Superfund: How States Establish and Apply Environmental Standards When
Cleaning Up Sites (Fact Sheet, 03/20/96, GAO/RCED-96-70FS).
Pursuant to a congressional request, GAO provided information on how
states establish and apply environmental standards when cleaning up
Superfund sites, focusing on whether states: (1) base their standards on
human health risks; and (2) provide flexibility so that the level of
cleanup can be adjusted according to the extent of contamination.
GAO found that: (1) 20 of the 21 states reviewed base their hazardous
waste site standards on the danger posed to human health, and the cost
and technical feasibility of achieving them; (2) states base their
groundwater standards on existing federal drinking water standards; (3)
when states set their environmental standards at levels other than the
federal limit, they tend to be more stringent; (4) states provide more
flexibility in adjusting the cleanup level when the cleanup involves
soil pollution rather than groundwater pollution, in order to reflect a
particular site's condition and health risk; (5) more than half of the
states with soil standards regularly allow their cleanup levels to be
adjusted for site-specific conditions; (6) less than one-fourth of the
states with groundwater standards allow their cleanup levels to be
adjusted; and (7) those states not allowing cleanup level adjustments
view their groundwater as a potential source of drinking water and
implement different standards, depending on the projected use of land or
groundwater.
--------------------------- Indexing Terms -----------------------------
REPORTNUM: RCED-96-70FS
TITLE: Superfund: How States Establish and Apply Environmental
Standards When Cleaning Up Sites
DATE: 03/20/96
SUBJECT: Environmental monitoring
Health hazards
State-administered programs
Standards evaluation
Water quality
Safety standards
Hazardous substances
Potable water
Pollution control
Water pollution control
IDENTIFIER: Superfund Program
EPA National Priorities List
EPA Integrated Risk Information System
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Cover
================================================================ COVER
Report to Congressional Committees
March 1996
SUPERFUND - HOW STATES ESTABLISH
AND APPLY ENVIRONMENTAL STANDARDS
WHEN CLEANING UP SITES
GAO/RCED-96-70FS
States' Environmental Standards
(160305)
Abbreviations
=============================================================== ABBREV
ARAR - applicable or relevant and appropriate requirement
EPA - Environmental Protection Agency
GAO - General Accounting Office
CERCLA - Comprehensive Environmental Response, Compensation,
and Liability Act of 1980, as amended by SARA
HEAST - Health Effects Assessment Summary Tables
IRIS - Integrated Risk Information System
MCL - maximum contaminant level
NPL - National Priorities List
PCB - polychlorinated biphenyl
SARA - Superfund Amendments and Reauthorization Act of 1986
Letter
=============================================================== LETTER
B-270973
March 20, 1996
The Honorable Bud Shuster
Chairman
The Honorable James L. Oberstar
Ranking Minority Member
Committee on Transportation and Infrastructure
House of Representatives
The Honorable Sherwood L. Boehlert
Chairman
The Honorable Robert A. Borski
Ranking Minority Member
Subcommittee on Water Resources and Environment
Committee on Transportation and Infrastructure
House of Representatives
During the current debate on reauthorizing the Superfund program, one
issue is whether to revise or eliminate the existing law's
requirement that cleanups of hazardous waste sites comply with
federal and certain state standards to protect public health and the
environment. Among these standards are numeric limits on the
concentrations of toxic chemicals in the environment, which were
intended to ensure an adequate level of protection for public health.
(See sec. 1 for more background information on standards.) Those
responsible for cleaning up Superfund sites, however, have raised
concerns that complying with these standards can result in more
extensive and costlier cleanups than are necessary to safeguard
public health. One criticism is that states, when setting standards,
may choose stringent limits that are not based on a consideration of
the human health risks posed by contaminants. Another concern is
that using standards to determine the extent of cleanup does not
allow a consideration of specific sites' conditions, such as the
local climate, that may increase or decrease the health risks posed.
As background for your deliberations on the use of standards as
requirements for cleanups, you asked us to provide information on the
bases for states' standards. Specifically, you asked us to determine
whether states, (1) when setting numeric standards, based them on
estimates of the human health risks posed by exposure to contaminants
and, (2) when using such standards, provided the flexibility to
adjust the level of cleanup prescribed by the standards to take into
account the conditions and risks found at individual hazardous waste
sites. You also expressed interest in the degree of correspondence
between the states' standards and the federal standards that may be
applied to the cleanup of groundwater determined to be a potential
source of drinking water. We summarized preliminary information on
these matters in a June 1995 testimony\1 and are now presenting our
final results.
