[Federal Register Volume 63, Number 223 (Thursday, November 19, 1998)]
[Rules and Regulations]
[Pages 64372-64402]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-30601]



[[Page 64371]]

_______________________________________________________________________

Part IV





Environmental Protection Agency





_______________________________________________________________________



40 CFR Part 261



Hazardous Waste Management System: Identification and Listing of 
Hazardous Waste, Solvents; Final Rule

  Federal Register / Vol. 63, No. 223 / Thursday, November 19, 1998 / 
Rules and Regulations  

[[Page 64372]]



ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 261

[SWH-FRL-6185-3]
RIN 2050-AD84


Hazardous Waste Management System: Identification and Listing of 
Hazardous Waste Solvents

AGENCY: Environmental Protection Agency.

ACTION: Final decision.

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

SUMMARY: The U.S. Environmental Protection Agency (EPA) is issuing a 
final decision not to list wastes generated from the use of 14 
chemicals as solvents as hazardous under the Resource Conservation and 
Recovery Act (RCRA). The determinations in this rule are limited to 
specific solvent wastes. This rule is a determination only that the 
solvent wastes considered will not be added to the list of hazardous 
wastes and is not a determination that the underlying chemicals are 
nontoxic in all circumstances in which they are used or discarded.

DATES: Today's final decision will become effective on December 21, 
1998.

ADDRESSES: Supporting materials are available for public viewing and 
photocopying in the RCRA Information Center (RIC), located at Crystal 
Gateway I, First Floor, 1235 Jefferson Davis Highway, Arlington, VA. 
The Docket Identification Number is F-98-SLDF-FFFFF. The RIC is open 
from 9:00 a.m. to 4:00 p.m., Monday through Friday, excluding federal 
holidays. To review docket materials, it is recommended that the public 
make an appointment by calling (703) 603-9230. The public may copy a 
maximum of 100 pages from any regulatory docket at no charge. 
Additional copies cost $0.15/page. The index and some supporting 
materials are available electronically. See the FOR FURTHER INFORMATION 
CONTACT section for information on accessing them.

FOR FURTHER INFORMATION CONTACT: The RCRA/Superfund Hotline, toll-free, 
at (800) 424-9346 or at (703) 920-9810. The TDD Hotline number is (800) 
553-7672 (toll-free) or (703) 486-3323 in the Washington, DC 
metropolitan area.
    For technical information on the RCRA hazardous waste listings, 
contact Ron Josephson or Robert Kayser, Office of Solid Waste (5304W), 
U.S. Environmental Protection Agency, 401 M Street, SW, Washington, DC 
20460. The telephone number is (703) 308-8890.

SUPPLEMENTARY INFORMATION: There are no regulated entities as a result 
of this action.
    The index and the supporting materials are available on the 
Internet: Follow these instructions to access the information 
electronically:

WWW: http://www.epa.gov/epaoswer/hazwaste.htm#id
FTP: ftp.epa.gov
Login: anonymous
Password: your Internet address
Files are located in /pub/oswer

    The contents of the preamble to this final rule are listed in the 
following outline:

I. Legal Authority and Background
    A. Statutory and Regulatory Authorities
    B. Existing Solvent Listings and the Regulatory Definition of 
Solvent
II. Summary of Proposed Rule
    A. Determinations Not to List Solvent Wastes as Hazardous Waste
    B. Summary of Risk Assessment Supporting the Proposed Rule
III. Peer Review of Calculated Toxicological Benchmarks
IV. Summary of Response to Comments and Rationale for Final Rule
    A. Data Collection
    1. Representativeness of Industry Characterization
    2. Engineering Site Visit Reports
    B. Methodology
    1. Definition of ``Solvent'
    2. Lack of Sampling and Analysis
    3. Consistency of Methodology With Other Listing Determinations
    4. Plausible Mismanagement Scenarios
    C. Risk Assessment
    1. Surface Impoundments
    2. Tank-Based Management of Wastes
    3. Multiple Solvents
    4. Comparison with HWIR Exit Levels
    5. Environmental Damage Incidents
    6. Spills, Leaks, and Overflows
    7. Non-Aqueous Phase Liquids
    8. Risk Modeling Parameters
    9. Comparison with Results of Air Characteristic Study
    D. Listing Determinations
    1. General Comments
    2. Sufficient Regulation of Solvents
    3. Waste-Specific Rationales and Response to Specific Comments
V. Regulatory Requirements
    A. Regulatory Impact Analysis Pursuant to Executive Order 12866
    B. Regulatory Flexibility
    C. Unfunded Mandates Reform Act
    D. Executive Order 12875: Enhancing Intergovernmental 
Partnership
    E. Executive Order 13045: Protection of Children from 
Environmental Health Risks and Safety Risks
    F. Environmental Justice E.O. 12898
    G. Paperwork Reduction Act
    H. National Technology Transfer and Advancement Act
    I. Executive Order 13084: Consultation and Coordination with 
Indian Tribal Governments
    J. Congressional Review Act

I. Legal Authority and Background

A. Statutory and Regulatory Authorities

    The Environmental Protection Agency (EPA) conducted this 
investigation and listing determination under the authority of sections 
2002(a), 3001(a), (b) and (e)(2) of the Solid Waste Disposal Act (42 
U.S.C. 6912(a), and 6921(b) and (e)(2)), as amended by various other 
laws, the most comprehensive of which was the Hazardous and Solid Waste 
Amendments (HSWA) of 1984. These statutes are commonly referred to as 
the Resource Conservation and Recovery Act (RCRA) and are codified at 
Volume 42 of the United States Code (U.S.C.), sections 6901 to 6992(k).
    Section 3001(a) of RCRA, 42 U.S.C. 6921(a), requires EPA to 
promulgate criteria for identifying characteristics of hazardous wastes 
and for listing hazardous wastes. Section 3001(b) of RCRA requires EPA 
to promulgate regulations, based on these criteria, identifying and 
listing hazardous wastes which shall be subject to the requirements of 
the Act. Section 1004(5) of RCRA, 42 U.S.C. 6903(5), defines the term 
``hazardous waste.'' There are two types of hazardous waste. First, 
hazardous wastes are those solid wastes which may cause or 
significantly contribute to an increase in mortality, serious 
irreversible illness, or incapacitating reversible illness. Second, 
hazardous wastes are those solid wastes which may pose a substantial 
present or potential hazard to human health or the environment when 
improperly managed. Id.
    EPA's regulations establishing criteria for listing hazardous 
wastes are codified at Title 40 of the Code of Federal Regulations 
(CFR) 261.11 (40 CFR 261.11). Section 261.11 presents three criteria by 
which EPA identifies wastes as hazardous.
    First, solid wastes may be classified as ``characteristic'' wastes 
if they exhibit any of the characteristics of hazardous waste 
identified at 40 CFR 261.21-24 (i.e., ignitability, corrosivity, 
reactivity, or toxicity).
    Second, solid wastes may be listed as acutely hazardous if they are 
fatal to humans at low doses, lethal in animal studies at particular 
doses designated in the regulation, or otherwise capable of causing or 
significantly contributing to an increase in serious illness.
    Third, solid wastes may be listed as hazardous if they contain any 
of the toxic constituents identified in Appendix VIII of 40 CFR part 
261 and the Agency concludes, after considering the eleven factors 
enumerated in 40 CFR 261.11(a)(3), that the waste is capable of

[[Page 64373]]

posing a substantial present or potential hazard to human health or the 
environment when improperly managed. A substance is listed in Appendix 
VIII if it has been shown in scientific studies to have toxic, 
carcinogenic, mutagenic, or teratogenic effects on humans or other life 
forms. Today's listing determination has been made pursuant to this 
third set of criteria.
    As part of its regulations implementing section 3001(b) of RCRA, 
EPA published a list of hazardous wastes that includes hazardous wastes 
generated from nonspecific sources (F-wastes) and a list of hazardous 
wastes from specific sources (K-wastes). These lists, published at 40 
CFR 261.31 and 261.32, respectively, have been amended several times.
    Persons who generate, transport, treat, store, or dispose of wastes 
listed as hazardous must do so subject to Federal requirements under 
RCRA. Facilities that must meet the hazardous waste management 
requirements, including the need to obtain permits to manage hazardous 
wastes, are commonly referred to as RCRA Subtitle C facilities. EPA 
standards and procedural regulations implementing Subtitle C are found 
generally at 40 CFR parts 260 through 279.
    Solid wastes that are not hazardous wastes may be disposed of at 
facilities that are overseen by State and local governments. These 
facilities are referred to as RCRA Subtitle D facilities. EPA 
regulations affecting Subtitle D facilities are found generally at 40 
CFR parts 240 through 247, and parts 255 through 258.
    Section 3001(e)(2) of RCRA requires EPA to determine whether to 
list as hazardous several specified wastes, including solvent wastes. 
The Environmental Defense Fund (EDF) and EPA entered into a consent 
decree to resolve issues raised in a civil action brought by EDF (EDF 
v. Browner, Civ. No. 89-0598 (D.D.C.)) in which the Agency agreed, 
among other things, to a schedule for making a listing determination on 
spent solvents. This listing determination is to consider spent 
solvents, still bottoms from the recovery of these solvents, and spent 
solvent mixtures when the following chemicals are used as solvents: 
cumene, phenol, isophorone, acetonitrile, furfural, epichlorohydrin, 
methyl chloride, ethylene dibromide, benzyl chloride, p-
dichlorobenzene, 2-methoxyethanol, 2-methoxyethanol acetate, 2-
ethoxyethanol acetate, and cyclohexanol.
    For an additional set of seven solvents, EPA agreed to conduct a 
study and issue a final report by August 30, 1996. This study, which 
EPA completed on August 22, 1996, discusses the wastes associated with 
the use of the materials as solvents, the toxicity of the wastes, and a 
description of the management practices for the wastes.
    Solvent uses are found throughout various industries and, thus, 
would fall under the category of wastes from nonspecific sources (F-
wastes) if listed in 40 CFR 261.31. In fact, wastes designated F001 
through F005 are various wastes from solvent uses of a number of 
chemicals. In today's action, EPA has decided not to amend 40 CFR 
261.31 to add wastes generated during the use of the 14 chemicals of 
concern as solvents.
    EPA emphasizes that the determination not to list these wastes only 
means that the Agency has found it is not appropriate to list as 
hazardous the wastes across broad industry categories that could result 
from solvent uses of the 14 chemicals. As will be more fully explained 
below, EPA did not find that solvent uses for these chemicals, in 
general, produce hazardous wastes that require listing. Many of the 
wastes examined are hazardous already because they are characteristic 
wastes under 40 CFR part 261, subpart C, or contain other solvent 
wastes currently listed as hazardous. In addition, some of the 
chemicals may produce wastes that are hazardous when used in ways other 
than as solvents, perhaps as catalysts, feedstocks or other uses in 
chemical manufacturing processes. Solvents use simply does not 
constitute an appropriate way to designate these chemicals as a 
hazardous waste category under RCRA for wastes from nonspecific 
sources. Particular industrial wastes from these chemicals might be 
hazardous, but such wastes were not examined in this determination.

B. Existing Solvent Listings and the Regulatory Definition of Solvent

    Five hazardous waste listings for specific solvents have been 
promulgated to date: F001, F002, F003, F004, and F005. These are found 
at 40 CFR 261.31. Today's decision applies the same criteria for 
defining solvent wastes as are applied to these existing solvents 
listings. These criteria are explained in the Federal Register of 
December 31, 1985 (50 FR 53316) and are also consistent with the 
requirements of the EDF Consent Decree.
    The December 1985 document amended the solvent listings to include 
spent solvent mixtures when the solvent, before it is used, contains 10 
percent or more of total listed solvents. The original listing included 
only the technical grade, practical grade or pure form of the solvents 
when used. This threshold level was considered by the Agency to be well 
below the minimum solvent concentration typically used in solvent 
formulations and was designed to bring the majority of listed solvent 
mixtures used in commerce into the hazardous waste management system, 
while excluding dilute mixtures or de minimis concentrations.
    In addition, the document issued several clarifications to the 
original listings. First, the listings apply to ``spent'' solvents--
those that are no longer fit for use without being regenerated, 
reclaimed, or otherwise processed. (See 40 CFR 261.1(c) (1) and (4); 
261.2(c) (3) and (e)). Second, the listings cover only those solvents 
used for their solvent properties--``to solubilize (dissolve) or 
mobilize other constituents.'' These include solvents used in 
degreasing, cleaning, fabric scouring, as diluents, extractants, 
reaction and synthesis media. The document stated that the listings do 
not cover wastes from the processing of products where a chemical that 
might be used as a solvent is, instead, used as a reactant or where a 
chemical is used as a solvent only as an ingredient in the formulation 
of a commercial chemical. This latter category would include chemicals 
used as a solvent in paint formulations to dissolve the paint itself. 
These uses do not generate ``spent solvent'' wastes. The wastes of 
concern for these products would be the production process wastes or 
wastes from the use of the product, not the solvent itself.
    This approach is also consistent with the requirements of the EDF 
Consent Decree. This is because the consent decree identifies a subset 
of solvent wastes that are potential candidates for listing and 
specifies that the listing determination applies to ``spent solvents,'' 
a term that tracks the language of the existing listings. Moreover, 
this approach had been the longstanding approach of the Agency to 
dealing with solvent listings at the time the Consent Decree was 
negotiated and should be interpreted as representing the understanding 
of the parties.
    This approach, whereby EPA has limited the scope of this rulemaking 
through this focused definition of solvents subject to the listing, is 
a reasonable interpretation of RCRA and is consistent with EPA's 
historical treatment of solvent listing descriptions. Use of the 
definition has allowed the Agency to place reasonable limits on the 
scope of its listing investigation for this rulemaking. RCRA 3001(e)(2) 
directs

[[Page 64374]]

EPA to make a listing determination on ``solvents,'' but provides no 
further direction on the meaning of that term. EPA, therefore, has the 
discretion to reasonably define the scope of the listing determination. 
Given the ubiquity of solvents, the great variety of uses and the huge 
differences in the composition of the waste streams, EPA could not 
gather the evidence to list ``solvent wastes'' as a general category. 
Under the Agency's regulations at 40 CFR 261.11(b), wastes may be 
listed as a category if they are ``typically or frequently'' hazardous. 
EPA could make no such findings for ``solvent'' wastes in general and, 
therefore, has reasonably focused its investigation and listing 
decision.
    As noted above, the existing solvent listings are limited to spent 
solvent mixtures when the solvent, before it is used, contains 10 
percent or more of total listed solvents. While wastes from this use 
threshold were the primary focus of today's listing determination, EPA 
also considered in its evaluations the few solvent uses that were 
reported to be below the 10 percent threshold.
    In a previous proposed hazardous waste listing for wastes from the 
production of dyes and pigments (59 FR 66072, December 22, 1994) EPA 
presented the general approach the Agency uses for determining whether 
to list a waste as hazardous pursuant to 40 CFR 261.11(a)(3). The 
discussion focused on the selection of waste management scenarios used 
in assessing risk and the use of information on risk levels in making 
listing determinations. This approach was further developed in EPA's 
listing for petroleum refining process wastes (proposed rule published 
at 60 FR 57747, November 20, 1995; final rule published at 63 FR 42110, 
August 6, 1988). EPA is employing the same general approach in this 
final rulemaking. Readers are referred to these documents for a 
description of EPA's listing policy. Also, section II.C.2. of the 
proposed rule, ``Risk Assessment,'' contains a discussion of how 
elements of EPA's listing policy were applied in today's listing 
determination.
    The following section contains a summary of the methodology used to 
arrive at the no-list determinations in today's document. For more 
details on this methodology, see the proposed rule, background 
document, and the response to comments document in the docket.

II. Summary of Proposed Rule

A. Determinations Not To List Solvent Wastes as Hazardous Waste

    EPA proposed the decision not to list the spent solvent wastes from 
the 14 chemicals noted above on August 14, 1996 (61 FR 42318). The 
Agency determined that these wastes did not meet the criteria for 
listing set out in 40 CFR 261.11. The proposed rule presented the waste 
characterization, waste management, mobility, persistence, and risk 
assessment data that were the bases for the Agency's proposed decision 
not to list these wastes as hazardous. Further details of EPA's 
approach are presented in the Hazardous Waste Listing Determination 
Background Document for Solvents (hereafter known as ``Listing 
Background Document'') in the docket for the proposal to today's rule.
    As explained in section II.B of the proposed rule, spent solvents 
differ from other listed wastes among EPA's waste listings in that the 
solvents are used in manufacturing and allied processes rather than 
being the principal waste streams generated by manufacturing processes. 
In order to characterize industrial solvent use, the Agency sent out 
almost 1,500 preliminary questionnaires to cover the 21 total chemicals 
(14 from the listing determination and seven from the study). An 
additional 60 facilities were surveyed on their use of these chemicals 
as solvents through the chlorinated aliphatics industry survey. EPA 
then sent out a full RCRA section 3007 survey to facilities using 
greater than a combined total of 1,200 kilograms of all the chemicals 
of concern.
    The Agency consulted various literature and reference sources, such 
as Chemical Abstracts, general reference books, the Agency's Toxic 
Release Inventory (TRI) compiled under section 313 of the Emergency 
Planning and the Right-to-Know Act (EPCRA), databases compiled for 
various EPA programs dealing with air and water pollution, and 
information available from trade associations. Of the 14 chemicals 
involved in the listing determination, 11 were on the TRI. Use of the 
literature, Chemical Abstracts, TRI, and other EPA databases allowed 
the Agency to focus on the industries that actually use these chemicals 
as solvents. In addition, many of these sources gave strong indications 
as to when major uses of a chemical were not as a solvent.
    Once the Agency narrowed down the potential solvent-using 
industries, the Agency developed a list of facilities to survey about 
their solvent use. These facility names and addresses were obtained 
again from a variety of sources, including TRI, trade associations, and 
other Agency media program sources. The Agency sent a short 
(``preliminary'') questionnaire to approximately 1,500 facilities 
inquiring about uses of any of the 14 listing determination chemicals 
as solvents and the quantities used.
    The Agency used the preliminary questionnaire data to develop the 
large questionnaire mailing list and to organize site visits. The 
Agency also made several hundred confirmatory telephone calls to 
determine that reported information was correct. The data from the 
preliminary questionnaire showed the Agency several distinct patterns 
of solvent use: facilities that use large amounts of any of these 
chemicals as solvent, those that use small quantities as solvents, and 
those that use none of the chemicals as solvents. The Agency found that 
a solvent use quantity of 100 kg per month, or 1,200 kg per year, 
provided a mathematically convenient separation of those facilities who 
use large amounts of solvent and those who use very little and provided 
an indication as to which facilities were likely to be large quantity 
generators of hazardous waste based on use of these chemicals as 
solvents. Based on careful analysis of the data, the Agency identified 
likely large-scale users of these chemicals as solvents.
    The Agency then developed the large questionnaire. This 
questionnaire reconfirmed data on solvent use and requested detailed 
information on a facility's solvent-using processes, waste generation, 
waste management, and waste minimization activities. The Agency sent 
this questionnaire to approximately 150 facilities that indicated to 
the Agency through the preliminary questionnaire that significant 
solvent uses of these chemicals exist. The data obtained from the 
questionnaire were applied to the risk assessment process described in 
today's document as well as the preparation of the background document.
    To summarize the results, 4 of the 14 chemicals showed no use as a 
solvent. The remaining 10 chemicals were analyzed in the Agency's risk 
assessment based on solvent uses found by the Agency. For the 10 
chemicals of the required listing determination for which there were 
solvent uses (acetonitrile, 2-ethoxyethanol acetate, 2-methoxyethanol, 
2-methoxyethanol acetate, cyclohexanol, cumene, phenol, furfural, 
isophorone, and methyl chloride), EPA found that the management of 
residuals from the use of these chemicals as solvents did not pose a 
risk to human health or the

[[Page 64375]]

environment under the plausible management scenarios assessed. The data 
used as the bases for these determinations were presented in sections 
II.D through II.M of the proposed rule (61 FR 42327). Detailed 
information is also presented in the background documents supporting 
the proposed rule (RCRA Docket number F-96-SLDP-FFFFF).
    Specifically, none of the solvents satisfy the criteria for listing 
in 40 CFR 261.11 (a)(3). For acetonitrile, 2-methoxyethanol, and methyl 
chloride, while risk analyses indicated some potential risk from air 
releases of these chemicals from onsite accumulation in open tanks, EPA 
believes this risk would not be significant because most, or in some 
cases all, of the nonwastewater residuals are already regulated as 
hazardous waste. For phenol, 2-ethoxyethanol acetate, furfural, cumene, 
cyclohexanol, isophorone, and 2-methoxyethanol acetate, the risk 
estimates indicated that spent solvent residuals from the use of these 
chemicals as solvents do not pose a substantial risk or potential 
hazard to human health or the environment through the plausible 
management scenarios and pathways assessed.
    For the remaining four chemicals subject to the required listing 
determination in the EDF Consent Decree (1,4-dichlorobenzene, benzyl 
chloride, epichlorohydrin, and ethylene dibromide), EPA proposed not to 
list residuals from their use as solvents, because the data collected 
by EPA showed that these chemicals are extremely unlikely to be used as 
solvents. One of the chemicals (p-dichlorobenzene) is a solid at room 
temperature, and the other three (benzyl chloride, epichlorohydrin, and 
ethylene dibromide) are relatively reactive chemicals not well suited 
to solvent use. EPA's information showed that the very limited solvent 
use reported for these four chemicals is linked to bench-scale or 
experimental laboratory settings, and no significant solvent uses were 
found. For more detail see sections II.N through II.Q of the proposed 
rule (61 FR 42347) and background documents supporting the proposed 
rule (RCRA Docket number F-96-SLDP-FFFFF).

