[Federal Register Volume 65, Number 217 (Wednesday, November 8, 2000)]
[Rules and Regulations]
[Pages 67068-67133]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-25928]



[[Page 67067]]

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Part III





Environmental Protection Agency





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40 CFR Part 148, et al.



Hazardous Waste Management System; Identification and Listing of 
Hazardous Waste; Chlorinated Aliphatics Production Wastes; Land 
Disposal Restrictions for Newly Identified Wastes; CERCLA Hazardous 
Substance Designation and Reportable Quantities; Final Rule

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / 
Rules and Regulations

[[Page 67068]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 148, 261, 268, 271, and 302

[SWH-FRL-6882-6]
RIN 2050-AD85


Hazardous Waste Management System; Identification and Listing of 
Hazardous Waste; Chlorinated Aliphatics Production Wastes; Land 
Disposal Restrictions for Newly Identified Wastes; and CERCLA Hazardous 
Substance Designation and Reportable Quantities

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is listing as 
hazardous two wastes generated by the chlorinated aliphatics industry. 
EPA is finalizing these regulations under the Resource Conservation and 
Recovery Act (RCRA), which directs EPA to determine whether certain 
wastes from the chlorinated aliphatics industry may present a 
substantial hazard to human health or the environment. The effect of 
listing these two wastes is to subject them to stringent management and 
treatment standards under RCRA and to subject them to emergency 
notification requirements for releases of hazardous substances to the 
environment. EPA is finalizing a contingent-management listing approach 
for one of these wastes. Under the contingent management listing 
determination, the waste will not be a listed hazardous waste, if it is 
sent to a specific type of management facility. EPA also is finalizing 
determinations not to list as hazardous four wastes generated by the 
chlorinated aliphatics industry.

EFFECTIVE DATE: This final rule is effective May 7, 2001.

ADDRESSES: Supporting materials are available for viewing in the RCRA 
Information Center (RIC), located at Crystal Gateway I, First Floor, 
1235 Jefferson Davis Highway, Arlington, VA. The Docket Identification 
Number is F-2000-CALF-FFFFF. The RIC is open from 9 a.m. to 4 p.m., 
Monday through Friday, excluding federal holidays. To review docket 
materials, it is recommended that the public make an appointment by 
calling (703) 603-9230. The public may copy a maximum of 100 pages from 
any regulatory docket at no charge. Additional copies cost $0.15/page. 
The index and some supporting materials are available electronically. 
See the beginning of the Supplementary Information section for 
information on accessing them.

FOR FURTHER INFORMATION CONTACT: For general information, contact the 
RCRA Hotline at (800) 424-9346 or TDD (800) 553-7672 (hearing 
impaired). In the Washington, DC, metropolitan area, call (703) 412-
9810 or TDD (703) 412-3323. For information on specific aspects of the 
rule, contact Ross Elliott of the Office of Solid Waste (5304W), U.S. 
Environmental Protection Agency, 1200 Pennsylvania Avenue, NW, 
Washington, DC 20460. [E-mail address and telephone number: 
<a href="/cdn-cgi/l/email-protection#3d58515154524949134f524e4e7d584d5c505c545113584d5c135a524b"><span class="__cf_email__" data-cfemail="a3c6cfcfcaccd7d78dd1ccd0d0e3c6d3c2cec2cacf8dc6d3c28dc4ccd5">[email protected]</span></a>, (703) 308-8748.]

SUPPLEMENTARY INFORMATION: Wherever ``we'' is used throughout this 
document, it refers to the Environmental Protection Agency (EPA).
    The index and some supporting materials for this rulemaking are 
available on the Internet. Follow these instructions to access these 
documents.

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

    EPA will keep the official record for this action in paper form. 
The official record is the paper record maintained at the address in 
ADDRESSES at the beginning of this document.
    The contents of the preamble to this final rule are listed in the 
following outline:

I. Who Potentially Will Be Affected By Today's Final Rule?
II. What Is The Legal Authority and Background of Today's Final 
Rule?
    A. What Are the Statutory Authorities for This Rule?
    B. Schedule Suit
III. Summary of Today's Action
IV. What Proposed Listing Determinations Led to Today's Final Rule?
    A. What was the Proposed Listing Determination for Chlorinated 
Aliphatic Wastewaters?
    B. What Were the Proposed Listing Determinations for Wastewater 
Treatment Sludges?
    C. Which Constituents did EPA Propose to Add to Appendix VIII of 
40 CFR part 261
    D. What Were the Proposed Treatment Standards Under RCRA's Land 
Disposal Restrictions Standards?
    E. What Risk Assessment Approach was used for Proposed Rule?
V. What Changes Were Made to the Proposed Rule?
    A. Listing Determination for Chlorinated Aliphatic Wastewaters
    B. Modification of Wastewater Treatment Unit Exemption and 
Application of Subpart CC Requirements for Tanks Managing 
Chlorinated Aliphatic Wastewaters
    C. Landfill Leachate Derived From Previously Disposed VCM-A 
Wastewater Treatment Sludges
VI. What Is the Rationale for Today's Final Rule, and What are EPA's 
Responses to Comments?
    A. Chlorinated Aliphatic Wastewaters (other than wastewaters 
from the production of VC-A using mercuric chloride catalyst in an 
acetylene-based process)
    B. Wastewater Treatment Sludges from the Production of EDC/VCM
    C. Wastewater Treatment Sludges and Wastewaters from the 
Production of VCM-A
    D. Wastewater Treatment Sludges from the Production of Methyl 
Chloride
    E. Wastewater Treatment Sludges from the Production of Allyl 
Chloride
    F. What is the Status of Landfill Leachate Derived from Newly-
listed K175?
    G. Population Risks
    H. Which Constituents are Being Added to Appendix VIII of 40 CFR 
part 261?
    I. What are the Land Disposal Restrictions Standards for the 
Newly-Listed Wastes?
    J. Is There Treatment Capacity for the Newly-Listed Wastes?
VII. What is the Economic Analysis of Today's Final Rule?
    A. What is the Purpose of the Economic Analysis?
    B. How Did the Public Participate in the Economic Analysis?
    C. What are the Expected Economic Impacts of this Final Rule?
VIII. When Must Regulated Entities Comply With Today's Final Rule?
    A. Effective Date
    B. Section 3010 Notification
    C. Generators and Transporters
    D. Facilities Subject to Permitting
IX. How Will This Rule be Implemented at the State Level?
    A. Applicability of Rule in Authorized States
    B. Effect on State Authorizations
X. What Are the Reportable Quantity Requirements For Newly-Listed 
Wastes (K174 and K175) under the Comprehensive Environmental 
Response, Compensation, and Liability Act (CERCLA)?
    A. What is the Relationship Between RCRA and CERCLA?
    B. Is EPA Adding Chlorinated Aliphatic Wastes to the table of 
CERCLA hazardous substances?
    C. How Does EPA Determine Reportable Quantities?
    D. When Do I Need to Report a Release of K174 or K175 Under 
CERCLA?
    E. What if I Know the Concentration of the Constituents in My 
Waste?
    F. How Did EPA Determine the RQs for K174 and K175 and Their 
Hazardous Constituents?
    G. How Do I Report a Release?
    H. Is CERCLA Reporting Required for Spills of EDC/VCM Wastewater 
Treatment Sludge That (Prior to the Spill) Does Not Meet the Listing 
Description for K174?
    I. What is the Statutory Authority for This Program?

[[Page 67069]]

XI. What Are the Administrative Assessments?
    A. Executive Order 12866
    B. Regulatory Flexibility Act
    C. Paperwork Reduction Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13084: Consultation and Coordination with 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children from 
Environmental Risks and Safety Risks
    H. National Technology Transfer and Advancement Act of 1995
    I. Executive Order 12898: Environmental Justice
    J. Congressional Review Act

I. Who Potentially Will Be Affected by Today's Final Rule?

    Today's final rule could directly affect those who generate and 
handle the types of chlorinated aliphatic hydrocarbon production wastes 
that EPA is adding to the Agency's list of hazardous industrial wastes 
under RCRA. Although there are an estimated 39 chlorinated aliphatic 
hydrocarbon chemical manufacturing facilities in the United States as 
of 1999, the K174 and K175 listing final rule only applies to 18 of 
these facilities (17 for the K174 listing and one for the K175 
listing), which manufacture two such chemicals; ethylene dichloride 
(EDC) and vinyl chloride monomer (VCM). Furthermore, because of the 
final rule's ``conditional listing'' approach, in comparison to current 
(baseline) waste management practices in this industry, EPA anticipates 
that three of the 18 chemical manufacturing facilities subject to the 
final rule as generators of K174 and K175 hazardous wastes, will incur 
costs to modify their current waste management practices, while the 
remaining 15 facilities will incur only minimal regulatory costs, 
primarily associated with documentation of current waste management 
practices. In addition, EPA anticipates that four industrial waste 
management facilities also will be affected by the final rule due to 
potential changes in the annual quantities of hazardous wastes handled 
and associated changes to business revenues that will be the result of 
modifications to current waste management practices to comply with the 
provisions of today's final rule.
    In addition to waste generators targeted by the rule, because of 
RCRA's ``cradle-to-grave'' statutory design, EPA anticipates that four 
waste handlers (three for the K174 listing and one for the K175 
listing) are likely to experience ``induced effects'' from this final 
rule. In addition, EPA's regional offices and states with RCRA-
authorized programs potentially will incur some costs because they must 
administer new RCRA listings. Several additional stakeholders also will 
have to read the final rule.
    As defined in the Economics Background Document prepared for 
today's final rule, ``targeted effects'' are the anticipated costs of 
the final rule incurred by the unique class of industrial facilities 
that generate the newly listed hazardous wastes K174 and K175. 
``Induced effects'' are anticipated costs of direct, indirect or 
secondary impacts the final rule may have on entities linked 
economically to the targeted facilities such as offsite waste 
management facilities, and on entities which are likely affected by 
other generic provisions of the final rule, such as states with RCRA 
authorized programs which will implement and enforce the rule. 
``Incidental effects'' are anticipated consequential impacts on other 
types of entities, such as on other chemical manufacturers (to read the 
rule), other Federal agencies (to read the rule), and other non-
governmental organizations (such as industry trade associations to read 
and propagate the rule to its member companies).
    EPA's estimate of expected regulatory costs for these 116 
potentially affected entities, is described in EPA's ``Economics 
Background Document'(USEPA 2000a) \1\ for this final rule, which is 
available for public review from the RCRA Docket. A summary of the 
potentially affected industry sectors (by respective SIC and NAICS 
codes) is displayed in the table below.
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    \1\ USEPA. 2000a. Economics Background Document, USEPA Final 
Rule Listing Industrial Wastewater Treatment Sludges Generated by 
Chlorinated Aliphatic Chemical Manufacturing Facilities, as RCRA 
Hazardous Wastecodes K174 & K175: Industry Profile and Estimation of 
Regulatory Costs. Office of Solid Waste. 31 July.

                    Summary of Entities Potentially Affected by the RCRA K174/K175 Final Rule
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                          Economic sector classification             Number entities potentially affected
        Item        --------------------------------------------------------------------------------------------
                       SIC     NAICS        Description         Targeted     Induced     Incidental     Total
----------------------------------------------------------------------------------------------------------------
1..................     2869    32511  Industrial organic              18            0           21           39
                                        chemical
                                        manufacturers*
                                        (waste generators).
2..................     4953   562211  Hazardous waste                  0            4            0            4
                                        treatment & disposal
                                        (waste handlers).
3..................     9511    92411  State government                 0           49            0           49
                                        environmental
                                        departments (public
                                        administration).
4..................     9511    92411  Federal government               0           11            1           12
                        9611    92611   offices
                        9621    92612   (environmental,
                                        economic &
                                        transportation
                                        public
                                        administration).
5..................     8742    54161  Management consulting            0            0           12           12
                                        services (non-
                                        governmental
                                        organizations).
                                                             ---------------------------------------------------
                                       Total................           18           64           34         116
----------------------------------------------------------------------------------------------------------------
Explanatory Notes:
(a) *Parent company codes may differ from the codes associated with the facility units targeted by the rule.
(b) This list of sector classification codes for ``induced effect'' entities may not be exhaustive for at least
  two reasons:
<bullet> Non-hazardous and hazardous industrial waste collection transporters (SIC 4212, 4953, NAICS 562111,
  562112) may be affected, depending upon whether waste collected from K174/K175 generators is transported by
  waste treatment/disposal facilities, or by separate, unaffiliated transporter companies.
<bullet> If waste remediation is required, such entities may be affected (SIC 4959, NAICS 56291).


[[Page 67070]]

    The list of potentially affected entities in the above table may 
not be exhaustive. Our aim is to provide a guide for readers regarding 
those entities that EPA is aware potentially could be affected by this 
action. However, this action may affect other entities not listed in 
the table. To determine whether your facility is regulated by this 
action, you should examine 40 CFR part 260 and 261 carefully in concert 
with the rules amending RCRA that are found at the end of this Federal 
Register notice. If you have questions regarding the applicability of 
this action to a particular entity, consult the person listed in the 
preceding section entitled FOR FURTHER INFORMATION CONTACT.

II. What Is the Legal Authority and Background of Today's Final 
Rule?

A. What Are the Statutory Authorities for This Rule?

    These regulations are being promulgated under the authority of 
sections 2002(a), 3001(b), 3001(e)(2) and 3007(a) of the Solid Waste 
Disposal Act, 42 U.S.C. 6912(a), 6921(b) and (e)(2), and 6927(a) as 
amended several times, most importantly by the Hazardous and Solid 
Waste Amendments of 1984 (HSWA). These statutes commonly are referred 
to as the Resource Conservation and Recovery Act (RCRA), and are 
codified at Volume 42 of the United States Code (U.S.C.), sections 6901 
to 6992(k) (42 U.S.C. 6901-6992(k)).
    Section 102(a) of the Comprehensive Environmental Response, 
Compensation, and Liability Act of 1980 (CERCLA), 42 U.S.C. 9602(a) is 
the authority under which the CERCLA aspects of this rule are being 
promulgated.