In conducting our work, we surveyed the 33 states with the greatest
number of Superfund sites, which together covered 91 percent of the
sites on the Environmental Protection Agency's (EPA) nationwide list
of the hazardous waste sites posing the greatest risks to human
health and the environment. We asked these states about their
standards for soil and groundwater because these are the two media
most frequently cleaned up at Superfund sites. We also limited our
focus to chemical-specific standards that set numeric limits on
concentrations of chemicals in order to protect public health.\2
Twenty-one of the surveyed states had established such standards for
soil, groundwater, or both.\3 In all, 13 states had set soil
standards, while 20 had set groundwater standards; about half of the
21 states had set both types of standards. (See app. I for more
information on our objectives, scope, and methodology and app. II
for a listing of the surveyed states that had set standards.)
In summary, we found the following:
When developing their standards, 20 of the 21 states told us that
they had based them, at least in part, on estimates of the human
health risks posed by exposure to chemical waste. For example,
they considered the increased probability that a person would
develop cancer or another illness from such exposure. These
states either adopted existing federal standards that were based
on such risk estimates or developed their own standards, taking
risk into account. Most of the 20 states said that in addition
to health risks, they considered other factors in setting their
standards, such as the cost and technical feasibility of
achieving the necessary cleanup. When setting their standards
for groundwater used as drinking water, the states typically
based them on the federal drinking water standards. However, we
found that some states had set some of their standards at levels
that differed from the levels in the federal standards. These
differing standards tended to be more stringent than the federal
standards. (See sec. 2 for a more detailed discussion of the
bases for the states' soil and groundwater standards.)
When applying their standards to determine the extent of the
cleanup needed at a Superfund site, the states in our survey
said that they provided more flexibility to adjust the cleanup
level derived from their soil standards than from their
groundwater standards, to reflect the specific conditions and
health risks at that site. More than half of the states with
soil standards regularly allowed the cleanup levels based on
these standards to be adjusted for site-specific conditions,
such as the amount of exposure to the contaminants that people
are likely to have. In contrast, less than a fourth of the
states with standards for groundwater that is or could be used
as drinking water said that they allowed the cleanup levels
based on these standards to be adjusted. This relative
inflexibility reflected the states' concerns that groundwater be
conserved as a potential source of drinking water. Some of the
states that did not allow such adjustments did provide a degree
of flexibility by setting different standards for different
projected uses of land or groundwater. (See sec. 3 for a more
detailed discussion of the extent to which the states said that
they were flexible in applying soil and groundwater standards.)
--------------------
\1 Superfund: EPA's Use of Risk Assessments in Cleanup Decisions
(GAO/T-RCED-95-231, June 22, 1995).
\2 Other standards, such as those intended to protect the
environment, could also be considered when deciding on the extent of
a site's cleanup.
\3 We counted a state as having standards if it had established or
proposed--in law, regulation, policy, or guidance--numeric limits on
the concentrations of chemicals allowable in soil or groundwater. We
did not count a state as having groundwater standards if it had
simply adopted the federal drinking water standards. About one-third
of the states that had not set their own soil standards said that
they use risk assessments to develop cleanup levels for soil on a
site-specific basis. About half of the states that did not have
groundwater standards said that they had used the federal drinking
water standards to set cleanup levels for groundwater.
---------------------------------------------------------- Letter :0.1
We based our analysis on the results of telephone interviews we
conducted with the 33 states surveyed and a review of background
documents on standards and risk assessment. To verify our analysis,
we gave each state a written summary to review and made any necessary
changes. We also provided copies of a draft of this report to EPA
officials, including the Director of the Office of Emergency and
Remedial Response and officials responsible for working with state
Superfund programs, for their review and comment. EPA generally
agreed with the report and provided several technical changes and
clarifications on the Superfund law's requirements for cleanups,
which we incorporated. We conducted our work from March 1995 through
March 1996 in accordance with generally accepted government auditing
standards.
As arranged with your offices, unless you announce its contents
earlier, we plan no further distribution of this report until 10 days
after the date of this letter. At that time, we will send copies to
the appropriate congressional committees, the Administrator of EPA,
and other interested parties. We will also make copies available to
others on request.
Please call me at (202) 512-6112 if you or your staff have any
questions. Major contributors to this report are listed in appendix
III.
Peter F. Guerrero
Director, Environmental
Protection Issues
BACKGROUND
============================================================ Chapter 1
Under the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA), which created the Superfund program in 1980,
the Environmental Protection Agency (EPA) assesses uncontrolled
hazardous waste sites and places those posing the greatest risks to
human health and the environment on the National Priorities List
(NPL) for cleanup. As of September 1995, this list included 1,232
sites.
