Wednesday
August 14, 1996
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
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42318 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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)(l) 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 axe 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
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 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
1. 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. Cutnene
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
Vm. 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
(EOF) and EPA entered into a consent
decree to resolve most of the issues
raised in a civil action undertaken by
the Environmental Defense Fund (EOF
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
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42320 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
(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
EOF 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
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 42321
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.
soilings, 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 n.N through n.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 n.B).
Folloxving 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.,
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42322 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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 § 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 § 3007
survey; and
• comparison of § 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
(cyclohexariol, isophorone, and furfural)
were not TRI chemicals in 1990, a
primary data source for the RCRA
§ 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
§ 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 H.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
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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, RICs, 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",
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42324 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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.
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Management practice
Combustion
Storage Tanks
Wastewater treatment tanks
Wastewater treatment surface impoundments
Pathway
Air
Air
Air
Air and Groundwater
Exposure route
Inhalation of emissions from combustion.
Inhalation of volatilized solvents
Inhalation of volatilized solvents.
Inhalation of volatilized solvents; ingestion of ground-
water 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 1x10 ~6 to 1x10 ~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
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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
n.D to n.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
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 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 °C), and it has a moderate
evaporation rate from water, as
evidenced by its Henry's Law Constant
(2.007xlO-5 atm-m3/mble). Acetonitrile
has a high vapor pressure 'at ambient
temperature, and is also flammable and
ignitable, with a flash point of 6 °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 K<,w) 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
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42328 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996. / Proposed Rules
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.belieyes 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.
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 42329
TABLE 1 .—GENERATION STATISTICS FOR ACETONITRILE
Management Practice
Incineration
BIF
WWT— Tank •
WWT— Surface Impoundment ;
POTW
Landfill Subtitle C
Landfill Subtitle D
Critical Oxidation
Distitlatton/Fractionation
# of facilities
33
11
19
15
3
4
2
1
4
1
3
# of streams
79
73
46
29
3
6
3
1
8
2
4
Total volume
(kg)
1 <6,000,000
2,410,944
622,870
8,988,222,016
95,118
16,911
72,755
4,181,818
150,123,631
315,000
771,966
Total loading
(kg)
1 <700,000
1,650,764
337,437
206,159
294
16
459
trace
54,706
18,900
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 n.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
theso 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
Plausible mismanagement practice
Wastewaters:
• Treatment in Aerated Tanks
Nonwastewaters:
• On Site Accumulation:
—Phase 1 & II (all wastes) .
• Boner
Hazard quotient (HQ)
Central tend-
ency
0.00002
0.09
Bounding
2.4
346
0.44
0.00000061
High end
0.002
200
All risks are direct inhalation. For a complete description of the risk assessment methodology and results, see the background document As-
sessment 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 •
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42330 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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 die 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°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°C, 2-
methoxyethanol is volatile, and the
Henry's Law Constant for 2-
methoxyethanol is 2.9x10 ~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 2x10 ~2 mg/m3 and a provisional
reference dose (RfD) of 5.7xlO~3 mg/kg/
day. The corresponding air HBL is
2xlO~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
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 42331
reported volumes and 2-methoxyethanol
loadings by management practice for the
wastes that contain spent 2-
mcthoxyothanol.
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
WWT-Aerated Tanks
WWT-Other Tanks
Fractions lion/Distillation
Management practice
offsits hazardous treatment)
Number of
facilities
11
6
5
6
2
1
2
Number of
streams
20
13
11
6
2
2
2
Total volume
(kg)
297,522
129,369
224,530
3,139,049,350
2,558
1 ,463,068
14,802
Total load-
ing (kg)
52,839
57,760
104,444
452,030
• 486
14,631
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 n.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 6x10 - 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 hazafd 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
Plausible mismanagement practice
Wastewaters:
• Treatment in Aerated Tanks
Hazard quotient (HQ)
Central
tendency
. 3x10-9
Bounding
0.98
High end
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42332 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
TABLE 4.—RISK ASSESSMENT RESULTS FOR 2-METHOXYETHANOL—Continued
Plausible mismanagement practice
Nonwastewaters:
• On Site Accumulation
—Phase 1 & II (all was
— Phase III (non-haz \
•Incineration
stes)
wastes)
Hazard quotient (HQ)
Central
tendency
0.007
Bounding
59
None
6x105-8
High end
16
All risks are direct inhalation. For a complete description of the risk assessment methodology and results, see the background document As-
sessment 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°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 4.5X10 ~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.
