements required in Sec. 745.325(d)(2)(iii)(C)
and (D) shall be adopted in accordance with the schedule for the
demonstration required in paragraph (e) of this section.
(v) * * *
* * * * *
(e) The State or Indian Tribe must demonstrate that it has lead-
based paint hazards standards, and clearance standards for dust, that
are at least as protective as the standards in Sec. 745.227 as amended
on [Insert date of promulgation of the final rule]. A State or Indian
Tribe with such a section 402 program approved before [Insert date 2
years following date of promulgation of the final rule] shall make this
demonstration no later than the first report submitted pursuant to
Sec. 745.324(h) after [Insert date 2 years following date of
promulgation of the final rule]. A State or Indian Tribe with such a
program submitted but not approved before [Insert date 2 years
following date of promulgation of the final rule] may make this
demonstration by amending its application or in its first report
submitted pursuant to Sec. 745.324(h). A State or Indian Tribe
submitting its program on or after [Insert date 2 years following date
of promulgation of the final rule] shall make this demonstration in its
application.
[FR Doc. 98-14736 Filed 6-2-98; 8:45 am]
BILLING CODE 6560-50-F