Cleanup standards and the degree of cleanup needed for Superfund
sites are discussed in section 121(d) of the CERCLA statute, as
amended by the Superfund Amendments and Reauthorization Act of 1986
(SARA). This section requires that Superfund sites be cleaned up to
the extent necessary to protect both human health and the
environment. In addition, cleanups must comply with requirements
under federal environmental laws that are legally "applicable" or
"relevant and appropriate" (ARAR) as well as with such state
environmental requirements that are more stringent than the federal
standards. Furthermore, Superfund cleanups must at least attain
levels established under the Safe Drinking Water Act and the Clean
Water Act, where such standards are relevant and appropriate as
determined by the potential use of the water and other
considerations.
The federal standards most frequently considered relevant and
appropriate for groundwater cleanups at Superfund sites are set under
the Safe Drinking Water Act. This act establishes standards, called
maximum contaminant levels (MCL), for certain contaminants in water
delivered by public drinking water systems. As of March 1996, the
MCLs included numeric limits on about 70 contaminants. The MCLs take
into account estimates of the human health risks posed by
contaminants. They also consider whether it is technically and
economically feasible to reduce the contamination to a level that no
longer poses a health risk. Although MCLs are legally applicable to
drinking water systems, section 121(d) of CERCLA generally requires
that they be considered relevant and appropriate standards for
cleaning up contaminated groundwater that is a potential source of
drinking water. For example, the MCL for benzene is 5 micrograms per
liter. This concentration would generally be the cleanup level for
benzene in groundwater that is a potential source of drinking water
unless the state has promulgated a more stringent standard or other
requirement that is relevant and appropriate.
There are few federal standards for contaminants in soil that are
considered potentially applicable or relevant and appropriate except
those for certain highly toxic contaminants, most notably
polychlorinated biphenyls (PCB) and lead. Under the Toxic Substances
Control Act, EPA sets requirements for cleaning up PCB contamination.
In addition, EPA has issued guidance for cleaning up lead in soil.
Early in its investigation of a site, EPA determines, on the basis of
the contamination present and the conditions at the site, which
chemical-specific and other standards may be considered applicable or
relevant and appropriate. As EPA proceeds with the selection of a
cleanup method, it adjusts the list of standards to be considered on
the basis of information gained during its investigation. Among the
potential standards considered are any state environmental standards
that are more stringent than the federal standards for the same
contaminants.
In addition to numeric standards for specific contaminants, some
states have set more generalized standards or policies that may have
to be considered when cleaning up Superfund sites. For example, some
states have established "antidegradation" policies for groundwater
that could require more stringent cleanups than cleanups based on
health risks. These policies are intended, among other things, to
protect the state's groundwater as a potential source of drinking
water.
If federal or state standards do not exist for a given contaminant,
the party responsible for cleaning up a Superfund site may use a
site-specific risk assessment to help establish a cleanup level for
that contaminant. A risk assessment evaluates the extent to which
people may be exposed to the contaminant, given its concentration and
the physical characteristics of the site. For example, the type of
soil and the depth of the groundwater may affect whether and how
quickly waste will migrate and reach a population. A risk assessment
uses exposure and toxicity data to estimate the increased
probability, or risk, that people could develop cancer or other
health problems through exposure to this contamination. A risk
estimate can be used along with the proposed waste management
strategy to help determine the extent of the cleanup necessary at a
site.
EPA has published guidance for conducting risk assessments, a set of
documents referred to collectively as the Risk Assessment Guidance
for Superfund. These documents outline the well-established risk
assessment principles and procedures that can be used to gather and
assess information on human health risks. The documents also include
information on mathematical models that can be used to estimate
health risks at a site, given the contaminants present and the means
of exposure to them. In addition to this guidance, EPA maintains an
Integrated Risk Information System (IRIS), an on-line database on the
toxicity of numerous chemicals, and publishes the Health Effects
Assessment Summary Tables (HEAST), another source of information on
contaminants' toxicity. EPA uses this guidance in conducting
baseline risk assessments at Superfund sites, which it uses in
deciding whether the human health and environmental risks posed by
the contaminants are serious enough to warrant cleaning up the sites.
Some states also use EPA's risk assessment guidance in setting their
standards for specific chemicals.
THE BASES STATES USED IN
DEVELOPING STANDARDS
============================================================ Chapter 2
States that have set environmental standards have made decisions
about what levels, or concentrations, of chemical contaminants can
remain at hazardous waste sites after cleanups. We analyzed the
processes that the states in our survey said they went through, as
well as the factors that they said they took into consideration, in
developing their soil and groundwater standards. In this section, we
first summarize (1) the extent to which the states based their soil
standards on estimates of the human health risks posed by
contaminants at the sites and (2) the methods that the states used to
estimate these risks. We then report on the factors other than
health risks that the states said they considered when developing
their soil standards. Since the bases for the states' standards for
groundwater differed somewhat from those for soil, we summarized the
information on groundwater standards separately. Finally, since
federal drinking water standards are frequently used as cleanup
standards for groundwater, we compared the states' groundwater
standards to the federal standards for the same contaminants to
determine the extent of their correspondence.