B. Summary of Risk Assessment Supporting the Proposed Rule

    As described in detail in the proposed rule (see 61 FR 42322-
42327), EPA carried out various analyses to determine the potential 
risk that might arise from the disposal of the spent solvent wastes 
under study. In carrying out the modeling for these assessments, EPA 
used available data it collected from industries using these solvents. 
The Agency used information gathered in the RCRA 3007 Questionnaires 
and site visits related to the waste characteristics, waste management 
practices, and potential pathways for release and exposure. EPA used 
other generic input parameters to fate and transport models to estimate 
the risk a waste might present under management scenarios known to 
occur. The data used in the modeling efforts included the 
concentrations and toxicity of the solvent constituents in the waste, 
the mobility and fate of such constituents in different disposal 
scenarios, likely exposure routes under these scenarios, and the 
location of receptors that might be exposed.
    The levels of receptor exposure estimated from modeling were 
compared with toxicological benchmarks to evaluate the potential health 
impacts. For noncarcinogenic constituents, EPA used reference doses for 
ingestion exposure (RfDs) and reference concentrations for inhalation 
exposure (RfCs); these are measures of acceptable daily intakes for a 
specific chemical. To assess the hazard to a hypothetical individual, 
EPA used hazard quotients (HQs). An HQ is the ratio of the modeled 
exposure (or dose) received compared with the acceptable daily dose 
(the RfC or RfD). An HQ above one indicates that exposures may occur 
above acceptable levels. For carcinogenic constituents, EPA compared 
exposure levels to carcinogenic potency estimates (carcinogenic slope 
factors, or CSFs) to calculate specific risk levels. The carcinogenic 
risks results are expressed in terms of individual risk, reflecting the 
additional incidence of cancer that may occur in an exposed population. 
For example, a risk of 1  x  10-5 (which will be presented 
in this document as 1E-05) corresponds to a probability of one 
additional case of cancer for every 100,000 people exposed.
    EPA used verified RfDs, RfCs, or CSFs when available in EPA's 
Integrated Risk Assessment Information System (IRIS). IRIS, which 
represents a consensus opinion of EPA health scientists, is a database 
of human health effects that may result from exposure to various 
substances found in the environment. For the chemicals that did not 
have complete verified IRIS data available (2-methoxyethanol acetate, 
cyclohexanol, phenol, and isophorone), EPA calculated provisional 
values when needed for use in the listing determinations.
    EPA performed a number of different types of risk analyses. First 
the Agency completed a ``bounding analysis'' to screen out solvent 
wastes from further consideration. In this analysis, the key input 
parameters were set to their ``high-end'' values (typically the 90th 
percentile point on the distribution of values available for each 
parameter). For solvent wastes that did not ``bound out,'' EPA then ran 
a high-end ``deterministic'' sensitivity analysis to determine which 
high-end input parameters result in the greatest risk. EPA calculated 
risks for all combinations when the most sensitive parameters were set 
at high-end values and then used the highest ``high-end'' risk. In this 
way, EPA attempted to estimate ``high-end'' risks that were somewhere 
above the 90th percentile, i.e., the risks would be below this level 
for at least 90% of the population at risk. EPA also calculated 
``central tendency'' risks, which correspond to the risk when all input 
parameters were set at their median value.
    Critical decisions for risk assessment include EPA's determination 
regarding which waste management scenarios to model and how to use the 
information on waste volumes and solvent concentrations disposed as 
modeling input. The Agency's modeling focused primarily on potential 
releases from wastes managed in aerated tanks, stored in open tanks, 
undergoing thermal treatment, and managed in surface impoundments. 
Modeling was based on the information EPA collected from facilities, 
including quantities of wastes managed. For each management scenario, 
EPA evaluated the full range of direct and indirect pathways through 
which the solvents could affect human health or the environment. Based 
on the physical and chemical properties of the constituents of concern 
and plausible management practices, certain routes of exposure for some 
scenarios were not considered to pose threats and were not further 
evaluated.
    In general, solvent wastes fell in several major categories. 
Wastewaters were typically diluted aqueous wastes that are managed in a 
biological treatment system (usually in tanks). Nonwastewaters includes 
two subcategories. These include: (1) wastes with high levels of 
solvents or other organic chemicals, which were sent for thermal 
treatment in incinerators, industrial boilers, or fuel blenders, and 
(2) treatment residuals, such as wastewater treatment sludges or 
incinerator ash, which contained negligible levels of solvents.

    EPA modeled storage in an open tank and thermal treatment for 
nonwastewater spent solvent residuals from use of all of the ten 
solvents. EPA modeled wastewater treatment in

[[Page 64376]]

aerated tanks for wastewater residuals resulting from the use of 
acetonitrile, 2-methoxyethanol, 2-ethoxyethanol acetate, phenol, 
furfural, and cumene as solvents.
    The surface impoundment scenario was assessed for five of the 
solvents; acetonitrile, phenol, cumene, furfural, and methyl chloride. 
For acetonitrile and cumene, the headworks concentrations (i.e., the 
concentrations after the spent solvent was mixed with other wastewaters 
at the headworks of the wastewater treatment system) potentially 
discharged to surface impoundment were below the health-based levels 
for these constituents, and thus were not evaluated further. For 
phenol, three wastewaters with spent phenol were reported to be managed 
in surface impoundments that are part of a wastewater treatment train. 
In two of these cases, the phenol concentration was below the drinking 
water health-based level after mixing at the headworks, prior to 
reaching the surface impoundment. In the third case the stream had 
levels ranging above the health-based level; however this level is 
expected to be efficiently treated by the activated sludge, such that 
little phenol would be available for release to groundwater. For methyl 
chloride, EPA modeled air releases from treatment in a surface 
impoundment, but not the groundwater pathway because the impoundment 
was a permitted hazardous waste management unit. (As described below, 
the unit treating methyl chloride wastes was unique due to the highly 
specialized nature of this solvent use). EPA modeled treatment in a 
surface impoundment for furfural; however, bounding analyses showed no 
significant risks via air or groundwater pathways. The solvent use of 
the chemicals modeled in surface impoundments are very specialized. 
This means that they have properties that only allow very particular 
solvent uses in a very narrow set of circumstances and only for some 
industries, or even for only one. For example, methyl chloride is a gas 
at room temperature, which severely limits its utility as a solvent. 
The only significant solvent use for this chemical is as a solvent in 
the polymerization of butyl rubber, during which methyl chloride is 
passed through aluminum chloride to form and solubilize the catalyst 
used. The chemical's special ability to generate such a catalyst 
solution is why it is used. Similarly, by far the largest solvent uses 
of furfural and phenol are in the extraction of a high molecular weight 
oil (lubrication oil) during petroleum refining; these chemicals have 
very limited solvent uses outside the petroleum industry. Therefore, 
EPA has a high degree of confidence that the concentrations of 
chemicals in the streams flowing into surface impoundments studied in 
this listing determination are representative of the universe of such 
uses and possible exposure scenarios.
    The landfill scenario was initially assessed for acetonitrile, 
methyl chloride, cumene, and cyclohexanol, but not modeled for spent 
solvent residuals from any of these solvents because the concentrations 
in the wastes were ``trace'' or ``negligible.'' Further general 
background for the risk assessment is provided in the preamble to the 
proposed rule (see 61 FR 42318).

III. Peer Review of Calculated Toxicological Benchmarks

    Standard inhalation toxicological benchmarks were not available to 
EPA for four of the solvents when the Agency was conducting the risk 
assessment for the proposed rule. The Agency therefore calculated 
values specifically for the rule. EPA has labeled these toxicological 
benchmarks ``provisional RfCs'' to clearly differentiate them from the 
Agency consensus values listed on IRIS. During the comment period, EPA 
solicited peer review of these calculated risk values. The peer review 
reports and the complete Agency response to the reports are in the 
docket for this rulemaking.
    In response to comments received in the peer review reports, EPA 
adjusted three of the provisional toxicological benchmarks used for 
this risk assessment. The changes are shown in Table 1.

                          Table 1.--Changes in Toxicological Benchmarks for Air Pathway
----------------------------------------------------------------------------------------------------------------
                                                                                     Previous           New
                                                                                    provisional     provisional
                 Solvent                             NOAEL \1\ (mg/m3)             toxicological   toxicological
                                                                                  benchmark (mg/  benchmark (mg/
                                                                                        m3)             m3)
----------------------------------------------------------------------------------------------------------------
Cyclohexanol............................  0.06..................................         0.00006         0.00002
Phenol..................................  19....................................         0.019           0.006
Isophorone..............................  37 (LOAEL) \2\........................         0.0037          0.012
----------------------------------------------------------------------------------------------------------------
\1\ No observed adverse effect level.
\2\ Lowest observed adverse effect level.

    The new benchmarks for cyclohexanol and phenol reflect additional 
uncertainty factors to account for insufficient toxicity databases. The 
benchmark for isophorone reflects a reduction in overall uncertainty 
factors to reflect Agency guidance limiting such factors to a total of 
3,000. Full documentation of the methodology for developing these 
benchmarks is in the docket for this rulemaking.
    In addition, the toxicological values for cumene were changed on 
IRIS during the comment period. The RfD (for noncancer ingestion risks) 
was changed from 0.04 mg/kg/day to 0.1 mg/kg/day. The RfC (for 
noncancer inhalation risks) was changed from 0.009 mg/m\3\ to 0.4 mg/
m\3\. These changes both reflect greater tolerance for cumene than the 
previous benchmarks and thus have no impact on EPA's decision not to 
list wastes derived from the use of this chemical as a solvent.
    The Agency has employed these revised ``provisional RfCs'' for all 
the updated risk assessments involving these solvents for the final 
rule. In addition, the Agency has re-estimated risks assessed for the 
proposed rule using these new benchmarks. Documentation of these re-
estimations appears in the supplemental risk assessment background 
document to this final rule. The final risk estimates for all the 
solvents are shown in Table 3 of this preamble.
    In all cases the changes to the toxicological values do not have 
any significant impact on EPA's risk results, nor do the changes affect 
any listing decisions. The solvent wastes for the chemicals examined 
still do not pose significant risks, and thus, these analyses confirm 
the proposed decisions not to list these wastes.

[[Page 64377]]

IV. Summary of Response to Comments and Rationale for Final Rule

    The Agency is responding in this preamble to the most significant 
comments received in response to the document of August 14, 1996, 61 FR 
42318. Other comments received by the Agency are addressed in the 
document entitled Hazardous Waste Listing Determination: Spent 
Solvents, Response to Comments (hereafter known as Response to Comments 
Document) that is available in the docket associated with this 
rulemaking.
    The Agency is responding to a variety of comments concerning data 
collection, methodology, risk assessment scenarios, and issues specific 
to each chemical in this listing determination. The responses, while 
touching many specific aspects of the listing determination effort, 
involve three major themes:
     The Agency used a very thorough survey, which 
characterized the risks of the spent solvents. The Agency researched 
various potential applications of these chemicals as solvents and found 
that solvent uses are confined to a limited set of industrial 
applications. Data collected from the questionnaires confirmed the 
general lack of wide solvent use, and are consistent with EPA's search 
of the literature. These findings allowed the Agency to consider the 
applicable waste generation and management practices, and define 
plausible management scenarios for use in evaluating potential risks 
associated with these solvent wastes.
     Facilities use the solvents for specific purposes that 
vary by the desired process. Some of the solvents in this listing 
determination have different applications over certain industries 
(i.e., acetonitrile). Even within one industry, the primary commonality 
among the processes is the solvent constituent itself. Other solvents 
were used in very limited ways and their primary uses were highly 
specialized (e.g., furfural). However, even for solvents with 
specialized uses, other minor uses were typically reported for 
different industries and processes. The resulting potential variability 
in waste compositions led the Agency to focus its efforts on evaluating 
the solvent constituent itself. The Agency believes it has captured the 
risks that arise from the solvents themselves, and that this is a 
reasonable approach to fulfilling its listing determination 
obligations.
     Little to no benefit would accrue from regulating these 
wastes because many are already regulated and treated as hazardous 
wastes. These solvent wastes, particularly nonwastewaters with a high 
organic content, are characteristically hazardous or mixed with other 
listed wastes, and are generally thermally treated. Other 
nonwastewaters, such as wastewater treatment sludges or filter media, 
do not contain measurable levels of the solvent constituents, and thus 
present no significant risks.

A. Data Collection

1. Representativeness of Industry Characterization
    One comment argues that EPA cannot fully characterize industry 
solvent management practices because the facilities that may be 
affected are too numerous to predict and specifically identify. 
Therefore, the Agency should project standard mismanagement scenarios 
in order to examine the full range of actual and potential waste 
management practices applicable to the wastes. This is the only way the 
Agency can discharge its mandate to protect human health and the 
environment.
    In response, EPA disagrees that it is not possible to predict and 
identify, as a practical matter, the facilities that may be affected. 
It is possible and appropriate to do so and EPA has, in fact, 
accomplished that purpose, as summarized below and explained more fully 
in the Response to Comments Document. The Agency outlined the general 
approach to the data collection process in the proposal (61 FR 42321-
42322). To summarize, the Agency began collecting data on all 14 
chemicals involved in the listing determination (plus the seven in the 
Solvents Study) as a means of collecting background information on 
these chemicals. The Agency identified solvent uses through cross-
referencing SIC codes in known and suspected process industries with 
data found in the TRI, Office of Water facility lists, and many other 
data sources. The Agency used many different facility address lists to 
create a list of potential solvent-using facilities.
    The sources used by the Agency provide a comprehensive view of the 
types of uses of these chemicals as solvents and the quantities used. 
The Agency identified industries using the 14 chemicals as solvents by 
conducting literature searches including Chemical Abstracts, the 
Chemical Engineering Handbook, the Industrial Solvents Handbook, and 
the SRI Chemical Economics Handbook. As today's document and the 
associated background documents explain, the process was a logical, 
iterative, step-by-step process. The chemicals in question are not 
likely to be widely used as solvents (with the exception of 
acetonitrile and, to a more limited extent, 2-methoxyethanol, which 
have significant solvent uses in some industries), because they have 
properties that limit their use to specific situations, and are 
generally noncompetitive in price. In addition, the Agency's data 
collection methodology combined a comprehensive view not only of the 
chemical's solvent use, but also of nonsolvent uses to confirm use 
data. The specificity of applications for these solvents, while 
sometimes cutting across more than one industry, is still limited 
enough that the listing determination could stay focused on the actual 
management scenarios found through questionnaires and site visits. The 
Agency is confident that the waste management practice data found in 
this investigation are adequate for risk assessment modeling, and that 
using other modeling practices not found would only lead to using 
hypothetical waste data that do not represent any activities that 
resemble reality. To engage in this kind of hypothesis would be likely 
to result in forcing significant additional costs on the public with no 
incremental risk reduction from regulating the wastes in question. The 
Agency notes that no commenter identified any specific solvent users of 
these chemicals not already found by the Agency. Also, the commenter 
could not suggest any alternative to the Agency's methodology other 
than a listing based on hypothetical uncertainties--an approach not 
justified by the data.
    The Agency sent almost 1,500 preliminary questionnaires asking 
facilities how much of each chemical was used as a solvent in 1991 and 
1992. The data showed that the Agency was successful in identifying 
many solvent users, although more than 900 facilities were eliminated 
from further consideration because they did not use any of the 
chemicals as a solvent. The Agency was also able to eliminate another 
400 facilities from consideration to receive the final questionnaires 
due to reporting errors, discontinued use, or reported use of small 
quantities of the solvents. The fact that the vast majority of 
facilities that received the preliminary questionnaire reported no 
solvent use supports EPA's view that many potential solvent users, in 
fact, do not use these chemicals this way. The Agency found that 
reported uses of very small quantities of the chemicals as solvents 
were often inaccurate, but facilities reported these quantities to err 
on the side of caution. The remaining

[[Page 64378]]

156 facilities received a large, detailed questionnaire requesting 
information on solvent uses and waste generation and management 
practices. The listing determination is based on these data.
    The details of the data collection effort also brought another 
point to the Agency's attention. While other solvents are used in 
countless industries and facilities and would be difficult to 
characterize, the particular set of solvents in this listing 
determination has much more limited applicability. EPA's literature 
search found these chemicals to have many and varied ``nonsolvent'' 
uses. Data collected from the questionnaires confirmed the general lack 
of wide solvent use, as discussed below.
    While reference sources (e.g., SRI Chemical Economics Handbook) 
indicated many of these chemicals are produced in fairly high 
quantities, these references reported significant quantities used as 
solvent for only four of the fourteen chemicals studied: acetonitrile, 
2-methoxyethanol, furfural, and methyl chloride. This is consistent 
with what EPA found in its 3007 Survey for these four chemicals. 
Furthermore, as described in the Listing Background Document and the 
proposed rule, the solvent uses of furfural and methyl chloride were 
limited to a single specialized use in each case, and these users were 
fully surveyed. Solvent use quantities were not reported in reference 
sources for the other ten chemicals. Four of the ten were those for 
which EPA also found no solvent uses (benzyl chloride, epichlorohydrin, 
ethylene dibromide, and p-dichlorobenzene). For an additional four, 
EPA's Survey found that the amounts of the production quantities used 
as a solvent were small compared to total production (cumene-0.026%; 
cyclohexanol-<0.1%; 2-ethoxyethanol acetate-1.2%; isophorone-1.7%); 
this is also consistent with the lack of significant quantities of 
solvent use reported in reference sources.
    The remaining two chemicals are special cases. The domestic 
production of 2-methoxyethanol acetate is reported to have ceased, and 
the small volume of total solvent use found by EPA in its Survey (1,673 
kg/year) confirms the lack of significant solvent use. EPA did find 
significant solvent use of the final chemical, phenol, which was not 
reported in most other reference sources. However, nearly all (>99%) of 
the solvent use quantity found in the Survey was from one facility that 
produces phenol for its own captive use. This ``native'' phenol is 
produced as a byproduct of other processes, and would not be reported 
in production or use data in reference sources. Leaving out this volume 
from one facility, EPA's Survey shows that the fraction of phenol 
production that is used as a solvent is low (<0.2%), which is 
consistent with the lack of any significant solvent use quantities 
reported in reference sources. In any case, the vast majority of phenol 
solvent use reported in the 3007 Survey was a very specialized use; the 
petroleum industry uses phenol to extract lube oil from residual oil. 
EPA surveyed all petroleum refiners in its Survey; thus EPA is 
confident the Survey captured all major solvent users for this 
chemical.
    The Agency disagrees that it should project standard mismanagement 
scenarios not indicated by the data, because the rationales for 
selection of a particular set of plausible management scenarios are 
specific to each solvent. Based on the general rationale just discussed 
and the data for each of the chemicals as given in detailed discussion 
in the Response to Comments Document for each of the chemicals, the 
Agency has confidence in the data set as the best available effort to 
assess the chemical use universe and actual waste generation and 
management scenarios. Merely developing hypothetical waste generation 
and management scenarios, as suggested by the comment, has no sound 
basis in fact. This would lead to the danger of over regulating risks 
that do not exist and siphoning off scarce resources to deal with those 
non-risks, rather than risks that may be more worthy of the public's 
attention.
    For these solvents, the Agency has no reason to project management 
scenarios beyond what was found through questionnaires and site visits. 
The Agency found the vast majority of wastes managed in tanks and 
incinerators. Where a waste was managed in a surface impoundment, the 
Agency performed that modeling under high-end exposure assumptions. The 
Background Document to the proposal and the Response to Comments 
Document both present more detailed assessments of how each individual 
chemical is used, what wastes are generated, and what management 
scenarios were selected. For example, no management scenarios were 
selected for p-dichlorobenzene, epichlorohydrin, ethylene dibromide, 
and benzyl chloride because none of these chemicals are used as 
solvents. For most other chemicals, the uses are extremely limited and 
specific. See the sections devoted to the individual chemicals for 
specific rationales, and the discussion of management scenarios in 
section IV.B.4.
    Below, EPA responds to the specific issues raised in comments that 
the Agency's survey was inadequate to characterize the solvent uses and 
mismanagement scenarios.
    One commenter pointed out that EPA surveyed only a small percentage 
of facilities within very few SIC codes. The commenter stated that for 
several solvents, the quantity of sectors potentially affected 
outnumbers the quantity of facilities forming the basis for EPA's 
plausible mismanagement conclusions. As an example, the commenter 
stated that for 2-methoxyethanol acetate, EPA identified seven 
industrial sectors potentially affected by this chemical, but sent only 
the questionnaire to three facilities using the solvent.
    The Agency disagrees with this comment. As previously mentioned, 
this listing determination covers 14 chemicals used as solvents. In 
order for the Agency to determine the universe of facilities 
potentially affected by this listing determination, it sent out 
preliminary information surveys to obtain basic solvent use 
information. The Agency sent this survey to nearly 1500 facilities 
based on an evaluation of chemical usage. Given this large universe of 
facilities and the potential to obtain useful information on solvent 
use in this mailing, the Agency also decided to include in this 
preliminary questionnaire questions concerning seven other chemicals 
(in addition to the 14 already included in this listing determination) 
which it was also investigating under a Solvent Study mandated by the 
court.
    The prequestionnaires showed that about 600 facilities reported any 
possible use of one or more of the chemicals as solvents. The Agency 
conducted further evaluations and screening and identified 156 
facilities to which it sent the more detailed ``full'' questionnaire 
concerning the use of the 21 chemicals as solvents (14 for this listing 
determination and 7 for a separate Solvents Study). Thus, only about 
10% of the facilities that were sent preliminary questionnaires used 
significant amounts of these chemicals as solvents. As described in 
today's document in response to other comments, this screening removed 
facilities that did not use the chemical as a solvent (as defined by 
EPA), and small volume users. For a more detailed description of this 
screening and evaluation see, please refer to section III.A in the 
Response to Comment Document for this rulemaking.
    The results of this final questionnaire showed that 4 out of the 14 
chemicals in this listing determination were not

