[Federal Register Volume 61, Number 158 (Wednesday, August 14, 1996)]
[Proposed Rules]
[Pages 42318-42354]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-20592]



[[Page 42317]]


_______________________________________________________________________

Part II





Environmental Protection Agency





_______________________________________________________________________



40 CFR Parts 261, 271, and 302



Hazardous Waste Management System; Identification and Listing of 
Hazardous Waste; Solvents; CERCLA Hazardous Substance Designation and 
Reportable Quantities; Proposed Rule

  Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / 
Proposed Rules  

[[Page 42318]]



ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 261, 271, and 302

[SWH-FRL-5551-3]
RIN 2050-AD84


Hazardous Waste Management System; Identification and Listing of 
Hazardous Waste; Solvents; CERCLA Hazardous Substance Designation and 
Reportable Quantities

AGENCY: Environmental Protection Agency.

ACTION: Notice of proposed rulemaking.

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

SUMMARY: After extensive study of 14 chemicals potentially used as 
solvents, characterization of the wastes generated from solvent uses, 
and a risk assessment evaluating plausible mismanagement scenarios for 
these wastes, the U.S. EPA is proposing not to list those additional 
wastes from solvent uses as hazardous waste under 40 CFR Part 261. This 
action is proposed under the authority of Sections 3001(e)(2) and 
3001(b)(1) of the Hazardous and Solid Waste Amendments (HSWA) of 1984, 
which direct EPA to make a hazardous waste listing determination for 
solvent wastes.
    The determinations in this proposed rule are limited to specific 
solvent wastes, and are made pursuant to the current regulatory 
structure that classifies wastes as hazardous either through a specific 
listing or as defined under the more generic hazardous waste 
characteristics. Many of the solvent wastes addressed in this proposed 
rule are already regulated as hazardous wastes due to their 
characteristics. It is important to note that the proposal not to list 
these solvent wastes as hazardous wastes is not a determination that 
these chemicals are nontoxic. It is a determination only regarding the 
need for specifically adding these solvent wastes to the lists of 
hazardous waste.

DATES: EPA will accept public comments on this proposed rule until 
October 15, 1996. Comments postmarked after this date will be marked 
``late'' and may not be considered. Any person may request a public 
hearing on this proposal by filing a request with Mr. David Bussard, 
whose address appears below, by August 28, 1996.

ADDRESSES: The official record for this proposed rulemaking is 
identified by Docket Number F-96-SLDP-FFFFF and is located at the 
following address. The public must send an original and two copies of 
their comments to: RCRA Information Center, U.S. Environmental 
Protection Agency (5305W), 401 M Street, SW, Washington, D.C., 20460.
    Although the mailing address for the RCRA Information Center has 
not changed, the office was physically moved in November 1995. 
Therefore, hand-delivered comments should be taken to the new address: 
1235 Jefferson Davis Highway, First Floor, Arlington, Virginia. Copies 
of materials relevant to this proposed rulemaking are located in the 
docket at the address listed above. The docket is open from 9:00 a.m. 
to 4:00 p.m., Monday through Friday, excluding Federal holidays. The 
public must make an appointment to review docket materials by calling 
(703) 603-9230. The public may copy 100 pages from the docket at no 
charge; additional copies cost $0.15 per page.
    EPA is asking prospective commenters to voluntarily submit one 
additional copy of their comments on labeled personal computer 
diskettes in ASCII (TEXT) format or a word processing format that can 
be converted to ASCII (TEXT). It is essential to specify on the disk 
label the word processing software and version/edition as well as the 
commenter's name. This will allow EPA to convert the comments into one 
of the word processing formats utilized by the Agency. Please use 
mailing envelopes designed to protect physically the submitted 
diskettes. EPA emphasizes that submission of comments on diskettes is 
not mandatory, nor will it result in any advantage or disadvantage to 
the commenter. Rather, EPA is experimenting with this procedure as an 
attempt to expedite our internal review and response to comments. This 
expedited procedure is in conjunction with the Agency ``Paperless 
Office'' campaign. For further information on the submission of 
diskettes, contact the Waste Identification Branch at the phone number 
listed below.
    Requests for a hearing should be addressed to Mr. David Bussard at: 
Office of Solid Waste, Hazardous Waste Identification Division (5304W), 
U.S. Environmental Protection Agency, 401 M Street, SW, Washington, 
D.C. 20460, (703) 308-8880.

FOR FURTHER INFORMATION CONTACT: The RCRA/Superfund Hotline toll-free, 
at (800) 424-9346, or at (703) 920-9810 in the Washington, D.C. 
metropolitan area. The TDD Hotline number is (800) 553-7672 (toll-free) 
or (703) 486-3323 in the Washington, D.C. metropolitan area. For 
technical information or questions regarding the submission of 
diskettes, contact Mr. Ron Josephson, U.S. EPA Office of Solid Waste, 
Waste Identification Branch (5304W), 401 M St., SW, Washington, D.C. 
20460, (703) 308-8890.

SUPPLEMENTARY INFORMATION: There are no regulated entities as a result 
of this action.

I. Background
    A. Statutory and Regulatory Authorities
    B. Existing Solvent Listings and the Regulatory Definition of 
Solvent
II. Today's Action
    A. Summary of Today's Action
    B. EPA's Evaluation of Solvent Use
    1. Development of Study Universe
    2. Applicability to National Use
    C. Description of Health and Risk Assessments
    1. Human Health Criteria and Effects
    2. Risk Assessment
    a. Selection of Waste Management Scenarios
    b. Exposure Scenarios
    c. Risk Assessment Methodology
    d. Consideration of Damage Cases
    e. Risk Assessment Results
    D. Acetonitrile
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Wastes
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    E. 2-Methoxyethanol (2-ME)
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    F. Methyl Chloride
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    G. Phenol
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Wastes
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity

[[Page 42319]]

    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    H. 2-Ethoxyethanol Acetate (2-EEA)
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    I. Furfural
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Wastes
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    J. Cumene
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Response
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    K. Cyclohexanol
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    L. Isophorone
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    M. 2-Methoxyethanol Acetate (2-MEA)
    1. Industry Identification
    2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses
    b. Physical/Chemical Properties and Toxicity
    c. Waste Generation, Characterization, and Management
    3. Basis for Proposed No-List Determination
    a. Risk Assessment
    b. Environmental Damage Incidents
    c. Conclusion
    N. Chemicals Not Used as Solvents
    1. p-Dichlorobenzene
    2. Benzyl Chloride
    3. Epichlorohydrin
    4. Ethylene Dibromide
    O. Relationship to RCRA Regulations and Other Regulatory
III. Waste Minimization
IV. State Authority
    A. Applicability of Rule in Authorized States
    B. Effect on State Authorizations
V. CERCLA Designation and Reportable Quantities
VI. Regulatory Impacts
    A. Executive Order 12866
VII. Environmental Justice
VIII. Regulatory Flexibility Act
IX. Paperwork Reduction Act
X. Unfunded Mandates Reform Act
XI. Compliance and Implementation

I. Background

A. Statutory and Regulatory Authorities

    This investigation and listing determination was conducted under 
the authority of Sections 2002(a), 3001(b) and 3001(e)(2) of the Solid 
Waste Disposal Act (42 U.S.C. 6912(a), and 6921 (b) and (e)(2)), as 
amended (commonly referred to as RCRA).
    Section 102(a) of the Comprehensive Environmental Response, 
Compensation, and Liability Act of 1980 (CERCLA), 42 U.S.C. 9602(a), is 
the authority for the CERCLA aspects of this proposed rule.
    Section 3001(e)(2) of RCRA (42 U.S.C. 6921(e)(2)) 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 most of the issues raised in a civil action 
undertaken by the Environmental Defense Fund (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. The 
consent decree was approved by the court on December 9, 1994. As 
modified, the consent decree provides that the listing determination is 
scheduled to be proposed for public comment on or before July 31, 1996; 
upon notification to EDF, this date may be extended for up to 15 days. 
Under the agreement, EPA must promulgate the final rule on or before 
May 31, 1997. This listing determination includes the following spent 
solvents, still bottoms from the recovery of the following solvents, 
and spent solvent mixtures thereof: 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 solvents, EPA agreed to conduct a study, 
in lieu of a listing determination, and issue a final report. The study 
is scheduled to be issued by August 30, 1996. This study is to discuss 
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. These additional chemicals are: diethylamine, aniline, 
ethylene oxide, allyl chloride, 1,4-dioxane, 1,1-dichloroethylene, and 
bromoform.
    As part of its regulations implementing Section 3001(e) of RCRA, 
EPA published a list of hazardous wastes that includes hazardous wastes 
generated from nonspecific sources and a list of hazardous wastes from 
specific sources. These lists have been amended several times and are 
published in 40 CFR 261.31 and 40 CFR 261.32, respectively. In today's 
action, EPA is proposing not to amend 40 CFR 261.31 to add wastes from 
nonspecific sources generated during the use of the 14 solvents. This 
is not a determination that these chemicals are nontoxic. Many of these 
solvent wastes are, in fact, already regulated as hazardous waste 
because they exhibit a hazardous waste characteristic under 40 CFR 261 
Subpart B, and/or because they are mixed with other solvent wastes that 
are, themselves, listed hazardous waste. Rather, this is a 
determination only regarding the need for adding these specific wastes 
to the RCRA hazardous waste listings based on the specific criteria in 
the listing regulations. Although the consent decree does not require a 
listing determination for the solvents covered by the study, the Agency 
may decide to make a listing determination for those solvents in a 
future rulemaking.

B. Existing Solvent Listings and the Regulatory Definition of Solvent

    Five hazardous waste listings for solvents have been promulgated to 
date

[[Page 42320]]

(40 CFR 261.31(a)): F001, F002, F003, F004, and F005. EPA has defined 
the universe of wastes covered by today's listing determination to 
include only those wastes generated as a result of a solvent being used 
for its ``solvent'' properties. This approach is consistent with the 
existing solvent listings (50 FR 53316; December 31, 1985); this is 
also consistent with the term ``spent'' in the Consent Decree.
    This definition of ``solvent use'' was included in the RCRA 3007 
Solvent Use Questionnaire used to obtain information to support today's 
proposed rulemaking.

    Solvents are used for their ``solvent'' properties--to 
solubilize (dissolve) or mobilize other constituents. Examples of 
such solvent use include degreasing, cleaning, and fabric scouring, 
use as diluents, extractants, and reaction and synthesis media, and 
for other similar uses. A chemical is not used as a solvent if it is 
used only for purposes other than those described above.

    Spent solvents are solvents that have been used and are no longer 
fit for use without being regenerated, reclaimed, or otherwise 
processed (50 FR 53316, December 31, 1985). The listing investigation 
undertaken to support today's proposal covered spent solvents, still 
bottoms from the recovery of spent solvents, and mixtures of spent 
solvents after use with other solid wastes. The Agency also 
investigated the residuals generated by processes that use the solvents 
of interest. Residuals include spent solvents, residuals generated 
during solvent recovery, and any residuals generated after the solvent 
has been introduced into the process that might include some 
concentration of spent solvent. The existing solvent listings in 40 CFR 
261.31 apply to spent solvents that contain at least 10 percent (by 
volume), before use, of the listed solvents are used for their 
``solvent properties,'' as defined in the December 31, 1985 Federal 
Register (50 FR 53316). In evaluating spent solvent wastes for today's 
determination, however, EPA considered all reported solvent uses, 
including those reported to be below the 10% threshold.
    EPA's listing investigation did not consider processes where the 
constituents of interest are used as raw materials or principally sold 
as commercial products (i.e., where the constituent is not used for its 
solvent properties) because the materials used as raw materials or 
products are not generally considered wastes under RCRA. This also is 
discussed in the December 31, 1985 FR, (``* * * process wastes where 
solvents were used as reactants or ingredients in the formulation of 
commercial chemical products are not covered by the listing''). EPA 
could examine the wastes from such nonsolvent uses, if deemed 
necessary. However, with a backlog of listing determinations to 
complete under court-ordered deadlines, EPA has focussed its current 
efforts on those determinations required by law. An example of the use 
of solvents as ingredients is the use of solvents contained in paints, 
coatings, or photoresist.
    EPA solvent listings are distinct from most other hazardous waste 
listings in 40 CFR Part 261 Subpart D because they cover hazardous 
wastes from the use of, rather than the production of, specified 
chemicals. As noted above, the Agency has used the same approach in 
this listing determination as in previous listings. EPA believes that 
applying this definition of spent solvent in today's rulemaking is a 
reasonable approach. RCRA 3001(e)(2) directs 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. 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.'' Use of the definition has allowed the Agency to 
place reasonable limits on the scope of its listing investigation for 
this rulemaking. Given the ubiquity of ``solvents'' in general, the 
Agency cannot take a census of a particular industry for a study (as 
other recent listing determinations have done) to arrive at a 
regulatory determination. Instead, the Agency has used the existing 
definition of solvent use and attempted to identify facilities and 
industries that use these chemicals as solvents.
    For this listing determination, this definition proved particularly 
useful as many of the chemicals (where used as solvents) are rather 
specialized in their solvent uses. The Agency has, therefore, retained 
the interpretations used in the past to define ``solvent use'' and 
``spent solvent'' waste generation.
    Finally, 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 focussed 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 proposed listing for petroleum refining 
process wastes (60 FR 57747, November 20, 1995). EPA is employing the 
same general approach in today's proposal. Readers are referred to 
these notices for a description of EPA's listing policy. Also, Section 
II.C.2., ``Risk Assessment,'' contains a discussion of how elements of 
EPA's listing policy were applied in today's listing determination.

II. Today's Action

A. Summary of Today's Action

    This action proposes not to list as hazardous wastes from solvent 
uses of the following 14 chemicals from the EDF consent decree: 
acetonitrile, 2-ethoxyethanol acetate, 2-methoxyethanol, 2-
methoxyethanol acetate, cyclohexanol, cumene, phenol, furfural, 
isophorone, methyl chloride, 1,4-dichlorobenzene, benzyl chloride, 
epichlorohydrin, and ethylene dibromide. The Agency has determined that 
these wastes do not meet the criteria for listing set out in 40 CFR 
261.11. Sections II.D through II.M of this preamble present waste 
characterization, waste management, mobility, persistence, and risk 
assessment data that are the bases for the Agency's proposal not to 
list these wastes.
    For the first 10 chemicals, EPA found that the management of 
residuals from the use of these chemicals as solvents does not pose a 
risk to human health and the environment under the plausible 
mismanagement scenarios. The data used as the bases for these 
determinations are presented in Sections II.F through II.M of today's 
proposal. Detailed information is presented in the background documents 
supporting today's proposal, which are available in the docket (see 
ADDRESSES).
    For the last four chemicals, the decision not to list residuals 
from the use of these chemicals as solvents is due to EPA's belief that 
these chemicals are extremely unlikely to be used as solvents based on 
a lack of data indicating widespread solvent use for these chemicals. 
These chemicals were originally put on the list in the consent decree 
because of initial indications that some solvent use may have existed. 
However, EPA did not find significant solvent use for these chemicals. 
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 shows that the reported use of these 
four chemicals as solvents is linked to bench-scale or experimental 
laboratory

[[Page 42321]]

settings, and no significant solvent uses were found.
    In short, the Agency is proposing not to list as hazardous benzyl 
chloride, epichlorohydrin, ethylene dibromide, and p-dichlorobenzene as 
hazardous spent solvents because these chemicals are extremely unlikely 
to be used as solvents. For more detailed Agency findings on these 
chemicals, see Sections II.N through II.Q of today's proposal and the 
background document supporting today's proposal. The Agency requests 
comment for new information on other solvent uses not covered in this 
proposal. If the Agency receives new data during the comment period, 
the Agency may use these data to revise risk assessment methodology and 
assumptions.

B. EPA's Evaluation of Solvent Use

1. Development of Study Universe
    Spent solvents differ from other listed wastes among EPA's waste 
listings in that they are not principal waste streams generated by 
manufacturing processes. Rather, they are used in a host of 
manufacturing and allied applications, such as cleaning, degreasing, 
extraction, purification, etc.
    As part of the solvent use study, the Agency researched uses for 
all 14 chemicals being considered in this listing determination (See 
Section II.B). Following the data gathering, the Agency sent out almost 
1,500 preliminary questionnaires in an attempt to characterize 
industrial solvent use. After compiling the data and conducting follow 
up phone calls to facilities, the Agency mailed out 156 questionnaires 
to facilities to further characterize solvent uses. Summary information 
from these questionnaires forms part of the basis of the listing 
determination and may be found in the background document supporting 
today's proposal.
    The solvents listing investigation focuses on facilities using 
specific chemicals for their solvent properties. At the outset of this 
investigation, EPA set out to identify probable solvent uses for these 
chemicals. The Agency conducted a thorough literature search to 
characterize the potential solvent uses. This search is fully described 
in the background document supporting today's proposal. The Agency 
identified industrial processes known or suspected of using the 14 
chemicals being investigated as solvents through such sources as 
chemical engineering and industrial manufacturing reference books. Also 
central to the results of the literature search was the location of 
four to ten years of abstracts from scientific publications that 
referenced the use of the 14 chemicals of concern as solvents. From 
these sources, the Agency developed profiles of known, suspected, and 
potential uses of these 14 chemicals as solvents.
    The solvent uses identified were correlated with specific 
industries, using Standard Industrial Classification (SIC) Codes. The 
list of SIC codes developed was cross-referenced, by solvent, with 
other Agency data sources, including the Toxic Release Inventory (TRI) 
reporters list, Office of Water facility lists, and other sources to 
obtain a final list of facilities that might reasonably be expected to 
use one of the 14 chemicals as a solvent. The other sources utilized 
included (1) the mailing list for EPA's RCRA 3007 Petroleum Industry 
Questionnaire, (2) EPA's effluent guidelines questionnaire recipients 
for the Pharmaceuticals and Organic Chemicals, Plastics, and Synthetic 
Fibers industries, (3) facilities included in the Agency's National Air 
Toxics Inventory of Chemical Hazards (NATICH) database, and (4) pulp 
and paper mills studied during an investigation of pulp and paper mill 
sludge disposal. Additional facilities were included that were 
identified by EPA's Office of Pollution Prevention and Toxics (OPPT) 
during an evaluation of solvents. The Agency also met with trade groups 
representing pharmaceutical, chemical, synthetic organic chemical, and 
semiconductor manufacturers.
    Where a suspected use of a chemical would affect industries other 
than those discussed above, EPA refined the facility mailing list 
through the use of publicly available industrial address books and 
product manufacturer listings. This approach to developing a mailing 
list is discussed in detail in the background document to support 
today's proposed rule.
    The Agency used a preliminary questionnaire to prescreen for 
solvent use by facilities on the mailing list. The RCRA 3007 
Preliminary Questionnaire of Solvent Use was mailed to 1,497 facilities 
in May 1993. Facilities were asked to provide the quantity of the 
chemical used as a solvent in 1991 and 1992. As a result of the 
preliminary questionnaire, the Agency removed more than 900 facilities 
from further analysis because they reported no use of the 14 chemicals 
as solvents.
    The Agency attempted to refine the results of the preliminary 
questionnaire further before sending out the full 3007 survey. Several 
hundred of the facilities were contacted to confirm and clarify the 
information reported. Some facilities misreported the use of a solvent 
(i.e., reported methyl chloride when methylene chloride was used), and 
such errors were corrected. (Telephone logs for these contacts are 
contained in the docket to today's rule.) Further, because EPA 
estimated that very little useful information would be gained from 
smaller facilities, EPA eliminated from further consideration those 
facilities that used less than a combined total of 1,200 kilograms of 
all of the chemicals of concern. The Agency chose this cutoff because 
it represents the maximum annual quantity of waste that would be 
generated by a conditionally exempt small quantity generator (i.e., one 
that generates less than 100 kilograms per month of a hazardous waste). 
Further, EPA's data collection effort showed that most facilities (90%) 
reporting less than 1,200 kg/year were in fact using significantly less 
than 1,200 kg/year, i.e., 120 kg/year or less. In all the Agency 
eliminated approximately 400 facilities from further study, either due 
to reporting errors, discontinued use, or use of small quantities of 
the solvents. As a result of this refinement, 156 facilities received a 
RCRA 3007 Questionnaire of Solvent Use.
    EPA believes that the elimination of most small quantity users does 
not significantly affect the risk assessment, because the volumes used 
were small compared to the larger volume users that were sent the full 
survey. The risk assessment results are based on the highest waste 
volumes (and solvent loadings) reported for each management practice 
(see section II.C.2), therefore any significant risks would be found in 
EPA's evaluation of the larger quantity users.
    The Agency did not conduct a sampling and analysis program for the 
spent solvent wastes. EPA found that obtaining representative samples 
would be almost impossible due to potential use of these solvents in a 
variety of different industries. The cost of such a program would have 
been prohibitive to the Agency.
2. Applicability to National Use
    For the solvents under review, the Agency believes that the 
industry study results obtained through the methodology described above 
accurately characterize solvent uses of the chemicals mandated for 
review. In addition, the industry study completed gives the Agency an 
accurate idea of the nationwide uses of these chemicals, whether or not 
the chemicals are used in large or small quantities as solvents. The 
Agency is confident that the collected information on solvent use 
covers the large solvent users.

[[Page 42322]]

    Once the industry study was completed, the resulting data for each 
of the 14 chemicals was evaluated to determine whether or not large 
users may have reasonably been missed during the RCRA Sec. 3007 survey 
process. Several considerations were evaluated for this review, 
including:
     the scope of anticipated solvent use obtained during the 
extensive literature search prior to pre-questionnaire mailing list 
development;
     whether or not the chemical was required to be reported in 
the 1990 Toxics Release Inventory;
     the number of facilities and type of solvent use 
eventually identified and characterized in the full RCRA Sec. 3007 
survey; and
     comparison of Sec. 3007 survey solvent use quantities with 
total chemical production volume and, where available, volume of the 
chemical used as a non-solvent.
    Three chemicals under evaluation (cyclohexanol, isophorone, and 
furfural) were not TRI chemicals in 1990, a primary data source for the 
RCRA Sec. 3007 pre-questionnaire mailing list. However, EPA believes 
that large users of these chemicals were captured through other data 
sources. Literature searches suggested limited solvent uses for these 
chemicals across several industries. Results from the full RCRA 
Sec. 3007 questionnaire confirmed limited solvent uses of greater than 
1,200 kg/year for two chemicals: a single facility for cyclohexanol and 
four facilities for isophorone. The one cyclohexanol facility was a 
petroleum refinery and all identified petroleum refineries were sent a 
pre-questionnaire.
    Isophorone solvent use was identified at four facilities across 
four SIC codes. Three of these facilities used isophorone as a solvent 
in a similar process (in the coating industry). As with cyclohexanol, 
no TRI data existed for isophorone to identify specific facilities.
    Furfural was used in large quantities as a solvent, however nearly 
all of the solvent use (>99.9%) was found in the petroleum industry, 
which EPA surveyed. Given that the major use of this solvent was very 
specialized (e.g., extraction of lube oil), the Agency believes that 
the collected information on solvent use covers all large solvent 
users.
    A detailed description of the methodology used to evaluate the 
coverage of the Agency's industry study for the 14 chemicals of concern 
is contained in the background document contained in the docket for 
today's rule (Hazardous Waste Listing Determination Background Document 
for Solvents). Statistics on production and solvent use for each 
solvent are also summarized in the discussions of the listing 
determination for each respective chemical (Sections II.D through 
II.N). The Agency requests comment on the use of these chemicals as 
solvents EPA may not have uncovered in its data collection efforts.
3. Comparison of Questionnaire and Prequestionnaire Data
    After the receipt of responses to the RCRA 3007 Questionnaire of 
Solvent Use, EPA compared the 1992 solvent use reported in the 
Preliminary Questionnaire with the solvent use reported in the 1993 
Questionnaire. With the exception of acetonitrile, for which a slight 
increase in solvent use is noted, the reported use of the remaining 13 
chemicals decreased. For all of the chemicals, the solvent use reported 
in the preliminary questionnaire included amounts of wastes containing 
the chemicals reported as managed by commercial treatment, storage, and 
disposal facilities (TSD). In some cases, such as benzyl chloride, 
ethylene dibromide and p-dichlorobenzene, nearly all quantities 
reported as used in 1992 were actually wastes received by TSDs. Other 
apparent decreases resulted from incorrect reporting of chemicals used, 
or because further review by EPA showed that the use did not meet EPA's 
definition of solvent use (see below). In addition to apparent changes 
that resulted from corrections to the data base, there were decreases 
in actual quantities used for some solvents. Specifically, significant 
decreases were noted for glycol ethers (e.g., 2-ethoxyethanol acetate, 
2-methoxyethanol, and 2-methoxyethanol acetate), because facilities 
were phasing out their use as solvents. Additional decreases were 
attributable to plant closures and other discontinued use.
    Based on a detailed review of the full Questionnaire responses, the 
Agency determined that certain uses reported in 1992 did not meet EPA's 
definition of solvent use. For example, further reductions from 
quantities reported in 1992 are attributable to the elimination from 
consideration of the use of a solvent as an ingredient in a photoresist 
in semiconductor and printed circuit board manufacture, and use of a 
solvent as a component of a paint or coating. (For example, for 
photoresist uses, Agency staff determined that such uses did not 
comport with the definition of ``solvent use'' as described earlier 
because the chemicals were not carriers, reaction media, extractants, 
etc. Rather, they were used in a way that suggested they were 
components of the manufacturing process.) Finally, variations in usage 
are to be expected. For many solvents, facilities reported either 
increases or decreases in use between 1992 and 1993 that indicate 
changes in production schedule or product slate. Additional details on 
these changes, on a solvent-by-solvent basis, are presented in the 
Background Document for today's rulemaking. EPA believes that all large 
users of the 14 solvents were identified and surveyed as part of 
today's determination because of the specialized nature of solvent use 
for such chemicals as observed in its literature search. EPA also notes 
that users of small amounts of one solvent were captured in many cases 
because they are large users of another solvent. For example, one 
refinery uses a large amount of phenol but also was captured as an 
acetonitrile user.) Further, the Agency believes that the solvent use 
reported in response to the full Questionnaire provides a more accurate 
characterization of solvent use patterns than the Preliminary 
Questionnaire because of the greater level of detail provided by the 
respondents.