We have included the information we obtained from the 33 states in
our survey. In all, 21 of the 33 states had set their own standards
for either soil or groundwater, or for both media.\4
(See table 2.1.)
Table 2.1
Number of States in Our Survey With
Their Own Cleanup Standards
Type of standards Number of states\a
-------------------------------------------------- ------------------
States with either soil or groundwater standards 21
or with both types of standards
States with soil standards 13
States with groundwater standards 20
----------------------------------------------------------------------
\a Our survey included 33 states, which encompass 91 percent of the
sites on EPA's list of the most contaminated sites in the nation.
Thirteen of the 21 states had set their own soil standards, and 20
had set some groundwater standards that were in addition to or
different from the MCLs for drinking water, as discussed in the
remainder of this section.
--------------------
\4 This report represents the status of the states' standards at the
time of our survey. For example, several states explained that they
had modified their standards within the last year, and six told us
that they were developing or considering whether to develop soil
standards. EPA officials working with the states on cleanups pointed
out that some states' standards have evolved and are less stringent
now than they were formerly.
CONSIDERATION OF HEALTH RISKS
IN SETTING SOIL STANDARDS
---------------------------------------------------------- Chapter 2:1
All 13 of the states with soil standards indicated that they
considered risks to human health when developing their standards.
The number of chemical-specific standards per state ranged from about
10 to nearly 600. All but one of these states generally relied on
EPA's guidance for estimating health risks from contaminants
(Missouri had developed its soil standards before EPA issued its
guidance). These states said that they had used EPA's guidance,
either alone or in combination with their own methodologies and
policies, to estimate health risks. (See table 2.2.) For example,
Pennsylvania said that it had used EPA's guidance to estimate the
toxicity of contaminants and its own model to estimate how much
contamination from the soil might travel into groundwater. These
estimates are two of the major components in the health risk
calculation.
Table 2.2
Health Considerations Used by 13 States
in Developing Their Own Soil Standards
Health considerations Number of states
-------------------------------------------------- ------------------
Use of EPA's guidance to estimate human health
risk
States used EPA's guidance only 3
States used both EPA's guidance and their own
methodology 9
State developed its standards before EPA issued
its guidance 1
Level of carcinogenic risk that states would allow
at a site after cleanup\a
States used a 1-in-100,000 increased probability
that exposure would cause cancer 5
States used a 1-in-1-million increased probability
that exposure would cause cancer 8
Concentration of contaminants causing other health
effects that states would allow to remain on site
States used a measure equivalent to EPA's 11
States used a more stringent measure than EPA 2
----------------------------------------------------------------------
\a EPA uses a range of risk levels between 1 in 10,000 and 1 in 1
million; the states all used risk levels within this range.
Even after a cleanup, contaminants remaining at a site will pose some
level of risk to human health. Therefore, the states, when setting
standards for contaminants in soil, had to decide what level of risk
they would allow to remain after a cleanup. For contaminants that
can cause cancer, or carcinogens, the states had to determine an
acceptable level of risk, or increased probability, that an
individual would develop cancer from a lifetime's exposure to the
remaining contamination. All 13 states generally chose risk levels
that fell within the range of increased probability that EPA uses at
Superfund sites, which extends from 1 in 10,000 to 1 in 1 million.
As shown in table 2.2, eight states chose the more stringent risk
level of 1 in 1 million for individual carcinogens in soil, while
five states chose the somewhat less stringent risk level of 1 in
100,000.\5
For noncarcinogens in soil, 11 states used the same measure that EPA
uses at Superfund sites, while 2 states used a somewhat more
stringent measure.
--------------------
\5 Some states chose different risk levels for different
contaminants. For example, a state may have used a 1-in-1-million
risk level for a contaminant linked by strong evidence to cancer in
humans, while using a 1-in-100,000 risk level for other carcinogens.
In these cases, we categorized the state as generally using a
1-in-1-million risk level.
CONSIDERATION OF OTHER FACTORS
IN SETTING SOIL STANDARDS
---------------------------------------------------------- Chapter 2:2
Ten of the 13 states considered factors in addition to health risks
when setting their soil standards. As a result, their standards
could be either more or less stringent than those based solely on
estimates of health risks. These other factors included the
following:
Chemical levels that occur naturally in the environment. In some
locations, certain contaminants may exist naturally in the soil
in concentrations differing from those that would be allowed
under standards based on risks to human health. For such
contaminants, the states typically set their standards at the
naturally occurring levels rather than at the levels based
solely on risk. In some cases, this practice would result in
less stringent cleanups than would be necessary to meet the
risk-based standards. However, since some chemicals do not
occur naturally in the environment, this practice would in some
instances result in more stringent cleanups than would otherwise
be required.