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 42333
Methyl chloride can biodegrade
nerobically. It will also hydrol;
Methj
anaerobically. It will also hydrolyze in
\vater 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
bo 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) -', EPA calculated that exposure to
a water concentration of 0.003 mg/L for
70 years would correspond to a cancer
risk of IxlO-6. The inhalation CSF is
l.BxlO"6 (ug/m3) -', which corresponds
to a 10~6 risk HBL in air of 6xlO~4 mg/
m».
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
Incineration
Energy Recovery (BIFs) ...
Land Disposal
WWT— Tanks
WWT— SI
Management practice
, Number of
facilities
4
1
1
1
1
Number of
streams
4
1
2
1
1
Total volume
(kg)
89,296,310
225,000
6,550,550
60,000,000
1,036,517,000
Total load-
ing (kg)
2
2,250
<5.5
600
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
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42334 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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 grouridwater 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 W~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
3.3x10"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 4x10 ~6.
The estimated high end risk assessment
exceeds 1x10~6 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 2x10 ~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 7x10 ~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
Plausible mismanagement practice
Nonwastewaters:
• On Site Accumulation
• Incineration
Wastewaters:
• Surface Impoundment
Central
tendency
2x10~'°
Risk
Bounding
1 8x10~5
33x10~14
7x10-fi
High end
A\s-\C\—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
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 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 4x10 ~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 7x10 ~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
§ 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
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42336 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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°C, indicating
that it is highly soluble. With a vapor
pressure of 35 mm Hg at 25°C, phenol
is moderately volatile at ambient
temperatures. The Henry's Law
Constant of 1.3x10 ~6 atm-m3/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 2xlO-2 mg/m3 and an RfD of
6xlO~' mg/kg/day; these correspond to
an air HBL of 2x10 ~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
Management practice
WWT Tanks
WWT— SI
Number of
facilities
14
4
1
1
1
3
Number of
streams
28
4
1
1
1
3
Total volume
(kg)
103,055
97,526
9
153
40,000,000
12,323,813
Total load-
ing (kg)
23,110
12,764
<0.001
92
3,600
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
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 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, tie
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 n.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 hi a boiler could result
in an inhalation HQ of l.lxlO"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
Plausible
Wastewaters
• Treatment in Aerated Tanks
N'onwastewaters:
• On Site Accumulation
• Incineration
mismanagement practice
Hazard quotient (HQ)
Central
tendency
2x10-7
0.005
Bounding High end
3.3 0.002
12. 0.5
1.1x10-5
All risks are direct Inhalation. For a complete description of the risk assessment methodology and results, see the background document As-
sessment 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.
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42338 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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-ethoxyethanbl 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°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 1.9xlO~6 atm-
m3/mole, indicating that it has a
moderate rate of evaporation from
water. The Log KQW 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 7x10 ~2 mg/m3 and a RfD
of 2xlO~2 mg/kg/day. These values
correspond to an air HBL of 7x10~2 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
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 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
Management Practice
Incineration
Energy Recovery (BIFs)
Fuel Blending
WWT— Tanks
POTW
Number of
facilities
g
7
8
2
1
Number of
streams
14
13
g
2
•|
Total vol-
ume (kg)
641 275
1 67 547
146612
3 161
243 500
Total load-
ing (kg)
23239
146554
ft
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42340 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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°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°C,
indicating that it is highly soluble in
water. Furfural has a vapor pressure of
1 mm Hg at 20°C indicating that furfural
is highly volatile. The Henry's Law
Constant for furfural is 8.1x10 ~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
Management practice
Wastewater Treatment — Surface Impoundment
Number of
facilities
1
3
1
Number of
streams
2
3
2
Total volume
(kg)
24,732,124
152,738,784
6,220
Total load-
ing (kg)
15,940
165,848
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 n.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 2.4x10^14 and on
site accumulation could result in an
inhalation HQ of 1.2x10 ~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.'