B. Schedule Suit

    In 1989, the Environmental Defense Fund (EDF) \2\ sued the 
Environmental Protection Agency (EPA), in part for failing to meet the 
statutory deadlines of Section 3001(e)(2) of RCRA (EDF vs. Browner; 
Civ. No. 89-0598 D.D.C.). To resolve most of the issues in the case, 
EDF and EPA entered into a consent decree, which has been amended 
several times to revise dates. The consent decree sets out deadlines 
for promulgating certain RCRA rules and for completing certain studies 
and reports. The consent decree obliges EPA to propose a hazardous 
waste listing determination for wastewaters and wastewater treatment 
sludges generated from the production of specified chlorinated 
aliphatic chemicals. The wastewater and wastewater treatment sludges 
subject to the consent decree are those from the production of 
chlorinated aliphatics for which other process wastes already have been 
designated as hazardous waste F024 in 40 CFR 261.31. According to the 
consent decree, EPA was required to propose listing determinations by 
July 30, 1999 and promulgate final listing determinations on or before 
September 30, 2000. Today EPA is promulgating listing determinations 
for these wastes in accordance with the consent decree.
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    \2\ Now known as Environmental Defense.
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III. Summary of Today's Action

    In today's notice, EPA is promulgating regulations that add two 
wastes generated by the chlorinated aliphatics industry to the list of 
hazardous wastes in 40 CFR 261.32. Below are the wastestreams EPA is 
listing as hazardous with their corresponding EPA Hazardous Waste 
Numbers.

K174  Wastewater treatment sludges from the production of ethylene 
dichloride or vinyl chloride monomer (EDC/VCM)
K175  Wastewater treatment sludges from the production of vinyl 
chloride monomer using mercuric chloride catalyst in an acetylene-
based process

    EPA is listing these wastes as hazardous based on the criteria set 
out in 40 CFR 261.11(a)(3) for listing a waste as hazardous. EPA 
assessed and considered these criteria for each of six wastestreams 
generated by the chlorinated aliphatics industry through the use of 
risk assessments and risk modeling, as well as a consideration of other 
pertinent factors. Today's final listing determination follows the 
elements of the Agency's listing decision policy that was presented in 
the proposed listing determination for wastes generated by the dye and 
pigment industries published in the Federal Register on December 22, 
1994 (see 59 FR at 66073). This policy uses a ``weight-of-evidence'' 
approach in which calculated risk information is a key factor 
considered in making a listing determination.
    Upon the effective date of the hazardous waste listings promulgated 
today, wastes meeting the listing descriptions will become hazardous 
wastes and need to be managed in accordance with RCRA subtitle C 
requirements. Residuals from the treatment, storage, or disposal of the 
wastewater treatment sludges proposed to be listed as hazardous also 
will be classified as hazardous wastes pursuant to the ``derived-from'' 
rule (40 CFR 261.3(c)(2)(i)). Also, with certain limited exceptions, 
any mixture of a listed hazardous waste and a solid waste is itself a 
RCRA hazardous waste (40 CFR 261.3(a)(2)(iv), ``the mixture rule'').
    In today's notice, the Agency is promulgating an alternative 
approach to listing wastewater treatment sludges from the production of 
ethylene dichloride or vinyl chloride monomer (EDC/VCM), rather than 
listing this waste in accordance with the Agency's traditional listing 
approach. The Agency is promulgating a conditional listing approach 
because the Agency evaluated the ways in which the wastes are likely to 
be managed and determined that the waste may present significant risks 
to human health and the environment, although it concluded that a 
particular waste management practice is protective of human health and 
the environment. Under the conditional listing approach, EPA is listing 
the waste as hazardous only if the waste is managed in a way other than 
the manner in which the Agency has determined is protective of human 
health and the environment. In developing this conditional-listing 
approach, the Agency has determined that wastes that fall outside the 
scope of the listing description (e.g., are destined for the 
appropriate type of disposal) are non-hazardous when generated. 
However, if it turns out that the waste actually is not handled in 
accordance with the conditions of the listing at any point in its 
management, the generators or other handlers of the waste will be 
subject to enforcement actions. The conditional-listing approach being 
promulgated today for certain wastes generated from chlorinated 
aliphatics processes is further discussed in section VI.B. of today's 
rule.
    Today's action also promulgates no list decisions for the following 
four wastes:
    <bullet> Process wastewaters from the production of chlorinated 
aliphatics (other than wastewaters from the production of vinyl 
chloride monomer using mercuric chloride catalyst in an acetylene-based 
process),
    <bullet> Process wastewaters from the production of vinyl chloride 
monomer using mercuric chloride catalyst in an acetylene-based process,
    <bullet> Wastewater treatment sludges from the production of methyl 
chloride, and
    <bullet> Wastewater treatment sludges from the production of allyl 
chloride.
    EPA considers the listing criteria set out in 40 CFR 261.11, in 
light of information relevant to the criteria, in making listing 
determinations. The criteria provided in 40 CFR 261.11 include eleven 
factors for determining whether a waste is capable of posing a 
``substantial present or potential hazard to human health and the 
environment.'' Nine of these factors, as described

[[Page 67071]]

generally below, are directly incorporated into EPA's completion of a 
risk assessment for the wastestreams of concern:
    <bullet> Toxicity (Sec. 261.11(a)(3)(i)) is considered in 
developing the health benchmarks used in the risk assessment modeling.
    <bullet> Constituent concentrations and waste quantities 
(Secs. 261.11(a)(3)(ii) and 261.11(a)(3)(viii)) are used to define the 
initial conditions for the risk evaluation.
    <bullet> Potential to migrate, persistence, degradation, and 
bioaccumulation of the hazardous constituents and any degradation 
products (Secs. 261.11(a)(3)(iii), 261.11(a)(3)(iv), 261.11(a)(3)(v), 
and 261.11(a)(3)(vi)) are all considered in the design of the fate and 
transport models used to determine the concentrations of the 
contaminants to which individuals are exposed.
    We consider two of the remaining factors, plausible mismanagement 
and other regulatory actions (Secs. 261.11(a)(3)(vii) and 
261.11(a)(3)(x)) in establishing the waste management scenario(s) 
modeled in the risk assessment.
    EPA conducted analyses of the risks posed by wastewaters and 
wastewater treatment sludges from the production of chlorinated 
aliphatic chemicals to assist in the determination of whether the 
wastes meet the criteria for listing set forth in 40 CFR 261.11(a)(3). 
In the preamble to the proposed rule (64 FR 46476), we discussed the 
human health risk analyses and ecological risk screening analyses EPA 
conducted to support our proposed listing determinations for 
chlorinated aliphatics wastewaters, EDC/VCM wastewater treatment 
sludges, and methyl chloride wastewater treatment sludges. These 
analyses, as well as comments EPA received on the analyses, are further 
discussed in this notice in section VI below. We considered the results 
of the risk analyses, as well as comments received, and the results of 
analyses conducted in response to information provided by public 
commenters in finalizing our listing decisions for each wastestream. 
The risk analyses conducted in support of our proposed listing 
determination are presented in detail in the Risk Assessment Technical 
Background Document for the Chlorinated Aliphatics Listing 
Determination and in the 1999 Addendum to Risk Assessment Technical 
Background Document for the Chlorinated Aliphatics Listing 
Determination which are located in the docket for the proposed rule. 
Additional information and analyses conducted with regard to our 
original risk assessment in response to comments received on our 
proposed rule are included in the September 2000 Addendum to Risk 
Assessment Background Document for the Chlorinated Aliphatics Listing 
Determination. This document is located in the docket for today's final 
rule.

IV. What Proposed Listing Determinations Led to Today's Final Rule?

    In the August 25, 1999 proposed rule (64 FR 46476), EPA proposed to 
list three wastes generated by the chlorinated aliphatics production 
industry as hazardous wastes under RCRA. The wastes the Agency proposed 
to list as hazardous included chlorinated aliphatics manufacturing 
process wastewaters, wastewater treatment sludges generated from the 
treatment of wastewaters from the production of ethylene dichloride 
and/or vinyl chloride monomer (EDC/VCM), and wastewater treatment 
sludges from the treatment of wastewaters from the production of vinyl 
chloride monomer using mercuric chloride catalyst in an acetylene-based 
process (VCM-A). EPA proposed a conditional listing approach for EDC/
VCM wastewater treatment sludges, based upon available information 
regarding the management of these sludges and the results of the 
Agency's risk assessment.
    In connection with the proposed listings, EPA proposed to amend 
Appendix VIII of 40 CFR Part 261 to add two constituents, 
octachlorodibenzo-p-dioxin (OCDD) and octachlorodibenzofuran (OCDF). 
These constituents are found in chlorinated aliphatic wastewaters and 
in EDC/VCM wastewater treatment sludges.
    In the proposed rule, the Agency also proposed not to list as 
hazardous wastewater treatment sludges generated from the treatment of 
wastewaters from the production of methyl chloride and the production 
of allyl chloride. In addition, the Agency proposed not to list process 
wastewaters from the production of vinyl chloride monomer using 
mercuric chloride catalyst in an acetylene-based process.
    The Agency proposed to add to the list of CERCLA hazardous 
substances those wastes that were proposed to be listed as hazardous. 
EPA also proposed adjusted Reportable Quantities (RQs) for each waste.

A. What Was the Proposed Listing Determination for Chlorinated 
Aliphatic Wastewaters?

    As explained in Section III.A.1. of the proposed rule (64 FR 
46479), the Agency segregated wastewaters from the chlorinated 
aliphatics industry into two waste groupings. Based upon current waste 
management practices, we grouped all chlorinated aliphatic wastewaters, 
except for those wastewaters generated from the production of vinyl 
chloride monomer using mercuric chloride catalyst in an acetylene-based 
process, into a single waste category for the listing determination 
investigation. We decided to study these wastewaters collectively 
because most chlorinated aliphatic manufacturers commingle wastewaters 
generated by individual processes prior to treating the wastewaters in 
a common wastewater treatment system. In addition, many process 
wastewaters generated from the production of chlorinated aliphatic 
hydrocarbons contain similar constituents of concern.
    EPA proposed to list as hazardous process wastewaters generated 
from the production of chlorinated aliphatic hydrocarbons (other than 
those wastewaters generated from the production of vinyl chloride 
monomer using mercuric chloride catalyst in an acetylene-based 
process). Results of the risk assessment conducted in support of the 
proposed rule, indicated that the wastewaters met the criteria set out 
at 40 CFR 261.11(a)(3) for listing a waste as hazardous. Risk 
assessment results identified risks of concern associated with air 
releases of dioxins from wastewater treatment systems using aerated 
biological treatment in open tanks.
    EPA proposed not to list as hazardous process wastewaters generated 
from the production of vinyl chloride monomer using mercuric chloride 
catalyst in an acetylene-based process (VCM-A wastewaters). EPA 
proposed not to list this waste as hazardous due to the fact that the 
wastewater exhibits the toxicity characteristic for both mercury and 
vinyl chloride. Therefore, the wastewater already is defined as 
hazardous waste. In addition, any risks associated with the management 
and disposal not addressed by RCRA (i.e., direct discharge) of the 
wastewaters are addressed by other environmental regulations. With 
respect to the discharge of this wastewater, the facility treats and 
discharges the wastewater in compliance with the conditions of a NPDES 
permit. Regarding any air emissions of vinyl chloride from these 
wastewaters, vinyl chloride is a hazardous air pollutant, therefore the 
facility is subject to the National Emissions Standards for Hazardous 
Air Pollutants (NESHAP) requirements specific to vinyl chloride 
emissions (40 CFR 61.65), as well as the Hazardous

[[Page 67072]]

Organic NESHAP for the synthetic and organic chemical manufacturing 
industry sector (40 CFR Part 63, subpart G)(59 FR 19468, April 22, 
1994). For these reasons, the Agency proposed not to list VCM-A 
wastewaters as hazardous waste.