[[Page 64379]]

used as solvents and that 10 of the 14 chemicals were used a solvents 
to varying degrees. The industry sectors listed by SIC code by the 
commenter are ones which typically do not use any of the 14 chemicals 
as solvents and, thus, did not yield data to be considered in 
evaluating plausible management scenarios. Further, as discussed 
earlier in this section, all other indications from the Agency's survey 
show that the amounts of solvent use EPA found were generally 
comparable to the solvent use found in other references. The volume of 
solvent use found by the Agency is also consistent with what the Agency 
knows about the likely technical usefulness of these chemicals as 
solvents. A limited set of industries exists in which these chemicals 
are used as solvents, as discovered through standard reference sources.
    The commenter presented a plethora of small companies on the SIC 
code list that operate on lower margins. The Agency believes that these 
companies are not likely to use these higher cost chemicals for generic 
solvent use processes. The Agency believes that if any of these 
chemicals had been used as solvents in other industries, as the 
commenter postulates, the Agency would have found this information 
during its data collection. The facilities surveyed by the Agency share 
many processes with the large number of smaller facilities in the lists 
presented by the commenters (equipment cleaning, electroplating, etc.). 
However, the chemicals at issue are rarely, if ever, used as solvents 
in those processes in the facilities found by the Agency.
    Also, the Agency recognizes that the commenter cites a greater 
number of facilities within each SIC code than the number to which EPA 
has sent questionnaires. These facility numbers are obtained from a 
data base (Dun & Bradstreet) that is not linked to chemical use. Many 
of the addresses represent corporate headquarters, not facilities that 
use or generate hazardous waste, and a single facility may have more 
than one Dun & Bradstreet number. Therefore, EPA believes that the 
number of facilities reported within each SIC code based on this data 
is exaggerated.
    The commenter cites 2-methoxyethanol acetate and methyl chloride as 
examples, stating that ``EPA identified seven industrial sectors 
potentially using 2-MEA, but only three facilities using the solvent 
received the final questionnaire.'' As presented in the background 
document, 14 facilities received the full questionnaire based on their 
response to the preliminary questionnaire. However, based on their 
response to the full Survey, 11 of these 14 facilities discontinued use 
of 2-MEA or did not use it in a manner that met the regulatory 
definition of solvent use. Only two industries reported using 2-MEA in 
1994 that met the definition of solvent use. The commenter further 
states ``In the case of methyl chloride, EPA identified eight SIC codes 
potentially using the solvent, while only seven facilities received the 
final questionnaire.'' As presented in the background document, 32 
facilities received the full questionnaire based on their response to 
the preliminary questionnaire. However, based on their response to the 
preliminary questionnaire, 24 facilities were TSDs, and as a result the 
chemical consumption reported could not be linked to solvent use. Other 
facilities did not use methyl chloride in a manner that met the 
definition of solvent use, or used extremely small volumes (less than 1 
kg) that generated wastes with no methyl chloride. Thus, this left only 
four facilities that reported solvent use of methyl chloride in two 
industries, and essentially all of this use was in the synthetic rubber 
manufacturing.
    One commenter stated that EPA chose to review chemical abstracts 
for only a four-year period, and for other solvents limited the search 
to a 10-year period. Therefore, older uses of the solvents would not 
have been identified through the literature search. The commenter also 
states that newer or less studied solvent uses would not appear in the 
public literature. The commenter disagrees with the Agency's assertion 
that few, if any, solvent uses were missed using this method.
    In response, the Agency does not believe that searching Chemical 
Abstracts for an unlimited time period for all 14 solvents is 
justified. If a process was developed more than ten years ago and is 
still in use today, it would appear in more recent Chemical Abstracts 
or be reflected in alternative data sources, such as Effluent 
Limitations Guidelines or the SRI Chemical Engineering Handbook. 
Furthermore, the further back the search is conducted, the more 
unlikely that the use identified will still be employed today. Newer 
solvent uses, if confined to small scale laboratory use, would not 
change the solvent use universe significantly and would be reported as 
laboratory waste (and managed accordingly, most likely as a hazardous 
waste because spent solvents exhibit a Characteristic or contain listed 
wastes). Once such a process enters large-scale commercial use, 
reporting generally appears on some standard database or literature 
source that the Agency would find. The probability that a solvent use 
would, in one year, not exist and then appear in large scale is 
extremely low. Small volume solvent uses of these chemicals are not 
critical to EPA's evaluation, because any risks from larger volumes 
usage (and corresponding larger loadings in wastes) are likely to be of 
greater concern. Most of the companies that would conduct the types of 
research and development to find new uses are generally reporters to 
databases like the TRI, and as such, would report any significant uses 
of these solvents.
    The commenter also stated that some chemicals, such as 
cyclohexanol, furfural, and isophorone, are not reported under TRI. For 
the remaining solvents, TRI reporting is not required when chemicals 
are ``otherwise used'' in quantities of 10,000 pounds or less 
(equivalent to 4,540 kg or less). The commenter argued that substantial 
quantities of the solvents can be used and not reported under TRI.
    In response, in cases of the three chemicals for which the TRI data 
base was inadequate, the Agency relied on other sources more heavily. 
In fact, the TRI was only one source for all chemicals in the listing 
determination, even those covered by TRI. Because the Agency was aware 
that these chemicals were not required to be reported pursuant to TRI 
at the time of the solvent use industry characterization, the Agency 
relied on additional sources cited in the Listing Background Document. 
Through literature searches, potential solvent uses were identified in 
several SIC codes for cyclohexanol, furfural and isophorone.
    Moreover, since the questionnaire data were collected, the Agency 
added cyclohexanol to the TRI. Analysis of TRI chemical use data on 
cyclohexanol confirms the Agency's literature search and determination 
of the universe of users of this chemical as a solvent. While 24 
facilities reported cyclohexanol manufacturing processes in the TRI, 
only one facility reported the ``otherwise use'' category of 
cyclohexanol that could potentially be solvent use. Thus, the TRI data 
show that the Agency might have sent out only one additional 
preliminary questionnaire (EPA received 37 responses to preliminary 
questionnaires for cyclohexanol). Further investigation by EPA revealed 
that cyclohexanol was not used as a solvent at this one site. This new 
information substantiates EPA's original findings that there are no 
other large users of cyclohexanol as a solvent. See section III of the 
Response to Comments Document in the docket for details of the new TRI 
information.

[[Page 64380]]

    The commenter argued that many of the solvent uses EPA did identify 
involve extremely high concentrations of the chemicals, up to and 
including pure solvent. These pure solvent uses can generate wastes in 
quantities 100 times larger with concentrations of 1%, still 
significantly in excess of concentrations that may pose a substantial 
risk to human health or the environment.
    The Agency disagrees with the commenter that the risks of concern 
were not analyzed. In fact, the Agency's modeling considered 
environmental loadings of these chemicals resulting from solvent uses 
ranging from 100 percent to the part-per-million (ppm) level. The 
Agency evaluated potential releases of high percentage solvent uses 
that lead to greater loadings than would result from a one percent 
level in the waste. Modeling of these chemical releases under high end 
exposure conditions did not result in risks of concern.
    In response to the commenter's concerns that small volume users 
might generate wastes of concern, perhaps due to different management 
practices, the Agency examined the data in hand from the Survey for 
such users. Facilities that received Surveys due to significant use of 
some solvents (>1,200 kg/yr), also used other solvents in lower volumes 
in some cases. Thus, the Agency has data on wastes from facilities that 
used small volumes of solvents, (see Listing Background Document, 
Appendix I). EPA reviewed the management practices for wastes generated 
by these smaller volume uses to see if any differences were evident. 
For all 10 solvents, EPA found a total of 73 wastes that were generated 
from solvent uses below 1,200 kg. The Survey data show that these were 
managed in ways that were very similar to practices reported for larger 
volume uses. Of these 73 wastes, 69 were incinerated or otherwise 
thermally treated (nearly all were classified as hazardous because they 
exhibited a hazardous Characteristic, or due to the presence of other 
listed hazardous waste), three wastewaters were treated in tanks, and 
one wastewater was treated in a surface impoundment (the chemical in 
the impoundment, acetonitrile, was evaluated through modeling). 
Furthermore, 67 of the 73 wastes reflected solvent use at 
concentrations of 50-100%, i.e., many of these wastes were generated 
from use of solvents at high concentration. None of these wastes from 
small volume users present any special risk, because risk analyses 
using larger loadings going to these management practices found no 
significant risks. Therefore, the existing data support EPA's belief 
that wastes from small volume users are not of any special concern. 
Furthermore, these wastes are nearly all handled as hazardous, which is 
also consistent with the general pattern found for other larger volume 
wastes.
    Two commenters stated that they agreed with EPA's decision to limit 
the solvents listing investigation to facilities that use a combined 
total of 1,200 kilograms or more per year of all chemicals of concern 
used as solvents because the commenters feel that this level represents 
a reasonable characterization of the universe of solvent users. One of 
these commenters requested clarification to ensure this approach would 
not be misconstrued by hazardous waste generators when determining 
their generator category. In response, the Agency is confirming that 
the cutoff categories used by the Agency in this listing determination 
are not to be construed by any actual or potential hazardous waste 
generators to be a means of determining waste generator categories. 
Furthermore, EPA did consider solvent uses below the 1,200 kg threshold 
as noted above, however, the Agency found that such small quantity use 
is highly unlikely to present risks of concern when compared to the 
risks from larger users.
    However, another commenter stated that EPA's rationale for deleting 
facilities using 1,200 kg or less of solvent in 1992 was that only 
large quantity solvent users could be expected to have treatment, 
storage, and disposal (TSD) units on-site, and that many of the solvent 
uses are peculiar to large companies. The commenter stated that this 
limitation in the data collection introduces bias against solvent 
generators relying upon commercial services, including offsite 
nonhazardous landfills, for their waste management needs. The commenter 
then argued that the Agency cannot assume offsite disposal in a 
nonhazardous waste landfill is rarely practiced when EPA intentionally 
excluded those facilities most likely to use such facilities by not 
surveying smaller volume users.
    The reasoning cited by the commenter is taken out of context and 
does not reflect EPA's rationale. EPA did not decide to eliminate small 
volume users because they would not have on-site treatment 
capabilities. Rather, EPA determined that the burden of completing a 
complex, 100-plus page questionnaire would not be commensurate with the 
value of the information EPA would receive. EPA would not gain useful 
information from small users because many of these facilities, if they 
use these chemicals as solvents at all, would present low risks 
compared to larger solvent users. Furthermore, as noted above, EPA did, 
in fact, capture small users of solvents in the full Survey, and found 
no special management or risk concerns that were not reflected in it 
evaluation of larger solvent users.
    Facilities are likely to use on-site as well as off-site waste 
management practices, and sometimes a combination of the two. This is 
evidenced in responses to the 3007 Survey, wherein respondents 
indicated that both on-site and off-site practices were employed. The 
3007 Survey has captured numerous facilities that use commercial 
services. Based on the results of the Survey, 62 percent of the 
wastestreams are managed in commercial offsite treatment or disposal 
units. As such, the Agency does not believe there is any significant 
bias in its Survey.
    In addition, EPA points out that the vast majority of small solvent 
users eliminated by EPA reported using amounts well below the 1,200 kg 
threshold. In fact more than 90% of those eliminated reported used less 
than 120 kg total for all of the solvents studied. EPA found that uses 
of such small volumes typically were reported for laboratory uses, are 
difficult to verify, and may be reported as solvent use if laboratory 
uses are not known. The 1,200 kg/yr cutoff is an appropriate surrogate 
for identifying facilities that may potentially generate large amounts 
of hazardous waste or waste with high solvent loadings. EPA believes 
the facilities with larger solvent uses would be most likely to provide 
useful data through the questionnaire, i.e., data based on verifiable 
solvent use that could then be used in developing risk assessments.
    One commenter argued that solvent use fluctuates from year to year, 
thus uses below 1,200 kg could increase dramatically in the future due 
to process changes, increases in production, or solvent substitutions. 
The commenter went on to state that use volumes for some solvents 
reported in the final questionnaire for 1993 were higher than the rates 
reported for the same facilities in the preliminary questionnaire for 
the prior year. The commenter stated that EPA fails to appreciate the 
consequence of these fluctuations and substantial changes can be 
expected from year to year, e.g., a facility using less than 1,200 kg 
of solvent one year may use more than that amount the next year. The 
commenter concludes that EPA lacks an objective basis for simply 
assuming the data it collected is fully dispositive with

[[Page 64381]]

respect to future solvent uses and management practices.
    EPA believes that the data collected provides a reasonable bases 
for decision-making. The purpose of the preliminary questionnaire was 
to capture what occurs at the facilities surveyed during a typical 
year. As was expected, some facilities' solvent use consumption 
decreased between the two years and other facilities' solvent 
consumption increased between the two years. The Agency does not expect 
solvent consumptions to be identical from year-to-year, but has no data 
to indicate that 1993 is an atypical year. Even if the specific 
facilities meeting the cutoff varied from year to year, EPA believes 
the data gathered from facilities studied provide a representative 
database. The Agency used the most recent data when determining the 
1,200 kg cutoff for those facilities receiving the full questionnaire.
    EPA considered whether or not solvent management practices were 
likely to change in the future from those reported in the 3007 Survey. 
The Agency determined that there was no reason to believe that they 
would, regardless of the volume fluctuation. In the case of 
wastewaters, EPA has no reason to believe that a facility would convert 
from a tank-based system to a surface impoundment given the capital 
investment and liability issues associated with land-based treatment, 
particularly when facilities do not have the physical space for a 
surface impoundment or have closed surface impoundments in favor of 
tank-based systems. For nonwastewaters, EPA has no reason to believe 
that a facility would switch from the thermal treatment of high organic 
wastes to disposal in a nonhazardous landfill due to the BTU value and 
the liability issues associated with land-based disposal.
    The Agency cannot accurately predict with specificity future uses 
of the fourteen chemicals, nor is it reasonable for EPA to regulate 
solvent waste based on some purely hypothetical future use. While the 
solvent consumption may change over time for some facilities, such 
fluctuations are unlikely to significantly affect EPA's current risk 
conclusions for several reasons. First, in its risk analyses EPA used 
high-end or maximum solvent loadings to project potential risks. Thus, 
EPA's evaluation is not likely to change due to some volume use 
fluctuations. In addition, for most of these solvents (and specifically 
for three noted by the commenter, acetonitrile, 2-methoxyethanol 
acetate, and isophorone), the vast majority of wastes are regulated as 
hazardous due to the hazardous waste characteristics (see 40 CFR 
261.20-261.24) or mixing with other listed wastes. Thus, any increase 
in volume use would result perhaps in somewhat higher solvent 
quantities reaching wastes that would be already regulated and thus 
unlikely to pose significant risk. Therefore, while EPA agrees that its 
Survey is more-or-less a ``snapshot'' of waste generation data, the 
Agency continues to believe that such an approach has yielded data that 
are representative, and is a reasonable way to assess potential risks.
    The commenter also stated that EPA excluded any laboratory uses of 
the solvents from the universe of facilities receiving the preliminary 
questionnaire, notwithstanding the Agency's observation that ``lab 
use'' of chemicals was not restricted to small volumes.
    The Agency did not exclude laboratory uses of solvent from the 
universe of facilities. The Agency was precluded from sending a 3007 
Survey to all laboratories due to the sheer number of labs that exist 
in the United States, approximately 183,000 according to an estimate by 
EPA. (For details please refer to the Response to Comments Document). 
Many of these laboratories are small, comprising research labs 
(12,500), medical laboratories (22,700), and university labs (108,000), 
as well as small analytical labs (40,000). The resources necessary to 
complete a RCRA 3007 questionnaire would be beyond the means of many of 
these small businesses as organizations. Nonetheless, the Agency 
captured the solvent uses and management practices of numerous (32) 
captive on-site laboratories of facilities who received the 3007 
Survey. In doing so, the Agency captured large research, QA/QC, and 
analytical laboratories that operate at the same or larger scale as the 
small labs not surveyed. Approximately 38% of the laboratories captured 
were small laboratories (i.e., using <1,200 kg of solvent use).
    The Agency found that in industrial facilities, the proportion of 
laboratory use of a solvent compared with the chemical process use is 
about 1% or less. After consulting with the American Chemical Society, 
college and university hazardous waste managers, standard references, 
and OSHA guidelines, the Agency determined that laboratory wastes are 
managed as hazardous because they are usually mixed with other 
hazardous wastes, often with acutely hazardous wastes. In addition, 
with the exception of acetonitrile (which has specialized uses in 
laboratories as a solvent for high pressure liquid chromatography, or 
HPLC), the reported use of any of these chemicals is suspect, and is 
attributable to facilities reporting ``solvent use'' in the 
questionnaires as a precautionary measure. Few of the chemicals under 
examination are likely to find extensive use as solvents in the 
laboratory. For example, very few of the standard laboratory test 
methods specified by EPA call for use of these chemicals as solvents. 
For a complete summary of the laboratory use of solvents please refer 
to the Response to Comments Document.
2. Engineering Site Visit Reports
    One commenter stated that the engineering site visits were 
superficial and did not encompass a thorough review of waste 
management, solvent waste characteristics, and potential environmental 
releases or damage from waste handling. The commenter acknowledged that 
EPA's objective for the site visits was simply to determine if a 
facility should be sent a full questionnaire, and to educate the 
facility on the solvent listing process, but stated that this seems 
like a waste of effort, given that more valuable information could have 
been obtained from the site visits regarding waste properties, handling 
and environmental damages.
    The commenter also noted that none of the visits involved any 
sampling efforts. No analytical or characterization data are presented 
on the concentrations of solvent constituents in the waste streams 
observed at the industrial sites visited. The visits were typically two 
hours, with anywhere from 0-60 minutes spent actually touring the 
facility. One site visit was conducted from a tour van and was strictly 
a ``windshield audit,'' and two were strictly conference room audits. 
The reports did not investigate, evaluate, or address any historical 
spills, releases to groundwater or surface water, or any other 
environmental damage from use of the solvent or handling of the wastes.
    These comments misconstrue the reasons EPA conducted the site 
visits and the information that could practically be developed from 
them. The purpose of the site visits was to familiarize the Agency with 
the multitude of processes and industries potentially subject to the 
investigation through ``first person'' experience rather than 
``textbook'' learning. The Agency disagrees that the Engineering Site 
Visits were superficial given their purpose of site familiarity, not 
data collection. The Agency points the commenter to the engineering 
site visits reports that each state EPA's objectives in undertaking the 
site visit--of which those cited by the commenter are but two. The site 
visits were performed to

[[Page 64382]]

obtain a first hand understanding of solvent utilization and also to 
develop a working relationship with the industries. Moreover, the site 
visits served as an outreach mechanism for EPA to interact with 
industry and inform potentially affected industries of the 
investigation. Site visits afforded EPA staff an opportunity to become 
familiar with processes used in specific industries, field test the 
questionnaire, and assess ongoing pollution prevention activities.
    EPA obtained the ``valuable information'' cited by the commenter in 
a more comprehensive way through the questionnaires. EPA collected data 
on waste properties and management practices through the 3007 Survey, 
which contains detailed, site-specific information from 156 facilities. 
It would not be practical for EPA to visit all sites to gather detailed 
information on solvent use. Therefore, EPA's reliance on the 3007 
Survey is eminently reasonable for collecting information on waste 
characterization data, release, and waste management practices. Visits 
conducted following the receipt of RCRA 3007 Questionnaires helped EPA 
to better understand the type of processes used in target industries 
and the data provided by respondents, and also provided confirmation of 
the data provided. The Agency was able to focus on larger scale users 
and specific processes up-close, based on the information reported in 
the 3007 Survey.
    As discussed in detail in the Response to Comments Document, tours 
of the facilities lasted as little as 1.5 hours and as much as 3.5 
hours, with a minimum of 30 minutes and a maximum of more than 2 hours 
spent on tour and/or on the plant floor. Information related to spills, 
releases and other environmental damage was requested in the 3007 
questionnaire and collection of this type of information was not the 
focus of these visits. The Agency takes issue with the commenter's 
characterization of the visits as ``windshield audits.'' None of the 
site visits were mere tours from a van. The Agency personnel witnessed 
many operations on a site and were able to walk around the facility. 
The commenter also mischaracterized several other details of individual 
site visit reports. The Agency has corrected these misconceptions in 
the Response to Comments document and provided clarification to clear 
up any confusion, as necessary. For more detail on the sampling issue, 
please refer to section IV.B.2 of today's document.