C. Description of Health and Risk Assessments

    In determining whether waste generated from the use of these 14 
chemicals as solvents meets the criteria for listing a waste as 
hazardous as set out at 40 CFR 261.11, the Agency evaluated the 
potential toxicity of the solvents, the fate and mobility of these 
chemicals, the likely exposure routes, and the current waste management 
practices.
1. Human Health Criteria and Effects
    The Agency uses health-based levels, or HBLs, as a means for 
evaluating the level of concern of toxic constituents in various media. 
In the development of HBLs, EPA first must determine exposure levels 
that are protective of human health and then apply standard exposure 
assumptions to develop media-specific levels. EPA uses the following 
hierarchy for evaluating health effects data and health-based standards 
in establishing chemical-specific HBLs:
     Use the Maximum Contaminant Level (MCL) or proposed MCL 
(PMCL), when it exists, as the HBL for the ingestion of the constituent 
in water. MCLs are promulgated under the Safe Drinking Water Act (SDWA) 
of 1984, as amended in 1986, and consider technology and economic 
feasibility as well as health effects.
     Use Agency-verified Reference Doses (RfDs) or Reference 
Concentrations (RfCs) in calculating HBLs for noncarcinogens and 
verified

[[Page 42323]]

carcinogen slope factors (CSFs) in calculating HBLs for carcinogens. 
Agency-verified RfDs, RfCs, and CSFs and the bases for these values are 
presented in the EPA's Integrated Risk Information System (IRIS).
     Use RfDs, RfCs, or CSFs that are calculated by standard 
methods but not verified by the Agency. These values can be found in a 
number of different types of Agency documents and EPA uses the 
following hierarchy when reviewing these documents: Health Effects 
Assessment Summary Tables (HEAST); Human Health Assessment Group for 
Carcinogens; Health Assessment Summaries (HEAs) and Health and 
Environmental Effects Profiles (HEEPs); and Health and Environmental 
Effects Documents (HEEDs).
     Use RfDs or CSFs that are calculated by alternative 
methods, such as surrogate analysis, including structure activity 
analysis and toxicity equivalency.
    All HBLs and their bases for this listing determination are 
provided in the risk assessment background document entitled Assessment 
of Risks from the Management of Used Solvents, which can be found in 
the RCRA docket for this rule at EPA Headquarters (see ADDRESSES 
section). That document also includes the evaluation of acute toxicity 
data, such as lethal doses for the oral and dermal routes, and lethal 
concentrations for the inhalation route.
2. Risk Assessment
    The risk characterization approach follows the recent EPA Guidance 
on Risk Characterization (Browner, 1995) and Guidance for Risk 
Assessment (EPA Risk Assessment Council, 1991). The guidance specifies 
that EPA risk assessments will be expected to include (1) the central 
tendency and high-end portions of the risk distribution, (2) important 
subgroups of the populations such as highly susceptible groups or 
individuals, if known, and (3) population risk. In addition to the 
presentation of results, the guidance also specifies that the results 
portray a reasonable picture of the actual or projected exposures with 
a discussion of uncertainties. These documents are available in the 
public docket for this action (see ADDRESSES section).
Individual Risk
    Individual risk descriptors are intended to convey information 
about the risk borne by individuals within a specified population and 
subpopulations. These risk descriptors are used to answer questions 
concerning the affected population and the risk for individuals within 
a population of interest. The risk methodology section specifies the 
process used by EPA to assess individual risk for these solvents.
    Due to the unique circumstances of this listing determination 
(e.g., variety of industries using solvents, limitations of the 
available data), EPA was unable to assess population risks. The generic 
management scenarios devised for this risk assessment were not 
industry-specific and EPA did not have sufficient data to allow for 
specific population risk assessment; such an assessment would have 
required inappropriate assumptions and with little accuracy in results. 
There is no need to conduct population risk assessment, however (even 
were it feasible), for today's action, because EPA did not find any 
significant individual risks of concern for any of the 14 chemicals 
examined.
Uncertainties Associated With the Risk Assessment
    One source of uncertainty derives from the generically constructed 
management scenarios used; EPA had to make a variety of assumptions in 
order to model releases and exposures. Due to data limitations, as 
noted above, EPA was also not able to characterize actually exposed 
populations. Another uncertainty stems from the assumptions of 
plausible mismanagement, as described below in the following section.
    The Agency completed an enormous task in the data gathering effort. 
These data helped EPA to identify the major waste generators, and the 
quantities of solvent waste most likely to pose a risk to human health 
and the environment. The questionnaire asked for detailed information 
on waste generation, management, and disposal for these chemicals when 
used as solvents. By closely examining facilities that use these 
chemicals as solvents, the Agency identified where these chemicals are 
used as solvents, and where wastes of interest are generated and 
managed. The Agency then used this information to focus on the 
appropriate exposure scenarios. Because EPA relied on the data provided 
from the questionnaires, the resulting analysis is dependent on the 
quality of the data collected.
    a. Selection of Waste Management Scenarios. EPA's regulations at 
261.11(a)(3)(vii) require the Agency to consider the risk associated 
with ``the plausible types of improper management to which the waste 
could be subjected'' because exposures to wastes (and therefore the 
risks involved) will vary by waste management practice. The choice of 
which ``plausible management scenario'' (or scenarios) to use in a 
listing determination depends on a combination of factors which are 
discussed in general terms in EPA's policy statement on hazardous waste 
listing determinations contained in the Dyes and Pigments Listing 
Determination (59 FR 24530, December 22, 1994). EPA applied this 
policy, with some specific modifications that reflect unique 
characteristics of the industry, in the petroleum refining listing 
determination (60 FR 57747, November 20, 1995). The general use of the 
policy described in the dyes and pigments listing determination and 
applied in the petroleum rule is continued here.
    The following discussion explains the selection of plausible 
management scenarios for the solvents listing determination. EPA's 
basic approach to selecting which waste management scenarios to model 
for risk analysis in listing determinations is to examine current 
management practices and assess whether or not other practices are 
available and would reasonably be expected to be used. Where a practice 
is actually reported in use, that practice is generally considered 
``plausible'' and may be considered for potential risk. EPA then 
evaluates which of these current or projected management practices for 
each wastestream are likely to pose significant risk based on an 
assessment of exposure pathways of concern associated with those 
practices. There are common waste management practices, such as 
landfilling, which the Agency generally presumes may be plausible for 
solid wastes and will evaluate it for potential risk. There are other 
practices which are less common, such as land treatment, where EPA will 
consider them plausible only where the disposal methods have been 
reported to be practiced. In some situations, potential trends in waste 
management for a specific industry suggest the Agency will need to 
project ``plausible'' mismanagement even if it is not currently in use 
in order to be protective of potential changes in management and 
therefore in potential risk.
    As experience is gained in listing determinations, the Agency 
recognizes the need to more specifically describe its approach to 
plausible management selection for the circumstances related to each 
listing. EPA believes it necessary to do so here, in part because of 
the unique nature of the solvents listing determination.
    Selection of plausible management scenarios can better be described 
by noting that there are three important elements of this selection 
that must be considered in the risk assessment process: selection of 
the management practice(s) considered ``plausible'',

[[Page 42324]]

selection of waste volumes evaluated as going to each plausible 
practice, and selection of exposure pathways for each practice 
evaluated.
    The first element is selection of plausible management practices. 
As described above, plausible practices are ones that are reported by 
generators and can also be ones that are common practices, such as 
landfilling. EPA may project less common or unreported practices as 
plausible if there are compelling reasons for doing so. For the 
solvents listing determination, all practices EPA considers common were 
reported.
    In general, solvent wastes were wastewaters, high concentration 
organic wastes, or treatment residuals. Facilities also had losses of 
solvents gases due to process vents, flares, or other air releases, but 
these releases are not typically considered spent solvent wastes 
because they are process-related. Wastewaters were typically fairly 
dilute and are generally managed in a biological wastewater treatment 
system or sent to a Publicly Owned Treatment Works (POTW). In most 
cases, wastewater treatment occurred in tanks, however, some treatment 
in surface impoundments did occur. Wastewaters for one solvent 
(acetonitrile) were reported to go to underground injection wells, 
however, essentially all (>99.99%) such discharges were to Subtitle C 
hazardous waste injection wells.
    Questionnaire data show that a high percentage of the high organic 
nonwastewaters go to thermal treatment in incinerators, industrial 
boilers, or fuel blenders. Because many of these solvent wastes are 
either characteristic hazardous wastes (primarily due to ignitability) 
and/or are mixed with listed hazardous wastes, the vast majority of 
these wastes are handled as hazardous. The other major category of 
nonwastewaters was treatment residuals (e.g., wastewater treatment 
sludges, incinerator ash) and were typically landfilled.
    The Agency evaluated potential risk for the following practices: 
storage, combustion, wastewater treatment tanks and surface 
impoundments, and underground injection wells. There were no compelling 
reasons for projecting other practices as plausible.
    Second, there is the selection of the volumes of each wastestream 
the Agency considers could be disposed of in that management practice. 
(Note that EPA must also consider the ``loading'' of waste going to 
disposal sites. The ``loading'' is the amount of the solvent itself 
contained in the volume of the wastestream reported.) Here the Agency 
must determine what the volume of a wastestream is or could be going to 
a selected plausible management practice. Because different volumes are 
reported by generators, the Agency most often puts these reported 
volumes into a distribution and selects a high percentile volume to be 
representative of a reasonable volume that could go to the disposal 
scenario, usually a volume falling at or above the 90th percentile of 
volumes reported. That volume is then used as the volume input 
parameter for the risk assessment model. For solvents, EPA used the 
highest reported volumes (and loadings) going to the different 
management practices, because the number of volumes (and loadings) were 
limited to a few data points in many cases. The Agency did not attempt 
to project higher volumes than those reported in this listing 
determination for the following reasons:
     Use of these solvents is mostly specialized. The volume 
distribution was often skewed by one or two very high volume users. EPA 
used these higher volumes in its risk assessment modeling and therefore 
believes the conservative high volumes were in fact modeled.
     For purposes of this listing determination, the Agency has 
assumed that wastestreams reported to be managed as hazardous waste 
will continue to be managed in that way in the future. In this listing 
determination in particular, that assumption is considered reasonable 
because solvent use most often requires very high concentrations of 
chemical. Spent solvent as initially generated is therefore often very 
high concentration waste, meaning that the wastestreams are often and 
will continue to be characteristically hazardous for ignitability. In 
addition, many solvents are often used as mixtures containing other 
solvents that are listed as hazardous when spent (i.e., the F001 
through F005 listings), or exhibit a characteristic (e.g., 
ignitability). Such wastestreams would have to continue to be managed 
as hazardous, and stringent requirements are in place to ensure that 
hazardous wastes do not pose a threat to human health or the 
environment. This also means that certain waste management practices 
could not be employed. It would be unreasonable to assume that large 
amounts of such concentrated organic wastestreams would be shifted from 
combustion or recycling to waste management practices for which they 
were not reported, such as landfilling, especially when the 
concentrated organic waste streams are already hazardous wastes subject 
to the land disposal restriction rules.
     Spent solvents with relatively high value are also 
recovered by onsite distillation/fractionation in a closed-loop recycle 
stream. These residuals would not usually be considered wastes (see 40 
CFR 261.2), and, therefore, these volumes (if reported) were not used 
in the risk assessment modeling.
     Investment by industry in waste management practices 
suggests that dramatic changes in reported volumes going to specific 
waste management practices would not occur. For example, it would be 
unreasonable to assume that a generator with a large investment in a 
wastewater treatment plant would abandon that management practice for 
another.
    For these reasons, the Agency has concluded that the use of 
reported volumes of solvent wastestreams going to specific waste 
management practices is a reasonable way to project potential risk from 
spent solvent waste management.
    The third element in selecting plausible management scenarios is 
the selection of the actual exposure pathways that could be expected to 
be created via that management practice. The exposure scenarios 
examined are discussed in the following section.
    b. Exposure Scenarios. For each management scenario, EPA chose the 
pathways through which the solvents could affect human health or the 
environment. EPA initially considered a wide range of direct and 
indirect exposure pathways, including direct inhalation, ingestion of 
groundwater, inhalation of soil and dust, ingestion of soil, ingestion 
of surface water, ingestion of crops, ingestion of animal/dairy 
products, and ingestion of fish and shellfish. Exposure through the 
ingestion of fish and shellfish were not quantitatively evaluated 
because the solvents are nearly all highly water soluble, and therefore 
are not expected to be absorbed or bioaccumulated. Vapor phase releases 
will have little tendency to deposit to soil or surface water and, 
thus, little tendency to enter the food chain or crops.
    Based on the physical and chemical properties of the constituents 
of concern and current management practices, direct inhalation was 
identified as the primary exposure route of concern. EPA also evaluated 
the groundwater pathway, where appropriate. Given the plausible waste 
management practices and the physical properties of the solvents, the 
following exposure scenarios were evaluated.

[[Page 42325]]



------------------------------------------------------------------------
      Management practice              Pathway          Exposure route  
------------------------------------------------------------------------
Combustion.....................  Air...............  Inhalation of      
                                                      emissions from    
                                                      combustion.       
Storage Tanks..................  Air...............  Inhalation of      
                                                      volatilized       
                                                      solvents.         
Wastewater treatment tanks.....  Air...............  Inhalation of      
                                                      volatilized       
                                                      solvents.         
Wastewater treatment surface     Air and             Inhalation of      
 impoundments.                    Groundwater.        volatilized       
                                                      solvents;         
                                                      ingestion of      
                                                      groundwater       
                                                      contaminated by   
                                                      solvents leaching.
------------------------------------------------------------------------

    To assess the risks posed by thermal treatment, EPA chose to model 
potential releases from a boiler as a plausible management practice. 
For preliminary screening, wastes currently managed in permitted 
hazardous waste management units (e.g., incinerators) were assumed to 
be managed in similar types of non-hazardous waste management units 
(e.g., Subtitle D industrial boiler). This approach results in risk 
estimates that are quite conservative, since the non-hazardous units 
are less protective than their hazardous counterparts. In addition, EPA 
modeled possible air releases from an open accumulation tank, because 
many solvent wastes are reported to be stored before treatment; for 
this analysis, EPA assumed that any waste that was thermally treated 
could be stored prior to treatment. To model potential air releases 
from wastewater treatment, EPA modeled aerated tanks and surface 
impoundments.
    EPA evaluated two scenarios, landfills and deepwell injection, and 
found that modeling was not necessary to determine that risks from 
these pathways would not be significant, as discussed below. A third 
scenario, treatment of wastewaters in surface impoundments, also did 
not require extensive analysis to determine that risks from potential 
releases to groundwater would not be significant (see below).
    The data from the 3007 Survey show that wastes that were sent to 
landfills contained negligible amounts of solvent; landfilling of 
wastes high in solvent content did not occur. As noted previously, 
solvent wastes are generally wastes with high organic content (spent 
solvent liquids, residuals from recycling), or dilute wastewaters. The 
vast majority of concentrated solvent wastes are hazardous due to 
characteristic or mixing with other listed wastes, and could not be 
landfilled, but are thermally treated. Therefore, organic or aqueous 
liquid wastes are not expected to be managed in a landfill. Few solids 
were generated that contained any residual solvent. The total loading 
of all solvents reported going to landfills was <500 kg per year, and 
nearly all went to Subtitle C landfills. Treatment residuals 
(wastewater treatment sludges and incineration residuals) were reported 
to be landfilled; however, they had negligible solvent levels. The lack 
of solvent in treatment residuals is expected because these solvents 
are efficiently treated by combustion and in wastewater treatment 
systems. Therefore, because the wastes that reported to go to landfills 
contained little or no solvent, and considering that nonwastewaters 
with any appreciable solvent content are generally hazardous and thus 
are managed as hazardous waste already, the Agency had no reason to 
model the landfill scenario.
    EPA also considered the potential for groundwater risks posed by 
treatment in surface impoundments for all solvents that had wastewater 
going to surface impoundments for treatment. EPA found that these 
wastes are diluted by the flow of other dilute wastewaters (i.e., at 
the ``headworks''). EPA gathered data on headworks flow in the 3007 
Survey, and this allowed EPA to estimate headworks concentrations of 
all solvents going to surface impoundments based on the loading of 
solvent in each waste and the total wastewater flow to the headworks. 
Solvent levels were generally found to be below the HBLs at the 
headworks. Thus, no modeling was needed to ``bound out'' nearly all 
reported impoundment practices for possible groundwater risks. EPA 
closely examined the few remaining cases for which solvent levels might 
enter impoundments above HBLs, and completed bounding analysis when 
appropriate. Potential risks from surface impoundment treatment are 
discussed in more detail in the specific sections for each solvent.
    The practice of deep-well injection was reported to occur for only 
one solvent (acetonitrile); nearly all of it was hazardous waste 
(except for wastes containing 2 kg of solvent), and all went to 
Subtitle C wells. Given that nearly all of the waste was hazardous and 
was disposed of in RCRA permitted units, the waste is adequately 
regulated. EPA found no evidence of any disposal in nonhazardous 
deepwells. Therefore, EPA did not evaluate this practice further.
    Finally, 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 chemical with some solvent use, cumene, is only 
slightly soluble in water. However, EPA found no significant land 
disposal of cumene wastes. The solubilities of the solvents are given 
in the section specific to each solvent.
Potential Risks From Spills
    The Agency considers significant risk from spillage of spent 
solvents to be unlikely for several reasons. First, most of the actual 
volume of residuals reported were low concentration wastestreams, i.e., 
wastewaters and treatment residuals. Their ``loading'' or mass of 
constituent in the reported waste is typically very low. These low 
reported concentrations (often reported as ``trace'' concentrations) 
were due to both treatment efficiencies of the spent solvents in 
wastewater treatment systems and dilution in the treatment system 
itself. Spills of such dilute wastestreams would not be of concern in 
terms of risk. The high concentration spent solvent wastes would be of 
most concern, but EPA found the vast majority to be already subject to 
hazardous waste management requirements as characteristically hazardous 
waste, or due to use or mixing with other listed solvents.
    c. Risk Assessment Methodology. The general approach used for this 
risk assessment involved successive iterations of risk screening. At 
each step, risk from waste management scenarios was compared to these 
levels of concern: for non-carcinogens, a hazard quotient exceeding 
1.0, and for carcinogens, a lifetime cancer risk factor in the range of 
1 x 10-6 to 1 x 10-4. For further explanation of levels of 
concern, see ``EPA's Hazardous Waste Listing Determination Policy'' in 
59 FR 66073 (December 22, 1994). The overall risk assessment was 
conducted in three steps, as outlined below. The results of

[[Page 42326]]

the risk assessment for each solvent are described in Sections II.D to 
II.M.
    First Phase of Risk Screening--Bounding Analysis: For each of the 
scenarios evaluated, EPA applied a screening methodology to arrive at 
``bounding'' estimates of risk. These estimates gauge the risk posed by 
the particular scenario under worst-case conditions: i.e., risk to the 
most exposed populations under the most conservative assumptions about 
releases, transport, and exposure. Bounding estimates therefore 
purposely overestimate the exposure for the purpose of screening out 
those scenarios which cannot pose any significant risk under any real-
life conditions. The scenarios that did not pose a significant risk 
under a bounding analysis were considered to have been screened out, 
and were not studied any further.
    Second Phase of Risk Screening--High-End and Central Tendency 
Analysis: For each scenario where bounding analysis risk was above a 
level of concern, EPA estimated the high-end and central tendency 
risks. High-end risk describes the individual risk for those persons at 
the upper end (above the 90th percentile) of the risk distribution; 
central tendency represents the typical risk using average or median 
values for all exposure parameters. For this analysis, high-end 
estimates were determined by identifying the two most sensitive 
exposure parameters and then using maximum (or near-maximum) values for 
these parameters. Median or average values were used for all other 
parameters.
    Third Phase of Risk Screening--Wastes Already Regulated as 
Hazardous: As stated above, EPA noted that many of the waste streams 
were already hazardous wastes; they were either characteristically 
hazardous (generally because of ignitability), or mixed with listed 
solvents (either during use or after waste generation). Current 
requirements for managing these wastes mean that they will not pose a 
threat to human health and the environment.
    Therefore, EPA applied a third phase of risk screening to those 
wastes which had not screened out in either of the first two phases. 
This third phase consisted of a bounding analysis restricted to 
wastestreams that could plausibly be managed as nonhazardous waste.
    d. Consideration of Damage Cases. EPA investigated damage incidents 
that contained reports of the 14 chemicals under evaluation as 
contaminants at the site. Sources for this investigation included the 
Record of Decision Database, the Damage Incident Database, and a 
literature search. The Record of Decision (ROD) is generated by EPA to 
document how the Agency plans to clean up a Superfund Site, and 
contains the results of a detailed study of the contamination at the 
site. Unlike industry studies in which wastes under study are generated 
from set processes that are site-specific, in the solvent's industry 
study it was not possible to determine a contaminant was used as a 
solvent meeting EPA's definition of solvent use. Wastes disposed at 
many sites were categorized only in broad terms as ``oily wastes,'' 
``pesticide wastes,'' ``organic wastes,'' or ``solvent wastes;'' the 
uses of specific wastes prior to disposal were not identified. 
Furthermore, sites were typically contaminated by a wide variety of 
chemicals, many of which are widely used F-listed solvents, and wastes 
containing these chemicals are more likely to represent any vaguely 
identified ``solvent wastes.'' In other damage incidents, waste 
categorization for buried drums or landfilled hazardous materials was 
not possible. Based on a review of identified damage instances, no 
single instance of damage was identified that could be tied to use of 
the target chemicals as a solvent.
    Most of the damage cases found for these solvents resulted from 
disposal that took place many years ago, typically well before 1980. 
Waste management regulations have changed dramatically since the RCRA 
regulations were first promulgated (1980), and the damage cases appear 
to reflect management practices that are no longer legal or likely. 
Therefore, these cases do not provide a useful guide to current or 
future disposal practices that may occur.
    Also, many of the 14 chemicals are produced in relatively large 
volumes, and only small percentages of most are used as a solvent. Some 
of the chemicals have been widely used as chemical intermediates (e.g., 
phenol) or as ingredients in products (e.g., cumene in paint and 2-
methoxyethanol in jet fuel). The presence of others may often be traced 
to their occurrence as an impurity in other chemicals (e.g., p-
dichlorobenzene is a common impurity in the listed solvent 1,2-
dichlorobenzene). Therefore, EPA believes that reported contamination 
is more likely to arise from nonsolvent uses. Furthermore, the solvent 
uses identified for the target chemicals studied were typically limited 
to a few industries, and none of these sectors were represented by 
facilities reported in the damage case databases.
    Many of the damage cases arose from mismanagement at older 
municipal or industrial landfills, and it is difficult to determine how 
a chemical may have been used prior to disposal. These sites invariably 
accepted a wide variety of wastes and were contaminated with many 
different chemicals. Some of the target chemicals are possible 
breakdown products from the degradation of other contaminants (e.g., 
phenol, methyl chloride). Therefore, because the ROD database does not 
specifically cite the uses of any of the wastes found at the site, the 
cases did not provide any direct evidence that contamination by any 
other chemicals evaluated in this listing determination was linked to 
disposal of spent solvents.
    Finally, the 3007 Survey showed that high percentages of most of 
the nonwastewater residuals reported are classified as hazardous, and 
are subject to strict regulation under RCRA. Thus, the solvent wastes 
currently generated generally could not be legally managed in the 
manner that led to the damage cases (e.g., landfills). Therefore, EPA 
did not find that the damage cases provided any relevant information on 
the potential risks posed by solvent wastes. The sections for each 
target chemical presents a more specific discussion for the damage 
cases identified.
    e. Risk Assessment Results. Sections II.D to II.N present a more 
specific analysis by each solvent of the waste generation and 
management information to justify the individual regulatory 
determinations. Risk assessment evaluations were not conducted for the 
four chemicals (benzyl chloride, epichlorohydrin, ethylene dibromide, 
and p-dichlorobenzene) for which EPA found no significant solvent use. 
The risk tables for each of the remaining 10 constituents indicate the 
estimated health risk associated with the current and plausible 
management scenarios. For greater detail, see the listing and risk 
assessment background documents available in the docket to this 
rulemaking proposal.
    EPA requests comment on all aspects of its listing determinations, 
including comments pertinent to the adequacy of the data base and the 
methodology used to evaluate the data, and comments regarding the 
extent to which EPA has adequately characterized solvent uses, users of 
the solvents and management practices for the solvent waste streams. 
EPA is also soliciting comment on the risk assessment methodology and 
assumptions, including the Agency's rationale for choosing plausible 
management scenarios.
    Comments suggesting changes to the Agency's data base or risk 
assessment methodology, or to the Agency's listing determination for 
any of the 14 solvent waste streams, should be accompanied by any 
relevant data or supporting

[[Page 42327]]

information. If EPA receives new data or information during the comment 
period, EPA may use this information to augment its data base or revise 
its methodology or assumptions for purposes of the final rule. If EPA 
receives relevant new information during the comment period on solvent 
uses, users or management practices for any of the specific solvent 
wastes addressed in this rulemaking, EPA may revise its individual 
listing determinations based on this information.
    In particular, EPA notes that while a number of these solvents 
might cause an unacceptable groundwater risk if significant volumes 
were land disposed in concentrated form, such a scenario does not 
appear to be plausible. Much of EPA's assessment of the risks from the 
use of these solvents derives from evidence that such wastes are not 
likely to be discarded on the land in significant concentrations. Nine 
of these chemicals are already listed as commercial chemical products 
and thus cannot be legally land disposed in their unused form without 
treatment; furthermore, they would be subject to manifesting and other 
RCRA controls when discarded. Many of the more concentrated wastes are 
ignitable as generated, or already covered by an existing hazardous 
waste listing, and are thus subject to RCRA regulation. Solid treatment 
residuals appear to contain negligible or very low concentrations of 
these solvents, because of the efficacy of treatment. Wastewaters do 
not pose significant risk to groundwater or air, because the 
wastewaters are generated in relatively dilute form, are further 
diluted in integrated wastewater treatment systems, and then 
effectively treated in those systems.
    If EPA receives comments that leads it to conclude that unregulated 
land disposal of concentrated wastestreams from the use of these 
solvents is likely, EPA will consider promulgating a listing to address 
those concerns. However, EPA currently believes that such a listing 
should be limited to those circumstances in which significant 
concentrations causing significant risk are plausible, such as listing 
only wastes with high concentrations of solvents. EPA would consider 
that approach in this case, given the analysis presented in this 
proposal indicating that the existing or plausible waste management 
scenarios do not pose significant risk. In particular, EPA believes 
that it may be inappropriate to list the full range of wastes that 
might otherwise be brought under regulation through application of the 
mixture and derived-from rule to such waste. EPA invites comment on 
such an approach.