Detection limits and practical quantification limits. When the
concentrations of some contaminants that could remain in the
soil without posing health risks fell below the levels that can
be accurately measured or detected by current technology, the
states said that they typically adopt less stringent, but
measurable, concentrations as their standards.
Secondary, or aesthetic, criteria. Some chemicals cause unpleasant
odors or other problems at levels that do not pose human health
risks. The states may set their standards for these chemicals
below risk-based levels to protect the public from such
problems.
CONSIDERATION OF HEALTH RISKS
IN SETTING GROUNDWATER
STANDARDS
---------------------------------------------------------- Chapter 2:3
Twenty of the 33 states we surveyed said that they had set some
chemical-specific standards that would limit the concentrations of
various toxic chemicals that could be present in groundwater at
Superfund sites. These states not only adopted some of the existing
federal standards, such as MCLs, but also set some standards in
addition to or different from them. The number of chemical-specific
standards per state ranged from about 30 to nearly 600. While the
remaining states that we surveyed had not developed any of their own
groundwater standards, the federal MCLs are typically used as
Superfund cleanup standards for groundwater.
Nineteen of the 20 states had based their groundwater standards, at
least in part, on estimates of the human health risks posed by
exposure to chemical contaminants. (See table 2.3.)
Table 2.3
Health Risk as the Basis for States'
Groundwater Standards in States Surveyed
States' use of health risk estimates to develop Number of
standards states
-------------------------------------------------- ------------------
States had set some of their own groundwater 20
standards
States developed their own risk estimates for some 16
of their standards
States predominantly adopted others' standards 3
based on health risks
State had no historical information on the 1
development of its standards
----------------------------------------------------------------------
In the remaining state, none of the officials currently involved in
implementing the standards could provide historical information on
how the standards had been developed. Sixteen of the states had
calculated their own health risk estimates when setting the standards
for at least some of the contaminants. Three of the states had not
predominantly developed their own estimates but had instead adopted
standards developed by others, including some or all of the MCLs,
that were based on estimates of health risks.
All 16 states that had developed formulas for calculating human
health risks had used guidance from EPA on how to estimate such
risks, either alone or in combination with their own procedures and
formulas. (See table 2.4.) In setting their standards, 13 of these
states used a risk level of 1 in 1 million for individual
carcinogens, while 3 states used the less stringent risk level of 1
in 100,000. For individual noncarcinogens, 15 states used a measure
that was as stringent as EPA's, while 1 state used a more stringent
measure.
Table 2.4
Health Considerations Used by 13 States
in Developing Their Own Groundwater
Standards
Health considerations Number of states
-------------------------------------------------- ------------------
Use of EPA's guidance to estimate human health
risk
States used EPA's guidance only 7
States used both EPA's guidance and their own 9
methodology
Level of carcinogenic risk that states would allow
at a site after cleanup\a
States used a 1-in-100,000 increased probability 3
that exposure would cause cancer
States used a 1-in-1-million increased probability 13
that exposure would cause cancer
Concentrations of contaminants causing other
health effects that states would allow to remain
on site
States used a measure equivalent to EPA's 15
States used a more stringent measure than EPA 1
----------------------------------------------------------------------
\a EPA uses a range of risk levels between 1 in 10,000 and 1 in 1
million; the states all used risk levels within this range.
CONSIDERATION OF OTHER FACTORS
IN SETTING GROUNDWATER
STANDARDS
---------------------------------------------------------- Chapter 2:4
All but 2 of these 16 states said that they had considered factors in
addition to human health risks when setting their groundwater
standards. Taking such factors into account can affect the
concentration of a chemical that a state will allow to remain under
its standard. As a result, a standard may be either more or less
stringent than one based solely on human health risks.
For groundwater as for soil, these factors included the levels of
chemical contaminants that occur naturally in the environment and
secondary, or aesthetic, factors, such as the taste and color of
drinking water. They also included the following:
Cost and technical feasibility. If achieving the cleanup level
required by a standard based on human health risk would be too
costly or technically infeasible, then some states would set the
standard at a less stringent level. Similarly, EPA takes cost
and technical feasibility into account when setting some federal
standards.
Groundwater protection policies/laws. Some states have adopted
conservative laws or policies to protect groundwater as a
potential source of drinking water. For example, some states
have "antidegradation" policies that, for chemicals that do not
occur naturally in the environment, may require more stringent
cleanups than would be required solely on the basis of risk.