B. Methodology

1. Definition of ``Solvent''
    One commenter objected to the Agency's characterization of solvent 
use as too limiting, stating that solvents contained in paints, 
coatings, dyes, fuels, etc. are still mobilizing agents, and that they 
unleash the same environmental impact when these products are spilled 
or released. The commenter also points out that being able to 
solubilize or mobilize other constituents in a formulation still meets 
the Agency's definition of solvent use.
    The Agency disagrees, and notes a long-standing policy of treating 
these cases differently. The discussion of the scope of the solvent 
listings and the applicable definitions appears in section I.B, above. 
As noted there, process wastes where solvents were used as reactants or 
ingredients in the formulation of commercial chemical products are not 
covered by the listing. The products themselves also are not covered. 
The commercial formulations in which solvents are often ingredients are 
generally products that are not wastes under RCRA. Where these products 
are not in some way already regulated, the Agency could examine these 
materials if they become wastes and if deemed necessary. However, with 
a backlog of listing determinations to complete under court-ordered 
deadlines, the Agency has focused its current efforts on those 
determinations required by law. The Agency is under direction from 
Congress to consider listing wastes from ``solvents'' and that 
direction has been incorporated into the Consent Decree. Thus, the 
Agency has focused its resources on the rather narrow set of risks 
described in this Federal Register document and the rulemaking record 
for this decision.
2. Lack of Sampling and Analysis
    Two commenters objected that EPA performed no sampling and analysis 
of these waste streams. One commenter stated it is impossible for EPA 
to come to any listing determination without some independent sampling 
and characterization of these wastes. Useful characterization data 
could have been obtained by sampling wastes from a subset of the 156 
respondents representative of all the SIC codes using the wastes, 
according to this commenter.
    EPA does not agree that it would obtain useful information from 
independent sampling of the solvent wastes. The solvents listing 
determination covers a number of industries using different solvents 
for different purposes and in different ways. The greatest challenge 
would be in collecting a sufficient number of samples to characterize 
each of these uses. Assuming that EPA were to sample all 10 solvents, 
obtain both a wastewater and a nonwastewater sample, and gather samples 
from the industries using the solvents (at an estimate of three 
industries on average per solvent), the baseline number of samples 
required would be 60. In addition to baseline samples, to conduct a 
valid sampling exercise the Agency also would need to sample for 
variability, that is, the Agency would take samples at several 
locations within a single facility and would take samples at several 
facilities within an industry group using the same solvent. Assuming 
that an additional two samples are taken within the same facility, and 
then an additional two facilities are visited, the total number of 
required samples reaches 540. This number still might not allow EPA to 
fully characterize solvent wastes. Thus, the Agency would be spending 
scarce resources on a massive sampling effort, when the data need could 
be more efficiently obtained by methods other than independent 
sampling. While EPA could attempt a more limited sampling approach, the 
result would not be likely to provide a sound basis for making listing 
decisions.
    By definition, the concentration of the solvent must be relatively 
high before use, and this would allow use of mass loadings in 
calculating maximum waste levels, as needed. The Agency felt that it 
could rely on the questionnaire data, and no information has been 
submitted in comments to show that sampling and analysis was needed to 
confirm the concentrations in the solvent wastes reported. The 
facilities provided ranges of concentration where concentrations within 
a waste stream varied. When data were reported as ranges, the Agency 
used the high end of concentration ranges as a conservative approach in 
its risk assessment.
    The Agency does not have reason to believe that the solvent 
concentrations reported are underestimated. In many instances copies of 
laboratory data showing the solvent concentration(s) in a sampled 
residual were provided with the respondents' 3007 survey. The reported 
data seem reasonable and correspond with observations of residual 
streams during Engineering Site Visits. The solvent concentrations and 
residual volumes were further substantiated through mass balances 
performed on the solvent use processes by reviewing the 3007 survey 
responses (see section III.B of the Response to Comments Document). EPA 
evaluated the data contained in the 3007 Survey

[[Page 64383]]

responses for any inconsistencies or missing residuals. If any 
inconsistencies or missing residuals were found, a follow up phone call 
was made to the appropriate facility for additional information. Where 
applicable, this additional information can be found in the docket 
along with the 3007 Survey Responses. Therefore, the Agency feels 
comfortable that it can rely on the reported data to adequately 
characterize risk.
    EPA has used 3007 Survey data extensively in the past in making 
listing determinations. In this case, each survey was signed by the 
responsible party to indicate that the information reported is 
accurate. The Agency does not have reason to believe that the 
facilities would falsify or omit any of their data in light of the 
substantial penalties for submitting false information. In instances 
where concentrations were unclear or unreported, telephone contact was 
made with the facility.
    Two commenters stated that EPA is required to consider the presence 
of any hazardous constituents, not just the solvent itself, because 
other hazardous constituents may be present in the waste due to 
impurities, other chemicals used in the same processes or managed in 
the same equipment as the solvents, and chemical reactions occurring in 
such processes or equipment.
    EPA does not agree that the Agency is required to consider other 
constituents present in the wastes examined. Indeed, due to the extreme 
variability of these other constituents in the solvent wastes across 
industries, EPA would undoubtedly find it impossible to categorize 
these wastes under 40 CFR 261.11(b) if it considered the other 
constituents. The solvent uses found for acetonitrile illustrate this 
problem graphically. Acetonitrile is used as a solvent in various 
industries, including pharmaceuticals, petrochemicals, photographic 
chemicals, and other chemical manufacturers (see the Listing Background 
Document, section 4.0). The actual uses of acetonitrile also are 
variable, and include uses as a reaction medium for the synthesis of 
numerous different chemicals, and as chromatographic eluent for 
analytical or preparative separation of various chemicals from 
different impurities. Wastes resulting from such widely varying 
processes across different industries cannot be expected to have 
consistent waste constituents, except for the solvent itself.
    As the commenter pointed out, other constituents could originate 
from various sources in the use of a solvent. Thus, other constituents 
are dependent on other solvents used, the specific solvent use, other 
processes carried out at a facility, other wastes that may be generated 
from other processes onsite, etc. Because of the wide variability in 
waste constituents that might arise in wastes from use of the solvents, 
the Agency focused on the solvent chemical itself. Other constituents 
may vary widely for different industries and solvent uses; thus, the 
Agency believes the only practical approach to evaluating such wastes 
for potential listing is to consider the risk posed by the solvent 
chemicals under examination.
    The language in the existing F-listed solvents illustrates EPA's 
special concern with the solvents themselves in defining the scope of 
the listings; the listings are applicable only to wastes derived from 
the use of the solvents at levels of ten percent or more. In the case 
of the current solvents rulemaking, the Agency evaluated the common set 
of chemicals, i.e, the 14 solvents of concern. The Agency's assessment 
of these 14 solvents shows no risk to human health or the environment 
from these wastes, as discussed in detail elsewhere in this document.
3. Consistency of Methodology With Other Listing Determinations
    One commenter asserted that, contrary to EPA's claim, the listing 
determinations in today's rule were based on scenarios that are 
different from those EPA used in both the proposed Dyes and Pigments 
listing determination (59 FR 66072, Dec. 22, 1994) and the proposed 
Petroleum Refining Process waste listing determination (60 FR 57747, 
Nov. 20, 1995). The commenter stated that in the Dyes and Pigments 
proposal, EPA used plausible mismanagement scenarios of disposal in 
unlined municipal landfills and on-site monofills, in addition to other 
plausible scenarios (wastewater treatment tanks, industrial boilers). 
The commenter stated that in the Petroleum Refining Waste determination 
EPA also considered plausible mismanagement scenarios, including 
disposal in on-site and off-site Subtitle D landfills. The commenter 
argued that EPA did not follow the policy used in the Dyes and Pigments 
and Petroleum Refining rules in the proposed solvent listing because 
EPA did not consider mismanagement scenarios that reasonably could be 
employed, particularly land disposal in unlined landfills. The 
commenter stated that there is nothing that prevents a solvent waste 
generator from land disposing the solvent waste, and substantial 
evidence of land disposal practices was found in the docket to the 
proposed solvent rule.
    In response, EPA disagrees that the methods for determining 
plausible management scenarios in this rule is inconsistent with either 
the proposed Dyes and Pigments listing or the Petroleum listing. In 
both cases, EPA used appropriate evidence to evaluate current 
conditions and to project plausible future scenarios. The Agency does 
not presume unlikely worst cases or hypothesize scenarios that are not 
likely in the interests of avoiding listing decisions that would not 
result in incremental benefits to public health or the environment. See 
Dithiocarbamate Task Force v. EPA, 98 F.3d 1394, 1401 (D.C. Cir. 1996).
    With respect to the Dyes and Pigments proposal, management in 
unlined municipal landfills and on-site monofills was reported in the 
3007 Survey for certain wastes. EPA found that nearly all dye and 
pigment waste sludges/solids studied had, in fact, been disposed in 
unlined municipal landfills. Thus, the Agency determined that placement 
in an unlined landfill was plausible for most dye and pigment 
wastestreams.
    However, EPA did not consider disposal in landfills plausible for 
all Dyes and Pigment wastes, and considered the specific facts for each 
waste. For example, EPA proposed not to list one category of waste, 
wastewater treatment sludges from the production of triarlymethane 
pigments using aniline as a feedstock, despite risks that might arise 
if the waste were send to a landfill. For this waste category, EPA 
determined a landfill was not plausible management (see 59 FR 66096). 
This was because the current management practice was blending with fuel 
for combustion, and EPA decided that the high organic content and fuel 
value of the waste made it implausible that landfill disposal would 
occur. This is entirely consistent with EPA's approach in today's rule 
for a similar waste derived from use of acetonitrile as a solvent. As 
described in the specific section on acetonitrile (section IV.D3), EPA 
does not view risks that might arise from landfill disposal as 
significant because such disposal is unlikely given the current 
practice of fuel blending and the confirmed fuel value of the material.
    The commenter is also incorrect in asserting that the approach used 
in today's rule is inconsistent with that used in the Petroleum 
Refining proposal. In that proposal the Agency evaluated landfill 
disposal for many of the wastes examined, because, in fact, this 
practice was reported to occur for those wastes. Contrary to what the 
commenter implied, EPA did not project landfill disposal in the 
Petroleum

[[Page 64384]]

Refining proposal as plausible for wastes that had no evidence of such 
disposal.
    The commenter also stated that the Agency violated its own risk 
assessment criteria as presented in the listing determination for the 
proposed Dyes and Pigments wastes (see 59 FR 66076). The commenter 
pointed out that EPA states in the preamble that it is the Agency 
policy that a high-end hazard quotient above 1 represents a risk level 
for presumptive listing, and a high-end hazard quotient above 2 is a 
definite basis to list. The commenter argued that, if EPA applies this 
policy to the solvent listing determination, at a minimum both 
acetonitrile and 2-methoxyethanol have hazard quotients exceeding this 
criteria (HQ of 200 and 16, respectively), and should have been listed.
    EPA disagrees that its decisions in today's listing are 
inconsistent with its listing policy. As the Agency explained in the 
proposed rule, EPA's risk assessment for acetonitrile indicated HQs 
below one at the bounding level for incineration and at the high-end 
for wastewater treatment tanks and for open storage tanks. EPA's risk 
assessment for 2-methoxyethanol indicated HQs below one in bounding 
analyses for wastewater treatment tanks and incineration and no risk 
for the storage tank scenario. The HQs cited by the commenter were 
reported as part of an intermediate stage of the analysis, as reported 
in the background document for the proposed rule, specifically, 
Sec. 5.7 of the Assessment of Risks from the Management of Used 
Solvents. This intermediate stage was used to decide if further 
evaluation was necessary. Because possible risks of concern were found, 
EPA proceeded to a third phase of assessment. After consideration of 
the fact that nearly all of the wastes evaluated in the intermediate 
analyses were already hazardous, EPA's assessments for these scenarios 
indicated risks below levels of concern for the remaining nonhazardous 
waste streams (see Supplemental Risk Assessment). These multi-phase 
assessments are discussed further in response to specific comments on 
acetonitrile in section IV.D.3 of today's document.
4. Plausible Mismanagement Scenarios
    Two commenters stated that EPA relied on incomplete data provided 
in the RCRA 3007 Questionnaires to identify actual management, and 
disregarded standard potential mismanagement scenarios based on an 
incorrect assumption that solvent waste management will not change over 
time. According to these two commenters, a valid solvent listing 
determination must also consider improper disposal in unlined 
landfills, impoundments, waste piles, land treatment units, and long 
term accumulation, which EPA overlooked. One of the commenters went on 
to state that the Agency's listing policy requires the presumption of 
land disposal in unlined landfills and surface impoundments, 
particularly in the case of solvents, where EPA's questionnaire data 
present a partial and misleading snapshot of solvent use due to 
limitations in the data collection methodology. This commenter also 
argued that due to the limitations of the data collection, EPA cannot 
claim that the specialized or limited uses of the solvents lead to a 
complete characterization of solvent users or solvent waste management 
practices. The commenter concluded that EPA's decision not to list 
these solvents is invalid and contrary to the criteria enumerated in 40 
CFR 261.11.
    The Agency disagrees with the two commenters. The data collected 
show that the management practices of most concern to the commenters 
(landfills and surface impoundments) are not widely used. Where land-
based disposal was reported in the 3007 Survey, the Agency considered 
whether the waste is capable of posing a substantial present or 
potential hazard to human health or the environment. For landfills, EPA 
found that modeling was not necessary because solvent loadings were 
very low. The few cases of surface impoundment use were fully evaluated 
via modeling and were found to present no significant risk.
    EPA relied on management practices reported in response to the 3007 
Surveys, and EPA evaluated the potential risks associated with those 
management practices that are used or likely to be used. As the Agency 
has explained in prior responses, EPA could and did target the 
facilities and industries actually using these chemicals as solvents. 
As a result, the Agency identified the largest users of these chemicals 
as solvents. EPA has responded in detail to comments regarding the 
adequacy of the characterization of solvent waste generators earlier in 
today's document (see section IV.A.1).
    The solvent wastes reported from the Survey fell into several 
classes: high concentration organic liquids or solids, treatment 
residuals (wastewater treatment sludge, incinerator ash), and 
wastewaters. The high content organic nonwastewaters were sent to 
thermal treatment in incinerators, boilers, or fuel blenders, and in 
some cases recovered via distillation for reuse. The vast majority of 
these wastes were managed as hazardous waste, because they exhibit a 
characteristic (primarily ignitability), or they are generated as a 
waste mixture with solvents that are already listed as hazardous.
    From the data available, EPA evaluated the potential for risks to 
arise from disposal of solids in landfills and the treatment of 
wastewaters in surface impoundment. Wastes reported to go to landfills 
were typically treatment residuals that contained negligible amounts of 
solvents. For the 10 solvents examined (the remaining 4 on the original 
list of 14 had essentially no solvent use), no landfill disposal was 
reported for six of these solvents. In fact, of the total 435 solvent 
wastes reported for the 10 chemicals, only 5 were reported to go to 
nonhazardous waste landfills. In the proposed rule and the Listing 
Background Document, EPA discussed why the few cases of landfill 
disposal reported for specific solvents (acetonitrile waste, methyl 
chloride, cumene, and cyclohexanol) were not of concern. This was 
principally because the solvent loadings in these wastes were very low. 
In response to comments, EPA further considered one waste that was 
reported to be disposed in a hazardous landfill. However as discussed 
in the specific section in today's rule on acetonitrile, the waste is 
no longer going to any type of landfill due to its thermal value.
    The Survey data show that wastes sent to landfills contained 
negligible amounts of solvent; landfilling of wastes with high solvent 
concentration was not reported. Thus, given these results, and the fact 
that nonwastewaters with high solvent content are generally hazardous 
and could not be placed in even a Subtitle C landfill without further 
treatment, EPA had no reasonable basis to conclude that disposal of 
spent solvent wastes in landfills poses a risk of concern.
    Similarly, treatment of wastewaters in surface impoundments was 
rare for the solvent wastes examined (the vast majority were treated in 
tanks). Of all the wastes reported (435), only 10 were reported to 
undergo treatment in surface impoundments. The solvent loadings for six 
of these (from solvent use of acetonitrile and cumene) were low and 
clearly present no risk after dilution/treatment in a wastewater 
treatment system. The others were larger volume wastewaters that arose 
from the specialized use of three different solvents: methyl chloride, 
phenol, and furfural. With the reported solvent loadings available, EPA 
examined these special cases closely, and completed further modeling in 
response to

[[Page 64385]]

comments (see section IV.C.1 on surface impoundment modeling).
    Concerning storage in waste piles and land treatment, EPA found no 
cases where such management practices were reported for any of the 
wastes examined. The lack of waste pile storage is not surprising given 
the nature of most wastes that are accumulated, i.e., organic liquids 
and aqueous wastewaters, which are stored in tanks. Further, many of 
these wastes are already hazardous, and are therefore kept in storage 
containers that meet stringent RCRA regulations. Other solids were 
either relatively low volume wastes, for which a pile is not needed, or 
wastewater treatment residuals, which have no appreciable solvent 
content, as noted above. The practice of land treatment is a special 
practice that is relatively rare, and as EPA has noted in the past (see 
Dyes and Pigments rule, 59 FR 66074), such practices would be 
considered plausible only when information indicates that the practice 
is in use, or likely to be used in the future.
    The Agency determined that the actual management practices 
represent the plausible management practices for the specific solvent 
wastes that are the subject of today's rule, because the Agency found 
no reason to believe that the current management practices would change 
significantly. In the case of wastewaters, EPA has no reason to believe 
that a facility would convert from a tank-based system to a surface 
impoundment given the capital investment and liability issues 
associated with constructing and operating land-based treatment units. 
The ongoing operating costs of managing wastewaters in an already 
installed tank are quite small relative to the costs of constructing a 
surface impoundment, or the costs of other alternatives such as sending 
the wastewaters offsite. Clearly, a large majority of facilities 
perceive a benefit from managing the waters in tanks, rather than 
impoundments, and EPA finds no reasons to project that those facilities 
would change their practices. For nonwastewaters, EPA has no reason to 
believe that a facility would switch from the thermal treatment of high 
organic wastes to disposal in a nonhazardous landfill due to the BTU 
value and the liability issues associated with land-based disposal. In 
fact, the data collected from the Survey clearly show that the use of 
impoundments and landfills is rare, and such practices are not common 
for these wastes. Also, as noted previously, the vast majority of 
nonwastewaters are already classified as hazardous waste, and cannot be 
land disposed without meeting treatment standards.
    EPA believes the Survey did, in fact, collect sufficient data from 
the significant solvent users, to allow a reasonable assessment of 
plausible mismanagement scenarios. However, even assuming the data do 
not reflect all management practices for whatever reason, the Agency 
still maintains that the data available support EPA's decisions on what 
constitutes plausible mismanagement. The data collected show that the 
management practices of most concern to the commenters (landfills and 
surface impoundments) are rarely used for these solvent wastes. 
Furthermore, when these practices are used they are used for only very 
dilute concentration (and low risk) solvent wastes, except for a few 
special cases that were specifically considered by the Agency. The 
existing data do not support the commenters' argument that other 
practices must be assumed to be generally plausible for all the wastes 
evaluated. Creating hypothetical waste management scenarios would have 
no apparent benefit, and may lead to regulating wastes which do not 
present risks.

C. Risk Assessment

    This section deals with comments on the hazard and exposure 
assessments conducted for the rulemaking. In response to comments, the 
Agency revised the risk assessment for some management scenarios. These 
updated results are presented in the following sections, along with 
responses to the comments. Full details of the updated analyses are 
presented in the background document for the risk assessment 
(Assessment of Risks from the Management of Used Solvents: Supplemental 
Risk Assessment Background Document, hereafter known as Supplemental 
Risk Assessment) provided in the docket to this rule. A summary of risk 
assessment results for all solvents are shown in Table 3. Comments 
dealing with the volumes and concentrations of wastes used as inputs 
for the risk assessment are dealt with in sections IV.A and IV.B.
1. Surface Impoundments
    EPA received a variety of comments relating to the assessment of 
risks from management of solvent wastewaters in surface impoundments. 
One comment focused on the routes of exposure that were assessed from 
the groundwater pathway from surface impoundments. The commenter 
indicated that EPA's consideration of direct ingestion alone was 
insufficient for assessing the risk from this pathway, and suggested 
that the Agency evaluate other routes of exposure from groundwater. EPA 
agrees that these additional routes of exposure should be evaluated, 
and conducted additional analysis as described below.
    In addition, two commenters suggested that the risk assessment 
should have assumed a higher concentration level for the solvents in 
these management units. The Agency used the headworks concentration (at 
the beginning of the wastewater treatment process), which represents a 
dilution of the solvent with other wastewaters. The high-end data on 
concentrations were taken from the section 3007 survey of all 
facilities, as noted in section IV.B.2, above.
    EPA does not agree that higher concentrations of solvents should be 
used, but rather believes that its approach described below is more 
appropriate. To respond to these comments, the Agency conducted further 
modeling of surface impoundments to reevaluate the risks from solvents 
managed in these units. The risk reevaluation is summarized below; see 
the Supplemental Risk Assessment document for a full description of the 
methodology and results.
    In the risk assessment for the proposed rule, EPA reviewed the 
high-end waste streams going to surface impoundments. The process of 
iterative risk screening rests on assessing high-end values, based on 
the premise that low-end values represent lower risk. Since the high-
end waste streams did not show significant risk, EPA did not review the 
impoundments further. For the current effort, EPA ensured that all 
relevant factors were accounted for by modeling all the surface 
impoundments receiving wastewaters with these solvents. EPA used a 
standard Agency model (CHEMDAT8) to assess the steady state 
concentration of solvent in these units; EPA used the precursor 
(CHEMDAT7) in modeling for the proposed rule. To the extent possible, 
EPA attempted to use actual influent concentrations into the 
impoundments; this information was only available for one of the 
impoundments (at the Exxon Baytown facility). For the other surface 
impoundments, EPA used the headworks concentrations again. EPA believes 
that these concentrations represent a conservative estimate of the 
concentration of solvent entering the impoundment, since they do not 
account for the significant pretreatment occurring (in all cases) after 
the headworks, before entering the impoundment. Because of this 
pretreatment, the actual solvent concentration of influent to the

[[Page 64386]]

impoundment will be much lower than the headworks concentrations that 
were assumed for the modeling.
    Using CHEMDAT8, EPA then modeled the resulting steady state 
concentrations of the solvents in each impoundment, as well as 
estimated quantities and concentrations of solvents that would be 
emitted to the air. EPA assessed direct inhalation risks using these 
airborne emissions from the solvent.
    Risks from the groundwater pathway were assessed for all 
impoundments where the groundwater was considered at risk. To assess 
the risks from the groundwater pathway, EPA assumed no attenuation from 
the impoundment to the leachate. EPA estimated groundwater 
concentrations at a high-end receptor, and from that groundwater 
pathway assessed risks of direct ingestion of the groundwater, as well 
as inhalation and dermal contact risks from use of the groundwater. 
This assessment used the same methodology employed by the Agency in a 
recent listing (Hazardous Waste Management System; Identification and 
Listing of Hazardous Waste; Petroleum Refining Process Wastes; 63 FR 
42109, August 6, 1998 ) to estimate non-ingestion risks from the 
groundwater pathway.
    The results of the assessment for the impoundments are summarized 
in Table 2. All hazard quotients represent cumulative figures for all 
pathways and routes of exposure. The assessment of cumulative risk from 
these routes of exposure is very conservative, in that it assumes that 
receptor locations were at the maximum exposure point for direct 
inhalation of airborne solvents, as well as for exposure to solvents in 
groundwater. EPA also added HQs from different chemicals in the same 
unit, making the highly conservative assumption that all of the 
noncarcinogens threatened similar health endpoints (i.e., cause the 
same type of damage to the same organs). This latter assumption is not 
likely to be true, but there was no need to refine the risk analysis to 
ascertain what the different endpoints might actually be, because the 
summed HQs were less than one. Because those multiple conservative 
assumptions were used in the analysis, the true high-end risk estimates 
would actually be lower than the numbers listed under the ``High-End'' 
column.