B. What Were the Proposed Listing Determinations for Wastewater 
Treatment Sludges?

1. EDC/VCM Wastewater Treatment Sludges
    EPA proposed to list as hazardous sludges generated from treating 
wastewaters from the production of ethylene dichloride (EDC) and/or 
vinyl chloride monomer (VCM). The Agency proposed to list this waste 
due to the fact that the Agency identified risks of concern associated 
with the management of this waste in a land treatment unit. Our risk 
assessment identified dioxin and arsenic as contaminants of concern, 
and found that high-end cancer risk to the farmer receptor from dioxin 
was 2E-04. The dioxin risks are associated with airborne releases and 
subsequent deposition and food chain contamination from dioxin. Surface 
erosion due to runoff also contributes to risk from dioxin. The risk 
assessment results for the land treatment unit scenario indicated a 
risk level above EPA's levels of concern for dioxin.
    The risk assessment for EDC/VCM wastewater treatment sludges also 
included modeling a landfill management scenario. Our risk assessment 
showed no significant risk from dioxin, and only marginal risk from 
arsenic associated with the groundwater pathway. Based upon the 
Agency's findings that EDC/VCM wastewater treatment sludges pose 
significant risks when managed in land treatment units but do not pose 
significant risks when managed in landfills, the Agency proposed a 
``contingent management listing'' for this waste. EPA proposed to list 
EDC/VCM wastewater treatment sludges as hazardous, unless the sludges 
are managed in landfills.
    As explained in the proposal, the Agency believes that allowing the 
waste to continue to be managed under a low risk management scenario 
(i.e., non-hazardous waste landfilling) outside of the subtitle C 
system achieves protection of human health and the environment, and 
that little additional benefit will be gained by requiring that all 
EDC/VCM wastewater treatment sludges be managed in accordance with RCRA 
subtitle C management standards. Given the Agency's finding that no 
significant risks are posed from managing EDC/VCM wastewater treatment 
sludges in a landfill, the Agency sees no reason to include sludges 
managed in this manner in the scope of the hazardous waste listing. 
Additionally (and after consideration of the predicted risk 
differential between land treatment and landfilling), because only one 
facility identified in the RCRA 3007 Survey employs land treatment for 
these wastes, this practice is somewhat anomalous compared with land 
disposal. The Agency proposed that it does not make sense to apply a 
traditional listing approach (i.e., list all wastes regardless of 
management practice) based upon a practice occurring at one facility, 
especially if a more tailored listing can prevent this risk.
2. VCM-A Wastewater Treatment Sludges
    EPA proposed to list as hazardous wastewater treatment sludges from 
the production of vinyl chloride monomer using mercuric chloride 
catalyst in an acetylene-based process (VCM-A). EPA proposed to list 
this waste as hazardous based upon the fact that it exhibited the 
toxicity characteristic for mercury when sampled by the Agency and 
based upon the Agency's assessment of potential risks from this waste, 
given its high mercury content and given the uncertainties associated 
with the disposal of untreated wastes of potential high toxicity in 
lined landfills.
3. Methyl Chloride Wastewater Treatment Sludges
    EPA proposed not to list as hazardous sludges from the treatment of 
wastewaters generated from methyl chloride production processes. The 
results of our risk assessment indicated that this waste does not pose 
a substantial present or potential hazard to human health or the 
environment. As explained in the proposal, EPA identified only one 
facility that generates sludges from the treatment of wastewaters from 
the production of methyl chloride and does not currently manage the 
waste as hazardous. This facility generates less than 800 metric tons 
of this sludge each year and disposes of the sludge in an on-site 
landfill along with other wastes from the facility. The landfill is 
lined and has a leachate collection system. The Agency analyzed 
potential risks from methyl chloride wastewater treatment sludge by 
modeling non-groundwater pathways and conducting a screening analysis 
for groundwater pathway risk. The Agency concluded that no significant 
risks are posed by the management of methyl chloride sludges in an on-
site landfill.
4. Allyl Chloride Wastewater Treatment Sludges
    EPA proposed not to list as hazardous sludges generated from 
treating wastewaters associated with the manufacture of allyl chloride. 
The Agency identified no risks of concern associated with the current 
management of the waste.
    Only one facility generates wastewater treatment sludge from the 
production of allyl chloride, and this facility does not currently 
manage the sludge as hazardous waste. The sludge is generated from the 
treatment of commingled wastewaters managed at the facility's 
centralized wastewater treatment system. This wastewater treatment 
system is a non-dedicated system in that wastewaters from the 
facility's multiple production processes are discharged to the single 
system for combined treatment. Wastewaters from the production of allyl 
chloride contribute less than two percent to the system's total sludge 
loading. The sludge generated from the facility's wastewater treatment 
system is incinerated on site in a non-hazardous waste incinerator.
    TCLP analyses of the sludge conducted by EPA indicated the presence 
of no TCLP constituents above regulatory levels. As explained in the 
proposal, the Agency does not anticipate any significant risk from the 
incineration of allyl chloride wastewater treatment sludge in a non-
hazardous waste incinerator, since both the total arsenic level and the 
dioxin level detected in the sludge are well within typical soil 
background levels for these constituents.

C. Which Constituents Did EPA Propose To Add to Appendix VIII of 40 CFR 
Part 261?

    EPA proposed to add two constituents, octachlorodibenzo-p-dioxin 
(OCDD) and octachlorodibenzofuran (OCDF) to the list of hazardous 
constituents at 40 CFR part 261, Appendix VIII. These two constituents 
of concern are present in the EDC/VCM wastewater treatment sludges and 
the chlorinated aliphatic wastewaters that the Agency proposed to list 
as hazardous. OCDD and OCDF are members of the large family of 
polychlorinated dioxins and furans. The Agency proposed to add these 
two dioxin congeners to Appendix VIII of 40 CFR part 261 because they 
are constituents of concern in the wastes proposed to be listed as 
hazardous, studies showed that OCDD and OCDF

[[Page 67073]]

have toxic effects and are therefore hazardous, and EPA also noted that 
OCDD and OCDF are the only congeners that make up 2,3,7,8-
tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD or ``TCDD'') toxic 
equivalence (TEQ) that are not currently listed in Appendix VIII.

D. What Were the Proposed Treatment Standards Under RCRA's Land 
Disposal Restrictions Standards?

    In the proposal, EPA proposed to apply existing universal treatment 
standards (UTS) to the regulated hazardous constituents of concern in 
the wastes that were proposed to be listed as K173 (chlorinated 
aliphatic wastewaters) and K174 (EDC/VCM wastewater treatment sludges). 
For K175 (VCM-A wastewater treatment sludges), EPA proposed a metals 
recovery requirement, roasting and retorting, as the treatment 
standard. Since treatment residuals would exist after mercury recovery, 
EPA proposed the residuals meet existing UTS prior to land disposal. 
Information available to the Agency at the time of the proposal 
indicated that each of the wastes proposed to be listed as hazardous, 
as well as the treatment residuals, could be managed in existing 
treatment and reclamation units that routinely manage similar or as-
difficult-to-treat hazardous wastes that currently are prohibited from 
land disposal. The BDAT background document provided detailed 
information on EPA's rationale for proposing to apply UTS to the wastes 
and for proposing a treatment standard of metals recovery to K175.
    In the case of hazardous debris contaminated with proposed K173, 
K174 and K175, EPA proposed that the provisions in 40 CFR 268.45 apply 
to the treatment and disposal of hazardous debris. Hazardous debris 
treated in accordance with the provisions of 40 CFR 268.45 may be 
allowed for land disposal in a hazardous waste disposal facility. As a 
result, debris contaminated with proposed K173, K174, and K175 would be 
required to be treated prior to land disposal, using specific debris 
treatment technologies such as extraction, destruction, or 
immobilization. Residuals generated from the treatment of contaminated 
debris would have to meet the applicable UTS limits proposed for K173, 
K174, and K175.
    In the case of proposed K175, EPA proposed an alternative treatment 
standard. The alternative standard proposed was to subject K175 to a 
numerical concentration limit of 0.025 mg/L TCLP mercury. Under the 
alternative proposal, K175 could be land disposed if a standard of 
0.025 mg/L TCLP mercury is achieved using any technology other than 
impermissible dilution.
    In the proposal, the Agency explained that the solubility of the 
mercury in K175 (in the form of mercuric sulfide) varies as a function 
of pH. In fact, above pH 6.0 the presence of sulfide complexes results 
in significantly increased solubility. Therefore, controlled treatment 
and disposal pH conditions were proposed to avoid mobilization of the 
mercury in the waste. To insure operational stability of the treatment 
process and proper long-term disposal, EPA proposed two conditions as 
part of the LDR treatment standards. First, the waste would have to be 
treated to (or otherwise be generated to meet) a pH of 6.0 or below. 
Second, EPA proposed that if K175 were to be co-disposed in a landfill 
with other wastes, co-disposal would be restricted to wastes with 
similar pH (i.e., pH not greater than 6.0). EPA proposed that disposal 
facilities be required to certify and maintain operating records 
demonstrating compliance with this disposal condition.
    EPA also proposed to add the numerical standards derived for the 
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8-
heptachlorodibenzofuran;, 1,2,3,4,7,8,9-heptachlorodibenzofuran; 
1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD); and 1,2,3,4,6,7,8,9-
octachlorodibenzofuran (OCDF) to the Table of Universal Treatment 
Standards (UTS) at 40 CFR 268.48. As explained in the proposal, these 
constituents have been shown to have the potential to cause significant 
risks to human health or the environment and their presence in wastes 
should be mitigated to avoid such potential risks. EPA proposed that 
all characteristic wastes which have these constituents as underlying 
hazardous constituents above the UTS be required to be treated to UTS 
levels for those constituents before land disposal.
    Furthermore, EPA proposed that the constituents 1,2,3,4,6,7,8-
heptachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8-heptachlorodibenzofuran; 
1,2,3,4,7,8,9-heptachlorodibenzofuran; OCDD; and OCDF be added to the 
list of regulated constituents in hazardous waste F039 multisource 
leachate. F039 applies to multiple listed hazardous waste landfill 
leachates in lieu of the original waste codes, and F039 wastes are 
subject to all numerical treatment standards applicable to all listed 
wastes. To maintain the regulatory implementation benefits of having 
one waste code for multisource leachate, the treatment standards for 
F039 must be updated to include the constituents of newly listed 
wastes.

E. What Risk Assessment Approach Was Used for the Proposed Rule?

    EPA conducted human health risk analyses for chlorinated aliphatics 
wastewaters, EDC/VCM wastewater treatment sludges and methyl chloride 
wastewater treatment sludges that provided estimates of the incremental 
human health risks resulting from exposure to contaminants detected in 
these wastes. The incremental human health risks were expressed as 
estimates of excess lifetime cancer risk for carcinogenic (cancer-
causing) contaminants and hazard quotients (HQs) for those contaminants 
that produce noncancer health effects.
    EPA used two different methods of analysis to estimate risks. These 
methods are called ``deterministic risk analysis'' and ``probabilistic 
risk analysis.'' A deterministic risk analysis produces a point 
estimate of risk or hazard for each receptor based on using a single 
value for each parameter in the analysis. A probabilistic analysis 
calculates risk or hazard by allowing some of the parameters to have 
more than one value, consequently producing a distribution of risk or 
hazard for each receptor.
    EPA conducted both ``central tendency'' and ``high end'' 
deterministic risk assessments to attempt to quantify the cancer risk 
or non-cancer hazard for the typical receptor in the population (the 
central tendency risk) and the risk or hazard for individuals in small, 
but definable ``high end'' segments of the population (the high end 
risk). In the case of the central tendency deterministic risk analyses, 
we set all parameters at their central tendency values. For the 
chlorinated aliphatics risk assessments, the central tendency values 
generally were either mean (average) or 50th percentile (median) 
values.
    We used high end deterministic risk analysis to predict the risks 
and hazards for those individuals exposed at the upper range of the 
distribution of exposures. EPA's Guidance For Risk Characterization 
(EPA 1995) \3\ advises that ``conceptually, high end exposure means 
exposure above about the 90th percentile of the population 
distribution, but not higher than the individual in the population who 
has the highest exposure,'' and recommends that ``* * * the assessor 
should approach estimating high end by

[[Page 67074]]

identifying the most sensitive variables and using high end values for 
a subset of these variables, leaving others at their central values.'' 
For the chlorinated aliphatics high end deterministic risk analyses, 
EPA set two parameters at their high end values (generally 90th 
percentile values), and set all other parameters at their central 
tendency values. We used a ``sensitivity analysis'' to identify the two 
parameters that we set at high end.
---------------------------------------------------------------------------

    \3\ EPA. 1995. Guidance for Risk Characterization. U.S. 
Environmental Protection Agency Science Policy Council. February.
---------------------------------------------------------------------------

    EPA used probabilistic risk assessment to support the results of 
the deterministic risk analyses and to allow us to quantify individual 
risk at selected percentiles of the risk distribution (for example, 
50th percentile, 90th percentile, 95th percentile). EPA conducted 
probabilistic risk analyses for those combinations of receptor, 
contaminant, and pathway for which risk or hazard estimated using a 
high end deterministic analysis exceeded the following criteria: a 
cancer risk of 1 x 10<SUP>-6</SUP> or a hazard quotient of 1. The Risk 
Assessment Technical Background Document for the Chlorinated Aliphatics 
Listing Determination describes the input parameters used in the 
probabilistic analysis. In the probabilistic analysis, risk was 
approximated through repetitive calculation of the fate and transport 
and exposure equations and models using input parameters randomly 
selected from the Probability Density Functions (PDFs). The result of 
the probabilistic analysis is a distribution of the risks or hazards 
for each of the receptors.
    The human health risk assessments that EPA conducted to support the 
chlorinated aliphatics listing determination included five primary 
tasks: (1) Establishing that there are constituents in the wastes that 
are of concern to the Agency and that warrant analysis to determine 
their risk to human health; (2) establishing a scenario under which 
contaminants are released from a waste management unit and subsequently 
are transported in the environment to a human receptor; (3) estimating 
the concentrations of contaminants to which the receptor might be 
exposed; (4) quantifying the receptor's exposure to contaminants and 
the contaminants' toxicity to the receptor; and (5) describing the 
receptor's predicted risk. The preamble to proposed rule provided a 
detailed discussion of how EPA completed each of these tasks for the 
risk assessments conducted to support the chlorinated aliphatics 
listing determination (see 64 FR 46483).

V. What Changes Were Made to the Proposed Rule?

    As a result of comments and additional information provided to the 
Agency in response to the proposed rule, we made certain modifications 
to the risk modeling assumptions used in the risk assessment for the 
proposed rule. Changes made to the risk analysis resulted in changes in 
our risk assessment results. These changes subsequently caused us to 
re-evaluate, and in some instances change, our proposed listing 
determinations. These changes and the consequent scope of today's final 
action are described below. Detailed reasoning behind these changes and 
a summary of each of our final listing determinations is provided in 
Section VI.

A. Listing Determination for Chlorinated Aliphatic Wastewaters

    In response to comments and information provided by commenters in 
response to the proposed rule, the Agency examined the record and 
reconsidered the risk assessment and proposed listing determination for 
chlorinated aliphatic wastewaters. Commenters to the proposed rule 
provided detailed comments on the risk assessment approach used to 
evaluate the potential risks from the management of chlorinated 
aliphatic wastewaters in aerated biological treatment tanks. These 
comments generally fell into one of six topic areas: concern about the 
waste management scenarios EPA evaluated; concern about the exposure 
scenarios EPA evaluated; EPA's methods for calculating exposure point 
concentrations; the way that EPA estimated exposure; EPA's assessment 
of contaminant toxicity; and EPA's characterization of estimated risks. 
To fully respond to critical issues raised by commenters, EPA decided 
to make modifications to some modeling assumptions and data inputs used 
in the risk assessment for the proposed rule. Modifications were made 
to fully consider the potential impacts of those issues raised by 
commenters that the Agency found to have merit. In addition, we 
evaluated the merits of other suggestions provided by commenters, and 
found these to be of no importance to the listing determination, or we 
disagreed with the suggested changes. Specifically, we agreed with 
commenters who pointed out that the intake rates that we used to 
calculate exposure to beef should have accounted for the mass of beef 
that is lost during cooking and post-cooking activities (for example, 
dripping and volatile losses, bones, excess fat, scraps, and juices). 
We also adjusted our analysis to reflect the variability of dioxin 
concentrations in air over an area that would be more consistent with 
the area of a pasture where cattle graze. In addition we were convinced 
by commenters that our modeling assumptions should have accounted for 
the removal of wastewater solids prior to wastewaters entering aerated 
biological treatment tanks.
    After we accounted for these modifications, our adjusted risk 
assessment results indicated that the management of chlorinated 
aliphatic wastewaters in aerated biological treatment tanks do not pose 
substantial risks to human health and the environment. The Agency has 
concluded that available information provides sufficient basis to 
determine that chlorinated aliphatic wastewaters should not be listed 
as hazardous waste. A more detailed discussion of the issues raised by 
public commenters and the modifications made to our risk assessment 
results to account for some of these issues is provided in Section VI 
below.
    The final listing determination for chlorinated aliphatic 
wastewaters is based upon EPA's consideration and review of public 
comments submitted in response to the proposed listing determination, 
and other relevant information available to the Agency and in the 
rulemaking record. The final determination is based on the Agency's 
evaluation as to whether the waste meets the criteria in 40 CFR 
261.11(a)(3) for listing wastes as hazardous. We have assessed and 
considered the factors contained in these criteria primarily by 
incorporating them as elements in the revised risk assessment, which is 
based on the methodology described in the preamble to the proposed rule 
and subsequent modifications described in this preamble and the support 
documents in the rulemaking record. EPA bases its final listing 
determinations on the entire rulemaking record, including applicable 
sections of the preamble to the proposed rule, analyses and background 
documents developed for the proposed rule, the Agency's responses to 
the comments on significant issues raised in the preamble to the 
proposal, and all other relevant information available to the Agency.