DIFFERENCES BETWEEN THE STATES'
GROUNDWATER STANDARDS AND THE
FEDERAL MCLS
---------------------------------------------------------- Chapter 2:5
Because the federal MCLs are typically used as cleanup standards for
groundwater used as drinking water at Superfund sites and many of the
states based some of their own groundwater standards on the federal
MCLs, we compared the states' standards for contaminants to the
corresponding MCLs. We found that if a federal MCL existed for a
chemical that was included in a state's standards, the state usually
set its standard at this level. However, a majority of the states
had standards for a few chemicals that differed from the MCLs. These
standards tended to be more stringent than the MCLs.
The states offered a variety of explanations for why their standards
were more stringent than the federal MCLs. Two states set more
stringent levels for certain contaminants if they could detect the
contaminants at levels below the MCLs. Several states reported that
some of their standards were more stringent because these standards
had not been adjusted, as the MCLs had been, for other factors, such
as cost or technical feasibility.
Some states' standards may also have been more stringent because the
states had antidegradation policies for groundwater. For example,
Wisconsin mandates that the environment be restored to the extent
practicable. Consequently, it has set "preventive action limits" for
contaminants in groundwater that may be used to determine the extent
of the cleanup required at Superfund sites unless it can be shown
that meeting such limits would not be technically or economically
feasible. All of the preventive action limits are more stringent
than the corresponding federal MCLs. They limit the concentrations
of chemicals that can cause cancer to one-tenth the concentrations
allowed under the MCLs, and they limit the concentrations of
chemicals that can cause other health effects to one-fifth the
concentrations allowed under the MCLs. However, the state allows
exemptions for contaminants that occur naturally at levels exceeding
the preventive action limits.
Nearly all of the states had only a few, if any, standards for
contaminants that were less stringent than the corresponding federal
MCLs. However, under SARA, only those numeric standards that are
more stringent than the federal standards are to be considered as
cleanup levels at Superfund sites.
THE FLEXIBILITY STATES PROVIDED IN
APPLYING STANDARDS TO CLEANUPS
============================================================ Chapter 3
Even though the states have set environmental standards, they have
found that applying these standards uniformly to all sites may not be
effective because conditions can vary from one hazardous waste site
to another. As a result, sites may pose different levels of health
risks and may, therefore, require different degrees of cleanup. We
examined whether the states (1) allow the level of cleanup determined
to be necessary under their standards to be adjusted to take into
account site-specific conditions and (2) set different standards for
different uses of the land or groundwater (e.g., set more stringent
cleanup standards for land that could be used for residential than
for industrial purposes). Overall, the states provided more
flexibility in applying their soil standards than their groundwater
standards.
FLEXIBILITY TO ADJUST CLEANUP
LEVELS BASED ON SOIL STANDARDS
TO ACCOUNT FOR SITE-SPECIFIC
CONDITIONS
---------------------------------------------------------- Chapter 3:1
Eight of the 13 states that had soil standards indicated that they
allow the extent of the cleanup deemed necessary under their
standards to be adjusted for site-specific factors. For example:
Georgia's risk reduction standards include the option of
determining cleanup target concentrations for contaminants on
the basis of site-specific risk assessments.
Minnesota characterized its standards as "quick reference numbers,"
rather than fixed limits, that are considered when determining
how extensively to clean up a site. Thus, cleanup levels can be
tailored to local conditions. For example, if exposure to
contaminants in soil were reduced or eliminated because the soil
was inaccessible, the cleanup levels would not need to meet the
standards. Alternatively, if multiple contaminants with the
same toxic effect were found at the same location, the cleanup
level for each individual contaminant might be more stringent
than the standard.
Pennsylvania said that it has developed interim standards pending
final regulations for about 100 soil contaminants but considers
these to be "worst case" numbers that can be adjusted to reflect
site-specific conditions.
In contrast, the remaining five states said that, in general, their
soil standards were fixed limits on the concentrations of
contaminants that must be met when cleaning up a site. While
adopting relatively inflexible standards, these five states said that
they do provide for certain exceptions under limited circumstances.
For example, one state mentioned that it did not require that soil
lying beneath a building be cleaned up to comply with the standards
because the building would prevent people's exposure to the
contaminated soil. Alternatively, under certain conditions, some
states allow cleanups to be based on site-specific risk assessments.
Three of these states also said that they permitted less stringent
cleanup levels than those based on their standards if meeting them
was not technologically feasible or if naturally occurring levels of
chemicals in the local environment were higher than the levels set by
the standards. However, the use of such alternatives was the
exception rather than the rule.
Some of the states also indicated that even if they do not provide
much flexibility in applying their standards, they may permit
flexibility in determining how to achieve the required level of
protection. For example, instead of requiring costly incineration of
contaminated soil to meet its standards, a state may allow the area
to be covered with a clay cap so that people cannot come into contact
with the contaminants.