D. Acetonitrile

1. Industry Identification
    Almost all acetonitrile is manufactured as an acrylonitrile by-
product. U.S. production of acetonitrile is estimated to be between 8 
and 11 million kilograms per year, of which more than 60 percent is 
believed to be used in solvent applications and about 40 percent in 
non-solvent applications.
    Acetonitrile may be used for many non-solvent purposes such as the 
production of nitrogen-containing compounds, including amides, amines, 
higher molecular weight mono- and dinitriles, ketones, isocyanates, and 
heterocyclic compounds. However, acetonitrile finds its primary use as 
a solvent in various industries, particularly in the pharmaceutical 
industry where it is used in the production of drugs and medicinal 
chemicals.
2. Description of Solvent Usage and Resulting Wastes
    a. Solvent Use and Questionnaire Responses. In response to the RCRA 
3007 Preliminary Survey of Solvent Use, 178 facilities reported the use 
of 5.8 million kilograms of acetonitrile as a solvent in 1992. The full 
RCRA 3007 Survey of Solvent Use Questionnaire was sent to the 74 
largest users of the 178 facilities that reported 1992 use of 
acetonitrile. Most (>94%) of the respondents to the preliminary survey 
that were not sent the full questionnaire reported using less than 120 
kg per year of acetonitrile as a solvent. Some of the facilities sent 
the 3007 survey used small quantities of acetonitrile, but were 
included because the total amount of target solvents used was above 
1200 kg. The facilities responding to the full 3007 survey reported a 
1993 use of 9.3 million kilograms of acetonitrile as a solvent.
    Literature searches indicate that acetonitrile is a common, 
versatile, polar solvent often used as an extraction medium or a 
recoverable reaction medium. Its high dielectric strength and dipole 
moment make it an excellent solvent for both inorganic and organic 
compounds, including polymers. RCRA 3007 Questionnaire responses 
indicate that acetonitrile is used across a broad range of industries 
as: a product and equipment wash; the mobile phase in high pressure 
liquid chromatography (HPLC) at laboratory, pilot, and production 
scale; a reaction, crystallization, or synthesis medium; an extractant 
or extractive distillation medium; a diluent; and a dissolution medium.
    Its largest use is in the pharmaceutical industry for the 
production of drugs and medicinal chemicals, where its applications 
range from laboratory use to pilot production in Food and Drug 
Administration drug trials to full-scale batch product preparation. It 
also is used in the organic chemicals industry as an extraction medium 
and in the petrochemical industry for the separation of butadiene from 
C4 hydrocarbons by extractive distillation. Literature searches 
indicated that acetonitrile may be used in electroplating operations, 
however, this use was not confirmed.
    A detailed discussion of the processes in which acetonitrile is 
employed is presented in the background document for today's proposal, 
which is available in the docket (see ADDRESSES section).
    b. Physical/Chemical Properties and Toxicity. Acetonitrile is a 
relatively polar compound and is completely miscible in water. Because 
of its miscibility, it is not expected to form a nonaqueous phase layer 
in groundwater (NAPL). It has a relatively low boiling point (82 
deg.C), and it has a moderate evaporation rate from water, as evidenced 
by its Henry's Law Constant (2.007 x 10-5 atm-m3/mole). 
Acetonitrile has a high vapor pressure at ambient temperature, and is 
also flammable and ignitable, with a flash point of 6  deg.C. 
Therefore, concentrated residuals from the use of acetonitrile as a 
solvent are expected to exhibit the characteristic of ignitability.
    The octanol-water partition coefficient (Log Kow) for 
acetonitrile is -0.34; this indicates that acetonitrile has a low 
tendency to sorb to soil organic matter, and is not expected to 
bioaccumulate in organisms.
    Acetonitrile is not classified as a carcinogen. The chemical has an 
RfC of 0.05 mg/m3 and an RfD of 0.006 mg/kg/day; these correspond 
to an air HBL of 0.05 mg/m3, and a water HBL of 0.2 mg/L.
    c. Waste Generation, Characterization, and Management. The 
respondents to the RCRA 3007 Survey of Solvent Use Questionnaire 
reported a combined total of greater than 9.15 billion kilograms of 
residuals generated from processes using acetonitrile as a solvent. The 
vast majority of the residuals, 9.13 billion kilograms, were 
wastewaters usually containing low to negligible concentrations of 
acetonitrile (average concentrations less than 1%). The remaining 
residuals, a combined total of greater than 15.0 million kilograms, are 
nonwastewaters containing widely varying levels of acetonitrile. Some

[[Page 42328]]

nonwastewaters usually have low to negligible solvent concentrations, 
such as filter-related materials, containers, and wastewater treatment 
sludges; other nonwastewaters, such as spent solvents and heavy ends 
from solvent recovery operations, typically have high levels of 
acetonitrile and/or other organic wastes.
    Nearly all wastewater residuals (98.4% by waste volume, and 79% by 
loading) are managed in on-site wastewater treatment systems; treatment 
in most cases included biological treatment in tanks, with a small 
amount (0.1% by loading, or 294 kg total) reported to be sent to 
surface impoundments. Some wastewaters (1.6% by volume, or 21% by 
loading) also went to Subtitle C deepwell injection as a hazardous 
waste. Very small quantities were reported to be discharged to Publicly 
Owned Treatment Works (POTWs).
    In 1993, more than 67 percent by volume of all nonwastewater 
residuals containing acetonitrile were classified as hazardous waste. 
However this percentage is skewed by one large volume (4.2 million kg, 
or 30% of nonwastewaters) of nonhazardous wastewater treatment sludge 
that had negligible acetonitrile concentration (see discussion below). 
Nonwastewaters with high organic content, such as spent solvent and 
heavy ends/distillates, were managed by some form of thermal treatment, 
including incineration, energy recovery in a BIF, or blending for fuel 
for future energy recovery.
    Based on the reported waste volumes and concentrations of the 
acetonitrile in the wastes, loadings of acetonitrile in the waste were 
calculated by multiplying the volume (in kilograms) by the 
concentration (in percent) and dividing by 100 (percent conversion). 
This calculation provides the total loading of acetonitrile in the 
waste that is available for potential release via management. Table 1 
presents the reported volumes and acetonitrile loadings by management 
practice for the wastes that contain spent acetonitrile from use as a 
solvent.
    EPA believes that the waste management practices reported in the 
questionnaires by industry capture the plausible management scenarios 
of concern for acetonitrile wastes. The full RCRA 3007 Questionnaire 
was sent to 74 facilities, and information was obtained concerning the 
management of over 250 wastestreams. The Agency believes that this 
sample of facilities revealed likely waste management practices that 
are or could be used in the management of these wastes. Therefore, EPA 
does not think it is warranted to project other management practices 
that could be employed. Further, the Agency anticipates the loadings to 
these different practices will not change significantly over time.
    To assess the potential risks for management of acetonitrile 
wastes, EPA selected several management practices for modeling. To 
represent the thermal treatment process (incineration, industrial 
boilers, fuel blending, critical oxidation), EPA chose an industrial 
boiler. To account for risks from the accumulation of residuals for 
thermal treatment, EPA modeled an uncovered storage tank. To assess 
risks arising from wastewater treatment, EPA modeled treatment in an 
aerated wastewater treatment tank.
    The Agency considered potential risks that might arise from the 
land-based management of acetonitrile wastes, i.e., deepwell injection, 
landfills, and surface impoundments. EPA does not believe that these 
management practices present significant risk for the following 
reasons.
    Concerning deepwell injection, as noted above, all of the disposal 
by this method occurs in Subtitle C units that are permitted to accept 
hazardous waste. Therefore, EPA does not believe that these wastes 
present any significant risk. Nearly all of the wastes sent to deepwell 
injection were classified as hazardous waste; only a total of 97 kg of 
wastes (containing 2 kg of solvent) sent to deepwell injection were 
nonhazardous. Thus, the Agency believes that future disposal of nearly 
all of these wastes will continue to be in a permitted unit, and EPA 
did not evaluate this practice further.
    EPA examined the practice of landfilling acetonitrile wastes and 
found that only four out of the 254 waste streams containing spent 
acetonitrile were reported to go to landfills. Of these four wastes, 
three were sent to Subtitle C landfills (2 after treatment, and 1 was 
small volume of filter material), and one wastewater treatment sludge 
was sent to a Subtitle D landfill. While the volume of the one waste 
sent to the Subtitle D landfill was relatively large (4.2 million kg), 
the sludge was reported to contain only a ``trace'' of miscellaneous 
organics. This specific sludge, and wastewater treatment residuals in 
general, are unlikely to contain significant levels of acetonitrile, 
because the chemical is removed by such treatment due to its volatility 
and susceptibility to biodegradation (>98%; see the U.S. EPA RREL 
Treatability Database). EPA also considered whether the practice of 
landfilling spent acetonitrile wastes was likely to increase, but could 
find no evidence to support this. To the contrary, the facility that 
had been sending the largest acetonitrile loading to a Subtitle C 
landfill (454 kg loading, 45,400 kg volume), indicated that it had 
ceased this practice during 1993 and started sending the waste for 
thermal treatment because of the waste's fuel value.
    Only three wastes with spent acetonitrile were reported to go to 
surface impoundments, and these were impoundments that were part of a 
wastewater treatment train. In all cases the annual loadings were very 
small (294 kg total), and acetonitrile levels would be negligible 
(i.e., orders of magnitude below the health-based level) after mixture 
with other wastewaters at the headworks prior to entering an 
impoundment. (For example, the largest loading reported treated in a 
surface impoundment, 230 kg per year, was mixed into a wastewater flow 
of more than 30 million gallons a day; thus, the estimated 
concentration at the headworks would be less than 0.04 ppm, well below 
the health-based level of 0.2 ppm.) Furthermore, acetonitrile is 
removed during wastewater treatment, such that any acetonitrile in 
treatment impoundments would be further reduced. Except for these three 
wastes, all reported wastewater treatment of acetonitrile wastes occurs 
in tanks. EPA has no reason to believe this practice would change, 
given the capital and regulatory costs associated with siting a new 
surface impoundment, and the investments already made in tank-based 
treatment systems.
    Overall, EPA concludes that nonwastewaters with all but negligible 
acetonitrile loadings are usually managed as hazardous under Subtitle C 
(because of the ignitability of these wastes, and/or the common 
practice of mixing with other hazardous solvent wastes), or recycled 
onsite. Wastewaters are primarily handled either as hazardous through 
deepwell injection, or treated in tank-based wastewater treatment 
systems.

[[Page 42329]]



                                Table 1.--Generation Statistics for Acetonitrile                                
----------------------------------------------------------------------------------------------------------------
                                                            # of         # of       Total volume        Total   
                  Management Practice                    facilities    streams          (kg)        loading (kg)
----------------------------------------------------------------------------------------------------------------
Incineration..........................................           33           79    \1\ <6,000,000  \1\ <700,000
BIF...................................................           11           73         2,410,944     1,650,764
Fuel Blending.........................................           19           46           622,870       337,437
WWT--Tank.............................................           15           29     8,988,222,016       206,159
WWT--Surface Impoundment..............................            3            3            95,118           294
POTW..................................................            4            6            16,911            16
Landfill, Subtitle C..................................            2            3            72,755           459
Landfill, Subtitle D..................................            1            1         4,181,818         trace
Deepwell Injection, Hazardous.........................            4            8       150,123,631        54,706
Critical Oxidation....................................            1            2           315,000        18,900
Distillation/Fractionation............................            3            4           771,966      429,300 
----------------------------------------------------------------------------------------------------------------
\1\ Exact value is withheld because some of the data for this practice are claimed as confidential business     
  information.                                                                                                  

3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a hazard quotient (HQ) for each plausible mismanagement 
scenario. Where the HQ exceeds 1, exposure is expected to pose a risk 
to human health and the environment. The results of these analyses are 
shown in Table 2.
    Using bounding assumptions, the Agency estimated that management of 
acetonitrile residuals in a boiler could result in an inhalation HQ of 
0.0000006. Risk based on bounding assumptions for the other plausible 
mismanagement scenarios (an aerated tank and on site accumulation) 
exceeded an inhalation HQ of 1, and EPA then conducted high end and 
central tendency risk analyses for these scenarios.
    The estimated high-end risk assessment with plausible mismanagement 
of acetonitrile wastes in an aerated tank is an inhalation HQ of 0.002, 
which indicates minimal risk through the inhalation pathway for this 
scenario. However, the high-end risk estimate for the plausible 
mismanagement of acetonitrile wastes through on site accumulation 
resulted in an inhalation HQ of 200; the central tendency HQ was 0.09. 
This was the only management scenario with a high-end HQ greater than 
1.
    EPA then conducted a third phase of risk screening on these 
acetonitrile wastes modeled in accumulation tanks. The 3007 survey data 
showed that the vast majority of these wastes are either 
characteristically hazardous (generally ignitable) or co-managed with 
other listed hazardous wastes. Since these wastes are already regulated 
under RCRA Subtitle C, this third phase of risk screening focused on 
the risk from waste streams that are not currently being managed as 
hazardous. A bounding analysis of these wastes resulted in an HQ of 
0.44, revealing risks below the HQ level of concern.
    Since all the other acetonitrile waste streams also showed hazard 
quotients below 1, EPA concluded that the risks from the portion of 
wastes that are nonhazardous are not significant. EPA also believes 
that the risk assessment overstates the risks from tank storage because 
the bounding and high end risk analyses assumed that all of the stored 
solvent would volatilize from the tank; such an assumption is very 
conservative because these wastes are being accumulated for thermal 
treatment or fuel blending.

                               Table 2.--Risk Assessment Results for Acetonitrile                               
----------------------------------------------------------------------------------------------------------------
                                                                                 Hazard quotient (HQ)           
                                                                     -------------------------------------------
                  Plausible mismanagement practice                       Central                                
                                                                        tendency       Bounding       High end  
----------------------------------------------------------------------------------------------------------------
Wastewaters:                                                                                                    
     Treatment in Aerated Tanks.............................       0.00002      2.4                0.002
Nonwastewaters:                                                                                                 
     On Site Accumulation:                                                                              
        --Phase I & II (all wastes).................................       0.09       346                200    
        --Phase III (nonhazardous wastes)...........................  ............      0.44        ............
     Boiler.................................................  ............      0.00000061  ............
----------------------------------------------------------------------------------------------------------------
All risks are direct inhalation. For a complete description of the risk assessment methodology and results, see 
  the background document Assessment of Risks from the Management of Used Solvents.                             

    b. Environmental Damage Incidents. Acetonitrile has been identified 
as a constituent of concern at one site investigated using the Hazard 
Ranking System (HRS). However, there are no sites that have undergone a 
Record of Decision (ROD) that identify acetonitrile as a constituent. 
In no instances has the use of acetonitrile as a solvent been linked to 
environmental damage in either the ROD or HRS databases.
    c. Conclusion. EPA believes that acetonitrile does not satisfy the 
criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA is 
proposing that wastes from the use of acetonitrile as a solvent should 
not be listed as hazardous waste under 40 CFR 261.31. While risk 
analyses indicate some potential risk from air releases of acetonitrile 
stored in open tanks, EPA believes that this risk would not be 
significant for these residuals because most of the nonwastewater 
residuals stored are regulated as hazardous waste. Some of those wastes 
are already listed; others are regulated as hazardous waste because of 
their characteristics (generally ignitability). EPA believes

[[Page 42330]]

that regulating the wastes this way is protective of human health and 
the environment. The wastes which are regulated as characteristically 
hazardous are being managed through incineration, an efficient 
mechanism for destroying the hazardous constituents. EPA believes that 
it is implausible that these wastes will be managed in an unsafe manner 
(as explained in section II-D-2-c). Regulations controlling air 
releases from storage of hazardous waste have recently been 
promulgated. (See December 6, 1994 at 59 FR 62896, and February 9, 1996 
at 61 FR 4903). These regulations address volatile organic compounds at 
levels much less (i.e., 100 ppm) than those that yielded the potential 
risks for acetonitrile. Furthermore, EPA believes that the risk 
assessment overstated the risks presented by storage in tanks because 
the scenario assumed that all of the stored solvent would escape; this 
seems unlikely if the waste is being stored expressly to send for 
further treatment or fuel blending. Therefore, given that nearly all of 
the nonwastewater acetonitrile residuals are either already being 
handled as hazardous, or contain negligible amounts of the solvent, EPA 
believes that spent solvent residuals are not likely to pose a 
significant hazard to human health and the environment.

E. 2-Methoxyethanol (2-ME)

1. Industry Identification
    In 1993, 24 million kilograms of 2-methoxyethanol, also known as 
ethylene glycol monomethyl ether, or 2-ME, were produced. Data on 
imports and exports are not available. 2-Methoxyethanol is widely used 
as a jet fuel additive to inhibit icing in fuel systems, with 76 
percent consumed for this purpose. It is used as a chemical 
intermediate (9 percent in 1993) in the production of the specialty 
plasticizer di-(2-methoxyethyl) phthalate (DMEP); as a chemical 
intermediate in the manufacture of esters such as 2-methoxyethyl 
acetate; and in the synthesis of the dimethyl ethers of ethylene 
glycol.
    The remaining 14 percent of 2-ME is used in a variety of 
applications, including the solvents use discussed in greater detail 
below.
2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses. In the RCRA 3007 
Prequestionnaire of Solvent Use, 111 facilities reported the use of 
15.4 million kilograms of 2-methoxyethanol as a solvent in 1992. Of the 
111 facilities reporting use in 1992, 47 were sent the RCRA 3007 
Solvent Use Questionnaire (nearly all of the remaining facilities used 
less than 100 kg). In the RCRA 3007 Questionnaire, 35 facilities 
reported the use of 3.7 million kilograms of 2-methoxyethanol, a 
decline from the previous year. This is primarily attributable to the 
elimination of use of 2-methoxyethanol at 12 facilities, and a large 
drop in use at five other facilities. In addition, EPA determined from 
the responses to the full questionnaire that some uses reported in the 
semiconductor industry and by TSDs were not solvent uses.
    Information from the RCRA 3007 Questionnaire indicates that 2-
methoxyethanol is used for cleaning purposes, including removal of 
product buildup from tanks and removal of polymer film during the 
production of integrated circuits. 2-Methoxyethanol is used as a 
reaction medium for the production of various products. It can be used 
as a diluent in the production of lacquers and coating formulations 
that subsequently are applied to a substrate, which may be aluminum, 
metal, or nonwoven fiber. It also is a diluent in the production of 
specialty chemicals. Additionally, 2-methoxyethanol is used in 
specialized laboratory analyses.
    2-Methoxyethanol is used in the formulation of a photoresist system 
used in the semiconductor manufacturing industry. Where the 2-
methoxyethanol is part of the formulation of purchased photoresist, its 
use does not constitute solvent use. However, in at least one case, 2-
methoxyethanol is used as a solvent for cleaning the edge of the 
semiconductor wafer after application of the photoresist; this use does 
meet the RCRA definition of solvent use. Discussions with the 
semiconductor industry and engineering site visits to many of these 
facilities leads EPA to believe that the use of 2-methoxyethanol, along 
with other lower order glycol ethers, is being phased out.
    Literature searches indicated that 2-methoxyethanol has the 
potential for use as a solvent in: the manufacture of polymeric 
materials, composite membranes, resins, and recording materials; the 
preparation of specialty chemicals; electroplating; and dye processing. 
However, the Agency could find no confirmation of these uses from the 
RCRA 3007 Questionnaire. In light of the Agency's extensive 
investigation of actual solvent use in connection with the 3007 Survey, 
EPA believes it is reasonable to consider only those solvent uses 
actually confirmed by he survey results.
    b. Physical/Chemical Properties and Toxicity. 2-Methoxyethanol is 
miscible in water, and is useful as a solvent for polar and nonpolar 
chemicals. 2-Methoxyethanol is flammable when exposed to heat or open 
flame, and is ignitable, with a flash point of 39.4 deg.C. Residuals 
with high concentrations of 2-methoxyethanol are expected to exhibit 
the characteristic of ignitability. With a vapor pressure of 6.2 mm Hg 
at 20 deg.C, 2-methoxyethanol is volatile, and the Henry's Law Constant 
for 2-methoxyethanol is 2.9 x 10-3 atm-m3/mole, indicating 
that 2-methoxyethanol rapidly evaporates from water.
    The Log Kow for 2-methoxyethanol is -0.77, indicating that 2-
methoxyethanol has a low tendency to sorb to soil organic matter and 
bioaccumulate in organisms. In the atmosphere, 2-methoxyethanol is 
subject to photodegradation, with a half-life of less than one day.
    2-Methoxyethanol is not classified as a carcinogen. The chemical 
has an RfC of 2 x 10-2 mg/m3 and a provisional reference dose 
(RfD) of 5.7 x 10-3 mg/kg/day. The corresponding air HBL is 
2 x 10-2 mg/m3 and the provisional water HBL is 0.2 mg/L.
    c. Waste Generation, Characterization, and Management. Twenty-three 
facilities reported a total of 3.14 billion kg of waste generated in 
1993. The vast majority (>99%) of the residuals generated are 
wastewaters contaminated with relatively low concentrations of 2-
methoxyethanol (average concentration of 0.01%). These wastes also 
include 2.1 million kg of nonwastewaters, containing variable amounts 
of 2-methoxyethanol, including spent solvents, sludges, and containers 
and rags. Where 2-methoxyethanol is incorporated into the final 
product, wastes may include off-specification materials and tank 
cleanout wastes.
    In 1993, over 96% percent by volume of nonwastewaters were reported 
to be hazardous. A large fraction (70%) of the nonwastewaters was 
recovered through distillation or fractionation, and most of the rest 
(29%) was managed by some type of thermal treatment, either by 
incineration, energy recovery in a boiler, or fuel blending. The 
wastewaters containing spent 2-methoxyethanol were all reported to be 
treated in tank-based wastewater treatment systems.
    Based on the reported waste volumes and concentration of the 2-
methoxyethanol in the wastes, loadings of 2-methoxyethanol were 
calculated by multiplying the volume (in kilograms) by the 
concentration (in percent) and dividing by 100 (percent conversion). 
This calculation provides the quantity of 2-methoxyethanol in the waste 
that is available for potential release via management. Table 3 
presents the

[[Page 42331]]

reported volumes and 2-methoxyethanol loadings by management practice 
for the wastes that contain spent 2-methoxyethanol.
    EPA believes that the waste management practices reported in the 
questionnaires represent the plausible management scenarios of concern 
for 2-methoxyethanol. EPA surveyed all significant users of this 
solvent, and collected information on the waste management practices 
for 54 wastestreams. The Agency believes that these facilities provide 
a good indication of all likely waste management practices. 
Furthermore, with the use of this chemical as a solvent declining, new 
management practices are unlikely to occur.
    To assess the potential risks for management of 2-methoxyethanol 
wastes, EPA selected several management practices for modeling. To 
represent thermal treatment (incineration, industrial boilers, fuel 
blending), EPA chose an industrial boiler. To account for risks from 
the accumulation of residuals in tanks, EPA modeled an uncovered 
storage tank. Finally, to assess risks arising from wastewater 
treatment, EPA modeled treatment in an aerated wastewater treatment 
tank.
    None of the 56 wastestreams were reported to go to land disposal in 
landfills or impoundments. Solids containing spent solvent are 
incinerated, and wastewaters are all treated in tanks. Wastewater 
treatment sludges generated do not contain significant levels of 2-
methoxyethanol, because the chemical is efficiently removed by such 
treatment due to its volatility. In the face of the existing practices, 
EPA finds it implausible that high organic wastes or aqueous liquids 
currently sent to thermal treatment would be managed in a landfill. 
Essentially all of the nonwastewater residuals that contain spent 2-
methoxyethanol are thermally treated or recovered, and more than 96% of 
this treatment is as a hazardous waste. The large percentage of spent 
2-methoxyethanol wastes that are already hazardous are precluded from 
land disposal in Subtitle D units, and no evidence exists to suggest 
that any wastes containing spent 2-methoxyethanol would be placed in a 
landfill. Any change from the current practice of treatment of 
wastewaters in tanks to treatment in

                                 Table 3.--Waste Statistics for 2-Methoxyethanol                                
----------------------------------------------------------------------------------------------------------------
                                                                                                        Total   
                  Management practice                     Number of    Number of     Total volume      loading  
                                                          facilities    streams          (kg)            (kg)   
----------------------------------------------------------------------------------------------------------------
Incineration...........................................           11           20           297,522       52,839
Energy Recovery........................................            6           13           129,369       57,760
Fuel Blending..........................................            5           11           224,530      104,444
WWT-Aerated Tanks......................................            6            6     3,139,049,350      452,030
WWT-Other Tanks........................................            2            2             2,558          486
Fractionation/Distillation.............................            1            2         1,463,068       14,631
Storage (for unspecified offsite hazardous treatment)..            2            2            14,802          704
----------------------------------------------------------------------------------------------------------------

    Impoundments also seems unlikely given the associated costs for 
such a change. As noted above, however, this solvent is easily removed 
from wastewaters by volatilization, therefore even if treatment in an 
aerated impoundment occurred, it would be expected to rapidly remove 
the solvent and make any releases to groundwater unlikely.
3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a hazard quotient (HQ) for each plausible mismanagement 
scenario. Where the HQ exceeds 1, exposure is expected to pose a risk 
to human health and the environment. The results of these analyses are 
shown in Table 4.
    Using bounding assumptions, the Agency estimated that management of 
2-methoxyethanol wastewater in an aerated tank could result in an 
inhalation HQ of 0.98 and management of nonwastewater in a boiler could 
result in an inhalation HQ of 6 x 10-\8\. Risk based on bounding 
assumptions for the other plausible mismanagement scenario (on site 
accumulation) exceeded an inhalation HQ of 1, and EPA then conducted 
high end and central tendency risk analyses for these scenarios.
    The estimated high-end risk assessment for plausible mismanagement 
of 2-methoxyethanol wastes through on site accumulation is an 
inhalation HQ of 16. This was the only management scenario where the 
high-end HQ was higher than 1.
    EPA then conducted a third phase of risk screening on these 2-
methoxyethanol wastes in open accumulation tanks. Since wastestreams 
which are hazardous are already being regulated under RCRA Subtitle C, 
this third phase of risk screening focused on the risk from waste 
streams that are not currently being managed as hazardous.
    EPA's data showed no waste streams in this management scenario 
which were nonhazardous; all of the waste streams were already being 
managed under RCRA Subtitle C. Since all the other 2-methoxyethanol 
waste streams showed hazard quotients below 1, EPA concluded that there 
was insignificant risk reduction which could be gained by listing 2-
methoxyethanol as a hazardous waste. EPA also believes that the risk 
assessment overstates the risks from tank storage because the bounding 
and high end risk analyses assumed that a large fraction of the stored 
solvent would volatilize from the tank; such an assumption is very 
conservative because these wastes are being accumulated for thermal 
treatment or fuel blending.