B. Modification of Wastewater Treatment Unit Exemption and Application 
of Subpart CC Requirements for Tanks Managing Chlorinated Aliphatic 
Wastewaters

    Because we are not finalizing the listing for chlorinated aliphatic 
wastewaters as proposed, the proposed amendments to regulations for 
tanks

[[Page 67075]]

managing chlorinated aliphatic wastewaters are not necessary and are 
not being finalized in today's rule. This includes the proposed 
amendments to the wastewater treatment unit exemption in 40 CFR 264.1 
and 265.1, as well as the proposed amendments to the 40 CFR parts 264 
and 265 subpart CC requirements for implementing the tank cover 
requirements and the waste sampling and analysis requirements.

C. Landfill Leachate Derived From Previously Disposed VCM-A Wastewater 
Treatment Sludges

    In the proposal, EPA proposed amending the existing exemption from 
the definition of hazardous waste (40 CFR 261.4(b)(15)) to include 
leachate derived from non-hazardous waste landfills that previously 
accepted newly-listed VCM-A wastewater treatment sludges (K175). The 
Agency would have temporarily deferred the application of the new waste 
code to such leachate to avoid disruption of ongoing leachate 
management activities during a time period in which the Agency would 
decide how to integrate RCRA and CWA regulations governing the 
management of landfill leachate.
    The Agency proposed the deferral because information available to 
EPA at the time of the proposal indicated that VCM-A wastewater 
treatment sludges may have been managed previously in non-hazardous 
waste landfills. However, information provided by the one generator of 
this waste in response to the proposed rule, indicates that since 1985 
these sludges have not been disposed in a non-hazardous waste landfill. 
The generator has assured EPA that the VCM-A sludges always have been 
disposed in subtitle C landfills. Based upon this information, the 
Agency sees no need to finalize the proposed deferral for landfill 
leachate at this time.
    The Agency is not finalizing (but is deferring a final decision on) 
the proposed temporary deferral for applying the new K175 waste code to 
leachate from non-hazardous waste landfills that previously accepted 
waste that meets the K175 listing description. Should the Agency 
receive information at a later date indicating that one or more non-
hazardous waste landfills did accept this waste prior to the effective 
date of today's rulemaking, we may re-consider our decision not to 
finalize the proposed deferral.

VI. What is the Rationale for Today's Final Rule, and What Are 
EPA's Responses to the Comments?

A. Chlorinated Aliphatic Wastewaters (Other Than Wastewaters From the 
Production of VCM-A Using Mercuric Chloride Catalyst in an Acetylene-
Based Process)

    The sections that follow provide a discussion of the comments 
received by the Agency in response to the EPA's proposal to list 
chlorinated aliphatic wastewaters as hazardous waste, the Agency's 
response to these comments, and the impact of the comments on the 
Agency's evaluation of risk and the final listing determination.
1. Summary of the Agency's Listing Decision for Chlorinated Aliphatic 
Wastewaters
    EPA is issuing a final decision not to list wastewaters from 
chlorinated aliphatic production processes. The Agency has determined 
that these wastewaters do not pose substantial risks when managed in 
aerated biological treatment tanks.
    The Agency proposed to list chlorinated aliphatic wastewaters based 
upon an estimated high-end deterministic risk from dioxin for an adult 
farmer of 2E-05. As explained in more detail below, as a result of our 
analysis of information provided by commenters, we determined that it 
was appropriate to adjust our risk assessment results to account for 
certain factors not addressed in the risk assessment for the proposed 
rule. These factors include accounting for cooking and post-cooking 
losses for beef, assuming a more realistic size of the pasture (or 
field) supporting cattle that are indirectly exposed to dioxin 
emissions, and accounting for the potential for solids removal prior to 
wastewater treatment in aerated biological treatment tanks. After 
calculating these adjustments to our proposed risk assessment results, 
EPA found that they would reduce our high end deterministic risk 
estimate for the adult farmer. Specifically, accounting for cooking and 
post-cooking losses for beef would modify the risk estimate by a factor 
of 0.78, and accounting for a more reasonable pasture size would modify 
the risk estimate by a factor of approximately 0.50, resulting in an 
overall risk estimate of 7E-06. Accounting for solids removal from the 
wastewater prior to biological treatment could modify the overall risk 
estimate by an additional factor of 0.67 to 0.94, that is, could result 
in a risk estimate as low as 4E-06.
    Given the Agency's finding, we are not finalizing the proposed 
amendment to the existing wastewater treatment unit exemption (40 CFR 
264.1(g)(6) and 265.1(c)(10)). In addition, the Agency is not 
finalizing the proposed requirement that wastewater treatment units 
used to treat chlorinated aliphatic wastewaters comply with specific 
RCRA air emissions standards.
    Today's decision not to list chlorinated aliphatic wastewaters 
applies to all chlorinated aliphatic wastewaters, including wastewaters 
managed in underground injection control units. As explained further 
below, in the case of chlorinated aliphatic wastewaters managed in 
surface impoundments, although the wastewaters are not listed hazardous 
wastes, sludges derived from EDC/VCM process wastewaters and generated 
in impoundments will meet the scope of the hazardous waste listing for 
EDC/VCM wastewater treatment sludges after the effective date of 
today's rule.
2. Response to Major Comments Received on Proposed Rule for Chlorinated 
Aliphatic Wastewaters
    EPA received comments on a number of issues concerning the data and 
analyses EPA used to arrive at our listing decision for chlorinated 
aliphatic wastewaters. The most significant comments that we received 
may be divided generally into six categories: (1) Comments on EPA's 
waste management assumptions; (2) comments on the exposure scenarios we 
evaluated in our risk assessment; (3) comments on how we calculated 
exposure point concentrations in the risk assessment; (4) comments on 
EPA's exposure assessment; (5) comments on EPA's toxicity assessment 
for dioxin and chloroform; and (6) comments on how we characterized 
risks associated with dioxin and chloroform. These comments, and the 
Agency's responses to these comments, are summarized below. We have 
developed responses to all of the public comments received in response 
to the proposed rule. The verbatim comments and our responses to all 
comments are provided in Response to Public Comments; Final Listing 
Determination for Chlorinated Aliphatics Industry Wastes in the docket 
for today's rule.
a. Waste Management Assumptions
    The majority of chlorinated aliphatic wastewaters is managed in on-
site, tank-based wastewater treatment systems prior to direct discharge 
of the wastewaters in accordance with facility-specific NPDES permits 
or discharge to an off-site POTW. As explained in the

[[Page 67076]]

preamble to the proposed rule, two chlorinated aliphatic production 
facilities manage their wastewaters in underground injection control 
(UIC) wells. In addition, commenters provided information indicating 
that one facility pipes its chlorinated aliphatic wastewaters off-site 
for treatment in a wastewater treatment system that includes biological 
treatment in surface impoundments.

i. Why Did EPA Only Evaluate Air Releases From Tanks?

    One commenter asserted that EPA did not consider releases from 
tanks other than air emissions from treatment tanks managing 
chlorinated aliphatics wastewaters. As the commenter pointed out, EPA 
assumed that the wastewater treatment system tanks are of sufficient 
integrity to prevent releases and that the tanks are equipped with 
overflow and spill controls that will prevent non-air releases of 
wastewaters, even though (as the commenter also points out) no overflow 
and spill controls are required for nonhazardous storage waste tanks, 
including tanks that manage wastewaters subsequently discharged either 
to Publicly Owned Treatment Works (POTWs) or surface waters. The 
commenter states that EPA's failure to consider non-air releases from 
wastewater treatment system tanks, which in the commenter's opinion are 
plausible mismanagement scenarios, violates EPA's criteria for listing 
determinations, which requires an assessment of ``plausible types of 
improper management.''
    When EPA set out to assess risks from managing wastewaters in tank-
based systems, we chose to model only air emissions because we 
determined that this was the greatest potential pathway of exposure for 
constituents from the tank systems (therefore causing the greatest 
potential risk), particularly since we knew from the RCRA Section 3007 
Survey responses that the industry uses aerated biological treatment 
tanks, many of which are uncovered, or open to the atmosphere. In 
addition, survey responses indicated that the tanks are positioned 
aboveground and a majority of them are equipped with secondary 
containment. Therefore, EPA determined that any leaks or catastrophic 
releases from such tanks would be detected relatively quickly and 
corrective measures likely would be implemented prior to a release of 
significant quantity. In addition, these types of releases, if they 
were to occur, are not predictable or routine but rather would be the 
result of inordinate events or accidents such as upset conditions or 
catastrophic failures, which the Agency presumes would not be routine, 
frequent or plausible (mis)management. In sum, we continue to believe 
that air emissions from aerated biological treatment tanks is the 
predominate exposure pathway and that risks resulting from this pathway 
are significantly greater than any risk that may periodically arise 
from spills or leaks.

ii. Why Did EPA Not Evaluate Storage of Wastewater?

    One commenter stated that EPA did not consider other air emissions 
from the storage of chlorinated aliphatic wastewaters prior to placing 
these materials in tanks. The commenter said that such analysis is not 
needed if EPA finalizes a ``standard'' listing mechanism for K173, but 
that EPA must undertake such an analysis if a concentration-based 
listing is adopted. EPA assumes that the commenter is describing 
wastewaters managed in tanks between the point the wastewater is first 
generated until it reaches the headworks of the wastewater treatment 
facility. (This is because under the proposed listing options, 
wastewater would not be tested to determine whether it exceeds the 1 
ng/L dioxin trigger until it enters the first tank in the wastewater 
treatment system.) Although EPA is not finalizing the proposed 
chlorinated aliphatic wastewater listing in today's rule, we note that 
the RCRA Section 3007 questionnaire results indicate that only a few 
facilities manage wastewaters in tanks that are not a part of the 
wastewater treatment train. In all cases where a facility indicated 
having wastewater storage tanks that are not part of the wastewater 
treatment system the facility indicated that the tanks are covered. The 
fact that such tanks are covered would limit the potential for air 
releases. In our risk assessment, we chose to analyze air emissions 
from wastewater treatment tanks because, based upon information 
provided to the Agency in facility responses to the RCRA Section 3007 
questionnaire, such tanks may be used to manage relatively large 
quantities of chlorinated aliphatic wastewaters, and often are not 
covered and are aerated. In view of our revised risk estimate for 
potential releases from these tanks, any potential risks from the 
covered, upstream tanks would not be substantial.
b. Exposure Scenarios Evaluated in EPA's Risk Assessment
    EPA received comments from a number of parties that challenged 
EPA's basic methodology for establishing the exposure scenarios 
evaluated in the chlorinated aliphatic wastewater risk analyses. The 
commenters believed that EPA should have used a site (or facility)-
specific approach for conducting the risk assessments. The commenters 
raised general concerns regarding EPA's approach, and also challenged 
specific aspects of EPA's analysis. These two issues are discussed 
separately below.

i. Evaluating Site-Specific Exposure Scenarios--General Comments

    Commenters on the proposed rule stated that EPA should have used a 
site-specific approach to assessing risks from management of 
chlorinated aliphatic wastewaters, and presented general arguments why 
EPA should adopt a site-specific approach. Specifically, the commenters 
believed that EPA should have conducted the chlorinated aliphatics risk 
assessments using an approach similar to that used in the final 
combustion Maximum Achievable Control Technology (MACT) rulemaking 
under the Clean Air Act. For that rulemaking, EPA used facility-
specific data in determining risks (64 FR 52828, September 30, 1999). 
The commenters contended that as a result of the public and peer review 
comments received on the risk assessment in the proposed combustion 
MACT, EPA modified its risk analysis to focus on the entire population 
of persons that are exposed to facility emissions rather than persons 
living on a few individual farms and residences. Some commenters 
recommended that EPA adopt a regulatory approach allowing generators 
themselves to determine the site-specific risk (using site-specific 
distances to the nearest receptor, wastewater concentrations, etc.) and 
subsequently the regulatory status of the wastes addressed under EPA's 
proposed rule.
    Similarly, some commenters expressed general concern over EPA's use 
of ``assumptions,'' rather than site-specific data, in the risk 
assessment. The commenters believe that if EPA were challenged with 
evaluating hundreds of scenarios across the entire nation, then the use 
of assumptions from statistical sampling of databases or best judgment 
could be better understood. However, with the limited number of 
facilities and waste management units involved in this proposed rule 
making (23), the commenters believe that EPA could have spent more time 
gathering real, site-specific data to reduce the uncertainty in risk 
modeling. The commenters pointed to the limited set of waste sample 
data, the lack of site-specific information regarding waste