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
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.
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 42341
ond and central tendency risk analyses mismanagement of furfural wastes in an This result indicates minimal risk
for these scenarios. aerated wastewater treatment tank through the inhalation pathway for this
The estimated high end risk resulted in an inhalation HQ of 0.0008. scenario.
assessment with plausible
TABLE 12.—RISK ASSESSMENT RESULTS FOR FURFURAL
Plausible
Wastowaters:
• Treatment in Aerated Tanks
• Treatment In Surface
Impoundment
Nonwastewaters:
• On Site Accumulation
• Incineration
mismanagement practice
I-
Central
tendency
2x10~4
azard quotient (HQ)
Bounding High end
79 o 0008
0 69 (inhalation)
0 8 (ingestion)
1 2x10~5
2.4x1 0-'4
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 261.1l(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.
/. 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°C, indicating that
it is only slightly soluble in water. It has
a vapor pressure of 3.2 mm Hg at 20°C,
indicating that it is highly volatile under
ambient conditions and can become an
air pollutant. The Log KQW 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
RfCis9xlO-3mg/m3.
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.
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42342 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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 waste waters, 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
Management practice
Incineration
Boiler/Industrial Furnace
Wastewater Treatment-Tank
Wastewater Treatment-Surface Impoundment .
Landfill
Storage Only
Recovery
Number of
facilities
3
1
1
1
1
1
3
Number of
streams
3
1
1
1
1
1
2
Total vol-
ume (kg)
14,620
160,088
(1)
4,738
1,631
3,670
39,117
Total load-
ing (kg)
2,242
128,070
<28
<47
<28
1,468
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 2.8x10 ~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 HQof 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
Plausible mismanagement practice
Hazard quotient (HQ)
Central
tendency
Bounding
High end
Wastewaters:
« Treatment in Aerated Tanks
Nonwastewaters:
• On Site Accumulation
0.03.
0.02
0.2
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 42343
TABLE 14.—RISK ASSESSMENT RESULTS FOR CUMENE—Continued
Plausible mismanagement practice
• Boiler J
h
Central
tendency
lazard quotient (HQ)
Bounding
2.8x10-'
High end
AH risks are direct inhalation. For a complete description of the risk assessment methodology and results, see the background document As-
sessment of Risks from the Management of Used Solvents.
b. Environmental Damage Incidents.
Of the three facilities identified with
cumena contamination in the Record of
Decision Database, only one was
reported to be in operation after 1980.
This facility xvas 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
cumeno 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°C,
indicating that it is highly soluble in
water. With a vapor pressure of 1 mm
Hg at 20°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 4.5xlOe atm-
m3/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 6x10~5 mg/m3 and
the RfD is 1.7xlO~5 mg/kg/day. These
correspond to HBLs of 6x10~5 mg/m3
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 Eire 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
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42344 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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 cyclonexanol 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
Management practice
Landfill
Incineration
Number of
facilities
1
4
Number of
streams
•\
5
Total volume
(kg)
750
43360
Total load-
ing (kg)
/n
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 7.2xlO~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
Nonwastewaters:
• On Site Accumulation .
• Incineration
Plausible mismanagement practice
1-
Central
tendency
001
lazard quotient (HQ)
Bounding
2
7.2x10-9
High end
0 3
All risks are direct inhalation. For a complete description of the risk assessment methodology and results, see the background document As-
sessment 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.