DIFFERENT SOIL STANDARDS FOR
DIFFERENT LAND USES OR
EXPOSURES
---------------------------------------------------------- Chapter 3:2
The states may also provide flexibility by establishing different
standards for different projected uses of the land at a site. Ten of
the 13 states with soil standards told us they had set such
standards. For example, Michigan said that it had defined soil
standards for three types of land uses: residential, industrial, and
commercial (with two subcategories). Generally, the more stringent
standards apply to residential property, since people are more likely
to be exposed to contaminants for a longer period of time on
residential property than on other types of property.
FLEXIBILITY TO ADJUST CLEANUP
LEVELS BASED ON GROUNDWATER
STANDARDS TO ACCOUNT FOR
SITE-SPECIFIC CONDITIONS
---------------------------------------------------------- Chapter 3:3
While most states allowed flexibility in their cleanup levels for
soil, the states were less flexible in setting cleanup levels for
groundwater. The degree of flexibility largely depended on whether
the groundwater was considered a potential source of drinking water.
Only 4 of the 20 states with groundwater standards said that they
regularly allowed the cleanup levels for groundwater used as drinking
water to be based on site-specific considerations. Texas, for
example, incorporated this option in one of its cleanup strategies:
Texas reported that it has three alternative "risk reduction"
standards, any one of which can be used to clean up a site, with
the state's approval. Cleanups under the first of these
standards must ensure that the levels of contamination are no
higher than the levels that occur naturally in the environment.
Cleanups under the second standard must meet fixed limits set by
the state, including federal MCLs that the state has adopted,
and place a notice in deed records to inform future property
owners of any contamination left on the property. Cleanups
under the third standard must also use federal MCLs when
available, but for contaminants without corresponding MCLs,
site-specific risk-based cleanup levels can be determined on the
basis of the site's projected use. The third standard also
requires deed notification.
The remaining 16 states indicated that, in general, for groundwater
used as drinking water or considered potentially usable as drinking
water, their standards were fixed limits that must be achieved during
cleanup. Most of these states did say, though, that they allowed
certain limited exceptions to their standards or the use of a
site-specific risk assessment under some circumstances. For example,
if the contaminated water came from an area where the contamination
would not immediately threaten communities, a state might let the
contamination be reduced naturally over time rather than require that
it be cleaned up immediately.
The states gave various reasons for the relative inflexibility of
their groundwater standards for drinking water. First, some of the
states said that they were mirroring the federal MCLs for drinking
water, which are also fixed limits. Some of the states also noted
that, as discussed in section 2, they consider groundwater that may
possibly be used as drinking water as a valuable resource that needs
to be conserved.
DIFFERENT STANDARDS FOR
DIFFERENT USES OF GROUNDWATER
---------------------------------------------------------- Chapter 3:4
Although the states in our survey told us that their standards for
groundwater used as drinking water are relatively fixed, some states
also reported that they provided some degree of flexibility by not
classifying all groundwater as drinking water. They also set less
stringent standards for groundwater that would not be considered a
potential source of drinking water. For example, Connecticut's
groundwater classification system acknowledges that in certain areas,
such as those that have had long-term industrial or commercial use,
the groundwater would not be a suitable source of drinking water
unless it were treated. The state does not usually require that the
groundwater in such areas be cleaned up to the standards for drinking
water. Also, some states do not classify groundwater as drinking
water if it has a high mineral content or if it is located in a
geological formation that does not yield much water.
Twelve of the 20 states with groundwater standards said that they set
different standards for different current or potential uses of
groundwater. Thus, these states set separate standards for
groundwater used for agricultural purposes, groundwater of special
ecological significance (e.g., supporting a vital wetland), and
groundwater in urban, industrial, or commercial areas.\6
Seven of these 12 states indicated that site-specific factors can be
taken into account when determining the extent of the cleanup needed
for these other types of groundwater. For example, Rhode Island told
us that it allows the cleanup levels for some contaminants to differ
from the levels set in its standards. For example, vapors escaping
from volatile organic chemicals in the groundwater could accumulate
in overlying buildings and cause potential health effects. In some
cases, these vapors could build up and cause threats of explosion.
In setting its "urban" groundwater standards, this state
conservatively assumed that the buildings would not be ventilated and
that the vapors from the underlying groundwater would be trapped in
the buildings. However, in deciding how extensively to clean up a
site, the state allows for a consideration of site-specific factors,
such as depths to groundwater. When site-specific factors are
considered, the cleanup levels may not need to be as stringent as the
standards alone would require.
--------------------
\6 While another five states exempted some of their groundwater from
meeting drinking water standards, these states did not set other
standards for the exempt water.
OBJECTIVES, SCOPE, AND METHODOLOGY
=========================================================== Appendix I
The Chairmen and Ranking Minority Members of the House Committee on
Transportation and Infrastructure and its Subcommittee on Water
Resources and Environment asked us to determine whether states (1)
when setting numeric standards for cleanups at hazardous waste sites,
based them on estimates of the human health risks posed by exposure
to contamination and (2) when using standards, provide the
flexibility to adjust the level of cleanup prescribed by the
standards to take into account the conditions and risks found at
individual waste sites.