[[Page 67077]]

management units for the chlorinated aliphatics industry, and the 
regional databases used to obtain the parameter values necessary to 
model containment fate and transport as data elements that should have 
been more site-specific.
    EPA acknowledges that we did not conduct site-specific risk 
assessments to support the chlorinated aliphatics wastewater listing 
determination, but rather evaluated plausible exposure scenarios that 
are based on a combination of national data, regional data, and data 
collected from the facilities themselves. In some cases we believe that 
only one specific management practice is plausible, and existing 
locations for that practice are not likely to change. For example, 
certain economic or natural resource factors may restrict the nature of 
wastes in terms of their constituent concentrations, their quantities, 
or the ways in which the wastes are managed. This generally is not the 
case for the chlorinated aliphatic chemicals production industry. EPA 
described the continued and projected growth of the chlorinated 
aliphatic chemicals industry in the Economics Background Document for 
the proposed rule, and documented evidence of the industry's 
historically dynamic nature (USEPA, 1999b).\4\ Nevertheless, there is 
considerable uncertainty in predicting a relationship between industry 
growth and waste generation and management. We cannot foresee the 
effects that potential (and possibly simultaneous) changes in 
technology, facility expansion practices (that is, increasing 
production capacity at existing facilities versus building new 
facilities), and waste minimization activities may have on waste 
generation and management. We also cannot predict whether there will be 
an increase in global marketshare of off-shore (non-U.S.) chlorinated 
aliphatic chemical production. Consequently, we based our evaluation on 
general information describing current chlorinated aliphatic waste 
management and exposure scenarios. This is not to say we based the 
modeling entirely on assumptions or hypothetical values. Rather, we 
used the combination of site-specific information, and other types of 
information that we thought would effectively capture what we expected 
would remain relatively consistent for one industry while accounting 
for likely future variability. For example, we surveyed the potentially 
affected facilities to identify existing waste management practices, 
and then assumed that those same management practices will continue to 
be used by the industry in the future. Additionally, we identified the 
location of chlorinated aliphatics facilities, and assumed that in the 
future, facilities might locate in the same general geographic regions 
(for example, regions with the same meteorological conditions), and in 
areas with the same general land use patterns (for example, 
agricultural areas). Similarly, we assumed that, although the exact 
numbers and locations of facilities may change, the quantities of the 
wastes, as well as the types and concentrations of contaminants in the 
wastes, will be generally the same over the near to long term. Again, 
the specific mix of site-specific and more general information will 
vary from one listing rule to another and potentially from one waste to 
another within a given rulemaking, depending on how dynamic EPA expects 
future waste management practices to be.
---------------------------------------------------------------------------

    \4\ USEPA. 1999b. Economics Background Document, Proposal by the 
USEPA To List Wastewaters and Wastewater Sludges from Chlorinated 
Aliphatic Chemical Manufacturing Plants, as RCRA Hazardous 
Wastecodes K173, K174, K175: Industry Profile and Estimation of 
Industry Regulatory Compliance Costs. Office of Solid Waste. 30 
July.
---------------------------------------------------------------------------

    By evaluating the data using the probabilistic and two-high end 
deterministic approaches discussed in the preamble to the proposed rule 
(64 FR 46483), EPA endeavors to avoid regulating wastes based on 
exposure scenarios that are unrealistic (that is, based on too many 
protective [high end] assumptions). However, in the case of the 
chlorinated aliphatics industry, we did not feel our information 
justified an assumption that there would always exist exactly 23 
chlorinated aliphatics facilities at 23 specific locations that 
continue to generate the same quantities of wastewaters, with the same 
types and concentrations of contaminants, that are managed in aerated 
biological wastewater treatment tanks under a static set of operating 
conditions. Historically, EPA's policy under the listing program has 
been to conduct national-scale evaluations that consider the general 
characteristics of the wastes under review, and allow facilities to 
petition the Agency to have their wastes ``delisted'' if they believe 
that the wastes do not meet the criteria for hazardous waste listing.
    EPA also notes that, in view of the Congressional mandate to make 
final listing determinations on seventeen waste categories in fifteen 
months, Congress does not appear to have anticipated that each of these 
listings efforts would involve a detailed, facility-by-facility 
analysis (RCRA 3001(e)).

ii. Evaluating Site-Specific Exposure Scenarios--Specific Comments

    Commenters on the proposed rule raised objections to three specific 
aspects of the exposure scenarios on which EPA's risk assessments for 
wastewaters are based. The following discussion describes those 
comments and EPA's response.
    A number of commenters noted that EPA's high end human health risk 
analyses are based on dioxin exposures to farmers who live at the same 
location within 300 meters (0.18 miles) of a chlorinated aliphatics 
facility for 48.3 years or more, who raise fruits, exposed vegetables, 
root vegetables, beef cattle, and dairy cattle within this 0.18 mile 
range, and whose diet consists of approximately 42 percent home-grown 
exposed vegetables, 17 percent home-grown root vegetables, 33 percent 
home-grown fruits, 49 percent home-produced beef, and 25 percent home-
produced dairy.\5\ Some commenters questioned why their operations 
would be regulated under EPA's proposed rule, contending that it does 
not make sense to regulate a waste stream or to require controls and 
expenditures to protect a type of individual that will not be present. 
Many of the commenters claimed that they were not aware of any farmers 
living within 0.18 miles of a chlorinated aliphatics facility that met 
all these criteria, and found it difficult to believe that such a 
farmer would grow fruit trees and vegetables, and raise beef and dairy 
cattle, all on the same plot of land. Moreover, the commenters 
maintained that in the south Texas area where several EDC/VCM 
manufacturing facilities are located, dairy cattle production is non-
existent due to the climate. One commenter that represents facilities 
in Louisiana stated that of the nine companies that they represent, 
only at two facilities is there farmland within 300 meters of the 
facility boundary (not 300 meters from the wastewater treatment tanks). 
The commenters stated that beef cattle are raised on one of the two 
farms, and that beef cattle and sugar cane are raised on the other 
farm.
---------------------------------------------------------------------------

    \5\ The public comments suggest that the commenters believe that 
EPA assumed that the farmer consumes 42 percent of the exposed 
vegetables, 17 percent of the root vegetables, 33 percent of the 
fruits, 49 percent of the beef, and 25 percent of the dairy products 
that the farmer grows. EPA assumes that the commenters meant to take 
issue with the EPA's assumption that 42 percent of the exposed 
vegetables, 17 percent of the root vegetables, 33 percent of the 
fruits, 49 percent of the beef, and 25 percent of the dairy products 
that the farmer consumes are home-produced (i.e., the rest of the 
farmer's diet would be obtained from other sources, such as a 
grocery store).

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

[[Page 67078]]

    In response, EPA notes that exposure duration was one of the two 
high end parameters in our proposed high end dioxin risk estimate for 
the farmer, and that the value of 48.3 years is the 90th percentile 
exposure duration for households in the ``farm'' housing category as 
presented in Table 15-164 of the Exposure Factors Handbook (USEPA, 1997 
\6\). Moreover, the information provided in the public comments 
confirms that an exposure scenario in which a farmer raises beef cattle 
on a farm located within 300 meters of a chlorinated aliphatics 
facility (and presumably a wastewater treatment tank located near the 
facility boundary) is plausible. Although the commenters clearly 
disagree that a farmer also might produce fruits and vegetables on this 
farm, these concerns are unwarranted. Table 5-3 of the Risk Assessment 
Technical Background Document (USEPA, 1999a) \7\ shows that for the 
adult farmer, 99.3 percent of the high end risk from chlorinated 
aliphatic wastewaters was due to ingestion of beef and dairy products 
and only 0.7 percent was due to ingestion of home grown fruits and 
vegetables. As a result, even though EPA believes it is plausible that 
a subsistence or hobby farmer would raise fruits and vegetables for 
home consumption, the validity of EPA's risk estimate depends almost 
entirely on the validity of our assumption that a farmer might consume 
both beef and dairy products from cattle raised on a farm located in 
the vicinity of a chlorinated aliphatics production facility. To 
evaluate the commenters' concerns regarding dairy cattle production in 
the vicinity of chlorinated aliphatics facilities, EPA referred to 
public data on agricultural production in the regions surrounding 
chlorinated aliphatics production facilities that are available from 
the Agricultural Census of the United States (see reference for http://govinfo.library.orst.edu that is included in the docket for the 
proposed rule). The census data demonstrate that, in fact, of the 23 
chlorinated aliphatic facilities that manage wastewaters, 21 
facilities, including all of the facilities in the south Texas area, 
are located in counties where dairy cattle were reported to have been 
raised in 1997 (all of the facilities are located in counties where 
beef cattle were reported to have been raised in 1997). EPA believes 
that an individual who raises cattle to support a subsistence lifestyle 
might reasonably consume both dairy and beef products from his/her 
cattle.
---------------------------------------------------------------------------

    \6\ U.S. EPA. 1997. Exposure Factors Handbook, Volumes I, II, 
and III. EPA/600/P-95/002Fa, b, c. Office of Research and 
Development, Washington, D.C., August.
    \7\ U.S. EPA. 1999a. Risk Assessment Technical Background 
Document for the Chlorinated Aliphatics Listing Determination. 
Office of Solid Waste. July.
---------------------------------------------------------------------------

    Some commenters also challenged EPA's assumptions regarding the 
percentages of beef and dairy products consumed by the farmer that are 
home produced (that is, assumed to be from a contaminated source). 
Specifically, EPA assumed that 25.4 percent of the dairy products a 
farmer consumes are home produced, and that 48.5 percent of the beef 
products a farmer consumes are home-produced. The commenters asserted 
that the percentages EPA used apply to a relatively small fraction of 
the surveyed population who farm, and as such are overly conservative 
by a factor of 21.2 for dairy,\8\ and a factor of 12.7 for beef,\9\ if 
applied to the general population (USEPA, 1997). The commenters held 
the opinion that the percentages used by EPA overstate the upper end 
homegrown beef and dairy consumption markedly. However, one of the same 
commenters acknowledged that the commenter was unable to confirm 
alternate values that EPA should have used for percentage of beef and 
dairy consumed by the farmer that is home grown. One peer reviewer 
asked where EPA obtained the values for the percentages of food eaten 
by the farmer (EPA provided the source of the values in the preamble to 
the proposed rule), but did not indicate whether he believed the 
percentages were right or wrong.
---------------------------------------------------------------------------

    \8\ The proportion of home-produced dairy consumed by 
``households who farm'' (0.254) divided by the proportion of home-
produced dairy consumed by persons in the general population 
(0.012).
    \9\ The proportion of home-produced beef consumed by 
``households who farm'' (0.485) divided by the proportion of home-
produced beef consumed by persons in the general population (0.038).
---------------------------------------------------------------------------

    EPA's estimates of the portion (percentage or fraction) of a 
farmer's diet that is home-produced are presented in EPA's Exposure 
Factors Handbook (USEPA, 1997), and are based on the U.S. Department of 
Agriculture's 1987-1988 Nationwide Food Consumption Survey (NFCS).\10\ 
We did not use the percentages that reflect the consumption of home-
produced foods by the general population in our risk assessment, as 
suggested by the commenters, because EPA's objective was to evaluate 
risks to farmers, not members of the general population, who consume 
home-produced food items. As one would expect, the data in the Exposure 
Factors Handbook indicate that farm households consume more home-
produced foods than do households in the general population. The 
percentages that correspond to the general population would be applied 
more appropriately to an evaluation of residential receptors.
---------------------------------------------------------------------------

    \10\ The 1987-1988 NFCS data on intake of home-produced foods 
are included for use in the recent (1997) Exposure Factors Handbook 
(U.S.EPA, 1997), which has been reviewed by EPA's Science Advisory 
Board (SAB) as well as numerous other external reviewers.
---------------------------------------------------------------------------

    One commenter claimed that in EPA's Combustion MACT rulemaking, EPA 
indicated that according to USDA information, only 40% of farmers who 
raise beef eat their own beef (64 FR 52998), and that the percentage of 
dairy farmers who consume home grown dairy products is only 40% in the 
Northeast, 20% in the Midwest, lower elsewhere in the country, and 
averages only 13% nationally (64 FR 52998). The commenter also noted 
that in the Combustion MACT rulemaking, EPA acknowledged that 
information on the number of farms that produce more than one food 
commodity (for example, beef and milk) is not available from the U.S. 
Census of Agriculture (64 FR 52828, see 53005-53006), and that in 
determining the risk to commercial farmers under the Combustion MACT 
rule, EPA stated: ``only the primary food commodity produced on the 
farm was assumed to be consumed by farm households (64 FR 52998).
    It appears that the commenter somewhat misrepresented the data from 
the final MACT rule. Specifically, the Federal Register notice to which 
the commenter refers is very clear that while ``[o]nly the primary food 
commodity produced on the farm was assumed to be consumed by farm 
households,'' ``[a] wide variety of foods was assumed to be produced 
and consumed by households engaged in subsistence farming'' (64 FR 
52999). In fact, under the subsistence farmer scenario evaluated for 
the MACT rulemaking, EPA assumed that 100 percent of the food that the 
farmer consumes is home-produced. This assumption clearly results in 
greater exposure than the assumptions used in EPA's analysis of the 
farmer scenario in the chlorinated aliphatics analysis. Moreover, the 
commenter misinterpreted data presented in the MACT rulemaking that 
describe the percentages of households that consume beef and dairy 
products in various parts of the country. The Federal Register notice 
to which the commenters refers states:

    In particular, we re-analyzed data collected by USDA to estimate 
consumption of home-produced foods, such as meat, milk, poultry, 
fish, and eggs. Over half of farm households report consuming home-
produced meats, including nearly 40 percent that report

[[Page 67079]]

consumption of home-produced beef. In the Northeast, nearly 40 
percent of farm households report consuming home-produced dairy 
products, and in the Midwest, nearly 20 percent do. The percentage 
is lower elsewhere, averaging about 13 percent nationally.