         Table 4.--Risk Assessment Results for 2-Methoxyethanol         
------------------------------------------------------------------------
                                            Hazard quotient (HQ)        
                                  --------------------------------------
 Plausible mismanagement practice    Central                            
                                     tendency     Bounding     High end 
------------------------------------------------------------------------
Wastewaters:                                                            
     Treatment in Aerated                                       
     Tanks.......................     3 x 10-9         0.98  ...........

[[Page 42332]]

                                                                        
Nonwastewaters:                                                         
     On Site Accumulation                                       
        --Phase I & II (all                                             
         wastes).................        0.007           59           16
        --Phase III (non-haz                                            
         wastes).................  ...........         None             
Incineration.............  ...........  6 x 105-\8\  ...........
------------------------------------------------------------------------
All risks are direct inhalation. For a complete description of the risk 
  assessment methodology and results, see the background document       
  Assessment of Risks from the Management of Used Solvents.             


    b. Environmental Damage Incidents. 2-Methoxyethanol has been 
detected at three Superfund sites, however, based on a review of 
identified damage instances, no single instance of damage was 
identified that could be tied to use of 2-methoxyethanol as a solvent. 
The RODs report that 2 methoxyethanol was detected, however, no 
concentrations were provided for any of the three sites. Two of the 
sites were landfills that accepted a wide variety of industrial and 
municipal wastes. One landfill ceased operation in 1980, and received 
liquid wastes (including latex and ``spent organic solvents'') from 
1968-1972. The other landfill received municipal wastes from 1969 until 
1984, and drummed industrial wastes between 1973 and 1975. The use of 
the 2-methoxyethanol prior to disposal at these landfills is impossible 
to ascertain. In both cases a wide variety of other contaminants were 
found. The third facility was a used oil recycling site that ceased 
operations in 1981, and was primarily contaminated by oil, PCBs, 
metals, and VOCs. 2-methoxyethanol has been used as a jet fuel 
additive, and it is likely that 2-methoxyethanol is present in used oil 
from this source.
    The solvent uses identified for 2-methoxyethanol (e.g., 
pharmaceutical manufacturing, coatings and lacquers, electronics, 
photographic chemicals, and laboratory use) are not represented in any 
of the facilities identified as having 2-methoxyethanol contamination. 
Therefore, it is not likely that the damage incidents identified were 
the result of mismanagement of 2-methoxyethanol following use as a 
solvent, and the Agency did not consider the damage incidents relevant 
to the listing determination. In addition, disposal of the wastes that 
are the potential sources of 2-methoxyethanol occurred well before RCRA 
regulations were in place. The vast majority of the nonwastewater 
solvent wastes identified in the 3007 Survey were reported to be 
hazardous waste, and are now subject to strict regulation. Therefore, 
the kind of disposal that led to these Superfund sites cannot occur for 
nearly all nonwastewaters resulting from solvent use of 2-
methoxyethanol.
    c. Conclusion. EPA believes that 2-methoxyethanol does not satisfy 
the criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA is 
proposing that wastes from the use of 2-methoxyethanol as a solvent 
should not be listed as hazardous waste under 40 CFR 261.31. While risk 
analyses indicate some potential risk from air releases of 2-
methoxyethanol stored in open tanks, EPA believes that this risk from 
residuals that are currently regulated hazardous waste would not be 
significant because all of the nonwastewater residuals were stored as 
regulated hazardous waste. Therefore, these wastes are already 
hazardous, and listing is not necessary. Regulations controlling air 
releases of volatile organics from storage of hazardous waste have 
recently been promulgated. (See 59 FR 62896, December 6, 1994, and 
February 9, 1996 at 61 FR 4903). Furthermore, EPA believes that the 
risk assessment overstated the risks presented by storage in tanks 
because the scenario assumed that a large fraction of the stored 
solvent would escape; this seems unlikely if the waste is being stored 
expressly to send for further treatment or fuel blending. For the 
foregoing reasons, spent solvent residuals are not likely to pose a 
significant hazard to human health and the environment.

F. Methyl Chloride

1. Industry Identification
    In 1993, U.S. production of methyl chloride was estimated to be 
218.8 million kilograms, of which 78 percent was used as an 
intermediate in the manufacture of chlorosilanes; 16 percent was used 
in the production of quaternary ammonium compounds, agricultural 
chemicals, and methycellulose; approximately 3 percent was exported; 
and the remainder is used for other purposes, including use as a 
solvent.
2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses. In the RCRA 3007 
Prequestionnaire of Solvent Use, 32 facilities reported the use of a 
combined total of 1.04 million kilograms of methyl chloride in 1992. In 
the RCRA 3007 Questionnaire, seven facilities reported the use of 
623,645 kilograms of methyl chloride as a solvent. This reduction 
occurred because EPA determined from responses to the full 
questionnaire that methyl chloride was not used as a solvent in some 
facilities. Of the seven facilities, three reported the use of small 
quantities in laboratories, primarily for liquid/liquid extraction. The 
major use was reported by two butyl rubber manufacturers, which 
accounted for greater than 99% of the solvent use of methyl chloride.
    Literature searches indicated that methyl chloride may be used 
commercially as a liquid (under pressure) and has solvent applications 
in the production of butyl rubbers, which was confirmed by the 
Questionnaire respondents. Other potential solvent uses include the 
dealumination of aluminosilicates; a polymerization medium; a blowing 
agent for Styrofoam; a medium for the synthesis of tert-chlorine-ended 
polyisobutylenes with allyltrimethyl-silane; and a specialty solvent in 
laboratory applications. These uses were not confirmed by the RCRA 3007 
Questionnaire respondents.
    b. Physical/Chemical Properties and Toxicity. Methyl chloride has a 
moderate solubility in water of 0.648 percent by weight at 30 deg.C. 
Methyl chloride is a gas under ambient conditions, and will have a high 
rate of evaporation from water to air, as evidenced by its Henry's Law 
Constant of 4.5 x 10-2 atm-m3/mole. It has a Log KOW of 
0.91, indicating that methyl chloride has a low potential for 
absorption to soil and bioaccumulation in organisms.

[[Page 42333]]

    Methyl chloride can biodegrade anaerobically. It will also 
hydrolyze in water to give methanol; at ambient temperatures, the half 
life in water is estimated to be about one year. Just considering 
hydrolysis alone, this means that in less than 10 years the 
concentration of methyl chloride would be decreased by a thousand-fold.
    Methyl chloride is a suspected carcinogen. Using an oral carcinogen 
slope factor (CSF) of 1.3x10-2 (mg/kg/day) -1, EPA calculated 
that exposure to a water concentration of 0.003 mg/L for 70 years would 
correspond to a cancer risk of 1 x 10-6. The inhalation CSF is 
1.8 x 10-6 (ug/m\3\) -1, which corresponds to a 10-6 
risk HBL in air of 6 x 10-4 mg/m3.
    c. Waste Generation, Characterization, and Management. Seven 
respondents to the RCRA 3007 Questionnaire reported the generation of 
more than 1.19 billion kg of residuals resulting from the use of methyl 
chloride as a solvent; nearly all of the waste from the production of 
butyl rubber. The vast majority of this volume was wastewaters (1.1 
billion kg), with relatively low solvent concentrations. The remaining 
wastes included residuals generated from treatment of the wastewaters 
(89 million kg of wastewater treatment sludge and 6.6 million kg of 
sludge/ash from further treatment of the sludge), and 0.52 million kg 
of spent solvent.
    The wastewaters were all sent to wastewater treatment systems, 
which included aeration/biological treatment in tanks or surface 
impoundments. The vast majority (89 million kg) of the nonwastewaters 
were further treated and ultimately landfilled (6.6 million kg). The 
balance of the nonwastewaters (0.52 million kg) were managed by thermal 
treatment (incineration or energy recovery in a boiler/industrial 
furnace).
    Based on the reported waste volumes and concentration of the methyl 
chloride in the wastes, loadings of methyl chloride to the environment 
were calculated by multiplying the volume (in kilograms) by the 
concentration (in percent) and dividing by 100 (percent conversion). 
This calculation provides the quantity of methyl chloride in the waste 
that is available for potential release via management. Table 5 
presents the reported volumes by management practice, and the amount of 
methyl chloride contained in the wastes.
    EPA believes that the waste management practices reported in the 
questionnaires represent the plausible management scenarios for spent 
methyl chloride wastes. Nearly all of the solvent use of this chemical 
was accounted for by the two facilities that produce butyl rubber. The 
other facilities that reported any waste containing methyl chloride 
reported corresponding loadings that were extremely small (2 kg total 
loading). One company owns both butyl rubber plants, and is the sole 
producer of butyl rubber in the country. Given this highly specialized 
solvent use of this chemical, the Agency is confident that no other 
significant waste management practice for the associated wastes exists.
    To assess the potential risks associated with the management of 
these wastes, EPA chose to model an industrial boiler to represent the 
thermal treatment practices (incineration and fuel blending). To 
account for storage prior to thermal treatment, EPA modeled the 
accumulation of spent methyl chloride in an open storage tank. To 
assess risks from wastewater treatment, EPA also modeled potential 
releases from wastewater treatment in a surface impoundment.

                            Table 5.--Waste Statistics for Methyl Chloride Residuals                            
----------------------------------------------------------------------------------------------------------------
                                                                                                        Total   
                  Management practice                     Number of    Number of     Total volume      loading  
                                                          facilities    streams          (kg)            (kg)   
----------------------------------------------------------------------------------------------------------------
Incineration...........................................            4            4        89,296,310            2
Energy Recovery (BIFs).................................            1            1           225,000        2,250
Land Disposal..........................................            1            2         6,550,550         <5.5
WWT--Tanks.............................................            1            1        60,000,000          600
WWT--SI................................................            1            1     1,036,517,000      175,000
----------------------------------------------------------------------------------------------------------------

    EPA considered the potential risks that might arise from the land-
based management of methyl chloride wastes in landfills and surface 
impoundments. EPA does not believe that these management practices 
present a significant risk for the following reasons.
    Two wastes were reported sent to Subtitle D landfills. The larger 
volume waste (6.55 million kg) is a residual from a sludge treatment 
unit, which includes an incinerator, that was sent off-site for 
stabilization and placement in a landfill. The residual was reported to 
have only a ``trace'' of hydrocarbons. Methyl chloride is readily 
treated by biodegradation and volatilization in an aerated system with 
activated sludge. Removal efficiencies for methyl chloride from 
industrial wastewater treatment systems are reported to be high 
(greater than 98.9%; see the U.S. EPA RREL Treatability Database). 
Therefore, it is unlikely that any appreciable level of the chemical 
remains in this treatment residual. The other waste sent to a landfill 
was a small volume of spent desiccant (550 kg), containing relatively 
little solvent (<5.5 kg). Neither of these wastes is expected to 
present any significant risk due to negligible amounts of solvent 
present.
    One other major wastestream (89 million kg) was reported as 
wastewater treatment sludge, however, as noted previously, this waste 
was actually the waste that entered the sludge treatment unit, where it 
was treated to give the 6.55 million kg sludge/ash wastestream noted 
above. For the reasons described previously, EPA believes that these 
very low-concentration wastes are typical of the types of wastes that 
are likely to be landfilled. Therefore, EPA believes that no 
significant risks are likely to arise from landfills for methyl 
chloride wastes. Furthermore, methyl chloride will also undergo 
hydrolysis in water with a half-life of less than one year, and 
hydrolysis would be significant for any methyl chloride reaching the 
groundwater. For example, over a ten year period (which would 
correspond to rapid movement off-site from a landfill in groundwater), 
the concentration of methyl chloride would drop to less than 0.001 of 
the level leaving the landfill.
    The two wastewater streams reported were sent to wastewater 
treatment systems; one included treatment in tanks, the other used 
treatment in an aerated surface impoundment. The wastewater sent to the 
impoundment was reported to contain relatively high amounts of methyl 
chloride (175,000 kg); thus, EPA examined this process in detail for 
risks from possible releases to air and groundwater. Using the

[[Page 42334]]

estimated loading of methyl chloride reaching the surface impoundment, 
EPA modeled the potential risks from air releases (see risks given in 
the next section). The Agency does not believe that risks are likely to 
arise from releases to groundwater because the impoundment is reported 
in the 3007 survey to be a permitted hazardous waste management unit. 
EPA confirmed that the unit is regulated under RCRA. The unit is 
subject to the applicable regulations in 40 CFR 264 including: 
groundwater monitoring, corrective action, and closure requirements. 
Therefore, EPA does not believe that methyl chloride wastewaters in 
this unit present any significant risk via groundwater releases. 
Furthermore, methyl chloride is readily treated by biodegradation and 
volatilization in wastewater treatment systems in general; the 
impoundment in question is an aerated system with activated sludge that 
should efficiently remove methyl chloride. Removal efficiencies for 
methyl chloride from industrial wastewater treatment systems are 
reported to be high (greater than 98.9%; see the U.S. EPA RREL 
Treatability Database).
    EPA also considered the possibility that the combustion of methyl 
chloride might lead to formation of toxic products of incomplete 
combustion (PICs) due to its chlorine content. The amount of methyl 
chloride in the wastes that go to incineration is relatively low. The 
actual loading in the wastes incinerated was reported to be 2 kg, and 
these wastes were reported to go to hazardous waste incineration. The 
waste sent offsite for combustion in a BIF had a higher loading (2,250 
kg), however this waste was hazardous due to ignitability (due to high 
levels of hydrocarbons such as hexane present) and the toxicity 
characteristic (due to the presence of benzene). Therefore, the wastes 
sent to combustion that contained an appreciable level of methyl 
chloride were burned as a hazardous waste. EPA recently proposed rules 
to address releases from hazardous waste combustion units (see 61 FR 
17358, April 19, 1996). Therefore, EPA does not believe that combustion 
products are likely to be of concern for the thermal treatment of 
methyl chloride wastes.
3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a risk for each plausible mismanagement scenario. 
Methyl chloride is a suspected carcinogen, and EPA used cancer risk 
estimations rather than hazard quotients (the latter are used to 
measure the risk for non-carcinogenic effects). Where the risk exceeds 
10-6 and approaches 10-4 , exposure poses risks of concern to 
human health and the environment. The results of these analyses, given 
in terms of the increase in life-time cancer risk, over are shown in 
Table 6.
    Using bounding assumptions, the Agency estimated that management of 
methyl chloride residuals in a boiler could result in an inhalation 
risk of 3.3 x 10-14. Risk based on bounding assumptions for the 
onsite accumulation mismanagement scenario exceeded an inhalation risk 
of 10-6, and EPA then conducted high end and central tendency risk 
analyses for this scenario. The estimated high end risk assessment with 
plausible mismanagement of methyl chloride wastes by onsite 
accumulation in an uncovered tank resulted is an inhalation risk of 
4 x 10-6. The estimated high end risk assessment exceeds 
1 x 10-6 only with the pairing of two high end parameters for (1) 
the waste stream and receptor distance and (2) the waste stream and 
storage duration. The estimated central tendency risk was 
2 x 10-10. EPA believes that the risk assessment overstates the 
risks from tank storage because the bounding and high end risk analyses 
assumed that all of the stored solvent would volatilize from the tank; 
such an assumption is very conservative because these wastes are being 
accumulated for fuel blending.
    Risk for air releases from an aerated impoundment were estimated 
using bounding-type assumptions, in addition to the relatively large 
size of the one impoundment in question. EPA estimated the risk from 
the aerated impoundment to be 7 x 10-6. The Agency did not attempt 
to calculate a high end risk for the impoundment, because the use of 
more realistic parameters was expected to reduce the risk level below 
levels of concern. For example, the closest residence to the only 
impoundment in question is 2300 feet, far beyond the bounding 
assumption distance of 100 meters. In addition, the surface impoundment 
is regulated as a hazardous waste management unit, and is therefore 
subject to the recently promulgated regulations limiting releases from 
impoundments (see Subpart CC in 40 CFR Part 264).

                              Table 6.--Risk Assessment Results for Methyl Chloride                             
----------------------------------------------------------------------------------------------------------------
                                                                                  Risk                          
                                                      ----------------------------------------------------------
           Plausible mismanagement practice                Central                                              
                                                          tendency               Bounding              High end 
----------------------------------------------------------------------------------------------------------------
Nonwastewaters:                                                                                                 
     On Site Accumulation....................       2 x 10-10   1.8 x 10-5                      4 x 10-6
     Incineration............................  ..............   3.3 x 10-14                  ...........
Wastewaters:                                                                                                    
     Surface Impoundment.....................  ..............  7 x 10-6                      ...........
----------------------------------------------------------------------------------------------------------------
All risks are cancer risk for direct inhalation. For a complete description of the risk assessment methodology  
  and results, see the background document Assessment of Risks from the Management of Used Solvents.            

    b. Environmental Damage Incidents. Methyl chloride has been 
detected at three Superfund sites. Two of the sites (a gravel pit and a 
landfill) ceased operation before 1980, and therefore disposal occurred 
prior to promulgation of the RCRA regulations. The third site was a 
manufacturing facility which was in operation from 1902 to 1982, 
indicating that all but a limited amount of disposal predated the RCRA 
controls. The major activities at this third site included milling, 
refrigeration, circuit board manufacturing, and photo processing. The 
primary constituents of concern at all three sites are a variety of 
volatile organic compounds, and it is possible that methyl chloride may 
be a degradation product from other chlorinated chemicals. The ROD 
database indicates that methyl chloride has contaminated the ground 
water at two of the sites (no information on

[[Page 42335]]

concentration levels or affected media is available for the third 
site).
    Wastes deposited at the manufacturing site were reported to include 
cleaning solvents used in circuit board manufacturing processes, but 
the ROD database does not cite the uses of any of the wastes found at 
the site. Most important, however, this site was also used as a 
refrigeration plant, and methyl chloride was used as a refrigeration 
agent in the past. Because methyl chloride is a gas under ambient 
conditions, EPA does not believe that it is likely that wastes at these 
sites were derived from the use of methyl chloride as a solvent. The 
3007 Survey indicated that the only significant use of this chemical as 
a solvent is in the butyl rubber industry, and none of the damage cases 
were from that industry. Furthermore, the vast majority of methyl 
chloride is used as a synthetic reactant in industrial chemical 
processes, with very little used as a solvent. Therefore, EPA did not 
consider these damage cases in its listing decision for methyl 
chloride.
    c. Conclusion. EPA believes that methyl chloride does not satisfy 
the criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA is 
proposing that wastes from the use of methyl chloride as a solvent 
should not be listed as hazardous waste under 40 CFR 261.31. Under 
certain circumstances, the risk assessment indicates some potential 
risk from onsite accumulation of methyl chloride residuals. However, 
the estimated high-end cancer risk was 4 x 10-6. This risk is at 
the low end of EPA's range of concern for listing (10-6 to 
10-4). Furthermore, EPA believes that the risk assessment 
overstated the risks presented by storage in tanks because the scenario 
assumed that all of the stored solvent would escape; this seems 
unlikely if the waste is being stored expressly to send for further 
treatment or fuel blending. In addition, EPA believes that this risk 
would not be significant for these residuals because they are regulated 
hazardous wastes. The air release from aerated wastewater treatment 
basins is a more plausible occurrence, and EPA calculated a bounding 
risk of 7 x 10-6, also at the low-risk end of the Agency's range 
of concern. However, as noted previously, the wastewaters generating 
the potential risk due to aeration in an impoundment are going to a 
unit that is a permitted hazardous waste management unit. Thus, in both 
cases, the recently promulgated regulations limiting air releases from 
storage tanks and impoundments would apply (see Subpart CC, 40 CFR Part 
264).
    Furthermore, potential air releases of methyl chloride from the key 
waste generators are being addressed by other EPA programs. Under the 
authority of the Clean Air Act, the Agency investigated air releases of 
methyl chloride by butyl rubber manufacturers. EPA proposed standards 
(see Standards for HAP Emissions from Process Units in the Elastomers 
Manufacturing Industry, 60 FR 30801, June 12, 1995) that address 
releases from these facilities, including storage tanks and wastewater 
treatment systems. The Agency believes that air regulations that result 
from this activity can lead to a more integrated control of risks than 
the limited hazardous waste regulations that could be imposed. For all 
of these reasons, therefore, the Agency has made a determination that 
wastes resulting from the use of methyl chloride as a solvent should 
not be listed as hazardous waste under 40 CFR 261.31.

G. Phenol

1. Industry Identification
    In 1993, U.S. production of synthetic phenol was estimated to be 
1.6 billion kilograms, of which 34 percent was consumed in the 
production of phenolic resins (particularly phenol-formaldehyde 
resins), 34 percent was consumed in the production of bisphenol-A, 15 
percent was consumed in the production of caprolactam and adipic acid, 
3 percent was consumed in the production of aniline, 5 percent was 
consumed in the production of alkyl phenols, and 5 percent was consumed 
in the production of xylenols. Five percent was exported and the 
remaining 2 percent was used in other ways, including as a solvent.
2. Description of Solvent Usage and Resulting Wastes
    a. Solvent Use and Questionnaire Responses. In response to the RCRA 
Sec. 3007 Prequestionnaire of Solvent Use, 99 facilities indicated that 
2.21 million kg of phenol were used as a solvent at the site in 1992. 
Thirty-one facilities reported a 1993 combined use of 1.43 billion 
kilograms of phenol as a solvent in response to the RCRA 3007 
Questionnaire of Solvent Use. This large increase was due to a change 
in reporting by one facility resulting in an increased use of over one 
billion kilograms. The facility produces its own phenol for use and did 
not report this use correctly in the Prequestionnaire. This facility (a 
petroleum refining facility) reported the production of native phenol 
as a byproduct of other processes. This native phenol is not reflected 
in the synthetic phenol production totals, although its use is 
reflected in 1993 totals. EPA surveyed all petroleum refineries and is 
confident that additional quantities of native phenol are not produced 
and subsequently used as a solvent in this industry.
    Literature searches indicated that phenol may be used as an 
extraction solvent in petroleum refining, especially in the processing 
of lubricating oils; in biological applications; in other chemical 
industry and laboratory processes; and as a reagent in chemical 
analysis. Minor uses may include use as a general disinfectant, either 
in solution or mixed with slaked lime, etc., for toilets, stables, 
cesspools, floors, drains, etc.; for the manufacture of colorless or 
light-colored artificial resins, and in many medical and industrial 
organic compounds and dyes.
    According to the respondents to the RCRA 3007 Questionnaire of 
Solvent Use, phenol is used as a solvent for four primary purposes: as 
an extraction medium in the production of lube oil stock using the 
``Duo-Sol'' process; as a coating remover in the microelectronic and 
automotive industries; as a reaction or synthesis medium; and as a 
solvent in laboratory analysis.
    The vast majority (>99.9%) of the solvent use of phenol is in the 
petroleum industry. The Duo-Sol process is used widely in the 
extraction of lube stock and fuel from crude oil residuals. In this 
process, phenol acts as an extraction medium to separate the extract 
(subsequently sent to fuels refining) and the raffinate (subsequently 
sent to a dewaxing unit). The extract and raffinate enter a second set 
of extraction units, where phenol is removed. The phenol is dried and 
forwarded to the first extractor along with makeup phenol and crude 
residual. The Duo-Sol solvent does not become spent. Losses are 
attributable to attrition to product and minor loss to wastewater. 
Phenolic wastewater is removed from the system and forwarded to waste 
management.
    Although the industries are quite different, the use of phenol as a 
coating remover by the microelectronic and automotive industry is 
similar. Phenol is used to remove photoresist in the production of 
semiconductors. In the automotive industry, phenol is used in 
combination with other solvents to remove coatings from automotive 
wheels. It is also used (in conjunction with other solvents) in the 
aircraft maintenance industry for depainting purposes.
    Finally, much smaller uses are attributable to the use of phenol as 
a reaction or synthesis medium in the

[[Page 42336]]

organic chemicals industry and as a laboratory solvent across a variety 
of industries.
    b. Physical/Chemical Properties and Toxicity. Phenol is a solid at 
room temperature. It has a solubility in water of 80 grams per liter at 
25 deg.C, indicating that it is highly soluble. With a vapor pressure 
of 35 mm Hg at 25 deg.C, phenol is moderately volatile at ambient 
temperatures. The Henry's Law Constant of 1.3 x 10-6 atm-m\3\/mole 
for phenol indicates that phenol has a relatively low evaporation rate 
from water. The Log Kow for phenol is 1.46, indicating that it has 
a relatively low tendency to sorb to soil organic matter, and a low 
tendency to bioaccumulate in organisms.
    Phenol rapidly biodegrades to CO2 and water in soil, sewage, 
fresh water, and sea water. This biodegradation will slow under 
anaerobic conditions, but still occurs in groundwater.
    Phenol is a Class D carcinogen and no carcinogen slope factor has 
been developed. Phenol has an provisional RfC of 2 x 10-2 mg/
m3 and an RfD of 6 x 10-1 mg/kg/day; these correspond to an 
air HBL of 2 x 10-2 mg/m3 and a water HBL of 20 mg/L. These 
health-based numbers are provisional and have not undergone external 
peer review. The Agency plans to complete an external peer review of 
these health-based numbers prior to issuing a final determination. EPA 
requests comments on the appropriateness of the provisional numbers, 
and seeks any additional data on the toxicity of phenol.
    c. Waste Generation, Characterization, and Management. Twenty-four 
facilities reported the generation of residuals from the use of phenol 
as a solvent totaling 52.5 million kilograms. The largest portion of 
these wastes, 52.3 million kilograms, or 99.6 percent, were phenolic 
wastewaters containing from 0.01% to almost 8 percent phenol. The 
remaining nonwastewater residuals were high organic wastes, primarily 
spent solvent (197,000 kg), and small volumes of filter media, spent 
carbon, and debris containing low levels of phenol. In 1993, 92 percent 
of the nonwastewaters were classified as hazardous waste, and 8 percent 
was classified as nonhazardous.
    Facilities generating high-volume wastewaters managed these wastes 
via wastewater treatment. These facilities consist predominantly of 
petroleum refineries and have sophisticated wastewater treatment 
systems in place that include primary treatment, biological treatment, 
and off-site secondary treatment. Facilities managed nonwastewaters 
through some form of thermal treatment, either blending of the residual 
for fuel or burning in a boiler or incinerator.
    Based on reported waste volumes and concentration of phenol in the 
wastes, loadings of phenol to each waste management practice were 
calculated. Table 7 presents the total volumes of wastes and total 
solvent content for the waste management practices.
    EPA believes that the waste management practices reported in the 
questionnaires represent the plausible management scenarios for spent 
phenol wastes. Nearly all of the solvent use of this chemical (>99.9%) 
was attributed the petroleum industry, which EPA surveyed. Furthermore, 
other minor uses were also examined in detail. Given that the major 
uses of this solvent were very specialized (e.g., extraction of lube 
oil), the Agency is confident that no other significant waste 
management practices for the associated wastes are likely to exist.
    To assess the potential risks for management of phenol wastes, EPA 
selected several management practices for modeling. To represent the 
thermal treatment process (incineration, industrial boilers, fuel 
blending), EPA chose an industrial boiler. To account for risks from 
the accumulation of residuals for thermal treatment, EPA modeled an 
uncovered storage tank. To assess risks arising from wastewater 
treatment, EPA modeled treatment in an aerated wastewater treatment 
tank.