            Table 2.--Risk Assessment Results For Management of Solvents in Surface Impoundments \1\
----------------------------------------------------------------------------------------------------------------
            Facility                Solvents in unit               Bounding HQ \2\              ``High-end'' HQ
------------------------------------------------------------------------------------------------------\2\-------
Tennessee Eastman..............  Acetonitrile, Phenol..  3.30e-02...........................  N/A \3\.
Exxon Baytown..................  Methyl Chloride \2\...  [4.60e-06].........................  [3.50e-06].
Mobil Beaumont.................  Furfural, Phenol......  1.20e+00...........................  8.00e-01.
Lyondell.......................  Cumene................  4.10e-02...........................  N/A.
Rhone-Poulenc..................  Acetonitrile..........  6.52e-02...........................  N/A.
Citgo..........................  Phenol, Furfural......  7.40e-01...........................  N/A.
----------------------------------------------------------------------------------------------------------------
\1\ Risks presented represent the total risk from concurrent exposure to air and groundwater releases, and also
  the sum of risks from all solvents in the unit. The ``high-end'' risks are above a high-end due to these and
  other conservative assumptions.
\2\ Risks for methyl chloride represent excess lifetime individual cancer risk .
\3\ N/A indicates high-end analysis was not done because the bounding analysis showed no risk of concern.

2. Tank-Based Management of Wastes
    In the process of responding to comments comparing EPA's evaluation 
of the solvent wastes in question with the results of a recent EPA 
study on potential air risks (see comment below related to the Air 
Characteristic Study), EPA reviewed the risk analyses conducted in the 
proposed rule for management of wastes in tanks. EPA discovered that an 
arithmetic error was made in the calculation of solvent emissions from 
tanks. This error resulted in an underestimation of emissions for all 
tank scenarios by a factor of 1,000.
    EPA has therefore revised the risk estimates for tank-based 
management of wastes. The analytical approach was to update the 
analyses that were completed for the proposed rule, using corrected 
emissions, the latest version of the emissions model (CHEMDAT8), and 
current chemical and toxicological benchmark data available for some 
chemicals. The analysis also refined parameter values to more closely 
approach high-end analyses; nevertheless, because of multiple high-end 
assumptions, all of the revised analyses are still characterized as 
more conservative than true high-ends. In addition, EPA conducted a 
second analysis to verify these results. This second analysis used air 
dispersion data and receptor distances from EPA's Air Characteristic 
Study (May, 1998). Both analyses, using the corrected source term data, 
indicated that risks for all tank-based scenarios were below levels of 
significant concern (see section IV.C for further discussion of listing 
decisions). More details of the analyses are presented in the 
Supplemental Risk Assessment Background document. The results of these 
analyses are presented in Table 3.

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3. Multiple Solvents
    A commenter noted that EPA failed to consider the cumulative 
impacts of multiple solvents and other hazardous constituents released 
via the same exposure pathways in the risk assessment. In order to 
fully respond to this comment, EPA conducted an assessment of the 
cumulative risks posed by exposure to multiple solvents. Inasmuch as 
the listing determination is based on the solvent constituents of these 
wastes, other constituents of the wastestreams were not assessed. These 
risk assessment results, therefore, only apply to the solvents 
themselves. In this analysis (see the Supplemental Risk Assessment for 
details) EPA assessed all cumulative solvents risks where multiple 
solvents were managed in one unit or in different units at a facility.
    This analysis used the same assumptions as EPA's prior assessments 
for the proposed rule. Wastestreams which were already classified and 
managed as hazardous were not assessed, since there is little 
likelihood of risk reduction through a listing determination. EPA 
focused its effort on currently unregulated wastes. The 
characterizations of waste management included the same conservative 
parameters as in the proposed rule, modified as described above, 
including the construction and operation of surface impoundments, 
meteorological conditions, and the proximity of hypothetical receptors. 
One particularly conservative assumption was storage of solvents in 
open-topped tanks permitting maximum volatilization. This assumption of 
extensive volatilization out of open-topped tanks is highly unlikely, 
because the wastes were being stored pending incineration or other 
thermal treatment. In addition to those factors, EPA included highly 
unrealistic assumptions in assessing cumulative risk from exposure to 
multiple solvents. Environmental receptors were considered to be 
located at maximum exposure points relative to all management units. 
EPA also added HQs from different chemicals, making the highly 
conservative assumption that all of the non-carcinogens threatened 
similar health endpoints (i.e., cause the same type of damage to the 
same organs). This latter assumption is not likely to be true, and 
overestimates risks, but there was no need to refine the risk analysis 
to ascertain what the different endpoints might actually be.
    Despite these assumptions, which suggested unrealistic conditions 
to maximize the probability of showing risk to human health, none of 
the assessed scenarios showed combined hazard indices over one. In one 
facility (Exxon, Baytown), a surface impoundment showed an increased 
cancer risk of 4E-06 in the high-end analysis, however, this risk was 
entirely due to the single solvent methyl chloride, as shown in the 
preceding section. As discussed in section IV.D, EPA has concluded that 
this does not represent a significant risk, especially in light of 
existing air regulations that apply to this unit.
    The scientific evidence represented by this risk analysis leads EPA 
to the clear conclusion that management of multiple solvents does not 
pose significant incremental risk to human health in any populations.
4. Comparison With HWIR Exit Levels
    A commenter argued that EPA should reconsider the risks from 
acetonitrile, phenol, methyl chloride, and isophorone based on the risk 
analysis presented by EPA in the proposed Hazardous Waste 
Identification Rule (HWIR; 60 FR 66344, December 21, 1995). For each of 
these chemicals, the HWIR analysis produced an ``exit level'' 
concentration, suggesting that concentrations of waste higher than the 
exit level might pose unacceptable risks. The commenter notes that the 
Sec. 3007 survey showed solvent wastes for each of these chemicals 
being generated at higher concentrations than the HWIR exit levels. The 
commenter noted that wastewaters of acetonitrile, phenol, methyl 
chloride, and isophorone are generated in concentrations higher than 
the HWIR exit levels for these chemicals.
    The commenter's comparison between HWIR exit levels and the solvent 
waste concentrations does not indicate that the solvent risks are of 
concern. The purpose of the HWIR exit levels is not to assess risk from 
a particular set of chemicals or a specific set of wastes. Unlike 
listings, where the Agency makes a decision based on actual information 
about how specific wastes are generated and managed, the HWIR levels 
are intended as broad risk screens, covering a large number of possible 
waste streams and waste management methods. The listing decisions for 
the chemicals examined in today's rule are limited to consideration of 
potential risks that arise only from the wastes generated after the 
chemicals are used as solvents. Therefore, these decisions are limited 
to considerations of waste characteristics and waste management 
practices specific to these uses.
    Because HWIR had a different purpose than this risk assessment, it 
used different methodologies. HWIR evaluated five management scenarios: 
aerated treatment tanks, quiescent surface impoundments, land 
application units, ash monofills, and wastepiles. Only two of these 
scenarios aerated treatment tanks and quiescent surface impoundments 
are similar to the management scenarios modeled for the used solvents 
risk assessment. Another obstacle to comparison is the waste volume 
modeled. HWIR modeled a range of waste volumes, bounded by the capacity 
of the waste management unit. From these volumes, HWIR calculated 
levels for specific chemicals on a nationwide basis, for any use in any 
industry, and made various assumptions for waste generations and 
management, as noted above. In contrast, the wastestream volumes (and 
constituent loadings) modeled for the solvents risk assessment were 
based on actual data from the industry survey.
    The Agency has not issued the HWIR in final form and is continuing 
to refine the analysis; therefore, the HWIR exit levels are currently 
being reviewed and revised. However, even the revised numbers, as a 
screening tool, cannot be automatically used in assessing the validity 
of other regulatory actions by EPA. Together, the differences in 
management units and wastes modeled mean that a simple comparison of 
HWIR exit level concentrations to the concentrations in modeled solvent 
wastes is not meaningful.
5. Environmental Damage Incidents
    Several commenters stated that the Agency screened out and ignored 
damage cases prior to 1980. EPA believes that the commenters have 
apparently misunderstood how the Agency evaluated the damage cases. The 
Agency did not screen out and ignore damage cases prior to 1980. All 
damage cases available were considered including those prior to 1980. 
However, most of the damage cases found for the 14 chemicals resulted 
from disposal well before 1980, before RCRA regulations were in place. 
Damage cases were reviewed to direct the analysis to industries and 
conditions that might show evidence of environmental damage from 
improper management of used solvents that might be occurring now or may 
occur in the future; the cases did not provide an exclusive or 
restrictive guide. EPA evaluated a variety of legal and financial 
factors that might affect plausible management, and technological 
factors affecting fate and transport of hazardous constituents.
    These other factors are especially important when examining the 
solvent wastestreams, since almost 90% of the non-wastewaters are 
already required to

[[Page 64390]]

be managed as hazardous under Subtitle C. Although these constituents 
may have been found at Superfund sites, it is not reasonable to suggest 
that RCRA-regulated hazardous wastes could be managed today in the same 
way they were managed at industrial facilities in the past. The damage 
cases that were found reflect mismanagement in the past, not the 
Subtitle C management (or even the likely Subtitle D management) of 
these chemicals which is the norm today.
    Furthermore, as described in the proposed rule, there were many 
other reasons why the damage cases were not useful (see 61 FR 42326). 
These reasons include: (1) EPA could not determine that any of the 
contaminants of concern were used as a solvent prior to disposal; (2) 
wastes at these sites were poorly defined, and the term ``solvent 
wastes'' likely referred to the more widely used solvents that are 
already listed; (3) many of the chemicals under study have other uses 
that are more likely to be the reason for contamination; and (4) EPA 
found no damage cases at sites within the industries that reported 
using the solvents under study.
6. Spills, Leaks, and Overflows
    One commenter stated that EPA's risk assessment did not include an 
evaluation of human health and environmental risks posed by leaking 
tank systems. According to this commenter, EPA argues the concentration 
of solvents is ``very low'' in wastewaters, and thus assessing the 
risks posed by tank leaks is not warranted. However, the commenter 
argued the database identifies solvent wastewaters containing 9% 2-
methoxyethanol, 8% phenol, 200 ppm 2-EEA, 169 ppm methyl chloride, and 
5,000 ppm furfural. The commenter concluded, given that no time limit 
would be placed on storage if the wastes are not regulated as 
hazardous, defective leaking containers and tanks are highly possible.
    EPA has examined the possibility of spills from management units 
such as tanks or surface impoundments. The Agency does not have the 
data or the means available to accurately assess the likelihood of such 
releases, the magnitude of releases, or other data that would be 
necessary to assess the risk of such spills. Based on the 
characteristics of these solvent waste streams, however, the Agency has 
concluded that to the extent that such releases would pose risks, a 
decision to list any of these wastes would not provide significant 
reduction in the potential hazards from such events. The Agency bases 
that conclusion on the following facts.
    The vast majority (over 98%) of the volume of solvent wastes are 
wastewaters in wastewater treatment units. These wastewaters are 
diluted to very low concentrations of solvents, and are treated further 
to even lower levels. When necessary, EPA has modeled the effects of 
release of some of these solvents from impoundments and found no 
significant risk to human health or the environment (see section IV.C.1 
for further discussion on potential risks from impoundments). For the 
specific wastewaters identified by the commenter, EPA notes that 
surface impoundment scenarios were modeled for phenol, methyl chloride, 
and furfural at the same or similar concentrations to those cited, and 
no significant risks were found. The wastewater mentioned that contains 
2-methoxyethanol is managed as hazardous in an off-site biological 
treatment system, so that any releases or risks are unlikely. 
Similarly, the 2-EEA waste cited is scrubber water that is classified 
as hazardous, and furthermore corresponds to a total of only 0.58 kg of 
EEA. Therefore, EPA does not agree that these wastes are likely to 
present significant risk even under a spill scenario.
    Of the nonwastewaters, almost 90% are already regulated under 
Subtitle C of RCRA. Spills from the RCRA units are already covered 
under contingency planning and corrective action requirements. Subpart 
CC includes additional requirements for spill protection during 
transfer of wastes (see 40 CFR 264.1084(j)). Therefore, EPA concludes 
that spills of these wastes from tanks, which would generally be 
episodic in any case and unlikely to produce long-term exposures 
comparable to those considered in listing determinations, are not of 
significant concern.
7. Non-Aqueous Phase Liquids (NAPLs)
    In the proposed rule, even though EPA could not find scenarios that 
could lead to significant releases to ground water, the Agency also 
considered whether the spent solvent wastes had the potential to form 
non-aqueous phase liquids (NAPLs) that might move as a separate phase 
either above or below the ground water table. These NAPLs may present 
special problems, especially in assessing their transport and potential 
impact. However, EPA found that nearly all solvents under consideration 
are miscible or very soluble in water and are not likely to form NAPLs 
in groundwater. One commenter suggested that EPA re-examine the 
possibility of formation of NAPLs from these solvents.
    To respond to this concern, EPA has conducted further analysis on 
the subject for this final rulemaking. Full details of this analysis 
are in the Supplemental Risk Assessment document for this rulemaking. 
Only four of the solvents are land disposed and pose a threat to the 
groundwater pathway: acetonitrile, phenol, furfural, and cumene. EPA 
assessed the possibility of formation of NAPLs from land disposal of 
these solvents.
    The first three are all highly soluble, which indicates that NAPL 
formation is unlikely. EPA then assessed the likelihood of NAPL 
formation from cumene, using the methodology which has been developed 
for assessing NAPL probabilities at Superfund sites. Conservative 
estimations of the concentrations of cumene in groundwater still fell 
an order of magnitude below the threshold at which NAPL formation is a 
serious possibility. Therefore, EPA concludes that there is little 
likelihood of these solvents contributing to formation of NAPLs.
8. Risk Modeling Parameters
    One commenter stated that the accumulation scenario modeled must 
assume long term storage, not a period of under 90 days. The commenter 
argued that extended on-site accumulation is a highly plausible 
mismanagement scenario, given that absent RCRA controls, a generator 
can accumulate such waste indefinitely. Thus, the commenter stated that 
EPA's risk model should not assume a finite storage time of 90 days, 
but should assume the more likely scenario of at least a two year 
period of storage.
    This comment is based on an incorrect assumption. The accumulation 
scenario was not modeled for a period of 90 days as stated by the 
commenter. For each scenario, EPA used a storage duration designed to 
maximize the total risk. Modeling a longer storage time does not 
necessarily increase the risk, because it implies less frequent 
refilling of the tanks with new wastes. As described in the risk 
assessment documentation, this storage duration time was calculated by 
first generating a tank profile to yield the largest downwind 
concentration at the nearest residence based on data in Hazardous Waste 
Treatment, Storage, and Disposal Facilities (TSDF)--Background 
Information for Proposed RCRA Air Emission Standards (referenced in the 
proposal risk documentation as U.S. EPA, 1991c; p. 29, July 1996). 
(This high-end tank also happened to be the most common. Therefore, 
this model tank was used for all three types of estimates: bounding, 
high-end, and

[[Page 64391]]

central tendency.) The throughput and other parameters of this model 
tank were used in combination with solvent throughputs and high-end and 
central tendency concentrations to obtain solvent-specific emissions 
rates. The storage duration times were then back-calculated to fit this 
maximum release profile. For the bounding analysis, the modeling was so 
conservative that it resulted in greater than 95 percent release of the 
solvent in seven out of ten cases. Thus, a longer accumulation time, as 
suggested by the commenter, would have led to lower emissions, lower 
concentrations at the receptor, and thus a less conservative analysis.
9. Comparison With Results of Air Characteristic Study
    EPA received a late comment suggesting that the risk analysis in 
the Air Characteristic Study recently released by the Agency (May, 
1998) indicated that air pathway releases from these solvents were 
riskier than EPA's initial analysis had indicated. The commenter 
compared concentration levels of potential concern developed for some 
chemicals in the Air Characteristic Study to concentrations of the 
solvents reported in the listing determination. The commenter argued 
that the study showed significant inhalation risks for some of the 
solvents when managed in tanks at concentrations significantly lower 
than those found in the solvents data collection.
    In response, EPA first notes that the purpose of the Air 
Characteristic Study was to evaluate the possible need for an air 
characteristic to address potential risks due to emissions from certain 
waste management units. The concentrations of concern estimated in the 
Study are screening values for the purpose of determining whether new 
regulatory controls are needed to fill potential gaps in existing 
regulations, and should be viewed in this context. The concentrations 
developed in the Study cannot be automatically used in assessing the 
validity of other regulatory actions by EPA, because the study uses 
waste data and certain modeling assumptions in its methodology that are 
different in a number of ways from the modeling assumptions and data 
used in other regulatory programs, such as listing determinations. In 
addition, the Study methodology is currently undergoing outside peer 
review. Therefore, the screening concentrations themselves could change 
pending the results of the review.
    In any event, a comparison of the results reached in the Air 
Characteristic Study with the results of this risk assessment confirms 
that the concentrations present in these solvent wastes do not pose a 
significant inhalation risk. As noted above, EPA found an error in the 
risk analyses for tanks, and revised these analyses accordingly. This 
was the principal reason for the apparent difference in risk estimates 
between the risk assessment for the proposed analysis and the Air 
Characteristic Study (see section IV.C.2). However, even with these 
revisions, some apparent differences in concentration levels of concern 
would remain.
    These differences in concentration, however, do not necessarily 
mean differences in risk. In this case, the source terms being compared 
are different. The Air Characteristic Study back-calculated to 
determine what loading of constituent could be safely managed in a 
given management scenario. For every management scenario, the loadings 
of constituent that the Air Characteristic Study concluded could be 
managed safely are larger than the loadings used in this risk 
assessment. The solvent constituent loading that the Air Characteristic 
Study determined could be safely managed in tanks ranged from twice the 
amount to millions of times the amount modeled for the solvents risk 
assessment. The analyses for today's listing determination used the 
solvent waste generation data (and subsequent loadings in management 
units) from the Sec. 3007 Survey. The purpose of this listing is to 
determine the risks that may be posed by current and plausible future 
management of these specific chemicals when used as solvents, 
therefore, the EPA feels that the solvents waste generation data 
submitted from the 3007 survey is appropriate to use in the analysis.
    To better understand the differences in risk assessment methodology 
used in the Air Characteristic Study, the Agency conducted a re-
analysis of the risk from the solvent wastestreams using a modified 
methodology from the Air Characteristic Study, but still using the 
waste generation data and solvent loadings from the listing Survey. The 
methodology was virtually the same as that used in the Air 
Characteristic Study, except for some inputs that the study derived 
through Monte Carlo analysis. The results of this verification analysis 
showed no significant risk for any of the solvent management scenarios, 
and confirm the previous results. These results appear in Table 3. More 
details on these comparisons appears in the response to comments 
document accompanying this rulemaking.