The data cited by EPA pertains to the number of all farm households 
that consume home-produced beef and dairy products. The commenters 
incorrectly assumed that the data applied specifically to households 
engaged in raising beef cattle and households engaged in raising dairy 
cows, respectively. EPA expects that the consumption of home-produced 
beef and dairy products would be much greater for households engaged in 
production of these commodities compared to the consumption for all 
farm households.
c. Calculation of Contaminant Concentrations at the Point of Human 
Exposure (Contaminant Fate and Transport Modeling)
    EPA received comments questioning the way that we estimated 
emissions from aerated biological wastewater treatment tanks, and the 
way that we estimated the concentrations of dioxins in beef and dairy 
products. These comments included concerns about how CHEMDAT8 evaluates 
dioxins that are sorbed onto solids in wastewaters, and about how EPA 
estimated the amount of solids influent to aerated biological 
wastewater treatment tanks. Commenters also took issue with the 
Agency's assumptions about the diet of dairy and beef cattle and the 
productivity of the modeled farm. Each of these assumptions 
significantly affects our calculation of contaminant concentrations to 
which human receptors are exposed.

i. EPA Did Not Correctly Consider Sorption of Dioxin Onto Solids and 
Solids Removal From Wastewater

    To evaluate the human health risks posed by dioxins in chlorinated 
aliphatic wastewaters, EPA modeled air emissions from aerated 
biological wastewater treatment tanks. We conducted the emissions 
modeling assuming that the concentrations of dioxins in wastewaters 
flowing to aerated biological treatment tanks were equivalent to the 
concentrations of dioxins in certain wastewater samples we collected. 
For the proposal, we constrained (``capped'') the influent 
concentrations of four congeners in the wastewaters at their aqueous 
solubility concentrations to account for the fact that dioxins are 
strongly hydrophobic and are expected to be sorbed to solids 
preferentially in the wastewater influent, thus are unlikely to exist 
in the dissolved phase in excess of their solubility limits.
    Commenters on the proposed rule expressed a number of concerns 
regarding the way that EPA evaluated the solids fraction of chlorinated 
aliphatics wastewaters. The commenters' primary concern was that EPA 
did not appropriately consider that most dioxins in chlorinated 
aliphatics facility wastewaters will be sorbed onto solids in the 
wastewaters even when the dioxin congener concentrations in wastewaters 
are less than their solubility limits. Certain commenters contended 
that in EDC/VCM production facilities that use fluidized bed 
oxychlorination processes, attrited catalyst fines (small particles 
that are 1 to 20 micrometers in size) that exit the facility process 
via the wastewater treatment system have very high surface area 
(approximately > 50 m2/g) and thus strongly sorb dioxins that are 
present in the wastewaters. The commenters asserted that EPA failed to 
account for the fact that almost all of the dioxins in wastewaters are 
sorbed to solids and are removed in primary clarifiers prior to 
aeration. Moreover, the commenters believed that EPA's model for 
estimating emissions from wastewater treatment tanks (CHEMDAT8) does 
not correctly model sorption. One commenter stated that CHEMDAT8 takes 
into account adsorption onto biomass solids, but claimed that CHEMDAT8 
does not adequately address the fact that most dioxin is already sorbed 
onto solids (and not available for volatilization) when it enters an 
aerated tank. Commenters submitted various analyses and data to 
substantiate their claims, and contended that EPA had overestimated the 
concentration of dioxins available for volatilization by at least an 
order of magnitude.
    Although EPA agrees that the primary removal mechanism of dioxins 
in wastewater treatment tanks will be through the sorption of dioxins 
onto solids (see p. 3-2 of EPA's 1999 Risk Assessment Technical 
Background Document, USEPA 1999a), EPA does not agree with the 
commenters' concerns that CHEMDAT8 fails to correctly account for 
sorption. CHEMDAT8 does in fact model sorption as a reversible, linear, 
equilibrium partitioning process, the same process that the commenters 
believed should be considered to account for the sorption of dioxins 
onto solids in wastewater. CHEMDAT8 is designed to evaluate the 
contaminant loss rates for the competing removal mechanisms of 
volatilization, biodegradation, sorption and hydrolysis based on the 
total contaminant load influent to the system (whether associated with 
the dissolved or solid phase). The contaminant loss rate due to 
sorption is based on the equilibrium solids partitioning coefficient 
and the rate at which solids enter or are generated within the system. 
Thus, in estimating the amount of solids available to sorb dioxins, 
CHEMDAT8 considers total suspended solids (TSS) in the influent stream 
as well as new biomass growth. It does not matter how dioxin is 
partitioned onto solids when the wastewater enters the tank, because 
the model repartitions the dioxins inside the tank according to the 
model's equilibrium partitioning relationship and the relative rates of 
the competing removal mechanisms. Consequently, in our analyses we 
evaluated the total contaminant load in the tank influent, regardless 
of whether the contaminants were associated with the dissolved or solid 
phase. In cases where solids are present in the influent, limiting a 
CHEMDAT8 analysis to dissolved phase wastewater influent concentrations 
might seriously under-represent the total contaminant load to the tank 
and result in greatly underestimating emissions, especially for 
sorptive chemicals like dioxins. Because CHEMDAT8 considers 
partitioning and removal by sorption within the tank, limiting the mass 
of dioxin influent to the system (by limiting the influent 
concentration to the dissolved phase concentration) may result in 
greatly underestimating emissions because only the contaminant mass in 
the dissolved phase would be partitioned in the tank, rather than the 
total contaminant mass associated with the influent's dissolved plus 
solid wastewater phases.
    In contrast, EPA agrees with the commenters concerns that we failed 
to accurately account for the fact that in aerated biological 
wastewater treatment systems, at least some solids removal generally 
will occur between the headworks of the wastewater treatment system and 
the influent to an aerated biological treatment tank (we addressed 
risks from the management of solids separately in this listing 
determination). In the preamble to the proposed rule, EPA specifically 
stated that we selected wastewater data for evaluation that we believed 
represented the concentrations of contaminants in wastewaters at the 
influent (headworks) of treatment systems that are used to manage only 
wastewaters from the production of chlorinated aliphatic chemicals 
(``dedicated'' chlorinated aliphatics wastewater samples; 64 FR 46483). 
In

[[Page 67080]]

retrospect, our assumption that the same data that represent 
contaminant concentrations at the headworks of wastewater treatment 
systems could represent contaminant concentrations at the influent to 
aerated biological wastewater treatment tanks was somewhat flawed. The 
Agency reviewed information previously provided to us in industry 
survey responses and determined that of the eleven facilities that 
employ aerated biological processes to treat their wastewaters, nine 
employ primary clarification or other processes that have the effect of 
removing solids from wastewaters prior to their discharge to aerated 
biological treatment tanks. (One of these nine facilities is the 
facility from which we collected the ``high end'' wastewater sample 
used in the risk analysis that served as the basis for our proposed 
listing decision.) The remaining two facilities perform wastewater 
equalization in tanks prior to aerated biological treatment. One of 
these two facilities also employs wastewater pH adjustment with 
resultant precipitation of metal hydroxides prior to aerated biological 
treatment. Both of these processes are expected to result in at least 
some solids removal from the wastestream. Moreover, EPA does not 
anticipate that treatment of the wastewaters in units such as primary 
clarifiers and equalization basins would result in dioxin air emissions 
greater than those that we originally predicted from aerated biological 
treatment tanks, because primary clarifiers are, by design, quiescent 
units (Metcalf and Eddy, 1991,\11\ p. 472), and we have no information 
that leads us to believe that the equalization tanks in use by the 
facilities are agitated.
---------------------------------------------------------------------------

    \11\ Metcalf & Eddy, Inc. 1991. Wastewater Engineering: 
Treatment, Disposal, and Reuse. Revised by G. Tchobanoglous and F. 
Burton. Irwin McGraw-Hill, Boston. 1334 pp.
---------------------------------------------------------------------------

    To model the aerated biological treatment tanks correctly, that is, 
to determine what the appropriate influent concentration to the 
biological treatment tank should be, would have required that EPA model 
the wastewater treatment train from the point where wastewater enters 
the headworks of the treatment system to the point where the wastewater 
enters the aerated biological tank. Metcalf and Eddy (1991, p. 473) 
state that ``efficiently designed and operated primary sedimentation 
tanks should remove from 50 to 70 percent of the suspended solids * * * 
'' from wastewater. Assuming this level of solids removal from 
chlorinated aliphatics wastewaters prior to biological treatment we 
estimate that the high end deterministic risk estimate for the adult 
farmer reported in the proposal would be reduced by a factor ranging 
from approximately 0.67 (70 percent removal of solids) to 0.94 (50 
percent removal of solids) (USEPA, 2000b).\12\ A complete description 
of our analysis is provided in the Addendum to the 1999 Risk Assessment 
Technical Background Document (USEPA, 2000).
---------------------------------------------------------------------------

    \12\ 12 U.S. EPA. 2000b. Risk Assessment Technical Background 
Document for the Chlorinated Aliphatics Listing Determination, 
Addendum. Office of Solid Waste. September.
---------------------------------------------------------------------------

ii. EPA Incorrectly Evaluated the Contribution of Feed to Dioxin Levels 
in Dairy and Beef

    To support the chlorinated aliphatics wastewater listing 
determination we estimated risks to a farmer who ingests beef and dairy 
products derived from cattle raised on a farmer's pastureland. EPA 
assumed that the beef and dairy cattle consume home-grown forage, 
grain, and silage, and incidentally ingest pasture soil. We assumed 
that beef cattle consume different quantities of the various food items 
(and pasture soil) than do dairy cattle. We also assumed that 100% of 
the cattle's feed is contaminated by releases from the wastes we 
evaluated, that is, that cattle are not provided feed from other 
(uncontaminated) sources.
    The commenters believed that EPA should have considered that a 
cow's consumption of various food sources varies according to the 
animal's life stage and intended use. The commenters contended that 
these considerations influence both a cow's exposure and the potential 
translocation of dioxin to meat or milk. As an example, the commenters 
pointed out that beef cattle may be raised for part of their lives on 
pasture, but typically are raised on grain prior to slaughter. The 
commenters noted that, for instance, the beef cow nurses and pastures 
for approximately 180 days, pastures exclusively for 55 days, and 
subsists on a grain only diet for the final 130 days of its life 
(Stevens and Gerbec, 1988). The commenters asserted that EPA's risk 
assessment should have considered contaminant losses from a beef cow's 
tissue in the time period between the cow's consumption of contaminated 
feed and the cow's slaughter. The commenters also presented alternate 
information that they said could be considered in EPA's evaluation of 
risk. First, EPA assumed that dairy cattle consume 13.2 kg/day of 
forage, 4.1 kg/day of silage, 3 kg/day of grain, and 0.4 kg/day of 
soil, based on data cited by Rice (1994)\13\. In contrast, the 
commenters presented data from Stevens and Gerbec (1988) \14\ who 
reported dairy cattle consumption rates of 6.8 kg/day of forage, 16.3 
kg/day of silage, 4.5 kg/day of grain, and 0.14 kg/day of soil. Second, 
EPA assumed that beef cattle consume 8.8 kg/day of forage, 2.5 kg/day 
of silage, 0.47 kg/day of grain, and 0.5 kg/day of soil (Rice, 1994). 
The commenters contended that during the nursing phase the beef cow 
receives practically all of its daily dioxin dose through the mother's 
milk and this dose has been (and could be) calculated for nursing 
cattle (Stevens and Gerbec, 1988). The commenters continued that EPA 
should assume that during the pasture phase of its life the beef cow 
consumes 13.6 kg/day of feed: 10.2 kg/day of forage, 3.4 kg of silage, 
and 0.05 kg/day of soil. The commenters argued that during the cow's 
fattening stage of growth prior to its slaughter, during which the beef 
cow gains as much as 60 to 70% of its body weight, the cow's diet 
consists entirely of grain. The commenters suggested that EPA needs to 
take into account the impact of this body weight gain and consider how 
dioxin half-life influences the concentration of dioxin residuals in 
the meat.
---------------------------------------------------------------------------

    \13\ Rice, G. 1994. Quantity of Plants and Soil Consumed by 
Animal. Draft Working Papers. Office of Research and Development. 
U.S. Environmental Protection Agency, Washington D.C.
    \14\ Stevens, J.B. and Gerbec, E.N. 1988. Dioxin in the 
agricultural food chain. Risk Analysis. 8(3):329-335.
---------------------------------------------------------------------------

    The commenters also asserted that EPA's assumption that all of a 
cow's feed is contaminated seemed unrealistic. The commenters believed 
that such an assumption implies that a farm not only has both a dairy 
and beef cattle operation, but raises grain and silage (in addition to 
crops for human consumption) while still maintaining enough pasture to 
graze the animals. They noted that the same issue was raised by the 
peer reviewers who found some of the assumptions on productivity of the 
theoretical farmer unrealistically high and suggested that productivity 
necessary to maintain such a farm be researched and used to adjust 
EPA's assumptions accordingly. The commenters reasoned that since grain 
and silage often are purchased elsewhere, it would be more appropriate 
to assume that less than 100% of the cattle's feed is contaminated. 
They believed that fixing the percentage of contaminated feed consumed 
by the cattle at 100% is not a central tendency assumption, and fails 
to reflect the lack of certainty in this parameter. Therefore, they 
recommended that EPA assume