                                  Table 7.--Waste Statistics for Phenol Residuals                               
----------------------------------------------------------------------------------------------------------------
                                                                                                        Total   
                   Management practice                      Number of    Number of    Total volume     loading  
                                                            facilities    streams         (kg)           (kg)   
----------------------------------------------------------------------------------------------------------------
Incineration.............................................           14           28         103,055       23,110
Fuel Blending............................................            4            4          97,526       12,764
Energy Recovery (BIFs)...................................            1            1               9       <0.001
Storage..................................................            1            1             153           92
WWT--Tanks...............................................            1            1      40,000,000        3,600
WWT--SI..................................................            3            3      12,323,813      355,758
----------------------------------------------------------------------------------------------------------------

    The Agency considered potential risks that might arise from the 
land-based management of phenol wastes, i.e., landfills, and surface 
impoundments. EPA does not believe that these management practices 
present significant risk for the following reasons.
    None of the 38 wastestreams containing spent phenol were reported 
to go to a landfill. This is not surprising given that there are few 
phenol wastes that are generated as solids. The only waste solids that 
contained any significant level of phenol was spent carbon, and this 
was sent for regeneration or incineration. EPA also could find no 
reason to suggest that the practice of landfilling was likely to 
increase. Wastewater treatment residuals may be landfilled, but are 
unlikely to contain significant levels of phenol, because the chemical 
is removed by such treatment due to its susceptibility to 
biodegradation (>99%; see the U.S. EPA RREL Treatability Database). 
Wastes with higher organic content were thermally treated, and most 
(about 92%) of the thermal treatment was in hazardous waste units or 
fuel blending. Therefore, none of the wastes with significant phenol 
concentration are likely to be placed in a landfill.
    Three wastewaters with spent phenol were reported to go to surface 
impoundments, and these were impoundments that were part of a 
wastewater treatment train. In two of these cases, the phenol 
concentration was below the water health-based level after mixing at 
the headworks, prior to reaching the surface impoundment. The phenol 
concentration for one wastewater sent to an off-site wastewater 
treatment system was reported to range from the HBL (20 mg/L) up to an 
order of magnitude higher (180 mg/L) at the headworks. However, as 
noted above, this level of phenol is expected to be efficiently treated 
(>99%) by the activated sludge, such that little phenol would be 
available for release to the groundwater. In general, facilities have 
effluent limitations for chemicals such as phenol, so that treatment 
must occur

[[Page 42337]]

prior to discharge. In addition, any phenol is quite susceptible to 
biodegradation, so that any of the chemical released to the groundwater 
is expected to undergo biodegradation, further reducing any potential 
risk. Information on the specific surface impoundment receiving the 
phenol wastewater of concern also indicates that groundwater releases 
from the unit are not likely to be significant. The ground water in the 
immediate area was reported to be a class 3 aquifer, which is not 
considered a potential source of drinking water, and the closest 
private or public well was reported to be 4,900 feet from the unit. 
Therefore, due to the dilution at the headworks, the susceptibility of 
phenol to biodegradation, and the specific facts related to the surface 
impoundment of concern, EPA does not believe that the treatment of 
phenol wastes in surface impoundments presents a significant risk.
3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a hazard quotient (HQ) for each plausible mismanagement 
scenario. Where the HQ exceeds 1, exposure is expected to pose a risk 
to human health and the environment. The results of these analyses are 
shown in Table 8.
    Using bounding assumptions, the Agency estimated that management of 
phenol residuals in a boiler could result in an inhalation HQ of 
1.1 x 10-5. Risk based on bounding assumptions for the other 
plausible mismanagement scenarios (an aerated tank and on site 
accumulation) exceeded an inhalation HQ of 1, and EPA then conducted 
high end and central tendency risk analyses for these scenarios.
    The estimated high-end risk assessment with plausible mismanagement 
of phenol wastes in an aerated tank is an inhalation HQ of 0.002, and 
on site accumulation is an inhalation HQ of 0.5. These results indicate 
minimal risk through the inhalation pathway for these scenarios.

              Table 8.--Risk Assessment Results for Phenol              
------------------------------------------------------------------------
                                           Hazard quotient (HQ)         
                                 ---------------------------------------
Plausible mismanagement practice    Central                             
                                    tendency     Bounding     High end  
------------------------------------------------------------------------
Wastewaters                                                             
     Treatment in                                               
     Aerated Tanks..............     2 x 10-7   3.3                0.002
Nonwastewaters:                                                         
     On Site                                                    
     Accumulation...............        0.005  12                  0.5  
     Incineration.......  ...........   1.1 x 10-5  ............
------------------------------------------------------------------------
All risks are direct inhalation. For a complete description of the risk 
  assessment methodology and results, see the background document       
  Assessment of Risks from the Management of Used Solvents.             

    b. Environmental Damage Incidents. EPA investigated damage 
incidents at which phenol was an identified contaminant at the site. 
Based on a review of identified damage instances, no single instance of 
damage was identified that could be tied to use of phenol as a solvent. 
Phenol is identified as a contaminant at 25 sites in the ROD database, 
however, ``phenol'' is often listed as a class of compounds. Listings 
where the contaminant was listed as ``phenols'' or ``phenolics'' were 
not considered by EPA further, unless a specific concentration of 
phenol was identified.
    Furthermore, most of the damage cases found for phenol were for 
sites at which disposal took place many years ago. Only seven 
facilities identified with phenol contamination appeared to have 
operated since the RCRA regulations were first promulgated (1980), and 
even at these sites, disposal typically occurred decades before 1980 
and ceased in the early 1980's. These seven cases included: two 
landfills, three chemical manufacturers (including a pesticide 
manufacturer and a textile dye manufacturer), one cement production 
facility, and one chemical waste storage and processing facility.
    Levels of phenol reported at these seven sites showed maximum 
concentrations of 20 ppm in soils, 8 ppm in groundwater, and 0.47 ppm 
in surface water. However, a wide variety of chemicals were present at 
these sites, and it is possible that the phenol present may have been a 
contaminant or degradation product of these other chemicals. No damage 
case was identified that could be tied to use of phenol as a solvent. 
In addition, phenol is produced in relatively large volumes, and only a 
very small fraction is used as a solvent, except for the specialized 
use of phenol in the petroleum industry (none of these sites were 
related to the petroleum industry). The solvent uses identified for 
phenol were limited to several types of industries (petroleum refining, 
electronics, and automotive industries), and none of these sectors were 
represented by facilities identified as having phenol contamination on 
site.
    The 3007 Survey showed that, of the phenol nonwastewater residuals 
reported to be generated in 1993, 92% were classified as hazardous. 
Therefore, most of the wastes currently generated from use of phenol as 
a solvent could not be legally managed under RCRA in the same manner as 
the wastes were at the contaminated sites. For all of the above 
reasons, therefore, EPA does not believe that the damage cases provide 
any relevant information on the potential risks posed by phenol solvent 
wastes.
c. Conclusion
    EPA believes that phenol does not satisfy the criteria for listing 
in 40 CFR 261.11(a)(3). Therefore, EPA is proposing that wastes from 
the use of phenol as a solvent should not be listed as hazardous waste 
under 40 CFR 261.31. The Agency's risk assessment indicates that spent 
phenol residuals are not considered to pose a substantial risk under 
the plausible management scenarios assessed. Thus, these residuals do 
not appear to be managed in a manner that poses a threat to human 
health and the environment. High-end analysis revealed air risks from 
wastewater treatment and storage tanks were below levels of concern. 
Furthermore, some of the assumptions made in these assessments are 
likely to have resulted in an overestimation of risk. For example, the 
storage tank scenario assumed the phenol would volatilize; this seems 
somewhat unlikely if the waste is being accumulated for subsequent 
incineration or fuel blending. Also, wastes with higher organic content 
were thermally treated, and most (92%) treatment was in hazardous waste 
units or fuel blending.

[[Page 42338]]

H. 2-Ethoxyethanol Acetate (2-EEA)

1. Industry Identification
    The 1993, U.S. production of 2-ethoxyethanol acetate, also known as 
ethylene glycol monoethyl ether acetate, was 22.3 million kilograms. 
Data indicate a rapidly declining market for 2-ethoxyethanol acetate. 
In 1983, total estimated use was 59.5 million kilograms. By 1987, that 
had dropped to 36.8 million kilograms and dropped again in 1988 to 31.8 
million kilograms. Exports have increased steadily and now represent 79 
percent of the production in 1993. 2-Ethoxyethanol acetate is used 
primarily for its solvent properties. Its most extensive use, until 
recently, has been in the formulation of photoresist used in the 
manufacture of semiconductors. While the formulators of photoresist 
would be considered solvent users for the purposes of this study, 
photoresist users generally are not. Semiconductor manufacturers may 
fall within the scope of this industry study if they use 2-
ethoxyethanol acetate to clean the edges of semiconductors. However, 
the use of a formulation that contains a solvent, such as photoresist, 
does not constitute use of the solvent.
    The use of 2-ethoxyethanol acetate in the semiconductor industry is 
being phased out. Other solvents, including n-methyl pyrollidone, n-
butyl acetone, and higher order glycol ethers, such as propylene glycol 
ethers, are being used as substitutes.
2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses. In the RCRA 3007 
Prequestionnaire of Solvent Use, 121 facilities reported the use of 
1.16 million kilograms of 2-ethoxyethanol acetate. In the RCRA 3007 
Questionnaire, 22 facilities reported the use of 0.27 million kilograms 
of 2-ethoxyethanol acetate. This decrease reflects the elimination from 
further analysis of 14 facilities that are semiconductor manufacturers 
whose sole use of 2-ethoxyethanol acetate is due to its presence in 
photoresist. Semiconductor manufacturers who reported the use of 2-
ethoxyethanol acetate as an edge cleaner or for other cleaning purposes 
were included in the use study. One additional facility was eliminated 
from study because its sole use of 2-ethoxyethanol acetate was due to 
its presence in a paint used in coating operations.
    The facilities who reported the use of 2-ethoxyethanol acetate in 
the RCRA 3007 Questionnaire use it most often for tank cleaning or 
degreasing in conjunction with processes that incorporate the solvent 
into the products. 2-Ethoxyethanol acetate is used for tank cleaning at 
three facilities between batch manufacturing operations in which 2-
ethoxyethanol is one of the materials in the formulation. At one 
facility, the tank clean out is incorporated into the next product 
batch, thus reducing losses to waste. Another facility uses 2-
ethoxyethanol acetate to clean filter housings.
    2-Ethoxyethanol acetate is used to adjust the viscosity of 
adhesives applied during the manufacture of circuit boards. A mixture 
of 2-ethoxyethanol acetate and methylene chloride (already regulated as 
Hazardous Waste Numbers F001 and F002) is used to clean curtain coating 
equipment in the same process. A small number of facilities in the 
semiconductor manufacturing sector use 2-ethoxyethanol acetate for 
thinning of photo lithographic materials. This 2-ethoxyethanol acetate 
is not part of the formulation of prepurchased photoresist and, thus, 
meets the Agency's definition of solvent.
    2-Ethoxyethanol acetate also is used as a reaction, synthesis, or 
dissolution medium for raw materials in the chemical manufacturing 
sector. Finally, 2-ethoxyethanol acetate is used to a small extent in 
laboratories for specialty analyses. Literature searches suggested 
other uses for 2-ethoxyethanol acetate, however these uses were not 
confirmed by the industry study, and were not considered in EPA's 
listing analysis.
    b. Physical/Chemical Properties and Toxicity. 2-Ethoxyethanol 
acetate has a solubility in water of 22.9 wt. percent in water, 
indicating that the solvent is highly water soluble. With a vapor 
pressure of 2.0 mm Hg at 20 deg.C, 2-ethoxyethanol acetate is highly 
volatile and can be expected to volatilize to air from open tanks and 
containers. The Henry's Law Constant for 2-ethoxyethanol acetate is 
1.9 x 10-6 atm-m3/mole, indicating that it has a moderate 
rate of evaporation from water. The Log Kow for 2-ethoxyethanol 
acetate is not known, however, given its high water solubility, the 
chemical is not expected to sorb to soils or bioaccumulate in 
organisms.
    2-Ethoxyethanol acetate is not classified as a carcinogen. The 
chemical has an RfC of 7 x 10-2 mg/m\3\ and a RfD of 2 x 10-2 
mg/kg/day. These values correspond to an air HBL of 7 x 10-2 mg/
m3 and a water HBL of 0.7 mg/L.
    c. Waste Generation, Characterization, and Management. The 22 
facilities reported the generation of 1.2 million kilograms of 
residuals from the use of 2-ethoxyethanol acetate as a solvent. The 
residuals include 0.95 million kilograms of nonwastewaters containing 
variable levels of 2-ethoxyethanol acetate. These facilities also 
reported the generation of 0.25 million kilograms of wastewaters 
containing 2 percent or less of 2-ethoxyethanol acetate.
    Essentially all (99.8%) of the nonwastewaters in 1993 were reported 
to be characteristically hazardous or mixed with listed hazardous 
waste, and therefore were managed as hazardous waste through some form 
of thermal treatment (fuel blending or combustion in a boiler or 
incinerator). The wastewaters were managed in aerated tanks, quiescent 
tanks, and through discharge to a Publicly Owned Treatment Works 
(POTWs).
    Based on reported waste volumes and concentrations of 2-
ethoxyethanol acetate in the waste, loadings of 2-ethoxyethanol acetate 
were calculated. Table 9 presents the total volumes of wastes and total 
solvent content for the different waste management practices.
    EPA believes that the waste management practices reported in the 
questionnaires represent the plausible management scenarios for spent 
2-ethoxyethanol acetate wastes. The use of 2-ethoxyethanol acetate has 
been decreasing dramatically in recent years, thus, other generators of 
this solvent waste are unlikely to exist. To assess the potential risks 
for management of 2-ethoxyethanol acetate wastes, EPA selected several 
management practices for modeling. To represent the thermal treatment 
process (incineration, industrial boilers, fuel blending), EPA chose an 
industrial boiler. To account for risks from the accumulation of 
residuals for thermal treatment, EPA modeled an uncovered storage tank. 
To assess risks arising from wastewater treatment, EPA modeled 
treatment in an aerated wastewater treatment tank.
    None of the 38 wastestreams were reported to go to land disposal in 
landfills or impoundments. Solids (rags, containers, lab wastes) 
containing spent solvent were all incinerated, and wastewaters are all 
treated in tanks. In the face of the existing practices, EPA finds it 
implausible that high organic wastes or aqueous liquids currently sent 
to thermal treatment would be managed in a landfill. The large 
percentage of spent 2-ethoxyethanol acetate wastes that are already 
hazardous is precluded from land disposal in Subtitle D units, and no 
evidence exists to suggest that any wastes containing spent 2-
ethoxyethanol acetate would be placed in a landfill. Any change from 
the current practice of treatment of wastewaters in tanks to treatment 
in impoundments also seems unlikely given the associated costs for such 
a

[[Page 42339]]

change. However, this solvent is removed from wastewaters by 
volatilization, therefore even if the practice occurred, treatment in 
an aerated impoundment would be expected to rapidly remove the solvent 
and make any releases to groundwater unlikely.

                        Table 9.--Waste Statistics for 2-Ethoxyethanol Acetate Residuals                        
----------------------------------------------------------------------------------------------------------------
                                                                                                        Total   
                     Management Practice                       Number of    Number of      Total       loading  
                                                               facilities    streams    volume (kg)      (kg)   
----------------------------------------------------------------------------------------------------------------
Incineration................................................            9           14      641,275       23,239
Energy Recovery (BIFs)......................................            7           13      167,547      146,554
Fuel Blending...............................................            8            9      146,612        8,569
WWT--Tanks..................................................            2            2        3,161            3
POTW........................................................            1            1      243,500        4,871
----------------------------------------------------------------------------------------------------------------

3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a hazard quotient (HQ) for each plausible mismanagement 
scenario. Where the HQ exceeds 1, exposure is expected to pose a risk 
to human health and the environment. The results of these analyses are 
shown in Table 10.
    Using bounding assumptions, the Agency estimated that management of 
2-ethoxyethanol acetate residuals in a boiler could result in an 
inhalation HQ of 2.2 x 10-8 and management in an aerated tank 
could result in an HQ of 0.006. Risk based on bounding assumptions for 
the other plausible mismanagement scenario (on site accumulation) 
exceeded an inhalation HQ of 1, and EPA then conducted high end and 
central tendency risk analyses for this scenario.
    The estimated high-end risk assessment with plausible management of 
2-ethoxyethanol acetate wastes in an uncovered onsite accumulation tank 
yielded an inhalation HQ of 0.7. This result indicates minimal risk 
through the inhalation pathway for this scenario.

     Table 10.--Risk Assessment Results for 2-Ethoxyethanol Acetate     
------------------------------------------------------------------------
                                           Hazard quotient (HQ)         
                                 ---------------------------------------
Plausible mismanagement practice    Central                             
                                    tendency     Bounding      High end 
------------------------------------------------------------------------
Wastewaters:                                                            
     Treatment in                                               
     Aerated Tanks..............  ...........     0.006                 
Nonwastewaters:                                                         
     On Site                                                    
     Accumulation...............        0.003     9                  0.7
     Incineration.......  ...........     2.2 x 10-8            
------------------------------------------------------------------------
All risks are direct inhalation. For a complete description of the risk 
  assessment methodology and results, see the background document       
  Assessment of Risks from the Management of Used Solvents.             

    b. Environmental Damage Incidents. 2-Ethoxyethanol acetate has been 
detected at one Superfund site. The ROD database indicates that 2-
ethoxyethanol acetate has contaminated the soil, sediments, and ground 
water at the site, although no information on the concentration level 
is available. Wastes deposited at the landfill site include industrial 
and municipal waste, including what was termed spent organic solvents. 
However, no disposal occurred at the site after 1980, and the site 
would reflect management practices that may no longer be 
representative. Essentially all of the nonwastewater solvent wastes 
identified in the 3007 Survey were reported to be hazardous waste, and 
are subject to strict regulation. Furthermore, the ROD database does 
not specifically cite the uses of any of the wastes found at the site. 
Therefore, EPA did not factor this damage case into its listing 
determination.
    c. Conclusion. EPA believes that 2-ethoxyethanol acetate does not 
satisfy the criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA 
is proposing that wastes from the use of 2-ethoxyethanol acetate as a 
solvent should not be listed as hazardous waste under 40 CFR 261.31. 
The use of 2-ethoxyethanol is declining rapidly in industry, and the 
Agency believes that this trend will continue. As discussed above, risk 
bounding estimates indicate that 2-ethoxyethanol acetate spent solvent 
residuals are not considered to pose a substantial risk or potential 
hazard to human health and the environment through the pathways and 
plausible mismanagement scenarios assessed. Furthermore, essentially 
all of the nonwastewaters are already incinerated as hazardous waste or 
sent to fuel blending. Risks from wastewater treatment were low and 
this practice bounded out. Thus, these residuals do not appear to be 
managed in a manner that poses a threat to human health and the 
environment.

I. Furfural

1. Industry Identification
    In 1993, U.S. production of furfural was estimated to be 39.5 
million kilograms. An estimated 85 percent was consumed as an 
intermediate in the production of furfural alcohol and as an 
intermediate in the production of tetrahydrofuran. Other non-solvent 
uses of furfural may include the manufacture of cold-molded grinding 
wheels, where phenol and furfural react to form fusible, soluble resins 
that may be thermally set in the presence of hexamethylenetetramine. 
Less than 1 percent of furfural produced in 1993 was exported. The 
remaining 14 percent is used for other purposes, including 4 percent 
identified as solvent use by Questionnaire respondents.

[[Page 42340]]

2. Description of Solvent Usage and Resulting Wastes
    a. Solvent Use and Questionnaire Responses. In response to the RCRA 
3007 Prequestionnaire, 32 facilities indicated that 3.87 million kg of 
furfural were used as a solvent at their site in 1992. Eight facilities 
reported use of furfural as a solvent in response to the 3007 
Questionnaire of Solvent Use, with a total 1993 use of 2.46 million 
kilograms. This apparent decrease was due to large volumes reported in 
the prequestionnaire that EPA determined from the full questionnaire 
were not used as a solvent
    Based on the responses to the Questionnaire, essentially all 
(>99.99%) of the use of furfural as a solvent is in the petroleum 
industry for lube oil extraction. The furfural refining process, 
developed by Texaco, Inc., involves extraction of raw lubricating stock 
with furfural at temperatures generally below 121 deg.C to yield 
refined oil extract. The undesirable aromatic and olefinic components 
of the oil are selectively dissolved by furfural and separated from the 
desired paraffinic and naphthionic components. In practice, oil enters 
near the bottom of a countercurrent extraction column, and furfural is 
applied at the point near the top. The extract is removed from the 
bottom of the column with the bulk of the furfural. Furfural is 
separated from the extracted material and recovered for reuse by flash 
distillation followed by steam distillation. Furfural-water mixtures 
from the steam distillation are readily separated in a decanter by 
drawing off the lower layer which consists of about 92 percent furfural 
and 8 percent water. This layer is subsequently dried for reuse. 
Furfural losses are generally 0.03 percent or less per cycle. EPA 
believes that the trend for furfural use is not favorable. The industry 
is moving toward the use of n-methyl pyrollidone for lube oil 
extraction. The remaining solvent use reported was in specialty 
applications in laboratory analyses.
    Literature searches indicated other potential uses for furfural, 
however Questionnaire responses did not indicate use of furfural for 
these purposes.
    b. Physical/Chemical Properties and Toxicity. Furfural has a 
solubility in water of 83 grams per liter at 20 deg.C, indicating that 
it is highly soluble in water. Furfural has a vapor pressure of 1 mm Hg 
at 20 deg.C indicating that furfural is highly volatile. The Henry's 
Law Constant for furfural is 8.1 x 10-5 atm-m3/mole, 
indicating that furfural has a moderate evaporation rate from water. 
The Log Kow is not available at this time, but the high water 
solubility suggests that furfural is not likely to sorb strongly to 
soils or bioaccumulate in organisms. However, the aldehyde functional 
group in furfural is fairly reactive and may lead to oxidation and 
degradation in the environment.
    Furfural is not classified as a carcinogen. It has an RfC of 0.05 
mg/m3 and an RfD of 0.003 mg/kg/day. These values correspond to 
HBLs of 0.05 mg/m3 for air, and 0.1 mg/L for water.
    c. Waste Generation, Characterization, and Management. The seven 
responding facilities reported a combined volume of just under 177.5 
million kilograms of waste, containing less than 0.1 percent furfural, 
generated from processes using furfural as a solvent. Furfural wastes, 
as reported in the RCRA 3007 Questionnaire of Solvent Use, are 
predominantly (>99.9%) wastewaters that are managed in wastewater 
treatment systems. These high-volume wastes are not likely to be 
managed in another manner. One facility has a surface impoundment in 
their wastewater treatment system and two treat the wastewater in 
tanks. Much smaller quantities of nonwastewater furfural wastes were 
reported and these were incinerated as hazardous waste.
    Based on reported waste volumes and concentration of furfural in 
the wastes, loadings of furfural to each waste management practice were 
calculated. Table 11 presents the total volumes of wastes and total 
solvent content for the waste management practices.
    EPA believes that the waste management practices reported in the 
questionnaires represent the plausible management scenarios for spent 
furfural wastes. Nearly all of the solvent use of this chemical 
(>99.9%) was attributed to the petroleum industry, which EPA surveyed. 
Given that the major use of this solvent was very specialized (e.g., 
extraction of lube oil), the Agency is confident that no other 
significant waste management practices for the associated wastes are 
likely to exist.
    To assess the potential risks for management of phenol wastes, EPA 
selected several management practices for modeling.