To accomplish these objectives, we conducted a telephone survey of 33
states, receiving a response rate of 100 percent. We selected these
states because they included approximately 91 percent of the sites
that the Environmental Protection Agency (EPA) had included on its
National Priorities List (NPL) as of April 1995. We obtained
information for standards for contaminants in soil and groundwater,
the two media most frequently cleaned up at Superfund sites. (See
app. II for a list of the states, the number of NPL sites in each
state, the types of standards in each state, and the types of
authority for the standards.)
We defined standards as limits on the concentrations of toxic
chemicals in soil and groundwater and included limits promulgated in
a state's laws or regulations or established as guidance or policy.
We also included in our definition only standards that might be used
as the basis for setting cleanup levels at a Superfund facility.
Because petroleum spills are not covered under Superfund legislation,
we excluded states that had established standards only for petroleum
products under their separate programs for cleaning up leaking
underground storage tanks. We excluded states that had simply
adopted the federal standards set under the Safe Drinking Water Act
or had established antidegradation policies without also setting
specific numeric limits on contaminants.
The questions in our survey included (1) whether a state's standards
were derived from a risk-based formula and/or other factors, such as
the naturally occurring levels of contamination in the soil and
groundwater; (2) whether the formulas were based on EPA's guidance or
on the state's own methodologies for estimating human health risks
from contamination; (3) what risk levels, such as a 1-in-1-million
increased probability of contracting cancer, were used in setting the
standards; (4) whether the standards were set for different uses of
the land or groundwater; and (5) whether the standards were
considered fixed limits or the state provided flexibility to adjust
the cleanup levels based on these standards to take into account
specific conditions at a site. We interviewed the managers of
states' Superfund programs, technical experts in these programs, and
other key officials responsible for developing and/or implementing
the states' standards. When necessary to clarify information, we
contacted officials again for follow-up questions.
The data we obtained were current as of September 1995. To ensure
the accuracy of our information, we provided state officials with a
summary of the information we had compiled on their standards for
their review. In addition, we provided copies of a draft of our
report to EPA officials, including the Director of the Office of
Emergency and Remedial Response and officials responsible for working
with state Superfund programs, for their review and comment. They
said that the report was an accurate discussion of states' standards
and provided several technical changes and clarifications on the
Superfund law's requirements for cleanups. We incorporated their
changes and suggestions. We conducted our audit work from March 1995
through March 1996.
STATES INCLUDED IN SURVEY AND
REPORTED STATUS OF STATES'
STANDARDS
========================================================== Appendix II
Number of Law/
Superfund regulation Policy/
State sites\a Standards s guidance
-------------------- ---------- -------------- ---------- --------
New Jersey 100 Soil X X
Groundwater X
Pennsylvania 95 Soil X
Groundwater X
New York 76 Soil X
Groundwater X
Michigan 74 Soil X
Groundwater X
California 69 Groundwater X
Florida 48 Groundwater X
Wisconsin 40 Soil X
Groundwater X
Washington 35 Soil X
Groundwater X
Minnesota 34 Soil X
Groundwater X
Illinois 33 Groundwater X X
Indiana 32 None
Ohio 31 None
Texas 25 Soil X
Groundwater X
South Carolina 23 None
Massachusetts 22 Soil X
Groundwater X
North Carolina 21 Groundwater X
Kentucky 19 None
Missouri 19 Soil X
Delaware 18 None
Virginia 18 Groundwater X
Iowa 16 None
New Hampshire 16 Groundwater X
Connecticut 14 Soil X\b
Groundwater X\b
Tennessee 14 None
Colorado 13 Groundwater X
Louisiana 13 None
Arkansas 12 None
Georgia 11 Soil X
Groundwater X
Kansas 10 Soil X
Groundwater X
Rhode Island 10 Groundwater X
Alabama 9 None
Oklahoma 9 None
Oregon 9 None
----------------------------------------------------------------------
Note: Status of states' standards is as of September 1995. (See
app. I for our definition of standards and a discussion of our
methodology.)
\a Does not include federal facilities.
\b Connecticut's standards for soil and groundwater were adopted as
state regulations on January 30, 1996.
MAJOR CONTRIBUTORS TO THIS REPORT
========================================================= Appendix III
Stanley J. Czerwinski, Associate Director
Eileen R. Larence, Assistant Director
Sharon E. Butler, Senior Evaluator
Susan E. Swearingen, Senior Evaluator
Luann M. Moy, Senior Social Science Analyst
Josephine Gaytan, Information Processing Assistant
*** End of document. ***