[[Page 67081]]

that only 50% of the feed is contaminated in the deterministic 
assessment, and that a uniform distribution of values be adopted for 
the Monte Carlo assessment, with percentages ranging from 0 to 100 
percent.
    To understand EPA's response to these comments, it is important to 
recall two pieces of information presented in EPA's Risk Assessment 
Technical Background Document for the proposed rule. First, as 
discussed previously in Section VI.A.2.b.ii, the risks that EPA 
estimated for the farmer are due almost exclusively to the farmer's 
ingestion of beef and dairy products (Table 5-3; USEPA, 1999a). Second, 
the dioxins in the beef and dairy products result almost entirely from 
the cattle's consumption of forage that is contaminated by air 
emissions from the modeled wastewater treatment tank--negligible levels 
of dioxins are contributed to cattle as a result of the cattle's 
ingestion of grain, silage, or soil (Appendix H.1, Table H.1-1a; USEPA, 
1999a). Consequently, all that is required for the adult farmer to 
realize the risk that EPA presented in the proposed rule is that the 
farmer consume beef and dairy products derived from cattle that consume 
forage from the farmer's pastureland/field. That is, it is not 
necessary that the farmer consume home-grown fruits and vegetables, or 
that the farmer produce grain or silage for use as cattle feed. 
Therefore, in responding to the concerns of the commenters, EPA focused 
primarily on the technical validity and plausibility of our assumptions 
regarding the (1) consumption rates of forage by beef and dairy cattle 
and (2) the percentage of the forage that cattle consume that is 
contaminated.
    EPA disagrees with the commenters' alternate recommendations 
regarding animal feeding practices. Although the feeding practices that 
the commenters describe, particularly those for beef cattle, may be 
applicable to commercial farming operations, EPA does not believe that 
such practices apply to hobby or subsistence farming. As noted by Rice 
(1994), a subsistence farmer will tend to feed his/her cattle an 
``unsupplemented'' diet, meaning that the cattle will primarily feed on 
forage (because the cattle are permitted to graze more in the pasture), 
and will not be fattened at a feedlot prior to slaughter. Rice (1994) 
explains that in the southern part of the country (where most of the 
chlorinated aliphatics facilities are located), cattle will consume 
pasture as their major source of roughage the entire year (except in 
drought). Consequently, we believe that our assumptions regarding 
cattle ingestion of forage under a subsistence/hobby farming scenario 
are reasonable. We used the assumptions presented by Rice (1994) in 
other rulemakings \15\ and have recommended that these assumptions be 
used in estimating risks under other hazardous waste programs (USEPA, 
1998 \16\). Furthermore, the feed ingestion rate for dairy cows 
presented by the commenters is an average ingestion rate for a dairy 
cow in Minnesota (Stevens and Gerbec, 1988). In contrast, EPA's data 
for the intake rates of forage, grain, and silage for dairy cows are 
based either on data from the South Carolina-Georgia region (see Boone 
et al., 1981 \17\) or on more general data (Shor and Fields, 1980; \18\ 
NAS, 1987; \19\ and Boone et al., 1981). Chlorinated aliphatics 
facilities are located primarily in Texas and Louisiana, which we 
believe are probably more similar to South Carolina-Georgia than 
Minnesota in terms of cattle feeding practices.
---------------------------------------------------------------------------

    \15\ We used the assumptions of Rice (1994) in the risk 
assessment to support the final combustion MACT Rulemaking (64 FR 
52828, September 30, 1999). In addition, we used some of the same 
assumptions in the Proposed HWIR Rule (November 19, 1999 Federal 
Register; 64 FR 63382) and the Petroleum Refining Residuals Final 
Listing (August 6, 1998 Federal Register; 63 FR 42210).
    \16\ USEPA. 1998. Human Health Risk Assessment Protocol for 
Hazardous Waste Combustion Facilities. Peer Review Draft. Office of 
Solid Waste and Emergency Response. EPA530-D-98-001A. July.
    \17\ Boone, F.W., Y.C. Ng, and J.M. Palms. 1981. Terrestrial 
Pathways of Radionuclide Particulates. Health Physics, vol 41, no. 
5, pp. 735-747. November.
    \18\ Shor, R.W. and D.E. Fields. 1980. ``Agricultural Factors 
Affecting the Radionuclide Foodchain Pathway: Green Forage 
Consumption of Dairy Cows.'' Health Physics. vol. 39, pp. 325-332.
    \19\ NAS. 1987. Predicting Feed Intake of Food-Producing 
Animals. National Research Council, Committee on Animal Nutrition. 
National Academy Press, Washington, D.C.
---------------------------------------------------------------------------

    With regard to EPA's assumptions for the percent of the cattle's 
feed derived from a contaminated source, EPA believes that it is 
appropriate to assume that a hobby or subsistence farmer is not 
supplying forage to his/her cattle from an outside source, such that 
100 percent of the forage that the cattle consumes will be from the 
farmer's pasture or field (in our risk assessment, a contaminated 
source). This assumption is consistent with the assumptions made for 
both the subsistence and commercial farmers in the combustion MACT 
final rulemaking, as well as other EPA rulemakings and guidance.\20\ 
However, in response to the commenters' concerns, we reviewed our 
methodology for estimating the concentrations of dioxins in forage to 
ensure that we were adequately considering the size of the contaminated 
source versus its expected productivity. In the proposed rule we 
explained that in evaluating the air pathway we always assume that the 
cattle are located along the centerline of the area most greatly 
impacted by air releases from the waste management units (64 FR 46486). 
We said that the air concentrations within about a 100-meter lateral 
distance from this point do not vary appreciably, and stated 
specifically in our Risk Assessment Technical Background Document 
(Addendum; USEPA, 1999a) that the concentrations vary about 20% within 
200 meters of the point of maximum concentration. In the course of our 
reevaluation of these data in response to public comments, we concluded 
that we should have considered how the concentrations of dioxins in 
air, therefore in forage, vary over a wider aerial extent that would be 
more consistent with the area of a pasture. We concluded that a more 
reasonable approach would be to consider that the size of the pasture 
that is used to support the cattle is approximately 275 meters by 275 
meters (75,625m <SUP>2</SUP>, approximately 19 acres). We believe a 
field of this size would be large enough to support sufficient cattle 
to sustain the family of a subsistence farmer (USEPA, 2000b). We used 
the results of the air modeling we conducted for the proposed 
rulemaking to determine the approximate difference between the air 
concentration that we used to calculate the proposed risk estimate (the 
air concentration corresponding to a point located 300m from the 
modeled wastewater treatment tank) and the average air concentration at 
a 75,625m <SUP>2</SUP> field located 300m from the modeled wastewater 
treatment tank. In fact, EPA determined that more reasonably 
considering the area that is affected by the emissions from the modeled 
wastewater treatment tank would reduce the risk estimate on which our 
proposed rule was based, modifying the risk estimate (2 x 10 
<SUP>-5</SUP>) by a factor of 0.50 (USEPA, 2000b).
---------------------------------------------------------------------------

    \20\ For example:
    USEPA. 1998. Human Health Risk Assessment Protocol for Hazardous 
Waste Combustion Facilities. Peer Review Draft. Office of Solid 
Waste and Emergency Response. EPA530-D-98-001A. July.
    USEPA. 1998. Methodology for Assessing Health Risks Associated 
with Multiple Pathways of Exposure to Combustor Emissions. National 
Center for Environmental Assessment. EPA600/R-98/137.
    Proposed HWIR Rule (November 19, 1999 Federal Register; 64 FR 
63382)
    Final Petroleum Listing Rule (August 6, 1998 Federal Register; 
63 FR 42210)

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[[Page 67082]]

d. Exposure Assessment--Cooking and Post-cooking Food Losses
    Commenters contended that the equations in the risk assessment used 
to characterize exposure to chemicals from the consumption of beef do 
not appear to account for loss of chemicals due to food preparation, 
cooking, and consumption practices. The commenters pointed out that The 
Exposure Factors Handbook (``the Handbook;'' USEPA, 1997; referenced in 
the preamble to the proposed rule) recommends that these losses be 
considered, and provides estimates for percent weight losses from 
preparation of various meats from cooking and post cooking actions. 
Beef-specific loss estimates range from 11%-42% (mean = 27%) due to 
cooking and 10%-46% (mean = 24%) due to post cooking actions. 
Therefore, the cancer risk estimates associated with the beef ingestion 
pathway should be adjusted by a factor of 0.55 (0.73 x 0.76).\21\
---------------------------------------------------------------------------

    \21\ The value 0.55 is calculated as follows: If 27 percent of 
the mass of meat is lost during cooking, then 73 percent of the meat 
remains. Of the remaining 73 percent, 24 percent more is lost after 
cooking (76 percent is retained). As a result, the mass of meat 
remaining after cooking and post-cooking activities is 76 percent of 
73 percent, or 55 percent of the original mass. Therefore, the 
amount of meat lost through cooking and post-cooking activities is 
45 percent.
---------------------------------------------------------------------------

    EPA agrees that the intake rates that we used for the adult farmer 
(and certain child of farmer age cohorts) should have incorporated loss 
of beef due to cooking and post-cooking activities. The Handbook 
explains that the intake rates it provides for home-produced food items 
do not reflect actual food consumption (intake), but instead were 
derived from the amount of household food consumption in an economic 
sense, that is, they are the measure of the weight of food brought into 
the household that has been consumed (used up) in some manner. The 
Handbook explains that in addition to food being consumed by 
individuals, food may be used up by spoiling, by being discarded (for 
example, inedible parts), through cooking processes, etc. The Handbook 
provides estimated preparation losses for beef that include cooking 
losses (which include dripping and volatile losses) and post-cooking 
losses (which include cutting, bones, excess fat, scraps, and juices.) 
The authors of the Handbook averaged these losses across all cuts and 
cooking methods to obtain a mean net cooking loss and a mean net post-
cooking loss for beef. The Handbook explains that the preparation loss 
factors presented ``are intended to convert intake rates based on 
`household consumption' to rates reflective of what individuals 
actually consume. However, these factors do not include losses to 
spoilage, feeding to pets, food thrown away, etc.'' EPA acknowledges 
that considering the mean cooking and post-cooking losses for beef 
(45%) as presented by the commenters would result in reducing the risk 
estimate, modifying the total (beef plus dairy, see section VI.A.3) 
high end deterministic dioxin risk estimate for the adult farmer (2E-
05) by a factor of 0.78.
e. Toxicity Assessment
    The proposed rule presented an assessment of the toxicity of 
dioxins and chloroform, the constituents of concern in chlorinated 
aliphatics wastewaters. Commenters on the proposed rule challenged data 
and analyses EPA relied upon to characterize the toxicity of the 
dioxins and chloroform. First, the commenters believed that EPA's use 
of draft documents under review was inappropriate for obtaining 
toxicity information for dioxins. Second, the commenters contended that 
EPA should have used a different cancer slope factor to calculate risks 
for two of the hexachlorodibenzo-p-dioxin (H<INF>X</INF>CDD) congeners. 
Third, the commenters believed that EPA overestimated certain toxicity 
equivalency factors (TEFs, described below) that we used in our risk 
analysis. Lastly, commenters on the proposed rule challenged two of the 
assumptions inherent in the development of the toxicity benchmarks that 
we used to evaluate dioxins and chloroform. These two assumptions are 
as follows:

    <bullet> To develop cancer benchmarks using animal studies, 
scientists often extrapolate dose-response data derived from the 
animal studies to lower levels that are within the range of human 
exposure. EPA historically has extrapolated response data in the 
low-dose range using a linear approach called the linearized 
multistage (LMS) model. However, in 1996, EPA published the Proposed 
Guidelines for Carcinogen Risk Assessment (hereafter referred to as 
the ``1996 Guidelines;'' USEPA, 1996 \22\) that provided new 
recommendations for evaluating responses in the low-dose range when 
biologically-based or case-specific models are not available. While 
still recommending a linear extrapolation (a straight line 
extrapolation) as a default procedure for evaluating low-dose 
response, the 1996 Guidelines also suggest that extrapolation in the 
low-dose range can be performed using a nonlinear approach, when the 
data on the mode of action for the contaminant are sufficient to 
support such an approach. Commenters on the proposed rule contended 
that, for 2,3,7,8-TCDD (``TCDD'') and chloroform, a nonlinear 
approach is more appropriate for extrapolating response data in the 
low-dose range than the LMS approach used by EPA.
---------------------------------------------------------------------------

    \22\ USEPA. 1996. Proposed Guidelines for Carcinogen Risk 
Assessment. 61 FR 17960.
---------------------------------------------------------------------------

    <bullet> To calculate human equivalent doses from animal doses 
used in toxicity studies, scientists typically scale animal doses 
based on the ratio of animal and human body weights. The 1996 
Guidelines recommend that the default approach is to scale daily 
applied doses experienced for a lifetime in proportion to body 
weight raised to the \3/4\ power. This recommendation is a change 
from EPA's previous recommendation to scale doses in proportion to 
body weight raised to the \2/3\ power.

Commenters on the proposed rule believed that EPA should account for 
this revised guidance in our risk assessments for dioxin and 
chloroform.

i. Assessment of the Toxicity of Dioxins and Furans

    EPA used a cancer slope factor of 156,000 (mg/kg-
day)<SUP>-</SUP>\1\ for TCDD to calculate cancer risk from exposure to 
dioxins and furans in chlorinated aliphatics wastes. The cancer slope 
factor is a measure of the relative potency of carcinogens. That is, 
the higher the cancer slope factor, the more potent the carcinogen. The 
toxicity of each of the 17 dioxin and furan congeners with TCDD-like 
toxicity is expressed in terms of TEFs. TEFs are estimates of the 
toxicity of specific dioxin and furan congeners relative to the 
toxicity of TCDD, which is assigned a TEF of 1. The sections that 
follow present public comments on the slope factor and TEFs that EPA 
used to evaluate dioxins and furans, and provide the Agency's response 
to those comments.

TCDD Cancer Slope Factor and Health Effects

    The existing cancer slope factor for TCDD is based on human 
equivalent doses calculated from laboratory animal data by scaling 
doses to body weight raised to the \2/3\ power. Commenters maintained 
that this practice is obsolete, and does not reflect a change in EPA 
policy recommending that doses be scaled to body weight raised to the 
\3/4\ power. The commenters calculated that compared to a cancer slope 
factor that is based on scaling doses to body weight raised to the \3/
4\ power, the existing cancer slope factor overestimates cancer risk 
from dioxin-like compounds by at least 35% (assuming a linear dose-
response), and as a result, all of EPA's cancer risk estimates for 
dioxin-like compounds should be adjusted by at least a factor of 0.65. 
Commenters also claimed that the existing slope factor for TCDD does 
not take into account mechanistic information suggesting there is a 
threshold for TCDD

[[Page 67083]]

carcinogenesis. The commenters noted that this point is emphasized in a 
recent letter to the editor of Risk Analysis, written and signed by 
nearly twenty of the world's leading pharmacologists (Byrd et al., 1998 
\23\) which states: ``A dose-response assessment for dioxin based on 
receptor binding would predict a nonlinear dose-response relationship 
with a threshold for tumor induction. A nonlinear relationship is more 
consistent with the available chronic animal bioassays and human 
epidemiology studies.'' The commenters contended that, given this 
information, the cancer risk posed by all of the dioxin-like dioxin and 
furans may well be zero for all pathways considered in EPA's risk 
assessment.
---------------------------------------------------------------------------

    \23\ Byrd III, D.M., Allen, D.O., Beamer, R.L., et al. 1998. 
Letter to the Editor: The dose-response model for dioxin. Risk 
Analysis. 18(1):1-2.
---------------------------------------------------------------------------

    Commenters also took issue with EPA's use of the Health Assessment 
Document for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related 
Compounds issued by EPA in 1994. These documents have been reviewed by 
the EPA Science Advisory Board (SAB), but have not been finalized. Some 
commenters noted that the SAB made substantial comments on the 1994 
draft documents that are directly relevant to the risk assessment for 
the Chlorinated Aliphatics Listing Determination, and, because the SAB 
comments have not yet been incorporated in a final document, it is 
premature and incorrect to use the draft in this current rulemaking. 
The commenters noted that the front cover of the draft chapters state: 
``Review Draft (Do not Cite or Quote)'' and

    Notice: This document is a preliminary draft. It has not been 
formally released by EPA and should not at this stage be construed 
to represent Agency Policy. It is being circulated for comment on 
its technical accuracy and policy implications.