                               Table 11.--Waste Statistics for Furfural Residuals                               
----------------------------------------------------------------------------------------------------------------
                                                                                                        Total   
                   Management practice                      Number of    Number of    Total volume     loading  
                                                            facilities    streams         (kg)           (kg)   
----------------------------------------------------------------------------------------------------------------
Wastewater Treatment--Surface Impoundment................            1            2      24,732,124       15,940
Wastewater Treatment--Tank...............................            3            3     152,738,784      165,848
Incineration.............................................            1            2           6,220         0.07
----------------------------------------------------------------------------------------------------------------

    To represent the thermal treatment process (incineration), EPA 
chose an industrial boiler. To account for risks from the accumulation 
of residuals for thermal treatment, EPA modeled an uncovered storage 
tank. To assess risks arising from wastewater treatment, EPA modeled 
treatment in an aerated wastewater treatment tanks and surface 
impoundments.
3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a hazard quotient (HQ) for each plausible mismanagement 
scenario. Where the HQ exceeds 1, exposure may pose a risk to human 
health and the environment. The results of these analyses are shown in 
Table 12.
    Using bounding assumptions, the Agency estimated that management of 
furfural residuals in a boiler could result in an inhalation HQ of 
2.4 x 10-14 and on site accumulation could result in an inhalation 
HQ of 1.2 x 10-5. For management of furfural wastewater in a 
surface impoundment using bounding assumptions (e.g., no 
biodegradation), the Agency estimated an inhalation HQ of 0.69, and an 
ingestion HQ of 0.8.1 Risk based on bounding assumptions for the 
other plausible mismanagement scenario (an aerated wastewater treatment 
tank) exceeded an inhalation HQ of 1, and EPA then conducted high

[[Page 42341]]

end and central tendency risk analyses for these scenarios.
---------------------------------------------------------------------------

    \1\ The bounding estimate for ingestion of contaminated 
groundwater from a surface impoundment assumed a leachate factor of 
1, a dilution and attenuation factor of 10, and ingestion of 2 
liters per day of water and a 70 kilogram body weight. After mixing 
with other wastewaters in the offsite treatment system, the initial 
concentration of furfural entering the impoundment was 0.80 mg/L.
---------------------------------------------------------------------------

    The estimated high end risk assessment with plausible mismanagement 
of furfural wastes in an aerated wastewater treatment tank resulted in 
an inhalation HQ of 0.0008. This result indicates minimal risk through 
the inhalation pathway for this scenario.

                                 Table 12.--Risk Assessment Results for Furfural                                
----------------------------------------------------------------------------------------------------------------
                                                                      Hazard quotient (HQ)                      
                                               -----------------------------------------------------------------
       Plausible mismanagement practice           Central                                                       
                                                  tendency                  Bounding                   High end 
----------------------------------------------------------------------------------------------------------------
Wastewaters:                                                                                                    
     Treatment in Aerated Tanks.......     2 x 10-4  7.9...................................       0.0008
     Treatment in Surface.............  ...........  0.69 (inhalation).....................             
    Impoundment...............................  ...........  0.8 (ingestion).......................             
Nonwastewaters:                                                                                                 
     On Site Accumulation.............  ...........  1.2 x 10-5............................             
     Incineration.....................  ...........  2.4 x 10-14...........................             
----------------------------------------------------------------------------------------------------------------
All risks are direct inhalation, unless otherwise noted. For a complete description of the risk assessment      
  methodology and results, see the background document Assessment of Risks from the Management of Used Solvents.

    b. Environmental Damage Incidents. Furfural has been identified as 
a constituent of concern at one site investigated using the Hazard 
Ranking System (HRS). However, there are no sites with a Record of 
Decision (ROD) that identify furfural as a constituent. The reason for 
the absence of furfural may be due to its breakdown in the environment 
prior to the ROD investigation. In no instance has the use of furfural 
as a solvent been linked to environmental damage in either the ROD or 
HRS databases.
    c. Conclusion. EPA believes that furfural does not satisfy the 
criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA is 
proposing that wastes from the use of furfural as a solvent should not 
be listed as hazardous waste under 40 CFR 261.31. Risk analyses 
indicate that furfural spent solvent residuals do not pose a 
substantial risk or potential hazard through the pathways assessed. 
Thus, these residuals do not appear to be managed in a manner that 
poses a threat to human health and the environment.

J. Cumene

1. Industry Identification
    In 1993, U.S. production and imports of cumene totaled 2.24 billion 
kilograms, of which 1.5 percent is exported. The major non-solvent use 
of cumene is in the production of phenol and co-product acetone, which 
utilizes nearly 95 percent of the available cumene. Three percent is 
used either in the production of poly(alpha-methyl styrene) or for 
unknown purposes, which may include use as a component in aviation 
gasoline to improve the octane rating or use as a solvent.
2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Response. In the RCRA 3007 
Prequestionnaire of Solvent Use, 67 facilities reported the use of 1.19 
million kilograms of cumene in 1992. In response to the RCRA 
Questionnaire, nine facilities reported the use of a combined total of 
0.60 million kilograms of cumene in 1993. Four other facilities were 
commercial treatment, storage, and disposal facilities that only 
received cumene wastes, and were eliminated from consideration. EPA 
also determined that a large amount of cumene reported as solvent use 
actually was cumene contained in purchased products.
    The major solvent use of cumene is as a reaction medium for 
chemical production; this accounted for 82% of the total solvent use. 
The other major use of cumene was for de-inking or paint removal in the 
commercial printing, automotive, and aviation industries. Solvents used 
for de-inking and paint removal generally contain small amounts (1 to 
3%) of cumene that are less than the 10 percent before use criterion in 
the existing spent solvents regulations (See 40 CFR 261.31(a)). 
Finally, cumene is used in small amounts as a reaction medium in 
laboratory experiments.
    b. Physical/Chemical Properties and Toxicity. Cumene has a 
solubility in water of 50 mg/L at 20 deg.C, indicating that it is only 
slightly soluble in water. It has a vapor pressure of 3.2 mm Hg at 
20 deg.C, indicating that it is highly volatile under ambient 
conditions and can become an air pollutant. The Log Kow for cumene 
is 3.66, indicating that cumene has a moderate tendency to sorb to 
soils and some ability to bioaccumulate in organisms. Cumene is non-
persistent in water due to volatilization, with a half-life of less 
than two days.
    Cumene is not classified as a carcinogen. It has a water HBL of 1 
mg/L, based on a reference dose of 0.04 mg/kg/day. The HBL for air 
based on the RfC is 9 x 10-3 mg/m\3\.
    Shortly before today's action was published, an industry group (The 
Cumene Panel of the Chemical Manufacturers Association) submitted a 
letter with information related to the toxicity of cumene. The letter 
cited the group's comments on another EPA proposal (Hazardous Waste 
Identification Rule; 60 FR 66344, December 21, 1995), which included 
extensive technical information concerning the toxicity of cumene. EPA 
will evaluate this information, along with information submitted by 
commenters, as it relates to this listing determination.
    c. Waste Generation, Characterization, and Management. Nine 
facilities reported a combined generation of 224 thousand kilograms of 
residuals from the use of cumene as a solvent. The majority of these 
wastes (>70%; 160 thousand kg) are collected as vapors and sent 
directly to on-site combustion; this accounts for the vast majority 
(>95%) of the cumene loading in all of the wastes that are generated 
from use as a solvent. Other wastes include spent solvent and process 
solids that are sent for recovery, incinerated as hazardous, or stored 
for fuel blending. Small amounts of process wastewaters are sent to 
wastewater treatment systems, and the process sludges are sent to a 
landfill.
    Based on reported waste volumes and concentration of cumene in the 
wastes, loadings of cumene were calculated. Table 13 presents the 
volumes and loadings reported for each management practice.

[[Page 42342]]

    EPA believes that the waste management practices reported in the 
questionnaires represent the plausible management scenarios for spent 
cumene. The uses of cumene as a solvent are very limited and other 
significant generators of this solvent waste are unlikely to exist.
    To assess the potential risks for management of cumene wastes, EPA 
selected several management practices for modeling. To represent the 
thermal treatment process (incineration, industrial boilers, fuel 
blending), EPA chose an industrial boiler. To account for risks from 
the accumulation of residuals for thermal treatment, EPA modeled an 
uncovered storage tank. To assess risks arising from wastewater 
treatment, EPA modeled treatment in an aerated wastewater treatment 
tank.
    Only one cumene waste was reported to go to a landfill, wastewater 
treatment sludges, and the cumene concentration was not reported. 
However, the cumene was used in small quantities in this case, so that 
the maximum amount of solvent that could be in the sludge would be <28 
kg. The amount actually in the sludge is expected to be much less after 
wastewater treatment. Such a very small amount of cumene is highly 
unlikely to present any risk in a landfill. Furthermore, cumene use in 
this case was at a level (1.7%), far below the 10% level used to define 
the currently listed solvents, suggesting that this particular waste is 
not derived from solvent use per se, but is essentially an impurity in 
the solvent mixture being used. Given the limited use of cumene as a 
solvent, and the minor volumes reported, EPA believes that the practice 
of landfilling will not increase. To the contrary, except for 
wastewaters, nearly all wastes generated are being treated as 
hazardous, suggesting that any change to Subtitle D landfills is 
implausible.

                                     Table 13.--Waste Statistics for Cumene                                     
----------------------------------------------------------------------------------------------------------------
                                                                                                        Total   
                     Management practice                       Number of    Number of      Total       loading  
                                                               facilities    streams    volume (kg)      (kg)   
----------------------------------------------------------------------------------------------------------------
Incineration................................................            3            3       14,620        2,242
Boiler/Industrial Furnace...................................            1            1      160,088      128,070
Wastewater Treatment-Tank...................................            1            1        (\1\)          <28
Wastewater Treatment-Surface Impoundment....................            1            1        4,738          <47
Landfill....................................................            1            1        1,631          <28
Storage Only................................................            1            1        3,670        1,468
Recovery....................................................            3            2       39,117        1,379
----------------------------------------------------------------------------------------------------------------
\1\ Not reported.                                                                                               

    One waste containing spent cumene was reported to go to a surface 
impoundment as part of a wastewater treatment train. However, the 
annual loading was very small (<47 kg) and cumene levels would be 
negligible (i.e., orders of magnitude below the health-based level) 
after mixture with other wastewaters at the headworks prior to entering 
an impoundment. Furthermore, cumene volatilizes relatively quickly from 
water and is efficiently removed during wastewater treatment (>97%; see 
U.S. EPA RREL Treatability Database); thus any cumene reaching 
treatment impoundments would be further reduced. All wastewaters 
generated from use of cumene as a solvent appear to contain very low 
levels of cumene, therefore EPA believes treatment in a surface 
impoundment is unlikely to present a significant risk, even if the 
practice were to increase.
    Finally, EPA also considered that spent cumene wastes have the 
potential to form non-aqueous phase liquids (NAPLs) that might move as 
a separate phase above the ground water table. These NAPLs may present 
special problems, especially in assessing their transport and potential 
impact. Unlike all the other target solvents that are miscible or very 
soluble in water and are not likely to form NAPLs in groundwater, 
cumene's water solubility is relatively low, and cumene could 
theoretically form NAPLs. However, EPA believes that NAPL formation 
from cumene used as a solvent is highly unlikely because such uses are 
very limited, and the cumene loading to land-based disposal was minimal 
(<28 kg to landfills).
3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a hazard quotient (HQ) for each plausible mismanagement 
scenario. Where the HQ exceeds 1, exposure is expected to pose a risk 
to human health and the environment. The results of these analyses are 
shown in Table 14.
    Using bounding assumptions, the Agency estimated that management of 
cumene residuals in a boiler could result in an inhalation HQ of 
2.8 x 10-7, management in an aerated tank could result in an 
inhalation HQ of 0.03. Risk based on bounding assumptions for the other 
plausible mismanagement scenario (on site accumulation) exceeded an 
inhalation HQ of 1, and EPA then conducted high end and central 
tendency risk analyses for these scenarios.
    The estimated high end risk assessment with plausible mismanagement 
of cumene wastes by on site accumulation in an uncovered tank resulted 
is an inhalation HQ of 0.2. This result indicates minimal risk through 
the inhalation pathway for this scenario.

                                  Table 14.--Risk Assessment Results for Cumene                                 
----------------------------------------------------------------------------------------------------------------
                                                                      Hazard quotient (HQ)                      
                                               -----------------------------------------------------------------
       Plausible mismanagement practice           Central                                                       
                                                  tendency                  Bounding                   High end 
----------------------------------------------------------------------------------------------------------------
Wastewaters:                                                                                                    
   Treatment in Aerated Tanks.........  ...........    0.03................................             
Nonwastewaters:                                                                                                 
   On Site Accumulation...............         0.02  3.....................................          0.2

[[Page 42343]]

                                                                                                                
   Boiler.............................  ...........  2.8 x 10-7............................  ...........
----------------------------------------------------------------------------------------------------------------
All risks are direct inhalation. For a complete description of the risk assessment methodology and results, see 
  the background document Assessment of Risks from the Management of Used Solvents.                             


    b. Environmental Damage Incidents. Of the three facilities 
identified with cumene contamination in the Record of Decision 
Database, only one was reported to be in operation after 1980. This 
facility was a landfill that operated from 1960 until 1984, when it was 
abandoned. The facility reportedly received a variety of wastes from 
1972 to 1974, including waste paints, painting sludges, and spent 
solvents. Therefore, the disposal of the potential wastes of concern 
appears to have occurred well before 1980. The specific solvents 
disposed at the facility are not identified, making it difficult to 
link cumene contamination to spent solvents. However, eleven solvents 
currently listed as hazardous wastes were found as contaminants at the 
site and may account for the reporting of spent solvent wastes. 
Furthermore, cumene is a common additive to paint formulations and may 
be present at the site as a result of the waste paints and painting 
sludges. Given the limited uses of cumene as a solvent identified in 
the 3007 Survey, and the likelihood that cumene was present as an 
ingredient in paint wastes, EPA does not believe that the damage cases 
are relevant to its listing decision.
    c. Conclusion. EPA believes that cumene does not satisfy the 
criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA is 
proposing that wastes from the use of cumene as a solvent should not be 
listed as hazardous waste under 40 CFR 261.31. Cumene has some limited 
use as a solvent, however, data indicate that the concentration of 
cumene before its use as a solvent is relatively low for the most 
prevalent use, deinking. As discussed above, risk bounding estimates 
indicate that cumene spent solvent residuals are not considered to pose 
a substantial risk or potential hazard to human health and the 
environment through the pathways assessed. Furthermore, essentially all 
of the cumene in the solvent wastes generated are thermally treated as 
hazardous or recovered. Thus, these residuals do not appear to be 
managed in a manner that poses a threat to human health and the 
environment.

K. Cyclohexanol

1. Industry Identification
    The combined production and import data show 10.0 million kilograms 
of available cyclohexanol, based on 1990 production and 1993 import 
data. Non-solvent uses of cyclohexanol include cyclohexamine production 
(54 percent) and pesticide production (14 percent). An unknown amount 
is used in the oxidation of cyclohexanol to adipic acid (a key 
ingredient in nylon 66) and cyclohexanol can be used in the production 
of caprolactam. Some cyclohexanol was reported as solvent use by RCRA 
3007 Questionnaire respondents within the petroleum industry. There is 
no evidence of significant use of cyclohexanol as a solvent outside the 
petroleum industry.
2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses. In the RCRA 3007 
Prequestionnaire of Solvent Use, 37 facilities reported the use of 
cyclohexanol as a solvent, with a total 1992 use of greater than 100 
thousand kg. In the RCRA 3007 Questionnaire, six facilities reported 
the use of cyclohexanol in 1993, with a total of greater than 1,000 kg 
and less than 20,000 kg (the exact volume used is confidential business 
information). The Agency removed a film manufacturer from further study 
because it was determined that the facility actually uses 
cyclohexanone, a portion was also found to be reported by a TSD, and 
other firms responding to the prequestionnaire in 1992 discontinued or 
reduced use in 1993.
    According to data collected in the RCRA 3007 Questionnaire, the 
major solvent use of cyclohexanol is as an extraction solvent in the 
production of cyclohexane; however, the cyclohexanol used in this 
fashion was reported to be recycled in the process. Therefore, wastes 
generated arose primarily from smaller amounts of cyclohexanol used in 
specialized laboratory settings.
    b. Physical/Chemical Properties and Toxicity. Cyclohexanol has a 
solubility in water of 56,700 mg/L at 15 deg.C, indicating that it is 
highly soluble in water. With a vapor pressure of 1 mm Hg at 20 deg.C, 
cyclohexanol is moderately volatile. The Log Kow for cyclohexanol 
is 1.23, indicating that cyclohexanol has a low potential for sorbing 
to soil. The Henry's Law Constant is 4.5 x 10\6\ atm-m\3\/mole 
indicates that cyclohexanol has a low evaporation rate from water.
    Data on the health effects of cyclohexanol are limited. Provisional 
values for the RfD and RfC have been calculated from one study. The 
provisional RfC is 6 x 10-5 mg/m\3\ and the RfD is 1.7 x 10-5 
mg/kg/day. These correspond to HBLs of 6 x 10-5 mg/m\3\ for air 
and 0.0006 mg/L for water. These health-based numbers are provisional 
and have not undergone external peer review. The Agency plans to 
complete an external peer review of these health-based numbers prior to 
issuing a final determination. EPA requests comments on the 
appropriateness of the provisional numbers, and seeks any additional 
data on the toxicity of cyclohexanol.
    c. Waste Generation, Characterization, and Management. Six 
facilities initially reported a combined generation of greater than 9 
million kilograms of residuals from the use of cyclohexanol as a 
solvent. However, essentially all of this volume was treatment 
residuals reported by one facility. This facility reported details for 
the treatment train that led to a misleading volume as follows. Spent 
solvent (5,000 kg containing 11 kg of cyclohexanol) is sent to an 
onsite incinerator; the scrubber water from this hazardous waste 
incinerator (320 million kg containing no solvent) is then treated in a 
wastewater treatment system (as hazardous waste) to produce 
biotreatment sludge (9 million kg containing no solvent). After 
incineration all subsequent treatment residuals are expected to contain 
negligible amounts of cyclohexanol. Therefore, only the initial volume 
going to the incinerator contained cyclohexanol, and this was the only 
volume from this treatment process that was considered further. The 
corrected volume of waste generated that contained spent cyclohexanol 
is actually 44,110 kg, consisting of 43,360

[[Page 42344]]

kg of spent solvent (containing 16 kg of cyclohexanol), and 750 kg of 
filter media reported to contain a ``negligible'' concentration of 
cyclohexanol. Table 8 presents the waste volumes and loadings of 
cyclohexanol for the management practices reported.
    In 1993, 98.3 percent of the wastes generated with spent 
cyclohexanol were treated as hazardous, and the remaining 750 kg of 
filter media as nonhazardous. Table 15 summarizes that volumes and 
loadings estimated for cyclohexanol.
    Nearly all of the cyclohexanol wastes were reported to be 
incinerated in a hazardous waste BIF. One small wastestream (750 kg) of 
filter media was reported to go to a landfill, however the 
concentration was negligible and presumed zero. Given the specialized 
and limited uses of cyclohexanol as a solvent, EPA does not believe 
that other wastes or management practices are likely to be significant. 
Therefore, to assess possible risks from management of cyclohexanol 
wastes from solvent use, EPA modeled combustion in a boiler to account 
for incineration, and storage in an open accumulation tank.

                                  Table 15.--Waste Statistics for Cyclohexanol                                  
----------------------------------------------------------------------------------------------------------------
                                                                                                        Total   
                   Management practice                      Number of    Number of    Total volume     loading  
                                                            facilities    streams         (kg)           (kg)   
----------------------------------------------------------------------------------------------------------------
Landfill.................................................            1            1             750        (\1\)
Incineration.............................................            4            5          43,360          16 
----------------------------------------------------------------------------------------------------------------
\1\ Negligible.                                                                                                 

3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a hazard quotient (HQ) for each plausible mismanagement 
scenario. Where the HQ exceeds 1, exposure may pose a risk to human 
health and the environment. The results of these analyses are shown in 
Table 16.
    Using bounding assumptions, the Agency estimated that management of 
cyclohexanol residuals in a boiler could result in an inhalation HQ of 
7.2 x 10-9. Risk based on bounding assumptions for the other 
plausible mismanagement scenario (on site accumulation) exceeded an 
inhalation HQ of 1, and EPA then conducted high end and central 
tendency risk analyses for these scenarios.
    The estimated high end risk assessment with plausible mismanagement 
of cyclohexanol wastes by on site accumulation in an uncovered tank is 
an inhalation HQ of 0.3. This result indicates minimal risk through the 
inhalation pathway for this scenario.

                               Table 16.--Risk Assessment Results for Cyclohexanol                              
----------------------------------------------------------------------------------------------------------------
                                                                      Hazard quotient (HQ)                      
                                               -----------------------------------------------------------------
       Plausible mismanagement practice           Central                                                       
                                                  tendency                  Bounding                   High end 
----------------------------------------------------------------------------------------------------------------
Nonwastewaters:                                                                                                 
   On Site Accumulation...............         0.01  2.....................................          0.3
   Incineration.......................  ...........  7.2 x 10-9............................  ...........
----------------------------------------------------------------------------------------------------------------
All risks are direct inhalation. For a complete description of the risk assessment methodology and results, see 
  the background document Assessment of Risks from the Management of Used Solvents.                             

    b. Environmental Damage Incidents. Cyclohexanol has been detected 
at one Superfund site. The ROD database indicates that cyclohexanol has 
contaminated the soil and ground water at the site. The site was 
occupied by a waste oil company for ten years, and it was contaminated 
by a wide variety of chemicals. The ROD database does not specifically 
cite the uses of any of the cyclohexanol found at the site, and given 
the rare use of this chemical as a solvent, EPA did not consider this 
damage case to be relevant to its decision.
    c. Conclusion. EPA believes that cyclohexanol does not satisfy the 
criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA is 
proposing that wastes from the use of cyclohexanol as a solvent should 
not be listed as hazardous waste under 40 CFR 261.31. It appears there 
is very limited use of cyclohexanol as a solvent. The residuals 
generated from the use of cyclohexanol as a solvent contain negligible 
levels of cyclohexanol and are generally managed by thermal treatment 
as a hazardous waste. As discussed above, risk bounding estimates 
indicate that cyclohexanol solvent residuals are not considered to pose 
a substantial risk or potential hazard to human health and the 
environment during combustion or storage.

L. Isophorone

1. Industry Identification
    Production information from 1995 shows 79.3 million kilograms were 
produced worldwide. However, only one domestic manufacturer exists. The 
non-solvent uses of isophorone include use as a raw material in the 
production of isophorone-derived aliphatic diisocyanates; as an 
intermediate in the manufacture of 3,5-xylenol-3,3,5-
trimethylcyclohexanol and 3,3,5-trimethyl-cyclohexamine; as a starting 
material and/or emulsifier for insecticides, xylenol-formaldehyde 
resins, disinfectants, and wood preservatives; and in the synthesis of 
vitamin E. Although isophorone may be used as a solvent for such 
purposes as commercial preparations of lacquers, inks, vinyl resins, 
copolymers, coatings and finishings, ink thinners, and pesticides, and 
formulators of these products would be considered solvent users for the 
purposes of this study, the use of these products generally is not. 
Users of these products may fall within the scope of the industry study 
only if they use isophorone for cleaning or other solvent purposes.