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 42345
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.
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-
boaring 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°C, indicating
that it is highly soluble in water. With
a vapor pressure of 0.38 mm Hg at 20°C,
isophorone is volatile. The Henry's Law
Constant of 6.2x10 ~6 atm-m3 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 9.5xlO~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 1x10 ~6. EPA also estimated a
provisional air HBL of 4x10 ~3 mg/m3.
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
TABLE 17.—WASTE STATISTICS FOR ISOPHORONE
BoHst/lndustrial Furnace
Fuel Blending
Management practice
Number of
facilities
3
1
1
Number of
streams
4
2
4
Total volume
(kg)
12,186
* 705,1 80
36,329
Total load-
ing (kg)
2,248
* 9,873
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
beliove 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 n.C) to
obtain a hazard quotient (HQJ 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 6.2X1Q-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.
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42346 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
TABLE 18.—RISK ASSESSMENT RESULTS FOR ISOPHORONE
Nonwastewaters:
• On Site Accumulation .
• Incineration
Plausible mismanagement practice
I-
Central
tendency
0 01
azard quotient (HQ)
Bounding
14
6.2x10-8
High end
n R
All risks are direct inhalation. For a complete description of the risk assessment methodology and results, see the background document As-
sessment 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°C, 2-
methoxyethanol acetate is moderately
volatile. The Henry's Law Constant is
7.6x10 ~7 atm-mVmole, 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 RED of 5.7x10~3 mg/kg/day.
These correspond to provisional HBLs
of 2x10 ~2 mg/m3 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
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 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-METHoxvETHANOL ACETATE
Boiler/Industrial Furnace
Management practice
Number of
facilities
1
1
Number of
streams
3
3
Total volume
(kg)
16,322
7
Total loading
(kg)
963
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 ~l3 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 RE-
SULTS FOR 2-METHOXYETHANOL AC-
ETATE
Management practice
Nonwastewaters:
• On Site Accumulation
• Incineration
Hazard
quotient
(HQ)
Bounding
0.4
7.3x10-"
All risks are direct inhalation. For a com-
plete description of the risk assessment meth-
odology and results, see the background doc-
ument Assessment of Risks from the Manage-
ment of Used Solvents.
b. Environmental Damage Incidents.
2-Mothoxyethanol 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 § 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
§ 3007 Questionnaire of Solvent Use.
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42348 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
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°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-dichlorohenzene 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
Prequestiormaire 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.
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Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules 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 xvaste, 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.
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42350 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
FIGURE 2.—PROPOSED UNIVERSAL TREATMENT STANDARDS FOR TARGET SOLVENTS
Solvent
Acetonitrile
p-dichlorobenzene (1 ,4-dicnlorobenzene)
Ethylene Dibromide (1 ,2-Dibromoethane)
Methyl Chloride (Chloromethane)
Pheno
Proposed non-
wastewater standard *
6 0 rng/kg
15.0mg/kg
30.0 mg/kg
I6.2 ma/ka
Proposed
wastewater
standard **
0 1 7 mg/l *
0 09 mg/l *
0 028 mg/l *
0 1 9 mg/l *
0.039 ma/I *
* 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 § 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
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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.
HI. Waste Minimization
In the Pollution Prevention Act of
1990 (42 U.S.C. 13101 etseq., 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
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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(1).
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
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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.0.12898 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.
VHI. Regulatory Flexibility Act
Pursuant to the Regulatory Flexibility
Act of 1980, 5 U.S.C. 601 etseq.,
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.
EX. 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 H 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.
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42354 Federal Register / Vol. 61, No. 158 / Wednesday, August 14, 1996 / Proposed Rules
Dated: August 2,1996.
Carol M. Browner,
Administrator.
[FR Doc. 96-20592 Filed 8-13-96; 8:45 am]
BILLING CODE 6560-50-P
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