D. Listing Determinations

    EPA received comments on various aspects of the proposed listing 
determinations. Many comments on the determinations were raised 
repeatedly for various wastes, and are discussed in preceding sections, 
or in sections IV.D.1 and IV.D.2 below. Comments that are more specific 
for individual solvent wastes are addressed in the section IV.D.3. For 
complete responses to comments on these and other issues, see the 
Response to Comments Document in the docket to today's rule.
1. General Comments
    Six commenters support EPA's decision not to list as hazardous 
waste the solvents at issue. However, one commenter disagreed with the 
decision not to list these compounds because they are similar in 
toxicity to the other solvents already listed as hazardous. The 
commenter stated that the solvents considered in this rule may be used 
by themselves, and their wastes, therefore, would not be mixed with the 
wastes from the other F-listed wastes, or the manufacturer can modify 
their processes to avoid using other F-listed solvents, so that their 
wastes would no longer be hazardous. The commenter went on to wonder if 
EPA's decision not to list these wastes was due to its ``anti-
combustion'' strategy, because the wastes would ``then be readily 
excluded from combustion as a logical disposal option.''
    EPA does not agree with the commenter's assertions regarding the 
decisions not to list. While some of the chemicals examined in today's 
rule may have toxicity similar to the solvents already listed as F-
wastes, the toxicity of a chemical alone is not a sufficient basis for 
listing. EPA considers a variety of factors, including waste management 
practices and all the other factors listed in 40 CFR 261.11(a)(3). 
After evaluation of all factors, EPA determined that listing for these 
solvent wastes was not warranted. When appropriate, EPA also evaluated 
wastes that resulted from use of the solvent by itself and found no 
significant risks.
    Further, EPA disagrees that in the absence of a listing decision a 
manufacturer would change its processes to segregate out the solvents 
considered in this rule. They had that incentive from the time the 
other solvents were listed in 1980 and 1986 and have either been mixing 
the wastes ever since or made decisions to make new mixtures with 
listed solvents. If a waste is hazardous under current regulations, due 
to mixture with other listed wastes or a characteristic, the

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manufacturer already has ample incentive to modify its process to avoid 
the cost of generating more hazardous waste. These manufacturers 
apparently weighed the risks and benefits of mixing, or not mixing the 
wastes and still pursued their mixing practices. As the Agency has 
stated in today's document and in the Response to Comments Document, 
many of these decisions are driven by specific process parameters, cost 
effectiveness, chemical compatibility, and regulations of other 
Agencies. EPA has no reason to believe they will change these practices 
in the event of a final no-listing decision, considering that this 
decision does not change the status quo. Thus, EPA does not agree that 
a non-list decision would alter this behavior. Finally, EPA points out 
that many of the wastes examined in today's rule are, in fact, treated 
by combustion, typically in hazardous waste incinerators. Therefore, 
the wastes are not ``readily excluded'' from combustion as result of 
the no-list decisions.
2. Sufficient Regulation of Solvents
    One commenter stated that EPA assigned appropriate weight to the 
fact that many solvents already are hazardous, a determination that is 
relevant to the Agency's assessment of plausible mismanagement 
scenarios, its determination in the risk assessment that no further 
risk reduction could be achieved through listing the solvents of 
concern as hazardous, and its determinations regarding the relevance 
and applicability of damage incidents identified. This commenter 
further stated that EPA gave due consideration to the benefits accorded 
by other regulatory programs. Another commenter, however, stated that 
the Agency should carefully consider the benefits associated with 
listing the solvent wastes that may exhibit a hazardous waste 
characteristic or are sometimes co-managed with presently listed 
solvent wastes. This commenter stated that there are important legal 
and policy reasons for listing the solvent wastes at issue in this 
rulemaking. The commenter noted that in the case of characteristic 
solvent wastes, listing the respective wastes obviates the need for 
testing to determine whether the waste is hazardous and could 
facilitate enforcement because inspectors need only compare the waste 
to the listing description to verify the applicability of hazardous 
waste requirements.
    In response, the Agency notes that it did carefully consider the 
impact listing might have for solvent wastes that are already hazardous 
due to the characteristics, or mixture with hazardous waste. For the 
wastes under consideration in this rulemaking, EPA believes that the 
characteristics provide adequate regulatory control. EPA initially 
evaluated potential risks from all wastes and found risks of possible 
concern due to air releases from some wastes (for acetonitrile and 2-
methoxyethanol; see proposed rule 61 FR 42327-42332). However, the 
wastes with the apparent risks were already regulated as hazardous. 
After considering the regulatory controls required, the residual risks 
were found to be below levels of concern. Based on assessments of risks 
posed by these wastes, in conjunction with the existing regulatory 
controls afforded by the existing characteristics and listings, the 
Agency determined that the solvent wastes as they are generated and 
managed do not pose a threat to human health or the environment. 
Therefore, the Agency has decided that listing is not warranted. While 
listing would obviate the need for testing (for those wastes not 
already listed or mixed with a listed waste), this is not a compelling 
reason by itself to list. A listing may assist enforcement to some 
extent; however, EPA has no indication that there is any problem in the 
implementation of the characteristic regulations for these wastes. On 
the contrary, the data collected indicate that generators are, in fact, 
managing the wastes of concern as hazardous when they are subject to 
such regulations.
    The commenter states that EPA never addresses the actual or 
potential reclamation of characteristic solvent sludges and byproducts 
(See 40 CFR 261.2, Table 1). The commenter also argued that the 
regulatory status of residuals from the recovery of spent solvent 
wastes are different for listed wastes; if listed, the residuals are 
hazardous, but if not listed the residuals would be unregulated, unless 
they exhibit a hazardous characteristic.
    The Agency disagrees with the statement that EPA did not consider 
reclamation. The Agency examined all residuals generated, including 
those generated from on-site recycling operations. Through the Survey, 
the Agency collected data on actual or potential solvent recycling and 
reclamation possibilities. Among the residuals evaluated are heavy 
ends, filtrates/decantates/distillates, organic/aqueous treated 
residuals, and filter related media; these were, in part, generated 
from the recovery of spent solvents or the treatment on-site of spent 
solvent residuals. Some facilities have the means and the financial 
incentive to perform reclamation of used solvents (often in-process). 
Other facilities are prevented from performing any sort of reclamation 
due to process purity requirements and product quality needs (e.g., 
pharmaceutical drugs, semiconductors), which may include regulatory 
requirements (e.g., purity requirements for drugs under the Food, Drug 
and Cosmetic Act). Aside from value to fuel blenders and incinerators, 
very little market seems to exist for many spent solvents or their 
sludges. While it is true that the regulatory status of recovery 
residuals is different for listed, as opposed to characteristic 
hazardous waste, EPA does not believe that this would, by itself, 
provide a strong reason for listing, unless risks can be demonstrated 
for such wastes. EPA has no data on the characteristics of such off-
site residuals, and in fact has no indication that many of the spent 
solvents at issue are sent for off-site reclamation, beyond thermal 
treatment. Furthermore, in making a listing determination, EPA's 
primary focus is the wastes generated on-site, and not treatment 
residuals that may be generated off-site. To fully consider these 
derivative wastes would expand the scope of a listing into a much 
larger effort. EPA has chosen to examine wastes for which it can 
reasonably expect to collect sufficient data to support a listing 
evaluation.
    The commenter goes on to state that in the HWIR rulemaking, EPA has 
not set exit levels for most of the solvents covered by the instant 
rulemaking. Therefore, wastes may meet the HWIR exit levels but still 
contain substantial concentrations of non-listed solvents. The 
commenter stated that by listing as hazardous the solvents in this 
rulemaking, EPA would then develop exit levels for the solvents, thus 
ensuring the concentrations of these solvents in waste mixtures are 
reduced to protective levels prior to leaving the Subtitle C regulatory 
system.
    The commenter is premature in assuming the content or effect of the 
HWIR rulemaking, and an assessment of the effect of that potential rule 
on residuals addressed in today's final rule is speculative. The Agency 
points out, however, that the concentrated waste mixtures reported for 
the solvents at issue are unlikely to be realistic candidates for 
exemption under HWIR. Due to the high levels of other constituents, 
these wastes most certainly have to be treated, such that the wastes 
that might ultimately exit the RCRA system would be treatment 
residuals. Concentrated organic wastes are invariably treated through 
incineration or other thermal treatment, and such treatment would 
likely destroy the solvents in question, as well as the

[[Page 64393]]

other hazardous constituents. Furthermore, wastes that are 
characteristic must be treated for underlying constituents under the 
Land disposal restrictions (LDR) regulations. Thus, residuals that are 
exempted under HWIR are not likely to have solvent levels of any 
concern.
    The commenter also stated that by listing the wastes as hazardous, 
EPA can encourage pollution prevention activities associated with 
solvent uses and waste management, including but not limited to solvent 
substitution, process changes and less reliance on combustion. The 
commenter noted that, through the listing process, EPA could ensure 
that the wastes will always be managed as hazardous, recognizing that 
attempts to identify solvent uses and users in the proposal are at 
best, substantially incomplete and subject to change. The commenter 
stated that it is entirely plausible that pollution prevention programs 
emphasizing hazardous waste generation reductions, the increasing cost 
of disposal associated with the upcoming hazardous waste combustion 
rules, and other factors will encourage hazardous solvent waste 
generators to reduce or eliminate the use of listed hazardous waste 
solvents. Under these circumstances, current codisposal practices are 
not indicative of future mismanagement scenarios.
    The Agency believes that the existing regulatory requirements for 
these wastes, many of which are hazardous already, provide ample 
incentives for pollution prevention, both because of liability concerns 
and disposal costs associated with hazardous wastes. In addition, as 
noted above, under the LDR regulations, characteristically hazardous 
wastes must be treated for underlying hazardous constituents. The 
Agency has reason to believe that industry voluntarily assesses 
opportunities for pollution prevention. As stated in the Listing 
Background Document (page 17), all but four of these chemicals are 
reportable in TRI Form R. Part of that reporting package includes 
pollution prevention and waste minimization. As an example, use of the 
three glycol ether chemicals under consideration in this rulemaking (2-
methoxyethanol, 2-methoxyethanol acetate, and 2-ethoxyethanol acetate) 
has diminished significantly, and production of 2-methoxyethanol 
acetate has been eliminated. Further, the cost of these chemicals is 
high in comparison with other comparable chemicals. These chemicals are 
used in industry only when their application is considered so suitable 
as to overcome any price disadvantages. As a result, for the solvents 
under consideration in this rulemaking, both regulatory requirements 
(e.g., characteristics, TRI) and economic factors play a role in 
encouraging companies to undertake pollution prevention assessments and 
institute changes where possible. Thus, EPA finds no reasonable basis 
to project changes in management practices reported in the 3007 Survey, 
as suggested by the commenter.
    The Agency has no reason to suspect that current management 
practices would be likely to change in the future to a practice that 
would pose a substantial risk to human health or the environment (e.g., 
from thermal treatment to land disposal or from a tank-based system to 
a surface impoundment) due to the regulatory prohibitions, heating 
value of the waste and/or requirements of the facility's wastewater 
treatment systems.
    The commenter also stated that EPA's assumption that analogous 
waste streams generated by all industry sectors using any of the 
solvents always generate an ignitable hazardous waste (based on the 
fact that some of the wastes reported to the Agency in the 
questionnaires are ignitable hazardous wastes), and will continue to do 
so, is not sustainable given the limitations associated with the 
preliminary and final questionnaires.
    EPA disagrees. Nowhere does the Agency assume that analogous 
wastestreams generated by all industry sectors using a particular 
solvent always generate an ignitable waste. The Agency has determined, 
based on reported management practices, that additional management 
practices for high solvent concentration/high organic containing wastes 
other than those considered in the risk assessment are not likely to 
exist. While some solvents may exist in mixtures at levels that do not 
exhibit the ignitability characteristic, EPA assessed risks from such 
mixtures as reported in the 3007 Survey. In fact, the initial risk 
analyses for all solvents did assess the risks from the wastes reported 
to be hazardous. Except for the cases of acetonitrile and 2-
methoxyethanol, EPA did not pursue the impact of the hazardous waste 
designations, because the risk results for the other solvents were 
below levels of concern. In the next phase of risk analyses for 
acetonitrile and 2-methoxyethanol, the Agency did not find significant 
risks from any remaining nonhazardous wastes. (See Supplemental Risk 
Assessment document for more details.)
    The Agency found that process and other limitations are a technical 
and regulatory bar to using the 14 chemicals alone or in combination 
with non-listed solvent wastes. For example, FDA regulations preclude 
solvent substitution in the pharmaceutical industry. Similarly, 
chemical purity concerns and final product quality requirements often 
specify the chemicals to be used.
    Another commenter stated that EPA had wrongly assumed that the 10 
solvent wastes are already captured as hazardous by the 
characteristics. The commenter states that four of the ten solvents of 
concern have flash points that do not meet the characteristic of 
ignitability: phenol, isophorone, furfural and cyclohexanol. Wastes 
from these four chemicals could never exhibit the characteristic of 
ignitability, unless generated in mixtures with some other component 
that has a low enough flash point. Two commenters provided 
calculations, using Raoult's Law and the lower flammability limit, of 
the potential concentration of solvents in a mixture that would result 
in an ignitable waste. These commenters contend that the solvent 
concentration in the mixtures must be very high to produce a mixture 
that is ignitable.
    As noted above, EPA did not need to rely on the fact that all waste 
mixtures would be ignitable. Certainly for the four solvents mentioned 
by the commenter, EPA did not rely only on the hazardous waste 
designations, but rather presented risk results for all wastes 
reported. In addition, the amount of solvent in nonwastewaters for two 
of the chemicals cited were extremely small (cyclohexanol-16 kg; 
furfural-<1 kg). Thus it is highly unlikely that these wastes could 
present any significant risk, regardless of whether or not the wastes 
were designated as hazardous.
    Furthermore, the commenters' calculations are based on the lowest 
solvent concentration waste being mixed with an organic chemical and 
the highest solvent concentration waste being mixed with water. 
However, most of the lower concentration solvent wastes reported are 
mixed with water (at concentrations of solvent much lower than those 
presented by the commenter), are managed in a tank-based wastewater 
treatment system, and undergo biological treatment. Most of the higher 
concentration solvent wastes reported are mixed with other organics and 
are managed by some type of thermal treatment due to the heating value 
of the waste.
3. Waste-Specific Rationales and Response to Specific Comments
    Acetonitrile. Decision. EPA is not listing wastes from the solvent 
use of acetonitrile as hazardous waste under 40 CFR 261.31. As 
described in the

[[Page 64394]]

proposed rule and as modified by subsequent analysis in response to 
comments, EPA finds no significant risks from treatment in aerated 
tanks or combustion in a boiler. EPA concludes that potential risks 
from air releases of acetonitrile stored in open accumulation tanks 
(i.e., on-site storage tanks) are also not significant, because the 
vast majority of the nonwastewater residuals stored are already 
regulated as hazardous waste. In the latter case regulatory controls 
afforded by the existing solvent listings and the characteristics 
(primarily ignitability) are protective of human health and the 
environment.
    EPA's final determination not to list this solvent is also based on 
the analysis in the proposed rule (see 61 FR 42328), as modified by 
subsequent analysis in response to comment, that potential risks from 
land-based management of acetonitrile wastes are not significant. All 
wastewaters found in EPA's 3007 Survey were treated in tanks, except 
for several wastes that were reported to enter impoundments as part of 
a wastewater treatment train in volumes that would not present 
significant risk. In response to comments, EPA conducted further 
analysis of the potential risks that might arise from treatment of 
acetonitrile wastewaters in a surface impoundment. This analysis 
included consideration of any additional risk resulting from 
noningestion exposure from groundwater (e.g., inhalation). As described 
in section IV.C, these analyses further confirmed this management 
practice presents no significant risks (see Table 3).
    The proposal also found that the few wastes reported to go to 
landfills typically contained negligible levels of acetonitrile 
solvents, and were not of concern. In response to comments, EPA further 
examined the potential for risks that might arise if more concentrated 
wastes were placed in an unlined Subtitle D landfill, but continues to 
believe such risks are not of concern (see specific comments below).
    As described in section IV.B, EPA updated its risk analysis for 
acetonitrile for some management scenarios. While the updated analyses 
confirmed the evaluation in the proposed rule, the updated analysis for 
aerated wastewater treatment tanks showed an HQ of two, which is 
slightly above the Agency's presumptive no-list HQ level of one. EPA 
does not believe this marginal risk is significant for the following 
reasons. First and foremost, as noted earlier in section IV.B, the 
analysis that resulted in the HQ of two is actually more conservative 
than a true double-high end analysis. The dispersion modeling used in 
calculating the HQ of two incorporates a high-end receptor distance, in 
addition to two other high-end parameters used (solvent loading and 
tank scenario). Furthermore, the solvent loading used for this analysis 
was the maximum reported for acetonitrile in wastewaters, rather than 
the 90th percentile value that EPA typically uses to estimate high-end 
risks (see for example the risk analyses in the recent Petroleum 
Listing, 63 FR at 42117). In the 3007 Survey for solvent use, 
facilities reported the treatment of 26 acetonitrile wastewaters in 
tanks (see the Listing Background Document, App. I), and the maximum 
was above the 90th% value for the mass loadings from this distribution. 
EPA used the second highest loading, which was an order of magnitude 
below the maximum, to see the impact of using this value in the updated 
analysis. When using the 2nd highest loading, EPA calculated an HQ of 
0.02, or well below one. Thus, the HQ of two is an overestimate and 
does not reflect a significant risk. As further confirmation, EPA also 
estimated risks for acetonitrile wastes using the methodology from the 
Air Characteristic Study. This methodology allowed receptor distance to 
be varied and was thus closer to a true high-end analysis. Using either 
the maximum acetonitrile loading or the second highest loading, the 
estimated HQ's were below 1.0 (0.7 and 0.08 respectively). Finally, EPA 
has recently promulgated regulations under the Clean Air Act (CAA) to 
control air releases from the industry represented by the one facility 
with the maximum loading (September 11, 1998, 63 FR 50280). These 
standards control releases of hazardous air pollutants, such as 
acetonitrile, from wastewater treatment systems at pharmaceutical 
producers. Therefore, for these reasons the Agency does not believe 
that the risks from acetonitrile in wastewater treatment tanks are 
likely to be significant.
    Given that nearly all of the nonwastewater acetonitrile residuals 
are either already being handled as hazardous, and those that are not 
handled that way contain negligible amounts of the solvent, these spent 
solvent residuals are not likely to pose a significant hazard to human 
health or the environment. Furthermore, treatment of wastewaters in 
tanks, or in rare cases in impoundments, presents no significant risks. 
Therefore, the Agency continues to believe that a no-list decision is 
warranted.
    Specific comments. Several commenters support EPA's no list 
decision on Acetonitrile. The commenters confirmed that the management 
practices and characterization of wastewater and nonwastewater 
residuals from the use of acetonitrile as a solvent have been properly 
identified. One commenter also noted that the risk assessment conducted 
by the Agency supports the determination not to list acetonitrile spent 
solvents. However, another commenter disagreed with the Agency's 
findings, stating that, despite shortcomings in EPA's risk assessment, 
the high-end analysis for tank storage resulted in an estimated HQ of 
200, orders of magnitude higher than the HQ of 1 typically warranting a 
hazardous waste listing. This commenter noted that only by performing 
the Phase III assessment was the Agency able to rationalize a no-list 
decision.
    In response, EPA wishes to clarify the meaning of the different 
phases of the risk assessment. The iterative process of risk assessment 
began with bounding analyses as the first phase. This type of analysis 
(by definition) involves conditions so unlikely as to be virtually 
impossible. Many scenarios did not show significant risk. Those 
scenarios which showed significant risk under bounding conditions were 
assessed under ``high-end'' conditions in Phase II. This was a more 
realistic assessment, but still reflected close to a ``worst-case'' set 
of conditions.
    Of all scenarios evaluated for acetonitrile, only one showed 
significant risk when modeled under high-end conditions, an uncovered 
storage tank (also called on-site accumulation in the proposal). The 
commenter refers to the hazard quotient of 200 calculated for this 
scenario. However, this result was reported as an intermediate step in 
the risk assessment process. EPA had significant concerns about this 
result for two basic reasons. First, this scenario involved storage of 
solvent wastes pending incineration. Modeling limitations required the 
Agency to estimate risks based on solvent storage in tanks without 
covers of any kind. In fact, the scenario assumed that essentially all 
of the stored acetonitrile would volatilize from the tanks before 
incineration could take place. The Agency judged this scenario highly 
unlikely because the waste is being stored for thermal treatment, and 
it is irrational to assume valuable fuels would be allowed to escape in 
such a manner. Further, as explained in the proposed rule, the vast 
majority of the wastes are already classified as hazardous waste 
because they are either characteristically hazardous, or co-managed 
with listed hazardous wastes. As such, the storage units would have to 
comply with RCRA regulations

[[Page 64395]]

promulgated to control such air releases (see 40 CFR part 264, subpart 
CC). Thus, the HQ of 200 is clearly an overestimate, because it was 
based on modeling releases for wastes that are already hazardous.
    In order to assess potential risks from the nonhazardous wastes 
that were not already subject to Subtitle C controls, the Agency 
refocused the assessment on the nonregulated waste streams in this 
scenario (acetonitrile in storage tanks). This third phase of the risk 
assessment, is a normal and logical step in the iterative risk 
assessment process. Phase III of the assessment showed that a bounding 
analysis of these wastes resulted in an HQ below one. Therefore, EPA 
concluded that the risks from the nonhazardous portion of the 
acetonitrile wastes are not significant, and that listing of solvent 
wastes from the use of acetonitrile is not warranted.
    One commenter states that large quantities of acetonitrile wastes 
are generated in concentrations well in excess of levels capable of 
posing a substantial risk to human health or the environment, and are 
managed in ways inconsistent with the Congressional directive to 
minimize the toxicity of mobility of wastes destined for land disposal. 
The commenter stated that large quantities of solids containing 10,000 
ppm solvent are disposed in hazardous waste landfills, while the 
Universal Treatment Standard (UTS) applicable to acetonitrile is 1.8 
ppm.
    EPA disagrees that large quantities are generated that present 
substantial risks. The Agency evaluated risks based on potential 
exposures arising from plausible management. The highest concentration 
of acetonitrile going into a surface impoundment is no higher than 0.04 
mg/L (see Listing Background Document, Table 3-2). In fact, it would 
likely be much lower, since those wastewaters are pretreated before 
entering the impoundment. As described in section IV.C.1, further 
modeling done for surface impoundments confirmed that risks from such 
levels were not significant.
    The commenter is incorrect in stating that large quantities of 
solids containing 10,000 ppm acetonitrile are disposed in hazardous 
waste landfills. First, as noted previously, very few acetonitrile 
wastes were sent to landfills, i.e., four out of the 254 wastes 
reported in the Survey. The commenter singled out the one waste with 
appreciable acetonitrile loading (454 kg/yr.). In EPA's view, this one 
waste is not reflective of ``large quantities'' going to landfills. 
Furthermore, as described further in the following response, the 
practice is no longer occurring, and the facility in question is 
currently sending this waste stream for fuel blending, in recognition 
of its fuel value.
    The Agency disagrees with the commenter's conclusion that current 
management practices are inconsistent with the Congressional directive 
to minimize the toxicity and mobility of wastes destined for land 
disposal. The vast majority of the acetonitrile waste (nonwastewater), 
both by volume (99%) and by acetonitrile loading (99%), is not managed 
in land-based units. Furthermore, as noted above, the vast majority of 
acetonitrile wastes are already hazardous, and as such, must meet the 
Land Disposal Treatment standards prior to land disposal.
    Finally, as described earlier in today's document, some commenters 
argued that EPA should examine more land disposal scenarios, such as 
landfills. In response, the Agency examined groundwater ingestion risks 
from the disposal of acetonitrile solids in an unlined landfill. The 
Agency still believes that landfill disposal of acetonitrile is not a 
plausible management scenario, and there is no evidence that such waste 
has ever been disposed in Subtitle D landfills. To the contrary, the 
only facility that had been sending a significant acetonitrile loading 
to a landfill (454 kg/yr) sent the waste to a Subtitle C landfill. 
Furthermore the facility indicated that it had ceased this practice 
during 1993 and started sending the waste for thermal treatment because 
of the waste's fuel value. (EPA has received confirmation from the 
generator of this waste that the material has fuel value on the order 
of 14,800 BTU per pound.1) Thus, EPA believes that such 
wastes will be sent for thermal treatment under the current regulatory 
structure. The Agency decided, however, to examine the resulting risks 
if such disposal were to occur in an unlined Subtitle D landfill. As 
described in more detail in the Supplemental Risk Assessment, the 
resulting analysis suggested hazard quotients in the range of 11-22 for 
a high-end scenario.
---------------------------------------------------------------------------

    \1\ See contact report dated June 10, 1998 documenting a 
telephone conversation with Dave Giffen, B.F. Goodrich, which is 
located in the docket accompanying today's rule.
---------------------------------------------------------------------------