[[Page 42345]]

2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses. In the RCRA 3007 
Prequestionnaire of Solvent Use, 30 facilities reported a combined use 
of greater than 0.3 million kilograms of isophorone. In the RCRA 3007 
Questionnaire, six facilities reported a total use of 0.24 million 
kilograms of isophorone as a solvent in 1993. The largest user of 
isophorone used a solvent mixture containing significantly less than 10 
percent isophorone before use.
    Questionnaire respondents indicate that isophorone is used 
primarily as a diluent cleaning out tank bottoms, and in coating 
processes. At an aluminum manufacturing facility, isophorone-bearing 
paint and additional isophorone paint thinner enter the coil coating 
operation. The coil is coated and waste paint/thinner is drummed prior 
to fuel blending. At a printing facility, isophorone is mixed with ink 
and screened onto the material to be printed. The printed material is 
dried. Waste ink from the operation is drummed prior to off-site fuel 
blending. A pilot plant in the chemical industry uses isophorone in the 
coating process, where it is added in the coating steps. Isophorone is 
used in the manufacture of magnetic disks during the coating process, 
where isophorone and other raw materials are mixed and coated onto the 
disk substrate.
    b. Physical/Chemical Properties and Toxicity. Isophorone has a 
solubility in water of 12,000 mg/L at 25 deg.C, indicating that it is 
highly soluble in water. With a vapor pressure of 0.38 mm Hg at 
20 deg.C, isophorone is volatile. The Henry's Law Constant of 
6.2 x 10-6 atm-m\3\ mole indicates that isophorone has a low to 
moderate rate of evaporation from water. It has a Log Kow of 1.70 
and it is expected to have limited tendencies to sorb to soils and to 
bioaccumulate. Isophorone can biodegrade.
    Isophorone is a suspected carcinogen by ingestion. Using an oral 
carcinogen slope factor (CSF) of 9.5 x 10-4 (mg/kg/day)-1, 
EPA calculated that exposure to a water concentration of 0.04 mg/L for 
70 years would correspond to a cancer risk of 1 x 10-6. EPA also 
estimated a provisional air HBL of 4 x 10-3 mg/m\3\. These health-
based numbers are provisional and have not undergone external peer 
review. The Agency plans to complete an external peer review of these 
health-based numbers prior to issuing a final determination. EPA 
requests comments on the appropriateness of the provisional numbers, 
and seeks any additional data on the toxicity of isophorone.
    c. Waste Generation, Characterization, and Management. Six 
facilities reported the generation of 0.75 million kilograms of 
residuals from the use of isophorone as a solvent. The concentration of 
isophorone in all these residuals ranges from 0.1 percent to 8 percent, 
except one that was 45 percent. All wastes contained little or no water 
and were primarily organic liquids. Because of the primary use of 
isophorone as a diluent for tank bottoms or coating processes, 
wastewaters were not generated. The solids generated were containers, 
rags and similar wastes contaminated with solvent. All isophorone 
residuals are managed by some type of thermal treatment, either fuel 
blending, energy recovery in a BIF, or incineration.
    Based upon reported waste volumes and concentration of isophorone 
in the wastes, loadings of isophorone were calculated. Table 17 
presents the volumes and loadings for each waste management practice.
    All of the wastes identified in the questionnaire are managed as 
hazardous. Most are hazardous because of a characteristic (usually 
ignitability) or are listed based on other constituents (e.g., F003). 
One waste volume generated (705 thousand kg) was not hazardous, but was 
sent to a hazardous waste BIF; this waste resulted from the use of 
isophorone as a minor ingredient in a diluent to thin heavy end 
residuals from waste storage tanks to aid pumping the heavy ends to an 
on-site hazardous BIF. This stream also results from use of isophorone 
at a concentration of 8.8 percent, which is just below the 10 percent 
threshold EPA has used in the past to define solvent use in previous 
solvent listings (e.g., F001). However, EPA included this waste in its 
evaluation in order to more fully characterize potential risks from 
these wastes.

                                   Table 17.--Waste Statistics for Isophorone                                   
----------------------------------------------------------------------------------------------------------------
                                                                                                        Total   
                   Management practice                      Number of    Number of    Total volume     loading  
                                                            facilities    streams         (kg)           (kg)   
----------------------------------------------------------------------------------------------------------------
Incineration.............................................            3            4          12,186        2,248
Boiler/Industrial Furnace................................            1            2       * 705,180      * 9,873
Fuel Blending............................................            1            4          36,329        1,816
----------------------------------------------------------------------------------------------------------------
* Based on two wastestreams in 3007 Questionnaire derived from isophorone at a before use concentration of <10%.

    Because of the limited uses of isophorone as a solvent, EPA does 
not believe that other wastes or management practices are likely to be 
significant. Therefore, to assess possible risks from management of 
isophorone wastes from solvent use, EPA modeled combustion in a boiler 
to account for thermal treatment (incineration, BIFs, and fuel 
blending), and storage in an open accumulation tank.
3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency performed risk bounding and high end 
risk estimates using the approaches described earlier (see Section 
II.C) to obtain a hazard quotient (HQ) for each plausible mismanagement 
scenario. Where the HQ exceeds 1, exposure is expected to pose a risk 
to human health and the environment. The results of these analyses are 
shown in Table 18.
    Using bounding assumptions, the Agency estimated that management of 
isophorone residuals in a boiler could result in an inhalation HQ of 
6.2 x 10-8. Risk based on bounding assumptions for the other 
plausible mismanagement scenario (on site accumulation) exceeded an 
inhalation HQ of 1, and EPA then conducted high end and central 
tendency risk analyses for this scenario.
    The estimated high end risk assessment with plausible mismanagement 
of isophorone wastes by on site accumulation in an uncovered tank 
resulted in an inhalation HQ of 0.6. This result indicates minimal risk 
through the inhalation pathway for this scenario. Furthermore, this 
risk resulted from one large wastestream that was used to mobilize tank 
heavy ends for pumping to an onsite hazardous waste BIF. The resulting 
waste mixture was not reported stored, and is likely pumped directly to 
the BIF for combustion, therefore the scenario appears to be 
unrealistic for this wastestream in any case.

[[Page 42346]]



                                Table 18.--Risk Assessment Results for Isophorone                               
----------------------------------------------------------------------------------------------------------------
                                                                      Hazard quotient (HQ)                      
                                               -----------------------------------------------------------------
       Plausible mismanagement practice           Central                                                       
                                                  tendency                  Bounding                   High end 
----------------------------------------------------------------------------------------------------------------
Nonwastewaters:                                                                                                 
   On Site Accumulation...............         0.01  14....................................          0.6
   Incineration.......................  ...........  6.2 x 10-8                              ...........
----------------------------------------------------------------------------------------------------------------
All risks are direct inhalation. For a complete description of the risk assessment methodology and results, see 
  the background document Assessment of Risks from the Management of Used Solvents.                             

    b. Environmental Damage Incidents. EPA investigated damage 
incidents at which isophorone was an identified contaminant at the 
site. Based on a review of identified damage instances, no single 
instance of damage was identified that could be tied to use of 
isophorone as a solvent. Isophorone was identified as a contaminant at 
17 sites in the ROD database, however most of these sites arose from 
disposal practices that occurred many years ago, prior to promulgation 
of the RCRA regulations. Of the four facilities identified with 
isophorone contamination that have operated since 1980, two were 
landfills, one a chemical waste storage and processing facility, and 
one a pesticide manufacturing facility. All four of these facilities 
have also been in operation for many years before 1980, and all sites 
were contaminated with a myriad of chemicals. The maximum levels of 
isophorone found at the four sites were 0.014 ppm in groundwater, 59 
ppm in soil, and 0.13 ppm in surface water. For the landfills and 
chemical treatment facility, the use of the isophorone prior to being 
found at the site is impossible to ascertain. However, in the case of 
the pesticide manufacturer, isophorone has been used as a starting 
ingredient in the production of pesticides and insecticides, and 
isophorone becomes part of the final product. This would not be 
considered a solvent use.
    The solvent uses identified for isophorone are limited to only two 
industry sectors--agricultural chemicals and coating/printing 
operations, and none of these sectors were represented by facilities 
identified as having isophorone contamination onsite. Given that the 
current use of isophorone appears to be very limited, and considering 
that all of the isophorone wastes generated in 1993 were treated as 
hazardous, EPA does not believe that these damage cases are relevant to 
the listing determination.
    c. Conclusion. EPA believes that isophorone does not satisfy the 
criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA is 
proposing that wastes from the use of isophorone as a solvent should 
not be listed as hazardous waste under 40 CFR 261.31. As discussed 
above, risk bounding estimates indicate that isophorone solvent 
residuals are not considered to pose a substantial risk or potential 
hazard to human health and the environment through the inhalation 
pathway from burning. Furthermore, all reported residuals were treated 
as hazardous waste, and all were sent to thermal treatment. Thus, these 
residuals do not appear to be managed in a manner that poses a threat 
to human health and the environment.

M. 2-Methoxyethanol Acetate (2-MEA)

1. Industry Identification
    In 1992, 2-methoxyethanol acetate (2-MEA) production was estimated 
to be approximately 500,000 kilograms based on 1988 data; however, the 
Chemical Manufacturers Association reported that production of this 
chemical ceased in 1992. It was manufactured only by Union Carbide, 
under the trade name Methyl Cellosolve Acetate. The use of 2-
methoxyethanol acetate is reported to be 82,000 kilograms. The demand 
for 2-methoxyethanol acetate has declined and current U.S. use is 
limited to specialty solvents. Based on industry contacts, EPA believes 
that reported use reflects consumption of stockpiled chemicals.
2. Description of Solvent Usage and Resulting Waste
    a. Solvent Use and Questionnaire Responses. In the RCRA 3007 
Prequestionnaire of Solvent Use, 16 facilities reported the use of 2-
methoxyethanol acetate, with use of greater than 4,000 kilograms in 
1992. In the RCRA 3007 Questionnaire, three facilities reported the use 
of 1,672 kilograms of 2-methoxyethanol acetate in 1993.
    Although limited in use, RCRA 3007 Questionnaire respondents 
indicated that 2-methoxyethanol acetate was used as a diluent in a 
coating formulation. It also was used as a reaction or synthesis medium 
and for dissolution.
    Literature searches indicate other past uses for 2-methoxyethanol 
acetate, however, these uses were not confirmed by the RCRA 3007 
Questionnaire respondents.
    b. Physical/Chemical Properties and Toxicity. 2-Methoxyethanol 
acetate is completely soluble in water. With a vapor pressure of 1.2 mm 
Hg at 20 deg.C, 2-methoxyethanol acetate is moderately volatile. The 
Henry's Law Constant is 7.6 x 10-7 atm-m3/mole, indicating 
that 2-methoxyethanol acetate has a low rate of evaporation from water. 
The Log Kow is -0.76, indicating that 2-methoxyethanol acetate has 
a low tendency to sorb to soil organic matter or to bioaccumulate.
    2-Methoxyethanol acetate is not classified as a carcinogen. EPA 
estimated a provisional RfC of 0.02 mg/m3 and RfD of 
5.7 x 10-3 mg/kg/day. These correspond to provisional HBLs of 
2 x 10-2 mg/m\3\ for air, and 0.2 mg/L for water. These health-
based numbers are provisional and have not undergone external peer 
review. The Agency plans to complete an external peer review of these 
health-based numbers prior to issuing a final determination. EPA 
requests comments on the appropriateness of the provisional numbers, 
and seeks any additional data on the toxicity of 2-methoxyethanol 
acetate.
    c. Waste Generation, Characterization, and Management. Three 
facilities reported the generation of 16,329 kilograms of 2-
methoxyethanol acetate solvent residuals. These residuals include 1,362 
kg of debris (i.e., rags and containers), almost 15,000 kg of spent 
solvents, and negligible amounts (<1 kg) of process sludges. For the 
most part, these residuals had very low (<1 percent) concentrations of 
2-methoxyethanol acetate in the residual. Only one residual from one 
facility had a higher concentration, in a range of 20-50 percent. Given 
the limited uses reported (diluent in coating and reaction media), 
wastewaters are not expected and were not reported. Waste management 
practices reported were hazardous waste incineration and energy 
recovery in a BIF.
    Table 19 presents the waste volumes and loadings of 2-
methoxyethanol

[[Page 42347]]

acetate for each waste management practice. All waste went to a 
hazardous waste incinerator or BIF. Given the limited and decreasing 
use of this chemical as a solvent, EPA believes that these represent 
the only significant management practices likely to be found. 
Therefore, to assess possible risks from management of 2-methoxyethanol 
acetate wastes from solvent use, EPA modeled combustion in a boiler to 
account for thermal treatment (incineration, BIFs), and storage in an 
open accumulation tank.

                            Table 19.--Waste Statistics for 2-Methoxyethanol Acetate                            
----------------------------------------------------------------------------------------------------------------
                                                           Number of    Number of    Total volume       Total   
                   Management practice                     facilities    streams         (kg)       loading (kg)
----------------------------------------------------------------------------------------------------------------
Incineration............................................            1            3          16,322        963   
Boiler/Industrial Furnace...............................            1            3               7          0.07
----------------------------------------------------------------------------------------------------------------

3. Basis for Proposed No-List Determination
    a. Risk Assessment. The Agency estimated risk using bounding 
assumptions as described earlier (see Section II.C) to obtain a risk 
for each plausible mismanagement scenario. Where the HQ exceeds 1, 
exposure may pose a risk to human health and the environment. The 
results of these analyses are shown inTable 20.
    Using risk bounding assumptions, the Agency estimated that 
management of 2-methoxyethanol acetate residuals in a boiler could 
result in an inhalation HQ of 7.9x10-13 and by onsite accumulation 
could result in an inhalation HQ of 0.4. These results indicate minimal 
risk through the inhalation pathway for these scenarios.

     Table 20.--Risk Assessment Results for 2-Methoxyethanol Acetate    
------------------------------------------------------------------------
                                                 Hazard quotient (HQ)   
            Management practice             ----------------------------
                                                       Bounding         
------------------------------------------------------------------------
Nonwastewaters:                                                         
   On Site Accumulation............  0.4                        
   Incineration....................  7.3 x 10-13                
------------------------------------------------------------------------
All risks are direct inhalation. For a complete description of the risk 
  assessment methodology and results, see the background document       
  Assessment of Risks from the Management of Used Solvents.             

    b. Environmental Damage Incidents. 2-Methoxyethanol acetate has 
been detected at one Superfund site. The ROD database indicates that 2-
methoxyethanol acetate has contaminated the soil, sediments, and ground 
water at the site, although no information on the concentration level 
is available. Wastes deposited at the municipal landfill site include 
drums of industrial waste that were buried either intact, punctured, or 
crushed. The ROD database does not specifically cite the uses of any of 
the wastes found at the site. Given the declining production and 
solvent use of 2-methoxyethanol acetate, and the fact that the small 
amount of waste currently generated is treated as hazardous waste, EPA 
does not believe this damage case provides any relevant information on 
possible future management of the chemical. Therefore, EPA did not 
consider this damage case information in the listing determination.
    c. Conclusion. EPA believes that 2-methoxyethanol acetate does not 
satisfy the criteria for listing in 40 CFR 261.11(a)(3). Therefore, EPA 
is proposing that wastes from the use of 2-methoxyethanol acetate as a 
solvent should not be listed as hazardous waste under 40 CFR 261.31. 
The use of 2-methoxyethanol acetate has been declining in recent years 
and does not appear to be manufactured domestically. Further, as 
discussed above, risk bounding estimates indicate that 2-methoxyethanol 
spent solvent residuals are not considered to pose a substantial risk 
or potential hazard to human health and the environment through the 
pathways assessed. Residuals from the use of 2-methoxyethanol acetate 
as a solvent generally are managed as hazardous waste, typically being 
co-managed with other wastes already listed under 40 CFR Part 261. 
Thus, these residuals do not appear to be managed in a manner that 
poses a threat to human health and the environment.

N. Chemicals With No Significant Use as Solvents

    The following four chemicals were not reported to have any 
significant uses as solvents: p-dichlorobenzene, benzyl chloride, 
epichlorohydrin, and ethylene dibromide. On the 1993 Preliminary 
Questionnaire, the major recipients were hazardous waste incinerators, 
fuel blenders, or cement kilns who could not tell if the wastes 
containing these chemicals had, in fact, solvent use. Except in once 
case (for p-dichlorobenzene), all other use reported as a solvent at 
any facility was below 10 kg per year. In these cases, reports of 
``solvent use'' often turned out to be quantities purchased for a 
facility's research laboratory, without regard as to whether the 
chemical was actually used as a solvent. The Agency contacted 
facilities that reported apparent solvent use of larger quantities of 
these chemicals to confirm whether or not solvent use was actually 
taking place. In all cases, the facility indicated that solvent use was 
not occurring.
    One of the chemicals, p-dichlorobenzene, is a solid at room 
temperature, which limits its utility as a solvent. The others are 
relatively reactive chemicals, which also makes them unsuitable for 
most solvent applications. All the chemicals may appear as an 
ingredient in product formulations, sometimes as a chemical impurity. 
The chemicals are most often used as chemical reactants, pesticides, 
sterilizing agents, or in other non-solvent uses. Information collected 
by EPA on each of the four chemicals is discussed below.
1. p-Dichlorobenzene
    In 1993, U.S. production of p-dichlorobenzene was reported to be 
35.9 million kilograms. Data from 1993 indicate that most of the uses 
that could be identified were nonsolvent uses, including the production 
of polyphenylene sulfide resin, in room deodorant blocks, and in moth 
control products. Industry studies indicate that p-dichlorobenzene is 
used in very limited amounts as a solvent, but is more typically found 
as a contaminant in o-dichlorobenzene, a listed solvent.
    In response to the RCRA Sec. 3007 Prequestionnaire of Solvent Use, 
the total volume used by 26 Prequestionnaire respondents for 1992 was 
greater than 25,000 kilograms. Much of that ``use'' was reported by 
facilities that treat waste by incineration or in a cement kiln; its 
use was also erroneously reported due to the presence of p-
dichlorobenzene as an impurity in o-dichlorobenzene, a listed solvent. 
Six facilities reported the use of 6,288 kilograms of p-dichlorobenzene 
as a solvent in response to the RCRA Sec. 3007 Questionnaire of Solvent 
Use.

[[Page 42348]]

The chemical was used in very small volumes (<2kg), except for one 
facility; this metal finishing facility reported using p-
dichlorobenzene in a solvent mixture to remove coatings from metal 
parts in paint stripping tanks. However the facility reported very 
little solvent in the resulting wastestreams; furthermore, this 
facility indicated in its questionnaire response that it intended to 
cease using p-dichlorobenzene and switch to a less toxic solvent. In 
general, the data from most industries indicate that the chemical is 
primarily used in research and laboratory applications. p-
Dichlorobenzene has a melting point of 54 deg.C and is a solid at room 
temperature, limiting possible solvent uses.
    Wastes from p-dichlorobenzene use were generated as spent lab 
solvents, laboratory wastewaters, spent solvents, and as part of 
process wastewaters. Five facilities reported that p-dichlorobenzene 
solvent waste was sent to hazardous waste incineration or a BIF; this 
includes the facility that used most of the p-dichlorobenzene. One 
facility reported discharging process wastewaters to a sanitary sewer 
(POTW). The total amount of p-dichlorobenzene reported in the 
wastestreams generated from solvent use in 1993 was <17 kg.
    No instance of environmental damage relating to the use of p-
dichlorobenzene as a solvent has been identified. This chemical is 
relatively common at CERCLA and other environmental damage sites, but 
always appears with other contaminants, most often solvents classified 
as F001-F005 wastes. p-Dichlorobenzene commonly occurs with high 
concentrations of o-dichlorobenzene, probably due to the presence of 
the p-isomer as an impurity. Other damage sites at which p-
dichlorobenzene has been detected include former dye manufacturers; 
however, a nonsolvent use for p-dichlorobenzene is as an intermediate 
in a dye manufacturing process. Given the extremely low solvent use 
identified for p-dichlorobenzene, it is not likely that any of the 
damage incidents identified were the result of mismanagement of p-
dichlorobenzene used as a solvent.
    The Agency proposes that wastes from the use of p-dichlorobenzene 
as a solvent should not be listed as hazardous waste under 40 CFR 
261.31. The use of p-dichlorobenzene as a solvent appears to be 
extremely limited, having specialty applications in laboratories and 
little or no industrial solvent use. p-Dichlorobenzene may be present 
in wastes generated from use of o-dichlorobenzene as a solvent, because 
the para-isomer is an impurity in the o-dichlorobenzene. However, o-
dichlorobenzene is already included in the F002 solvent listing, 
therefore, these wastes would already be regulated as hazardous. 
Residuals from the use of p-dichlorobenzene as a solvent generally are 
very small volumes and the total amount of p-dichlorobenzene in 
residuals was only 17 kg in 1993. Given that wastes generated were 
either incinerated or sent to a POTW where it would be further diluted 
by large volumes of other wastewater and treated, EPA believes that 
these wastes present no significant risks to human health and the 
environment.
2. Benzyl Chloride
    Data from 1993 indicate that U.S. demand for benzyl chloride was 
33.2 million kilograms. Nonsolvent applications account for nearly 100 
percent of the reported uses of benzyl chloride. There were no 
industrial solvent uses of benzyl chloride identified during the 
industry study. Monsanto Corporation informed EPA in February 1993 that 
it is the only U.S. producer of benzyl chloride and that benzyl 
chloride has no current solvent uses.
    Data from the RCRA 3007 Prequestionnaire reported the total volume 
used by the 12 Prequestionnaire respondents was 21,809 kg in 1992. 
Nearly all of that ``use'' was reported by TSD facilities that accepted 
the constituent for thermal treatment. Five facilities reported the 
1993 use of 6.4 kg of benzyl chloride in response to the RCRA 3007 
Questionnaire of Solvent Use; the 1992 solvent use was reported to be 
5.9 kg. Data for 1993 indicated that the total amount of benzyl 
chloride solvent waste generated by five facilities in 1993 was 36,817 
kg, and that these waste contained a total loading of 1.9 kg of benzyl 
chloride.
    Benzyl chloride hydrolyzes in water and decomposes rapidly in the 
presence of most common metals (e.g., iron). The aqueous hydrolysis 
rate for benzyl chloride corresponds to a half-life of 14 hours; this 
means that the concentration of benzyl chloride in water would decrease 
by a factor of 1000 in less than 6 days. Due to its rapid 
transformation in environmental media, benzyl chloride is not expected 
to be persistent in moist soil or water. Given its high reactivity, it 
is highly unlikely that this chemical could find significant use as a 
solvent. Of the facilities providing information in the RCRA 3007 
Questionnaire, each facility used 1 kg or less of benzyl chloride. The 
benzyl chloride solvent waste generated in 1993 were classified as 
spent solvents, and all were reported incinerated as hazardous. Given 
the extremely low use rates, the concentration of benzyl chloride in 
the waste solvents is negligible (<2kg).
    Benzyl chloride has been identified as a constituent of concern at 
one site investigated using CERCLA. However, there are no sites that 
have undergone a ROD that identifies benzyl chloride as a constituent. 
The reason for the absence of benzyl chloride may be due to its 
breakdown in the environment prior to the ROD investigation. In no 
instances has the use of benzyl chloride as a solvent been linked to 
environmental damage in either the ROD or HRS databases.
    The Agency proposes that waste from the use of benzyl chloride as a 
solvent not be listed as hazardous waste under 40 CFR 261.31. The use 
of benzyl chloride as a solvent appears to be very limited, having 
specialty applications in laboratories and no known industrial solvent 
use. Residuals from the apparent use of benzyl chloride as a solvent 
generally are very small volumes and contain negligible concentrations 
of the solvent. The reactivity of the chemical severely limits any 
solvent use. The relatively rapid hydrolysis of benzyl chloride also 
indicates that the substance will not persist long enough to present 
significant risk even if released to the environment in such small 
quantities. Furthermore, all residuals are managed as hazardous waste. 
Thus, EPA believes that there are no residuals from solvent use that 
pose a threat to human health and the environment.
3. Epichlorohydrin
    The estimated U.S. production and import of epichlorohydrin were 
229.6 million kilograms, based on 1989 production data and 1993 import 
data. Nonsolvent use of epichlorohydrin includes use in the production 
of epoxy resins, glycerin, epichlorohydrin elastomers.
    In response to the prequestionnaire, 14 facilities indicated that 
epichlorohydrin was used as a solvent at their site. These facilities 
reported a total use of more than 76,365 kilograms in 1992. Nearly all 
of these ``uses'' were either misreported as solvent use (when 
epichlorohydrin was, in fact, a chemical reactant) or the use was 
reported by a facility that accepted the constituent for thermal 
treatment or reclamation. Three facilities reported use 3.4 kilograms 
of epichlorohydrin as a solvent in response to the RCRA section 3007 
Questionnaire of Solvent Use. The sharp decline reflects the 
elimination of a treatment facility from further study, since the use 
of the epichlorohydrin as a solvent prior to treatment could not be 
confirmed.

[[Page 42349]]

    Literature searches indicate that epichlorohydrin has been used as 
an ingredient in natural and synthetic resins, gums, cellulose esters 
and ethers, paints, varnishes, nail enamels, lacquers, and cement for 
celluloid. Finally, epichlorohydrin has been used by the textiles 
industry to modify the carboxyl groups of wool, in the preparation of 
fibers, and in dyeing fibers.
    Three facilities provided data in the section 3007 Questionnaire of 
Solvent Use. One facility used only .001 kg in 1993; the wastes 
generated (25 kg) were classified as lab wastes and sent off-site to a 
hazardous waste incinerator or to a nonhazardous energy recovery 
facility. The other two facilities, both pharmaceutical companies, used 
1 kg and 2.36 kg of epichlorohydrin, respectively, in 1993. One of the 
two pharmaceutical facilities reported the generation of a total of 
17,254 kg of spent solvent or lab waste, which was sent off-site for 
hazardous waste incineration. The other facility generated 5,000 kg of 
spent solvent or lab waste, which was incinerated on-site in a 
hazardous waste incinerator. These wastes contained epichlorohydrin in 
part per million concentrations.
    Epichlorohydrin has not been identified as a constituent of concern 
at any sites investigated using the HRS. In addition, there are no 
sites that have undergone a ROD that identify epichlorohydrin as a 
constituent. The reason for the absence of epichlorohydrin may be due 
to its breakdown in the environment prior to the ROD or HRS 
investigation. Epichlorohydrin hydrolyzes relatively rapidly in water 
with a half-life of 8.2 days. In no instances has the use of 
epichlorohydrin as a solvent been linked to environmental damage in 
either the ROD or HRS databases.
    The Agency proposes that waste from the use of epichlorohydrin as a 
solvent not be listed as hazardous waste under 40 CFR 261.31. The use 
of epichlorohydrin as a solvent, if it truly occurs, appears to be 
limited to specialty applications in laboratories and no known 
industrial solvent use. Residuals from the apparent use of 
epichlorohydrin as a solvent generally are very small volumes and 
contain negligible concentrations of the solvent. The reactivity of the 
chemical severely limits any solvent use. The relatively rapid 
hydrolysis of epichlorohydrin also indicates that the substance is 
unlikely to persist long enough to present significant risk even if 
released to the environment in such small quantities. Furthermore, all 
of the waste was reported to be incinerated as hazardous waste. Thus, 
EPA believes that there are no residuals from solvent use that pose a 
threat to human health and the environment.
4. Ethylene Dibromide
    The estimated U.S. capacity for ethylene dibromide production and 
import totals 61.6 million kilograms for 1993, based on 1981 production 
capacity and 1993 import data. However, production has been declining 
since 1974, and 1993 production was 11.3 million kg. The industry study 
confirms that ethylene dibromide has no significant use as a solvent. 
Nonsolvent uses included use as a lead scavenger in gasoline, as an 
insect and soil fumigant, and as an intermediate in the synthesis of 
dyes, pharmaceuticals, and vinyl bromide.
    According to industry data obtained in the RCRA 3007 Preliminary 
Questionnaire, 11 facilities used a total of 127,760 kilograms of 
ethylene dibromide in 1992. Only two facilities used more than 1,000 kg 
per year. In response to the full RCRA 3007 Questionnaire, three 
facilities reported use of 14 kg of ethylene dibromide as a solvent in 
1993. The apparent sharp decline reflects the elimination of a TSD from 
further study, since the use of ethylene dibromide as a solvent prior 
to treatment could not be confirmed by questionnaire responses. EPA did 
not find any evidence of significant solvent uses in industrial, rather 
than research settings. EPA believes that the facilities that reported 
using it as a solvent in the 3007 Survey probably used the chemical in 
an undefined manner in a laboratory, which may or may not include minor 
use as a solvent.
    Of the three facilities providing data in the RCRA 3007 
Questionnaire, a total of 34,197 kg of waste was generated, from a 
total use of 14 kg. All this waste was classified as spent laboratory 
waste. According to the Questionnaire data, all the wastes generated 
were sent to a hazardous waste incineration facility, either on-site or 
off-site. While no exact non-CBI waste concentrations were reported, 
given that only 14 kg of ethylene dibromide was reported used, the 
Agency believes that the wastes sent to incineration have very low 
(part per million range or lower) concentrations of ethylene dibromide.
    Ethylene dibromide (EDB) has been detected at two sites undergoing 
a ROD evaluation. The ROD database indicates that EDB has contaminated 
soil, soil gas, and ground water at the two sites. Records indicate 
that the source of the contamination for the two sites can be linked to 
the use of EDB as a grain fumigant/pesticide. At a pesticide 
manufacturing facility EDB has been detected in the soil in an area 
where pesticide production wastes had been dumped. EDB has also been 
detected at a site that includes a grain storage facility where EDB was 
used to fumigate grain. None of the information on these sites 
indicates that ethylene dibromide was used as a solvent in these 
situations. In water ethylene dibromide hydrolyses relatively rapidly; 
the half-life of this reaction is 5-10 days.
    The Agency proposes that waste from the use of ethylene dibromide 
as a solvent not be listed as hazardous waste under 40 CFR 261.31. The 
use of ethylene dibromide as a solvent, if it occurs, appears to be 
very limited, having specialty applications in laboratories and no 
known industrial solvent use. Residuals from the apparent use of 
ethylene dibromide as a solvent contain negligible concentrations of 
the solvent. Furthermore, all wastes were reported to be incinerated as 
hazardous waste. The reactivity of the chemical severely limits any 
solvent use. Thus, EPA believes that there are no residuals from 
solvent use that pose a threat to human health and the environment.

O. Relationship to RCRA Regulations and Other Regulatory Programs

    There are several recent regulations and ongoing rulemaking efforts 
that may affect the usage, generation, and management of certain 
solvents being examined under the current judicially mandated listing 
determinations. Each of these rules is briefly described below.

Resource Conservation and Recovery Act Regulations

    The Agency recently has published universal treatment standards for 
several of the chemicals addressed in today's proposal (59 FR 47980, 
September 19, 1994). These standards establish consistent concentration 
limits for constituents that previously may have been subject to 
inconsistent standards under various land disposal rulemakings. Under 
the final rule, universal standards are established for four of the 14 
currently targeted solvents when found in nonwastewaters, and for four 
of the 14 solvents in wastewaters. Figure 2 presents the universal 
treatment standards proposed for solvents subject to the current 
listing determination.

[[Page 42350]]



                      Figure 2.--Proposed Universal Treatment Standards for Target Solvents                     
----------------------------------------------------------------------------------------------------------------
                                                                                    Proposed wastewater standard
                 Solvent                      Proposed non-wastewater standard *                 **             
----------------------------------------------------------------------------------------------------------------
Acetonitrile.............................  .......................................  0.17 mg/l *                 
p-dichlorobenzene (1,4-dichlorobenzene)..  6.0 mg/kg..............................  0.09 mg/l *                 
Ethylene Dibromide (1,2-Dibromoethane)...  15.0 mg/kg.............................  0.028 mg/l *                
Methyl Chloride (Chloromethane)..........  30.0 mg/kg.............................  0.19 mg/l *                 
Pheno....................................  l6.2 mg/kg.............................  0.039 mg/l *                
----------------------------------------------------------------------------------------------------------------
* Based on grab samples.                                                                                        
** ased on composite samples.                                                                                   

    Under 40 CFR 268.7(a), a waste generator must test the waste or an 
extract thereof (or apply knowledge of the waste) to determine whether 
the waste is hazardous and restricted from land disposal under the LDR 
program. If the waste is restricted from land disposal and does not 
meet the applicable treatment standards set forth in Part 268, the 
generator must notify any facility receiving the waste of the 
appropriate treatment standards. If a generator determines that a 
restricted waste meets all applicable treatment standards, he/she must 
submit a notice to facilities receiving the waste certifying that the 
waste meets applicable treatment standards.
    Finally, regardless of the impact of the regulations discussed 
above, it is anticipated that a significant portion of the regulated 
community will opt for recycling as a management technique for any 
solvents that may be listed as a result of this investigation. 
Recycling exemptions in the hazardous waste regulations provide 
significant incentives for recycling wastes rather than managing them 
through traditional means (See 40 CFR 261.2, 261.4, 261.6, and Part 
266).

Occupational Safety and Health Administration Regulations

    One notable regulatory initiative is the Occupational Safety and 
Health Administration (OSHA) examination of the health impacts of 
glycol ethers. OSHA has recently proposed amendments to its existing 
regulation for occupational exposure to certain glycol ethers, 
specifically 2-methoxyethanol, 2-ethoxyethanol, and their acetates (2-
methoxyethanol acetate, 2-ethoxyethanol acetate) (58 FR 15526; March 
23, 1993). This proposed rule will reduce the existing 8-hour time-
weighted average (TWA) permissible exposure limit, as well as establish 
guidelines to achieve generally lower exposure for employees to these 
chemicals. This proposal appears to have affected facility usage of 
these glycol ethers. In response to the Agency's RCRA Sec. 3007 
inquiries, a number of facilities reported that use of these glycol 
ethers had been discontinued at their site due to health concerns. 
Others reported that the use of these glycol ethers will be phased out 
in the near future.

Clean Air Act Regulations

    The Clean Air Act (CAA) Amendments of 1990 require EPA to expand 
the regulation of air toxics to 189 substances over a 10-year period 
(such substances are presumed to warrant regulation as air toxics--the 
list may be modified by the Administrator). This statutory list of air 
toxics includes all but two of the 14 solvents addressed in today's 
proposal. The two that are not listed as presumed air toxics are 
cyclohexanol and furfural. The CAA amendments do not require that the 
air toxics be regulated on a constituent-specific basis. Rather, EPA is 
required to identify categories of industrial facilities that emit 
substantial quantities of one or more air toxics. A list of the source 
categories, as well as a schedule for promulgation of hazardous air 
pollutant regulations, is published at 58 FR 63952 (December 3, 1993). 
The Agency has identified 174 source categories (including 8 area 
sources). The source categories include: pharmaceutical production 
processes; agricultural chemicals production; polymer and resins 
production; production of inorganic chemicals; production of organic 
chemicals; and numerous miscellaneous processes, including 
semiconductor manufacturing. Categories of area sources include, for 
example, halogenated solvent cleaners. Such increased regulation of 
many of the industries that use the 14 target solvents may prompt 
increased recapture and reuse of the constituent, or encourage the use 
of alternative compounds.

Emergency Planning and Community Right-to-Know Act Regulations (EPCRA)

    Section 313 of EPCRA requires that any facility with 10 or more 
employees in SIC codes 20-39 that manufactures, processes, or otherwise 
uses specified chemicals in amounts exceeding established thresholds 
must report, to EPA and designated state agencies, any releases of 
these chemicals to the environment. The reported data comprise the 
Toxics Release Inventory (TRI). The chemicals in the TRI are listed at 
40 CFR 372.65, and include all but three (cyclohexanol, isophorone, and 
furfural) of the 14 solvents addressed in today's proposal. Under 
EPCRA, the quantity threshold for chemical use is 10,000 pounds per 
calendar year. The reporting quantity threshold for manufacturing, 
importing or processing is 25,000 pounds per year (1989 and- 
thereafter). Although TRI release reporting does not have a direct 
impact on hazardous waste generation or management capacity, it is 
generally accepted that these reporting requirements create strong 
incentives for facilities to reduce releases and alter operating 
practices to reduce or eliminate the use of specified chemicals. Annual 
TRI reporting was initiated in 1988 (addressing releases during 1987) 
and is undergoing expansion. For example, a final rule published on 
November 30, 1994 (59 FR 61432) added 286 chemicals and chemical 
categories to the TRI reporting inventory. Among the chemicals added 
are cyclohexanol and isophorone.

Clean Water Act Regulations

    The Agency currently is revising the effluent guidelines and 
standards for the pharmaceutical manufacturing category. This work, 
which is being conducted under a Consent Decree (NRDC v. Browner, 
(D.D.C. 89-2980; January 31, 1992)), involves the review and revision 
of the existing effluent guidelines and will consider inclusion of 
limitations on toxic and non-conventional volatile organic pollutants. 
A notice of proposed rulemaking was published on May 2, 1995. The 
Agency has also revised the effluent guidelines and standards 
applicable to the organic chemicals, plastics, and synthetic fibers 
industry (OCPSF) (58 FR 36872; July 9, 1993). These revisions add BAT 
and NSPS

[[Page 42351]]

standards for 19 additional constituents (including p-dichlorobenzene, 
methyl chloride, and phenol) and pretreatment standards for 11 of these 
19 pollutants (including p-dichlorobenzene and methyl chloride).
    The Agency also has developed effluent guidelines and standards for 
the pesticide chemicals category. This work (also being conducted under 
the NRDC Consent Decree) limits the discharge of pollutants into U.S. 
waters and POTWs from new and existing facilities that manufacture 
pesticide active ingredients. A final rule was published on September 
28, 1993 (58 FR 50638), which included standards for p-dichlorobenzene 
and phenol, two constituents addressed by the solvents listing 
investigation. EPA is also completing effluent standards for facilities 
that formulate, package, and/or repackage pesticide active ingredients 
into final products. EPA expects to complete this rule by September 30, 
1996.
    As noted in the discussion of other rules above, these new and 
revised effluent standards may result in the generation of wastes 
already regulated under the CWA and/or may encourage the recycling or 
reduction of CWA-regulated constituents. It is noteworthy that, 
although not imposed as part of these rulemakings, the Agency routinely 
evaluates zero discharge effluent standards (usually based on 
recycling) as an option for new sources.

III. Waste Minimization

    In the Pollution Prevention Act of 1990 (42 U.S.C. 13101 et seq., 
P.L. 101-508, November 5, 1990), Congress declared pollution prevention 
to be a national policy of the United States. The act declares that 
pollution should be prevented or reduced at the source whenever 
feasible; pollution that cannot be prevented should be recycled or 
reused; pollution that cannot be prevented/reduced or recycled should 
be treated in an environmentally safe manner wherever feasible; and 
disposal or release into the environment should be chosen only as a 
last resort, and should be done in an environmentally safe manner. This 
section provides a general discussion of some generic pollution 
prevention and waste minimization techniques that facilities may wish 
to explore.
    Waste minimization practices fall into three general groups: change 
in production practices, housekeeping practices, and practices that 
employ the use of equipment that by design promote waste minimization. 
Some of these practices/equipment listed below conserve water, others 
reduce the amount of product in the wastestream, while others may 
prevent the creation of the waste altogether. EPA acknowledges that 
some of these practices/equipment may lead to media transfers or 
increased energy use. This information is presented for general 
information, and is not being proposed as a regulatory requirement. 
Production practices include:
     Triple-rinsing raw material shipping containers and 
returning the rinsate directly to the reactor;
     Scheduling production to minimize changeover cleanouts;
     Segregating equipment by individual product or product 
``families;''
     Packaging products directly out of reactors;
     Steam stripping wastewaters to recovery reactants or 
solvents for reuse;
     Using raw material drums for packaging final products; and
     Dedicating equipment for hard to clean products.
    Housekeeping practices include:
     Performing preventive maintenance on all valves, fittings, 
and pumps;
     Promptly correcting any leaky valves and fittings;
     Placing drip pans under valves and fitting to contain 
leaks; and
     Cleaning up spills or leaks in bulk containment areas to 
prevent contamination of storm or wash wasters.
    Equipment promoting waste minimization by reducing or eliminating 
waste generation include:
     Low-volume/high-pressure hoses for cleaning;
     Drum triple-rinsing stations;
     Reactor scrubber systems designed to return captured 
reactants to the next batch rather than to disposal;
     Material storage tanks with inert liners to prevent 
contamination of water blankets with contaminants which would prohibit 
its use in the process; and
     Enclosed automated product handling equipment to eliminate 
manual product packaging.
    Waste minimization measures can be tailored to the needs of 
individual industries, processes, and firms. This approach may make it 
possible to achieve greater pollution reduction with less cost and 
disruption to the firm.
    Defined process control and good housekeeping practices often can 
result in significant waste volume or toxicity reduction. Evaluations 
of existing processes also may point out the need for more complex 
engineering approaches (e.g., waste reuse, secondary processing of 
distillation bottoms, and use of vacuum pumps instead of steam jets) to 
achieve waste minimization objectives. Simple physical audits of 
current waste generation and in-plant management practices for the 
wastes also can yield positive results. These audits often turn up 
simple nonengineering practices that can be implemented successfully.

VI. State Authority

A. Applicability of Rule in Authorized States

    Because this proposal would not change the Federal program, it 
would not affect authorized State programs. However, the relevant State 
authorization provisions are as follows.
    Under section 3006 of RCRA, EPA may authorize qualified States to 
administer and enforce the RCRA program within the State. (See 40 CFR 
Part 271 for the standards and requirements for authorization.) 
Following authorization, EPA retains enforcement authority under 
sections 3007, 3008, 3013, and 7003 of RCRA, although authorized States 
have primary enforcement responsibility.
    Before the Hazardous and Solid Waste Amendments of 1984 (HSWA) 
amended RCRA, a State with final authorization administered its 
hazardous waste program entirely in lieu of the Federal program in that 
State. The Federal requirements no longer applied in the authorized 
State, and EPA could not issue permits for any facilities located in 
the State with permitting authorization. When new, more stringent 
Federal requirements were promulgated or enacted, the State was 
obligated to enact equivalent authority within specified time-frames. 
New Federal requirements did not take effect in an authorized State 
until the State adopted the requirements as State law.
    By contrast, under section 3006(g) of RCRA, 42 U.S.C. 6926(g), new 
requirements and prohibitions imposed by the HSWA (including the 
hazardous waste listings proposed in this notice) take effect in 
authorized States at the same time that they take effect in non-
authorized States. EPA is directed to implement those requirements and 
prohibitions in authorized States, including the issuance of permits, 
until the State is granted authorization to do so. While States must 
still adopt HSWA-related provisions as State law to retain final 
authorization, the Federal HSWA requirements apply in authorized States 
in the interim.

B. Effect on State Authorizations

    Because any regulations that EPA might propose (with the exception 
of the actions proposed under CERCLA authority) would be promulgated

[[Page 42352]]

pursuant to the HSWA, a State submitting a program modification is able 
to apply to receive either interim or final authorization under section 
3006(g)(2) or 3006(b), respectively, on the basis of requirements that 
are substantially equivalent or equivalent to EPA's requirements. The 
procedures and schedule for State program modifications under 3006(b) 
are described in 40 CFR 271.21. It should be noted that all HSWA 
interim authorizations are currently scheduled to expire on January 1, 
2003 (see 57 FR 60129, February 18, 1992).
    Section 271.21(e)(2) of EPA's State authorization regulations (40 
CFR Part 271) requires that states with final authorization modify 
their programs to reflect federal program changes and submit the 
modifications to EPA for approval. The deadline by which the States 
must modify their programs to adopt a final rule will be determined by 
the date of promulgation of a final rule in accordance with section 
271.21(e)(2). If any HSWA regulations are adopted in the final rule, 
Table 1 at 40 CFR 271.1 would be amended accordingly. Once EPA approves 
the modification, the State requirements become RCRA Subtitle C 
requirements.
    States with authorized RCRA programs already may have regulations 
similar to those EPA may issue. These State regulations have not been 
assessed against the Federal regulations being proposed to determine 
whether they meet the tests for authorization. Thus, a State would not 
be authorized to implement any such regulations as RCRA requirements 
until State program modifications are submitted to EPA and approved, 
pursuant to 40 CFR 271.21. Of course, States with existing regulations 
that are more stringent than or broader in scope than current Federal 
regulations may continue to administer and enforce their regulations as 
a matter of State law.
    It should be noted that authorized States are required to modify 
their programs only when EPA promulgates Federal standards that are 
more stringent or broader in scope than existing Federal standards. 
Section 3009 of RCRA allows States to impose standards more stringent 
than those in the Federal program. For those Federal program changes 
that are less stringent or reduce the scope of the Federal program, 
States are not required to modify their programs. See 40 CFR 271.1(i).

V. CERCLA Designation and Reportable Quantities

    All RCRA hazardous wastes listed in 40 CFR 261.31 through 261.33, 
as well as any solid waste that exhibits one or more of the hazardous 
waste characteristics, are also hazardous substances under Section 
101(14) of the Comprehensive Environmental Response, Compensation, and 
Liability Act (CERCLA) of 1980, as amended. Hazardous substances are 
listed in Table 302.4 at 40 CFR 302.4, along with their respective 
reportable quantities (RQs). Because EPA is not proposing to list any 
wastes, the Agency is not proposing changes to Table 302.4.
    Under CERCLA 103(a), the person in charge of a vessel or facility 
from which a hazardous substance has been released in a quantity that 
equals or exceeds its RQ must immediately notify the National Response 
Center of the release as soon as that person has knowledge of the 
release. In addition to this reporting requirement under CERCLA, 
Section 304 of the Emergency Planning and Community Right-To-Know Act 
(EPCRA) requires owners or operators of certain facilities to report 
the release of a hazardous substance to State and local authorities. 
EPCRA Section 304 notification must be given to the community emergency 
coordinator of the local emergency planning committee (LEPC) for each 
area likely to be affected by the release, and to the State emergency 
response commission (SERC) of any State likely to be affected by the 
release.
    Under Section 102(b) of CERCLA, all hazardous wastes are assigned a 
statutory RQ of one pound unless and until adjusted by regulation. The 
Agency's methodology for adjusting RQs of individual hazardous 
substances begins with an evaluation of the intrinsic physical, 
chemical, and toxicological properties of each hazardous substance. The 
intrinsic properties examined, called ``primary criteria,'' are aquatic 
toxicity, mammalian toxicity (oral, dermal, and inhalation), 
ignitability, reactivity, chronic toxicity, and potential 
carcinogenicity. Generally, for each intrinsic property, the Agency 
ranks hazardous substances on a scale, associating a specific range of 
values on each scale with an RQ of 1, 10, 100, 1,000, or 5,000 pounds. 
The data for each hazardous substance are evaluated using various 
primary criteria; each hazardous substance may receive several 
tentative RQ values based on its particular intrinsic properties. The 
lowest of the tentative RQs becomes the ``primary criteria RQ'' for 
that substance.
    After the primary criteria RQs are assigned, substances are further 
evaluated for their susceptibility to certain degradative processes, 
which are used as secondary adjustment criteria. These natural 
degradative processes are biodegradation, hydrolysis, and photolysis 
(BHP). If a hazardous substance, when released into the environment, 
degrades relatively rapidly to a less hazardous form by one or more of 
the BHP processes, its RQ, as determined by the primary RQ adjustment 
criteria, is generally raised one level. This adjustment is made 
because the relative potential for harm to public health or welfare or 
the environment posed by the release of such a substance is reduced by 
these degradative processes. Conversely, if a hazardous substance 
degrades to a more hazardous form after its release, the original 
substance is assigned an RQ equal to the RQ for the reaction product. 
The downward adjustment is appropriate because the hazard posed by the 
release of the original substance is increased if it degrades to a more 
hazardous form.
    The methodology summarized above is applied to adjust the RQs of 
individual hazardous substances. An additional process applies to RCRA 
waste streams that contain individual hazardous substances as 
constituents. In the August 14, 1989 Federal Register (54 FR 33440), 
the Agency stated that, in assigning an RQ to a waste stream, the 
Agency determines the RQ for each waste stream constituent and then 
assigns the lowest of these constituent RQs to the waste stream itself.

VI. Regulatory Impacts

A. Executive Order 12866

    Under Executive Order 12866 (58 FR 51735; October 4, 1993), the 
Agency must determine whether a new regulation is a ``significant 
regulatory action'' and, therefore, subject to the requirements of the 
Executive Order and to review by the Office of Management and Budget. 
The E.O. defines ``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 a 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 thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the

[[Page 42353]]

President's priorities, or the principles set forth in the Executive 
Order.
    The Agency has analyzed the costs associated with this proposal, 
which are discussed in the following section, and has determined that 
this proposed rule is not a significant regulatory action. Because the 
Agency is not proposing to change any regulatory requirements for these 
chemicals, there are no costs to industry associated with this 
proposal, nor any economic impacts.

VII. Environmental Justice

    Executive Order 12898 (59 FR 7629; February 16, 1994) requires 
Federal agencies to identify and address, as appropriate, 
disproportionately high and adverse human health and environmental 
effects of their programs, policies, rulemakings, and other activities, 
on minority populations and low-income populations. The Order directs 
each Federal agency to develop an agency-wide environmental justice 
strategy that will list agency programs, policies, public participation 
processes, enforcement activities, and rulemakings related to human 
health and environment that should be revised to, at a minimum: (1) 
promote enforcement of all human health and environmental statutes in 
areas with minority and low-income populations; (2) ensure greater 
public participation; (3) improve research and data collection relating 
to the health and environment of minority and low-income populations; 
and (4) identify differential patterns of natural resource consumption 
among minority and low-income populations.
    Specifically, E.O. 12898 directs Federal agencies, in connection 
with the development and implementation of Agency strategies on 
environmental justice, to collect, maintain, and analyze information on 
the race, national origin, income level, and other appropriate 
information for areas surrounding facilities or sites expected to have 
a substantial environmental, human health, or economic impact on the 
surrounding populations, when such facilities or sites are the subject 
of a substantial Federal environmental administrative or judicial 
action.
    Today's proposal not to list any of the target solvents as 
hazardous waste is expected to have no impact on any minority or low-
income populations. EPA has evaluated risks to hypothetical receptors 
that might live close to facilities using these chemicals as solvents, 
and in all cases the Agency found no significant risks are likely to 
any nearby population. Therefore, EPA does not believe that any further 
analysis is required under Executive Order 12898.

VIII. Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act of 1980, 5 U.S.C. 601 et 
seq., whenever an agency publishes a notice of rulemaking, it must 
prepare and make available for public comment a Regulatory Flexibility 
Analysis (RFA) that describes the effect of the rule on small entities 
(i.e., small businesses, small organizations, and small governmental 
jurisdictions). This analysis is unnecessary, however, if the rule is 
estimated not to have a significant economic impact on a substantial 
number of small entities.
    According to EPA's guidelines for conducting an RFA, if over 20 
percent of the population of small entities is likely to experience 
financial distress based on the costs of the rule, then the Agency 
considers that the rule will have a significant impact on a substantial 
number of small entities, and must perform an RFA. Because today's 
proposal would not change any regulatory requirements, the Agency 
estimates that this action will not significantly impact 20 percent of 
the population of small entities. Therefore, the Agency has not 
conducted an RFA for today's proposed rule.

IX. Paperwork Reduction Act

    Today's proposed rule does not contain any new information 
collection requirements subject to OMB review under the Paperwork 
Reduction Act of 1980, 44 U.S.C. 3501 et seq. Because there are no new 
information collection requirements proposed in today's rule, an 
Information Collection Request has not been prepared.

X. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), P.L. 
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.
    Today's rule contains no Federal mandates (under the regulatory 
provisions of Title II of the UMRA) for State, local, or tribal 
governments or the private sector.

XI. Compliance and Implementation

    Because no regulatory action is being proposed today, the Agency 
expects no change in regulatory status for authorized and nonauthorized 
states.

List of Subjects

40 CFR Part 261

    Environmental Protection, Hazardous Materials, Waste treatment and 
disposal, Recycling.

40 CFR Part 271

    Environmental protection, Administrative practice and procedure, 
Confidential business information, Hazardous material transportation, 
Hazardous waste, Indians--lands, Intergovernmental relations, 
Penalties, Reporting and record keeping requirements, Water pollution 
control, Water supply.

40 CFR Part 302

    Environmental Protection, Air pollution control, Chemicals, 
Emergency Planning and Community Right-to-Know Act, Extremely hazardous 
substances, Hazardous chemicals, Hazardous materials transportation, 
Hazardous substances, Hazardous wastes, Intergovernmental relations, 
Natural resources, Pesticides and pests, Reporting and record keeping 
requirements, Superfund, Waste treatment and disposal, Water pollution 
control, Water supply.


[[Page 42354]]


    Dated: August 2, 1996.
Carol M. Browner,
Administrator.
[FR Doc. 96-20592 Filed 8-13-96; 8:45 am]
BILLING CODE 6560-50-P