    EPA does not view these risks as significant, however, for several 
reasons. First, as noted above, landfill disposal is unlikely given the 
fuel value of the material, thus EPA does not view disposal in a D 
landfill plausible. In any event, the elevated HQs were projected for 
only one waste out of the 254 acetonitrile wastes identified in the 
3007 Survey. Even if EPA found that the elevated HQs reflected a 
plausible management scenario, the Agency might well decide that the 
potential risk posed by this one waste does not merit listing of all 
acetonitrile residuals generated. Given the widely varying nature of 
the industries and wastes involved, and the very small percentage of 
management activities that even arguably could present a risk of 
concern, the Agency believes that a broad listing for solvent use would 
result in over regulation. In any case, EPA concludes that wastes such 
as these are not likely to be disposed in landfills, and are therefore 
unlikely to pose significant risks.
    Phenol. Decision. EPA is not listing wastes from the solvent use of 
phenol as hazardous waste under 40 CFR 261.31. As described in the 
proposed rule and as modified by subsequent analysis in response to 
comments, EPA finds no significant risks from treatment in aerated 
tanks, storage in tanks, or combustion in a boiler. Furthermore, EPA 
does not believe that potential risks from land-based management of 
phenol wastes are significant. None of the wastes containing phenol 
were reported to go to landfills. Wastes with high organic content that 
contain any appreciable levels of phenol were classified as hazardous 
waste, and were sent for fuel blending or incineration as hazardous. 
Wastewaters were generated from the specialized use of phenol as a 
solvent in the extraction of materials from crude oil, and the 
resulting spent phenol wastes were sent to wastewater treatment systems 
for treatment in tanks or surface impoundments. EPA found risks from 
impoundments would be low given the dilution and treatment that occurs 
in these wastewater treatment systems, and the specific facts 
associated with the impoundment of potential concern (see 61 FR 42337).
    In response to comments, EPA conducted further analyses of the 
potential risks that might arise from treatment of phenol wastewaters 
in a surface impoundment. In these analyses EPA also included 
consideration of any additional risk resulting from noningestion 
exposure from groundwater (e.g., inhalation), as well as codisposal 
with other solvent wastes under evaluation. As described in section 
IV.C, these analyses further confirmed this management practice 
presents no significant risks. EPA used the updated toxicological 
benchmark discussed in section III of today's rule for all additional 
analyses. The Agency also used the updated toxicological benchmark to 
revise the risk assessment results for other practices, i.e., storage 
and treatment in tanks, and found this

[[Page 64396]]

had no significant impact on the risks (see Table 3).
    Based the results of the risk analyses in the proposal, as well as 
the updated evaluations, these spent solvent residuals are not likely 
to pose a significant hazard to human health or the environment. 
Therefore, the Agency continues to believe that a no-list decision is 
warranted.
    Specific comments. One commenter supported EPA's decision not to 
list wastes from solvent uses of phenol as hazardous wastes. The 
commenter agrees with EPA that phenol does not satisfy the criteria for 
listing in 40 CFR 261.11(a)(3). However, another commenter stated that 
there are cases where phenol is currently used by itself (without being 
mixed with other F-listed wastes) as an industrial solvent and with 
this decision ``not to list'' phenol as a hazardous waste, EPA would 
seem to provide disposal option ``carte blanche'' for current users. 
Manufacturers can modify their processes to use these solvents, which 
would no longer be considered hazardous wastes, according to this 
commenter.
    In response, the Agency believes it unlikely that facilities would 
change their management practices based on the information collected in 
the Survey. The Survey indicated that all nonwastewater residuals 
containing phenol were managed as hazardous except one, which is 
managed by incineration. Thus, the solvent users managed their wastes 
as hazardous under the existing regulatory framework. There is no 
evidence that any facility that has not modified their process to use 
these solvents to date will do so after a no-list decision. Except for 
the facilities that use phenol for extracting lube oil, most facilities 
that use phenol as a solvent use it in laboratories or other specialty 
uses, and the waste solvents are sent for offsite treatment via 
incineration as hazardous waste. EPA has no indication that such 
generators could easily modify their use and accumulation practices in 
an attempt to generate nonhazardous material, nor is there any 
indication that facilities would do so.
    A third commenter stated that EPA's decisions regarding plausible 
mismanagement scenarios are especially suspect in the case of phenol, 
because phenol is the 33rd highest volume chemical produced in the 
United States, is already widely used, and its use is projected to 
increase. The commenter stated that EPA did not adequately evaluate 
groundwater risks posed by phenol.
    EPA disagrees with the commenter's inference that projected 
production increases in phenol are destined for solvent use. In fact, 
more than 96% of the phenol consumed in the U.S. is for nonsolvent uses 
(see SRI Chemical Economics Handbook, 1996). Increasing demand for 
products produced from phenol is due to increases for production of 
caprolactam, aniline, and bisphenol-A, (e.g., see http://
www.chemicalweek.com/marketplace/prod__focus.html). Nearly all of the 
solvent use of this chemical (>99.9%) was attributed to the petroleum 
industry, of which the Agency conducted a complete survey. Given that 
the major uses of this solvent were very specialized (i.e., extraction 
of lube oil), the Agency is confident that no other significant uses 
are likely to exist. Contrary to the comment, damage from groundwater 
contamination was evaluated for the proposed rule, and a refined 
assessment was conducted for the final rule, and noted in section IV.B. 
These analyses did not find significant groundwater risks (see Table 
2), and details are given in the Supplemental Risk Assessment document 
in the docket.
    The commenter also noted that EPA's Hazardous Waste Characteristic 
Scoping Study (November 1996) showed that phenol releases originated 
from nonhazardous waste management units, principally landfills and 
surface impoundments. The Scoping Study, which expressly excluded 
product spills and accident releases, presents clear evidence of the 
potential risks posed by the improper management of phenol wastes, and 
the use of nonhazardous surface impoundments and landfills as plausible 
mismanagement scenarios for phenol and other solvent wastes. The 
commenter went on to state that EPA assumed tanks never leak, and 
landfills would never be used, because none were reported by the 31 
facilities receiving the final questionnaire.
    The Agency disagrees that this aspect of the Characteristic Scoping 
Study is relevant to the Solvents Listing Determination. As EPA noted 
in the proposed rule, damage cases reviewed did not show evidence 
linking the phenol contamination at damage sites, including 
nonhazardous landfills and surface impoundments, to phenol use as a 
solvent. Without evidence that the mismanagement of phenol wastes 
resulting in contamination is linked to solvent use, the damage 
incidents are not an adequate basis for listing phenol as a spent 
solvent. As noted above, the vast majority of phenol is used for 
nonsolvent uses. Therefore simply pointing to damage case analyses is 
not compelling evidence for listing phenol wastes that result only from 
its use as a solvent. If EPA were to determine that certain industries 
that use phenol for nonsolvent uses are mismanaging wastes and causing 
significant environmental problems, then the Agency would consider 
other regulatory approaches. However, EPA's examination of the limited 
solvent use of this chemical indicates that such uses are not likely to 
generate wastes of concern. Thus, a listing of spent solvent wastes for 
this chemical would not be a practical way to address the types of 
environmental concerns raised by the commenter.
    EPA responded to the general issues of tanks and landfill disposal 
elsewhere in today's document. In the case of phenol, the Agency did 
not consider the disposal of phenol-containing wastestreams in a 
landfill to be a plausible management scenario for several reasons. 
None of the 38 wastestreams containing spent phenol reported in the 
3007 Survey are managed in a landfill. One reason for this is that very 
few phenol wastes are solids (most are organic or aqueous liquids). 
Only one solid wastestream, spent carbon, contained significant levels 
of phenol. This was sent offsite for regeneration or incineration. EPA 
has no reason to conclude that the practice of landfilling will 
increase. Wastes with higher organic content are thermally treated, and 
92% of the thermal treatment was conducted in hazardous waste units or 
through fuel blending for future burning. Therefore, EPA has no basis 
to project that wastes with significant phenol concentration are likely 
to be placed in a landfill.
    Methyl Chloride. Decision. EPA is not listing wastes from the 
solvent use of methyl chloride as hazardous waste under 40 CFR 261.31. 
As described in the proposed rule and as modified by subsequent 
analysis in response to comments, EPA finds treatment in aerated tanks 
and surface impoundments, storage in tanks, or combustion in a boiler 
do not present significant risk. The vast majority of methyl chloride 
produced is used as an intermediate in chemical manufacturing, and very 
few uses as a solvent were identified. Essentially all of the wastes 
reported from the solvent uses of methyl chloride were limited to two 
facilities that produce butyl rubber. While some of the updated 
lifetime individual excess cancer risks in Table 3 for storage in tanks 
and wastewater treatment in tanks/surface impoundments were above 1E-
06, the risks are below the 1E-05 level typically used by the Agency 
for identifying

[[Page 64397]]

candidate wastes for listing. Furthermore, as described below, the 
consideration of other factors indicate these risks are not 
significant.
    The high-end risks for storage tanks (4E-06 from the updated 
analysis and 2E-06 from the Air Characteristic approach) are highly 
likely to be overestimates, because the analyses assumed that all of 
the methyl chloride in the stored solvent waste would be released. This 
assumption is unlikely for materials being stored expressly to send for 
thermal treatment. Furthermore, these wastes were reported to be 
already regulated as hazardous, and would be subject to RCRA 
regulations limiting air releases under 40 CFR part 264, subpart CC.
    The risks found for wastewater treatment tanks (1E-06 from the 
updated analysis, and 1E-07 from the Air Characteristic approach) are 
at or below EPA's presumptive no-list level of 1E-06, and do not appear 
of concern. In addition, these are likely to be overestimates, because 
the concentration modeled for this scenario was 10 ppm, even though the 
value was actually reported as less than 10 ppm. EPA's updated 
assessment of the one wastewater reported to be treated in a surface 
impoundment showed a high-end risk of 4E-06. However the one 
impoundment that managed this waste is already a permitted Subtitle C 
hazardous waste unit, and is therefore subject to regulations limiting 
air releases (see 40 CFR part 264, subpart CC) and groundwater release 
( 40 CFR part 264, subparts F and K,).
    In addition, potential air releases from this industry are being 
addressed by other regulations promulgated under the Clean Air Act (see 
61 FR 46906, September 5, 1996). These regulations control releases of 
hazardous air pollutants from process units, storage tanks and 
wastewater treatment systems. EPA believes that these air regulations 
provide a more integrated approach to controlling air risks than would 
be possible under the limited controls available for air releases under 
the RCRA listing program.
    Based on the analysis in the proposal, the updated evaluations, and 
the other factors discussed in this document and the proposal, the 
methyl chloride solvent wastes are not likely to pose a significant 
hazard to human health or the environment. Therefore, the Agency 
continues to believe that a no-list decision is warranted.
    Specific Comments. One commenter supported the Agency's decision 
not to list methyl chloride. However, another commenter stated that the 
Agency left potential risks posed by the groundwater exposure pathway 
unevaluated by assuming methyl chloride was managed only in a permitted 
surface impoundment, that tanks never leak, and that landfills would 
never be used.
    As discussed more detail in the proposed rule (see 61 FR at 42334-
42335), the Agency did evaluate the groundwater exposure pathway 
through management scenarios where groundwater exposure was plausible. 
Wastes with high organic content were regulated as hazardous and 
incinerated. Waste solids were rarely sent to landfills, and in these 
cases the concentrations of methyl chloride were negligible. The only 
wastes sent to landfills were a small volume of spent desiccant that 
contained <5 kg of methyl chloride, and a larger volume sludge/ash from 
a sludge treatment unit which was reported to have a ``trace'' amount 
of methyl chloride. Given that this chemical is readily treated by 
biodegradation and volatilization in an aerated biological treatment 
system, it is unlikely that any significant levels of methyl chloride 
remain in this residual. EPA believes that these very low concentration 
wastes reflect the types of waste solids that are likely to be sent to 
landfills. EPA also notes that other nonwastewaters containing any 
reported levels of methyl chloride (a total loading of 1.6 kg) were 
regulated as hazardous waste, making disposal in an unlined Subtitle D 
landfill illegal. Thus, significant groundwater risks from landfills 
are unlikely to occur.
    The very limited solvent use of this chemical, and its unique 
characteristics (a gas at room temperature) lead EPA to conclude that 
it is unlikely that other solvent wastes would be generated that are 
managed in other surface impoundments beyond the example documented in 
the 3007 survey. As noted above, this impoundment is a hazardous waste 
unit, and is therefore subject to RCRA regulations limiting groundwater 
releases. Furthermore, as noted in the proposed rule, methyl chloride 
is readily treated by biodegradation and volatilization in waste water 
treatment systems, and thus is unlikely to migrate to the groundwater. 
Also, the tendency of methyl chloride to hydrolyze in water to methanol 
suggests that transport to receptors by groundwater is not likely to be 
significant.
    One commenter argued that EPA failed to adequately consider the 
formation of products of incomplete combustion (PICs) for methyl 
chloride. The commenter stated that EPA claimed PIC emissions were not 
cause for concern because the reported waste in question happened to be 
managed in a hazardous waste combustor, and disagreed with EPA's 
presumption that this one waste management practice reported represents 
current and future combustion activities.
    As noted above, the solvent uses of methyl chloride are very 
specialized, and the number of wastes sent for incineration are 
limited. The three wastes with reported concentrations that went to 
thermal treatment were all classified as hazardous waste and were 
treated as such under RCRA regulations. (Two wastes incinerated were 
treatment sludges that were reported to contain no significant levels 
of methyl chloride). Given these reported practices, and the very 
limited solvent uses for this chemical, EPA believes that combustion of 
solvent wastes with appreciable methyl chloride is likely to occur in 
RCRA regulated units. Therefore, the Agency believes its presumption 
for management is valid in this case. In addition, EPA is not aware of 
any precise way of predicting the kinds or levels of PICs that might be 
generated in a nonhazardous boiler, especially because the wastes in 
question would make up only a very small fraction of the wastes being 
treated.
    Nevertheless, EPA did consider the possibility of PIC formation for 
incineration of methyl chloride wastes. As discussed in the preamble to 
the proposed rule (61 FR 42334), the amount of methyl chloride in the 
wastes that are incinerated is extremely small (i.e., 2 kg). The 
loading of methyl chloride sent to a boiler or industrial furnace 
(BIF), although larger (i.e., at 2,250 kg) than the amount sent to an 
incinerator, is in a waste that is hazardous due to ignitability and 
toxicity characteristics, and therefore must be treated as hazardous 
wastes. This latter waste is generated from the use of methyl chloride 
in butyl rubber manufacturing, and it is unlikely that such a complex 
process could (or would) be modified to avoid generating waste methyl 
chloride in association with high levels of ignitable hydrocarbons. 
Thus, combustion in a RCRA-regulated unit seems likely to occur for 
this waste due to the specialized nature of this solvent use. These 
combustion units are operated according to stringent air emission 
standards that limit PIC formation (e.g., see 40 CFR part 264, subpart 
O, for incinerators and part 266, subpart H, for Boilers and Industrial 
Furnaces). EPA has also proposed revisions to these standards (see 
61FR1538, April 19, 1996 and 62FR24212, May 2, 1997). Given these 
facts, as well as the results of the risk assessment for these wastes, 
EPA

[[Page 64398]]

does not believe that combustion of these wastes poses a significant 
risk.
    2-Methoxyethanol (2-ME). Decision EPA is not listing wastes from 
the solvent use of 2-methoxyethanol (2-ME) as hazardous waste under 40 
CFR 261.31. As described in the proposed rule and as modified by 
subsequent analysis in response to comments, EPA found no significant 
risks from treatment in aerated tanks or combustion in a boiler. EPA 
also concluded that potential risks from air releases of 2-ME stored in 
open accumulation tanks are also not significant, because all of the 
nonwastewater residuals stored under this scenario are already 
regulated as hazardous waste, either because the wastes exhibit a 
characteristic, or because the 2-ME waste is commingled with listed 
wastes. EPA believes that regulatory controls afforded by the existing 
solvent listings and the characteristics (primarily ignitability) are 
sufficiently protective of human health and the environment.
    None of the wastes examined were sent to land disposal in a 
landfill or impoundment. Spent solvent solids are thermally treated, 
and wastewaters are all treated in tanks. In the face of the existing 
practices, EPA finds it implausible that high organic wastes currently 
sent to thermal treatment would be sent to landfills. Essentially all 
of the nonwastewater residuals that contain spent 2-ME are thermally 
treated or recovered, and nearly all (96%) are treated as hazardous 
waste. Because all wastewaters are treated in tanks, EPA also does not 
expect risks from surface impoundment management for these wastes.
    Given that nearly all of the nonwastewater 2-ME residuals are 
already being handled as hazardous, or contain negligible amounts of 
the solvent, these spent solvent residuals are not likely to pose a 
significant hazard to human health or the environment. Furthermore, 
treatment of wastewaters in tanks presents no significant risks. 
Therefore, the Agency continues to believe that a no-list decision is 
warranted.
    More general comments on EPA's methodology and approach that relate 
to 2-ME are discussed elsewhere in today's document. The few comments 
specific to 2-ME are discussed below.
    Specific comments. One commenter stated that EPA completely failed 
to evaluate potential risks from groundwater contamination, 
notwithstanding three groundwater contamination incidents involving 
this solvent identified by EPA from damage incidents.
    EPA described in the proposed rule why the damage cases cited by 
the commenter were not useful (see 61 FR at 42332). Of the three 
problem site identified, two were old landfills that received a wide 
variety of industrial and municipal wastes, and the use of 2-ME prior 
to disposal was impossible to ascertain. The chemical is widely used as 
a fuel additive and as a chemical intermediate. Thus, the damage could 
not be tied to wastes generated from the use of this chemical as a 
solvent. Damage at the third site also could not be linked to a 
specific use of 2-ME. However, this site was a used oil recycling site, 
and the contamination found may be related to the use of 2-ME as a fuel 
additive. Furthermore, none of the reports examined by the Agency 
provided any concentration of 2-ME in the groundwater. Thus, the 
limited data from the damage incidents provide no reliable support for 
listing wastes from the use of 2-ME as a solvent. In addition, the 
industries EPA identified as solvent users of 2-ME are not represented 
in the damage incidents. Finally, the vast majority of nonwastewater 
solvent wastes identified in the Survey were reported to be hazardous 
waste, and could not be placed in nonhazardous landfills. Thus, the 
damage incidents did not provide useful information on current or 
likely future waste management practices.
    One commenter argued that EPA's high-end risk analysis of onsite 
accumulation tank storage resulted in a HQ of 16, well above the HQ of 
1 that typically warrants a hazardous waste listing. Only by performing 
the completely misguided Phase III assessment was EPA able to arguably 
rationalize a no-list decision.
    EPA's response to this comment is similar to the response above to 
essentially the same comment raised for acetonitrile. The apparent 
risks cited by the commenter were from an intermediate stage of the 
risk assessment, and did not reflect the fact that all nonwastewaters 
were managed as hazardous waste. EPA concluded that the management 
scenario referred to in the comment (on-site accumulation of 
nonwastewaters in unregulated tanks) does not apply to any 2-
methoxyethanol waste streams.
    2-Ethoxyethanol Acetate (2-EEA). Decision. EPA is not listing 
wastes from the solvent use of 2-ethoxyethanol acetate (2-EEA) as 
hazardous waste under 40 CFR 261.31. As described in the proposed rule 
and as modified by subsequent analysis in response to comments, EPA 
found no significant risks from treatment in aerated tanks, storage in 
tanks, or combustion in a boiler. Furthermore, essentially all (99.8%) 
of the nonwastewaters were reported to be hazardous and were managed as 
hazardous waste through some form of thermal treatment.
    None of the wastes were reported to go to land disposal in 
landfills or impoundments, and these scenarios were not modeled. Given 
the existing waste management practices, EPA finds it implausible that 
high organic waste solids currently sent to thermal treatment would be 
sent to a landfill. The high percentage of wastes that are hazardous 
are precluded from disposal in an unlined Subtitle D landfill, and EPA 
has no evidence to indicate that spent 2-EEA wastes would be placed in 
a landfill. Due to the nature of the primary industries using 2-EEA as 
a solvent (e.g., the semiconductor and electronics industries), very 
few wastewaters are generated. Nearly all of the wastestreams generated 
are spent solvent wastes that undergo some type of thermal treatment. 
None of the wastestreams that were reported in the 3007 Survey go to a 
surface impoundment. Any change from the current treatment in tanks to 
treatment in impoundments seems unlikely given the capital investment 
associated with tanks and the liability issues associated with 
treatment in a surface impoundment. These facilities made an investment 
in tank-based systems in the absence of any listing, and EPA sees no 
reason why this would change if the status quo is not changed, i.e., if 
the wastes are not listed. In addition to cost considerations, some 
facilities may perceive other benefits from managing the waters in 
tanks, such as the current exemption from RCRA permitting requirement 
for such units (see 40 CFR 264.1(g)(6)). If hazardous waste were to be 
treated in a wastewater treatment system, impoundments in the system 
would require permitting as a Subtitle C unit. In addition, the use of 
2-EEA has been decreasing in recent years, thus other new generators of 
this spent solvent are unlikely.
    Given that nearly all of the nonwastewater 2-EEA residuals are 
already being handled as hazardous, or contain negligible amounts of 
the solvent, these spent solvent residuals are not likely to pose a 
significant hazard to human health or the environment. Furthermore, 
treatment of wastewaters in tanks presents no significant risks. 
Therefore, the Agency continues to believe that a no-list decision is 
warranted.
    More general comments on EPA's methodology and approach that relate 
to 2-EEA are discussed elsewhere in today's document. The few comments

[[Page 64399]]

related specifically to 2-EEA are discussed below.
    Specific comments. Two commenters stated that EPA failed to 
consider in its risk assessment, that many of the generators manage 2-
EEA with other solvents associated with this proposed rule. EPA 
calculated an HQ for 2-EEA for on-site accumulation of 0.7. Thus, 
additional risk from other solvents would cause the HQ level to exceed 
the threshold of one. One of the commenters went on to cite examples of 
facilities in several industries (e.g., printed circuit board 
manufacturers) at which multiple solvents were reported.
    EPA disagrees with the commenters' concerns about multiple solvent 
risks. First, the comment cited examples where the hazard quotient 
would exceed one at facilities that use more than one solvent in 
combination. However, the use of the chemicals at the facilities cited 
by the commenter are not solvent use, within the Agency's definition. 
These facilities used 2-EEA and other chemicals as components in 
formulations. Thus, no spent solvent is generated and was not included 
in the risk assessment.
    Furthermore, the HQ value of 0.7 cited by the commenter for on-site 
accumulation is likely to be unrealistically high for the reasons cited 
for the Phase II results for acetonitrile. The key reason is that 
essentially all residuals stored prior to thermal treatment were, in 
fact, already hazardous waste. Thus, air emissions from these wastes 
are already regulated under RCRA subpart CC to 40 CFR part 264, making 
the scenario of storage in an open tank unrealistic. EPA did not pursue 
a third phase of analysis for 2-EEA because the HQ was below one in the 
Phase II evaluation. Furthermore, the only wastes reported that were 
not hazardous consisted of one insignificant loading (<1 kg), and one 
waste characterized as ``containers/rags'' which contained very low 
levels of the solvent (<6 kg). Thus, EPA decided further analysis was 
not needed. As described in the Risk Assessment section, EPA addressed 
the general comment of the impact of multiple solvents in some wastes 
by conducting an assessment of the potential for cumulative risks.
    One commenter stated that the concentrations of 2-EEA in solvent 
nonwastewaters range from 0.1% to 100%. These ranges are not consistent 
with the Agency's position that nonwastewaters would always be managed 
as a hazardous waste due to ignitability, particularly where the 
solvent is not co-managed with listed solvent wastes. The commenter was 
also concerned because the concentration of 2-EEA in wastewaters ranges 
from 200-20,000 ppm.
    While the levels of 2-EEA in solvent nonwastewaters are variable, 
the reported data clearly indicate that essentially all 2-EEA solvent 
wastes generated were hazardous, and that these were all incinerated. 
Concerning the wastewaters, EPA believes the commenter's concern is 
unfounded. EPA's risk assessment included an analysis of potential 
risks from air releases from an aerated wastewater treatment tank, and 
found risks to be well below levels of concern.
    Furfural. Decision. EPA is not listing wastes from the solvent use 
of furfural as hazardous waste under 40 CFR 261.31. As described in the 
proposed rule and as modified by subsequent analysis in response to 
comments, EPA found no significant risks from treatment in aerated 
tanks or surface impoundments, storage in tanks, or combustion in 
boilers. Essentially all of the solvent use of this chemical (greater 
than 99.99%) is in the petroleum industry as an extractant for lube 
oil. Thus, solvent use of furfural is limited, and the Agency 
identified only a handful of wastes derived from this use.
    The furfural solvent wastes are virtually all wastewaters (greater 
than 99.99%), which were managed in wastewater treatment systems. One 
of the three facility's wastewater treatment systems uses a surface 
impoundment, and EPA's bounding analysis for the proposed rule showed 
no risks of concern from ingestion of groundwater, or inhalation of 
possible air releases (HQ <1; see 61 FR at 42341).
    In response to comments, EPA conducted further analyses of the 
potential risks that might arise from treatment of furfural wastewaters 
in a surface impoundment. In these analyses EPA also included 
consideration of any additional risk resulting from non-ingestion 
exposure from groundwater (e.g., inhalation). As shown in Table 3, the 
high-end risk analyses showed that these wastewaters do not present 
significant risks via either groundwater releases (HQ = 0.46), or air 
releases (HQ = 0.11).
    Based the results of the risk analyses in the proposal, the updated 
evaluations, and the other factors discussed in this document and the 
proposal, the furfural solvent wastes are not likely to pose a 
significant hazard to human health or the environment. Therefore, the 
Agency continues to believe that a no-list decision is warranted.
    General comments on EPA's methodology and approach that relate to 
furfural are discussed elsewhere in today's document. EPA did not 
receive any other specific comments on EPA's decision not to list 
furfural solvent wastes.
    Cumene. Decision. EPA is not listing wastes from the solvent use of 
cumene as hazardous waste under 40 CFR 261.31. As described in the 
proposed rule and as modified by subsequent analysis in response to 
comments, EPA found no significant risks from treatment in aerated 
tanks, storage in tanks, or combustion in boilers. While cumene is used 
in large volumes in the production of other chemicals, such as phenol, 
its use as a solvent is limited. Essentially all of the wastes 
containing cumene are thermally treated as hazardous or recovered. 
Small amounts of wastewaters are sent to treatment systems, and one 
resulting sludge was reported to be landfilled. However, the amount of 
cumene in this sludge would be well below the maximum of 28 kg that was 
used in the original solvent mixture (which contained only 1.7 % of 
cumene to start with). Thus, after treatment, any risks from cumene 
would be negligible. Similarly, one wastewater was reported to undergo 
treatment in a surface impoundment, however, as EPA noted in the 
proposal, the amount of cumene in the wastewater was small (<47 kg), 
and would be further reduced by treatment.
    In response to comments, EPA conducted further analyses of the 
potential risks that might arise from treatment of cumene wastewaters 
in a surface impoundment. In these analyses EPA also included 
consideration of any additional risk resulting from non-ingestion 
exposure from groundwater (e.g., inhalation during showering). As shown 
in Table 2, the revised bounding analyses showed that these wastewaters 
in impoundments do not present significant risks via either groundwater 
releases (HQ = 0.0001), or air releases (HQ = 0.003). As noted earlier 
in today's document, the toxicological values for cumene were updated 
during the comment period. The new benchmarks were used in the revised 
analyses, and were also used to recalculate risks derived in the 
proposed rule (see Table 1). The changes reflect greater tolerance for 
cumene than the previous benchmarks, and thus have no impact on EPA's 
decision not to list cumene solvent wastes.
    EPA also considered the potential for cumene to form NAPLs, which 
might present special problems in assessing potential risks. EPA noted 
in the proposed rule that cumene's water solubility is relatively low, 
such that NAPLs are theoretically possible.

[[Page 64400]]

However, EPA considered the potential risks from NAPLs to be very low, 
because cumene loading in wastes sent to land-based disposal was 
minimal. In response to comments, EPA provided further analysis showing 
that NAPL formation for these wastes is unlikely (see section IV.B).
    Based the results of the risk analyses in the proposal, the updated 
evaluations, and the other factors discussed in this document and the 
proposal, the cumene solvent wastes are not likely to pose a 
significant hazard to human health or the environment. Therefore, the 
Agency continues to believe that a no-list decision is warranted.
    General comments on EPA's methodology and approach that relate to 
cumene are discussed elsewhere in today's document.
    Cyclohexanol. Decision. EPA is not listing wastes from the solvent 
use of cyclohexanol as hazardous waste under 40 CFR 261.31. As 
described in the proposed rule and as modified by subsequent analysis 
in response to comments, EPA found no significant risks from 
accumulation in storage in tanks or combustion in boilers. The solvent 
uses of cyclohexanol are limited, and few wastes containing 
cyclohexanol were reported. All wastes but one are hazardous waste due 
to other waste constituents or properties of the waste material. The 
incinerated material contains low levels of cyclohexanol (16 kg total 
loading per year). The one other waste generated was reported to go to 
a nonhazardous landfill, however, this waste is a small volume (750 kg) 
of filter material that contains negligible level of cyclohexanol. 
Given the limited solvent uses of this chemical, and the management 
practices reported, EPA believes other wastes or management practices 
are not likely to be significant.
    As noted earlier in today's document, the toxicological inhalation 
benchmark (``provisional RfC'') for cyclohexanol was adjusted somewhat 
based on peer review comments. Thus, EPA used the new benchmark to 
recalculate risks derived in the proposed rule (see Table 3). The 
revised HQs remain below one, and thus the updated health-based number 
has no material effect on EPA's decision not to list cyclohexanol 
solvent wastes.
    Based the results of the risk analyses in the proposal, the updated 
evaluations, and the other factors discussed in this document and the 
proposal, the cyclohexanol solvent wastes are not likely to pose a 
significant hazard to human health or the environment. Therefore, the 
Agency continues to believe that a no-list decision is warranted.
    More general comments on EPA's methodology and approach that relate 
to cyclohexanol are discussed elsewhere in today's document.
    Isophorone. Decision. EPA is not listing wastes from the solvent 
use of isophorone as hazardous waste under 40 CFR 261.31. As described 
in the proposed rule and as modified by subsequent analysis in response 
to comments, EPA found no significant risks from accumulation in 
storage in tanks or combustion in boilers. The solvent uses of 
isophorone are limited, and few wastes containing isophorone were 
reported. All wastes but one were hazardous waste due to mixture with 
other listed wastes or the ignitability characteristic of the waste 
material. All wastes were reported to undergo some form of thermal 
treatment as a hazardous waste. Given the limited solvent uses of this 
chemical, and the management practices reported, EPA believes other 
wastes or management practices are likely to be significant.
    As noted earlier in today's document, the toxicological value 
(``provisional RfC'') for isophorone was adjusted somewhat based on 
peer review comments. Thus, EPA used the new benchmark to recalculate 
risks derived in the proposed rule (see Table 1). The revised HQs 
remain below one, and thus the updated health-based number has no 
material effect on EPA's decision not to list isophorone solvent 
wastes.
    Based on the results of the risk analyses in the proposal, the 
updated evaluations, and the other factors discussed in this document 
and the proposal, the isophorone solvent wastes are not likely to pose 
a significant hazard to human health or the environment. Therefore, the 
Agency continues to believe that a no-list decision is warranted.
    More general comments on EPA's methodology and approach that relate 
to isophorone are discussed elsewhere in today's document.
    2-Methoxyethanol Acetate (2-MEA). Decision. EPA is not listing 
wastes from the solvent use of 2-methoxyethanol acetate (2-MEA) as 
hazardous waste under 40 CFR 261.31. As described in the proposed rule 
and as modified by subsequent analysis in response to comments, EPA 
found no significant risks from storage in tanks or combustion in a 
boiler. 2-MEA is reportedly no longer produced domestically, and 
solvent use of this chemical is limited. The few wastes generated were 
classified as hazardous and were all thermally treated as hazardous 
waste. Given the limited and decreasing use as a solvent, and the waste 
information reported, EPA believes that other wastes and management 
practices are unlikely. None of the wastes were reported to be disposed 
of in landfills or impoundments, and these scenarios were not modeled.
    Given the existing practice, EPA finds it implausible that high 
organic waste solids currently sent to thermal treatment would be sent 
to a landfill. The wastes are hazardous and thus precluded from 
disposal in an unlined Subtitle D landfill. EPA has no evidence to 
indicate that spent 2-MEA wastes would be placed in a landfill. Due to 
the nature of the solvent uses reported for 2-MEA (diluent in coating 
and reaction media), no wastewaters are generated, nor were they 
expected.
    Based on the results of the risk analyses in the proposal, the 
updated risk analysis, and other factors noted above and in the 
proposed rule, these spent solvent residuals are not likely to pose a 
significant hazard to human health or the environment. Therefore, the 
Agency continues to believe that a no-list decision is warranted.
    More general comments on EPA's methodology and approach that relate 
to isophorone are discussed elsewhere in today's document. EPA did not 
receive any specific comments on EPA's decision not to list 2-MEA 
solvent wastes.
    Chemicals with no significant solvent use. As described in the 
proposed rule and reaffirmed in this final decision, EPA did not find 
any significant solvent use for four chemicals: p-dichlorobenzene, 
benzyl chloride, epichlorohydrin, and ethylene dibromide. All but one 
are relatively reactive chemicals, which makes them unsuitable for most 
solvent applications. The other substance, p-dichlorobenzene, is a 
solid at room temperature, limiting its utility as a solvent. In all 
cases, the data collected by the Agency showed that any solvent use of 
these chemicals is extremely limited. Some may perhaps have specialty 
applications in laboratories, but no significant solvent uses were 
identified. Any residuals reported from the 3007 Survey were primarily 
from possible solvent use by laboratories and contain low levels of the 
chemicals under study. All were coded as hazardous, except one dilute 
wastewater, and were thermally treated as hazardous waste.
    The Agency received no new information during the comment period 
indicating that these four chemicals, (benzyl chloride, 
epichlorohydrin, ethylene dibromide, and p-

[[Page 64401]]

dichlorobenzene) were used as solvents. Comments received by EPA on 
this issue concurred with the Agency's decision that these four 
chemicals are not used as solvents, and that they would not fit the 
description for such a listing. Based on the analyses and factors noted 
above and in the proposed rule, these spent solvent residuals do not 
pose a significant hazard to human health or the environment. 
Therefore, the Agency continues to believe that no-list decisions for 
these four chemicals are warranted.

V. Regulatory Requirements

A. Regulatory Impact Analysis Pursuant to Executive Order 12866

    Executive Order No. 12866 requires agencies to determine whether a 
regulatory action is ``significant.'' The Order defines a 
``significant'' regulatory action as one that ``is likely to result in 
a rule that may: (1) have an annual effect on the economy of $100 
million or more or adversely affect, in a material way, the economy, a 
sector of the economy, productivity, competition, jobs, the 
environment, public health or safety, or State, local, or tribal 
governments or communities; (2) create serious inconsistency or 
otherwise interfere with an action taken or planned by another agency; 
(3) materially alter the budgetary impact of entitlements, grants, user 
fees, or loan programs or the rights and obligations of recipients; or 
(4) raise novel legal or policy issues arising out of legal mandates, 
the President's priorities, or the principles set forth in the 
Executive Order.''
    The Agency estimated the costs of today's final rule to determine 
if it is a significant regulation as defined by the Executive Order. 
Because the Agency has decided not to list as hazardous the wastes 
generated from the use of the solvents evaluated in this rulemaking, no 
specific action is required under this action. As a result, there are 
no costs associated with this final rule. This rule was deemed 
significant for novel policy reasons by the Office of Management and 
Budget (OMB) and was submitted to OMB for review.

B. Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq., 
as amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA) of 1996) whenever an agency is required to publish a document 
of rulemaking for any proposed or final rule, it must prepare and make 
available for public comment a regulatory flexibility analysis that 
describes the effect of the rule on small entities (i.e., small 
businesses, small organizations, and small governmental jurisdictions). 
However, no regulatory flexibility analysis is required if the head of 
an agency certifies the rule will not have a significant economic 
impact on a substantial number of small entities.
    SBREFA amended the Regulatory Flexibility Act to require Federal 
agencies to provide a statement of the factual basis for certifying 
that a rule will not have a significant economic impact on a 
substantial number of small entities. The following discussion explains 
EPA's determination. This rule has no effect as the Agency is issuing 
this final decision not to list wastes generated from the use of 14 
chemicals as solvents as hazardous under the Resource Conservation and 
Recovery Act (RCRA). The determinations in this rule are limited to 
specific solvent wastes. The rule does not impose new burdens on small 
entities. Therefore, I hereby certify that this rule will not have a 
significant economic impact on a substantial number of small entities. 
This rule, therefore, does not require a regulatory flexibility 
analysis.

C. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law No. 104-4, establishes requirements for Federal agencies to assess 
the effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with Federal mandates that may 
result in expenditures to State, local, and tribal governments, in the 
aggregate, or to the private sector, of $100 million or more in any one 
year. Before promulgating an EPA rule for which a written statement is 
needed, section 205 of the UMRA generally requires EPA to identify and 
consider a reasonable number of regulatory alternatives and adopt the 
least costly, most cost-effective, or least burdensome alternative that 
achieves the objectives of the rule. The provisions of section 205 do 
not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost-effective, or least burdensome alternative if the 
Administrator publishes with the final rule an explanation why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including tribal governments, it must have developed under 
section 203 of the UMRA a small government agency plan. The plan must 
provide for notifying potentially affected small governments, enabling 
officials of affected small governments to have meaningful and timely 
input in the development of EPA regulatory proposals with significant 
Federal intergovernmental mandates, and informing, educating, and 
advising small governments on compliance with the regulatory 
requirements.
    EPA has determined that this rule does not include a Federal 
mandate that may result in estimated costs of $100 million or more to 
either State, local, or tribal governments in the aggregate. The rule 
would not impose any federal intergovernmental mandate because it 
imposes no enforceable duty upon State, tribal or local governments. 
States, tribes and local governments have no compliance costs under 
this rule. For the same reasons, EPA also has determined that this rule 
contains no regulatory requirements that might significantly or 
uniquely affect small governments. In addition, as discussed above, the 
private sector is not expected to incur costs exceeding $100 million. 
By these findings, EPA has fulfilled the requirement for analysis under 
the Unfunded Mandates Reform Act.

D. Executive Order 12875: Enhancing the Intergovernmental Partnership

    Under Executive Order 12875, EPA may not issue a regulation that is 
not required by statute and that creates a mandate upon a State, local 
or tribal government, unless the Federal government provides the funds 
necessary to pay the direct compliance costs incurred by those 
governments, or EPA consults with those governments. If EPA complies by 
consulting, Executive Order 12875 requires EPA to provide to the Office 
of Management and Budget a description of the extent of EPA's prior 
consultation with representatives of affected State, local and tribal 
governments, the nature of their concerns, copies of any written 
communications from the governments, and a statement supporting the 
need to issue the regulation. In addition, Executive Order 12875 
requires EPA to develop an effective process permitting elected 
officials and other representatives of State, local and tribal 
governments ``to provide meaningful and timely input in the development 
of regulatory proposals containing significant unfunded mandates.''
    Today's rule does not create a mandate on State, local or tribal 
governments. The rule does not impose any enforceable duties on these 
entities.

[[Page 64402]]

It issues a final decision not to list wastes generated from the use of 
14 chemicals as solvents as hazardous under the Resource Conservation 
and Recovery Act (RCRA). Accordingly, the requirements of section 1(a) 
of Executive Order 12875 do not apply to this rule.

E. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045: ``Protection of Children from Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies 
to any rule that: (1) is determined to be ``economically significant'' 
as defined under E.O. 12866, and (2) concerns an environmental health 
or safety risk that EPA has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, the Agency must evaluate the environmental health or 
safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    This final rule is not subject to the Executive Order because it is 
not economically significant as defined in E.O. 12866, and because the 
Agency does not have reason to believe the environmental health or 
safety risks addressed by this action present a disproportionate risk 
to children. The Agency performed a risk assessment to assist in its 
determination whether to list or not to list the solvent wastes in this 
final rule as hazardous waste. This risk assessment calculated the 
potential risk resulting from the current management of these wastes to 
individuals (including sensitive populations like children). The Agency 
has determined that management of these solvent wastes as hazardous is 
not required and that the environmental health risks or safety risks 
addressed by this action do not have a disproportionate effect on 
children.

F. Environmental Justice E.O. 12898

    EPA is committed to addressing environmental justice concerns and 
is assuming a leadership role in environmental justice initiatives to 
enhance environmental quality for all residents of the United States. 
The Agency's goals are to ensure that no segment of the population, 
regardless of race, color, national origin, or income bears 
disproportionately high and adverse human health and environmental 
impacts as a result of EPA's policies, programs, and activities, and 
that all people live in clean and sustainable communities. In response 
to Executive Order 12898 and to concerns voiced by many groups outside 
the Agency, EPA's Office of Solid Waste and Emergency Response formed 
an Environmental Justice Task Force to analyze the array of 
environmental justice issues specific to waste programs and to develop 
an overall strategy to identify and address these issues (OSWER 
Directive No. 9200.3-17). The Agency has determined that a hazardous 
waste listing is not justified for the wastes examined in this rule. As 
a result, no specific action is required under this rule. It is, 
therefore, not expected to result in any disproportionately negative 
impacts on minority or low income communities relative to affluent or 
non-minority communities.

G. Paperwork Reduction Act

    This rule does not contain any information collection requirements 
subject to OMB review under the Paperwork Reduction Act of 1980, 44 
U.S.C. 3501 et seq.

H. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Pub L. No. 104-113, Sec. 12(d) (15 U.S.C. 272 
note) 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, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. The NTTAA directs EPA 
to provide Congress, through OMB, explanations when the Agency decides 
not to use available and applicable voluntary consensus standards. This 
action does not involved technical standards. Therefore, EPA did not 
consider the use of any voluntary consensus standards.

I. Executive Order 13084: Consultation and Coordination With Indian 
Tribal Governments

    Under Executive Order 13084, EPA may not issue a regulation that is 
not required by statute, that significantly or uniquely affects the 
communities of Indian tribal governments, and that imposes substantial 
direct compliance costs on those communities, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by the tribal governments, or EPA consults with those 
governments. If EPA complies by consulting, Executive Order 13084 
requires EPA to provide to the Office of Management and Budget, in a 
separately identified section of the preamble to the rule, a 
description of the extent of EPA's prior consultation with 
representatives of affected tribal governments, a summary of the nature 
of their concerns, and a statement supporting the need to issue the 
regulation. In addition, Executive Order 13084 requires EPA to develop 
an effective process permitting elected officials and other 
representatives of Indian tribal governments ``to provide meaningful 
and timely input in the development of regulatory policies on matters 
that significantly or uniquely affect their communities.''
    Today's rule does not significantly or uniquely affect the 
communities of Indian tribal governments. As mentioned above, no 
specific action is required by this action. Today's rule does not 
create a mandate on State, local or tribal governments. The rule does 
not impose any enforceable duties on these entities. Accordingly, the 
requirements of section 3(b) of Executive Order 13084 do not apply to 
this rule.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA has submitted a report containing this rule and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. This action is not 
a ``major rule'' as defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 261

    Environmental protection, Hazardous materials, Waste treatment and 
disposal, Recycling.

    Dated: October 30, 1998.
Carol M. Browner,
Administrator.
[FR Doc. 98-30601 Filed 11-18-98; 8:45 am]
BILLING CODE 6560-50-P