    In addition, the commenters pointed out that page 5-33 of EPA's 
Risk Assessment Technical Background Document for the Chlorinated 
Aliphatics Listing Determination, July 30, 1999, states: ``Most of the 
information in this summary is from this draft document and is subject 
to change, pending release of the final document.'' Thus, the 
commenters believe that conclusions made concerning dioxin in the risk 
assessment for chlorinated aliphatics wastes are based on a document 
that is preliminary and possibly incorrect.
    In contrast to the comments above, one commenter strongly supported 
the proposal to list chlorinated aliphatics wastewaters because of 
significant risks posed by dioxins, and cited the 1994 draft Health 
Assessment Document for 2,3,7,8-TCDD and Related Compounds that was 
challenged by other commenters. The commenter asserted that dioxins are 
a probable human carcinogen and that, in animal testing, TCDD is one of 
the most potent carcinogens ever evaluated. The commenter noted that 
noncarcinogenic effects resulting from TCDD exposure also have been 
reported. Specifically, some studies suggest evidence of 
immunotoxicity, such as alteration in lymphocyte populations, cell 
surface markers or lymphocyte proliferative response. There also is 
evidence of reproductive and developmental effects from exposure to 
dioxins. The commenter pointed out that studies discussed in EPA's 
draft Dioxin Reassessment provide evidence of further health impacts.
    EPA acknowledges the commenters' concerns regarding the use of a 
draft document to support our toxicity assessment for dioxin-like 
compounds. In the preamble to the proposed rule, and in the Risk 
Assessment Technical Background Document for the Chlorinated Aliphatics 
Listing Determination (USEPA, 1999a), we presented a summary of the 
health effects believed to be associated with exposure to dioxins. 
Although the source of our information concerning dioxin health effects 
was the 1994 draft health assessment document challenged by commenters, 
the health effects we presented at the time of proposal continue to 
reflect our understanding of the health affects associated with 
exposure to dioxins. A December 1998 toxicological profile for 
chlorinated dibenzo-p-dioxins published by the Agency for Toxic 
Substances and Disease Registry (ATSDR, 1998 \24\) supports our 
appraisal of the adverse health effects associated with dioxin 
exposure. Our reassessment of dioxin risks is still ongoing and we are 
not relying on draft findings for this final listing determination.
---------------------------------------------------------------------------

    \24\ ATSDR. 1998. Toxicological Profile for Chlorinated Dibenzo-
p-Dioxins (Update). U.S. Department of Health and Human Services. 
December.
---------------------------------------------------------------------------

    As discussed above, the Agency also received comments on the value 
of the TCDD cancer slope factor that we used to evaluate cancer risk 
due to dioxins. The cancer slope factor that we used in our proposed 
chlorinated aliphatics risk analyses, 156,000 (mg/kg-
day)<SUP>-</SUP>\1\, is cited in a final Agency report published in 
1985, \25\ and is comparable to the TCDD slope factor published in the 
Health Effects Assessment Summary Tables (HEAST; USEPA, 1997), 150,000 
(mg/kg-day)<SUP>-</SUP>\26\. We understand that the 1996 Proposed 
Guidelines for Carcinogen Risk Assessment recommends the body weight 
scaling factor approach noted by the commenters, and provides guidance 
for considering nonlinear contaminant dose-response relationships in 
developing cancer slope factors. EPA anticipates that we will consider 
these recommendations of the 1996 Guidelines, as well as other relevant 
recommendations of the 1996 Guidelines, in the course of future 
development or reevaluation of contaminant cancer slope factors. 
However, given that the Agency has not completed its comprehensive 
reassessment of TCDD carcinogenicity and toxicity, the Agency has 
decided to use the 1985 cancer slope factor for TCDD (USEPA, 1985) for 
this rulemaking. Moreover, decreasing the slope factor for TCDD as 
recommended by commenters would not have any impact on our ultimate 
listing decisions for chlorinated aliphatics wastewaters, EDC/VCM 
wastewater treatment sludges, or methyl chloride wastewater treatment 
sludges. Our decision not to list chlorinated aliphatic wastewaters is 
supported by other factors that decrease our proposed risk estimate 
(section VI.A.3), and reducing the slope factor as recommended by the 
commenters would not reduce our risk estimates enough to alter our 
listing decisions for the EDC/VCM wastewater treatment sludges (section 
VI.B.2.b.iv). Nevertheless, EPA may choose to reevaluate today's 
listing decisions in the future, pending the final outcome of the 
Agency's ongoing reevaluation of TCDD toxicity.
---------------------------------------------------------------------------

    \25\ USEPA. 1985. Health Assessment Document for Polychlorinated 
Dibenzo-p-Dioxins. Office of Health and Environmental Assessment. 
EPA/600/8-84/014F. September.
    \26\ The cancer slope factor for TCDD that we used to calculate 
the cancer risk resulting from exposure to dioxins in chlorinated 
aliphatics wastewaters, as well as EDC/VCM wastewater treatment 
sludges (see section VI.B) was 156,000 (mg/kg-
day)<SUP>-</SUP>\1\(USEPA, 1985). We incorrectly cited HEAST as the 
source of our slope factor in Appendix C of the Risk Assessment 
Technical Background Document (USEPA, 1999a). A risk estimate 
calculated using the slope factor presented in HEAST would be only a 
factor of 0.96 (150,000/156,000) times a risk estimate calculated 
based on the slope factor presented in the 1985 document. This 
difference would have no discernable impact on our risk estimates 
(use of either would have resulted in the high end risk estimate for 
the adult farmer, 2E-05, that we presented in the proposed rule).
    USEPA. 1997. Health Effects Assessment Summary Tables: Annual 
Update (HEAST). Office of Emergency and Remedial Response. 
Washington, D.C. July.

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[[Page 67084]]

Use of the Cancer Slope Factor for HxCDD

    EPA's Integrated Risk Information System (IRIS) database includes a 
cancer slope factor of 6,200 (mg/kg-day)<SUP>-</SUP>\1\ for HxCDD 
mixtures. Commenters believed it was curious that EPA did not choose to 
use this slope factor for any of the HxCDDs or hexachlorinated 
dibenzofurans (HxCDFs) evaluated in the chlorinated aliphatics risk 
assessment. Instead, EPA used the TCDD cancer slope factor of 156,000 
(mg/kg-day)<SUP>-</SUP>\1\ and a TEF value of 0.1, yielding an 
effective cancer slope factor of 15,600 (mg/kg-day)<SUP>-</SUP>\1\, to 
evaluate all dioxin-like HxCDDs and HxCDFs. Commenters argued that the 
risk assessment for HxCDDs and HxCDFs would be greatly improved if it 
were based on the value of 6,200 (mg/kg-day)<SUP>-</SUP>\1\ because (1) 
The cancer slope factor for HxCDD mixtures is verified on USEPA's IRIS 
database, whereas the value for TCDD is not, and (2) the slope factor 
for HxCDD mixtures is based on exposure to a mixture of congeners, 
whereas the value for TCDD is based on exposure to a single congener. 
The commenters believe that the slope factor for HxCDD mixtures 
replaces the TEF approach, which was created as an interim approach in 
the absence of chemical-specific data, with one that is based on 
chemical-specific dose-response data for this family of congeners. The 
commenters assert that in using the cancer slope factor for HxCDD 
mixtures, the inherent uncertainties associated with the application of 
the TEF approach would be eliminated. For these reasons, the commenters 
recommended that all cancer risk estimates for HxCDDs and HxCDFs be 
adjusted by a factor of 0.40 (6,200/15,600). Additionally, since the 
slope factor of 6,200 (mg/kg-day)<SUP>-</SUP>\1\ is based on scaling 
doses using body weight raised to the \2/3\ power, the commenters 
believed that the slope factor should be reduced further to account for 
the Agency's more recent recommendation that doses be scaled to body 
weight raised to the \3/4\ power, resulting in a net adjustment factor 
of 0.26 for HxCDD and HxCDF risk estimates.
    EPA disagrees with the commenters' suggestion that the slope factor 
for HxCDD mixtures that is presented in IRIS is applicable to all 
dioxin-like HxCDDs and HxCDFs. The slope factor presented in IRIS 
clearly is based on studies of only the 1,2,3,6,7,8- and 1,2,3,7,8,9- 
congeners of HxCDD, thus these are the congeners to which the slope 
factor would apply if EPA chose to use it in the chlorinated aliphatics 
risk analyses. Although the commenters suggested that use of the IRIS 
slope factor would have an impact on the results of the risk analysis, 
particularly if the slope factor is adjusted using a revised scaling 
factor, EPA strongly disagrees. Upon review of the congener-specific 
risk estimates provided in the Risk Assessment Technical Background 
Document for the proposed rule (USEPA, 1999a) it is clear that 
eliminating the 1,2,3,6,7,8- and 1,2,3,7,8,9- congeners of HxCDD from 
the risk analysis completely would have the impact of modifying the 
high end risk estimate for the adult farmer only by a factor of 0.96.

Use of the WHO TEFs

    Commenters contended that a hidden area of conservatism in EPA's 
risk assessment lay in the fact that the TEF values for many congeners, 
including 2,3,4,7,8-PeCDF and 1,2,3,4,7,8-HxCDF (the congeners that are 
the primary contributors to EPA's risk estimates), do not reflect 
central tendency values, but are instead upper bound values. Using the 
World Health Organization's (WHO's) database of Relative Potency (REP) 
estimates for these two congeners, the commenters determined that the 
TEF value of 0.5 for 2,3,4,7,8-PeCDF is equivalent to the 81st 
percentile of REP estimates obtained from 59 in vivo studies, and that 
the geometric mean from these 59 studies corresponds to a value of 
0.19. Similarly, the commenters determined that the TEF value of 0.1 
for 1,2,3,4,7,8-HxCDF is equivalent to the 93rd percentile of REP 
estimates obtained from 10 in vivo studies for this congener, and that 
the geometric mean from these 10 studies corresponds to a value of 
0.041. The commenters asserted that EPA's risk estimates for dioxin 
should be adjusted downward to correct for EPA's use of upper-bound TEF 
values. Curiously, one of the same commenters who opposed the manner in 
which the WHO-TEFs were developed, also applauded the use of the WHO-
TEFs: ``Thus, [the commenter] fully supports EPA's shift from I-TEF to 
WHO-TEF. This replacement by WHO-TEF needs to be adopted promptly by 
all EPA programs to avoid unnecessary confusion among the general 
public'' and ``[the commenter] commends EPA for several good policy 
decisions in this proposal. Specifically [the commenter] supports EPA's 
adoption of the WHO-TEF * * *.''
    In response, EPA points out that the TEF values are based on all 
available studies. These studies were conducted under a variety of 
exposure scenarios, including chronic, subchronic, short-term and 
acute, and examining a broad spectrum of endpoints including 
biochemical, developmental, immunotoxicological, neurological, 
carcinogenic and teratogenic. Whereas the resulting range of in vitro/
in vivo REP values for a particular congener may span 3-4 orders of 
magnitude, final selection of a TEF value gave greater weight to REPs 
from repeat dose in vivo experiments (chronic > subchronic > subacute > 
acute). Furthermore, studies examining toxic effects were given greater 
weight than studies examining biochemical effects. This weighting 
scheme and the use of professional judgment are designed to give more 
weight to studies that provide exposure scenarios similar to humans and 
for studies examining effects of concern.
    As pointed out by the commenter, the range of the REPs for a 
particular chemical can vary across studies. However, the commenters' 
proposed use of the geometric mean or Monte Carlo simulations is cause 
for concern. The variability in the REPs for a particular chemical can 
be due to several factors. As with any other determination, there is 
variability in the measurement which can be due to either inter-
laboratory variability and variability in the actual measurement (that 
is, experimental variability in determining ethoxyresorufin O-
deethylase [EROD] activity). Another source of variability could be due 
to species or endpoint differences in the REP of a chemical. Finally, 
the REP of a chemical can be due to differences in study design, for 
example, in vitro studies vs. in vivo studies, or short-term vs. long 
term in vivo studies. The use of expert judgment and the weighting 
scheme described above allows for consideration of the important 
biological factors regulating the relative potency of a chemical. Use 
of the geometric mean ignores this biological information.
    More importantly, the information presented by the commenters is 
not representative of the actual data available on TEFs and how this 
information is used. Of all the chemicals included in the TEF 
methodology, only 5 of these chemicals account for over 80% of the TCDD 
equivalents in human tissues, 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 
1,2,3,6,7,8-HxCDD, 2,3,4,7,8-PeCDF and PCB 126. The TEF values for, PCB 
126, 1,2,3,7,8-pentachlorodibenzo-p-dioxin, and 2,3,4,7,8-
pentachlorodibenzofuran, are similar to the mean of the relative 
potencies of these chemicals from in vivo studies and in some cases 
they are lower than the mean of the relative potencies. Chemicals for 
which there is limited data tend to have TEFs assigned that are 
conservative estimates of the

[[Page 67085]]

relative potencies specifically because of the limited data.
    Another short-coming of the proposed statistical method for 
determining the TEF is the lack of a weighting scheme. In assigning a 
TEF value for a particular congener, all available data comparing the 
relative potency of a chemical to TCDD or PCB 126 are considered. The 
expert panel examines these data sets and places more emphasis on 
studies which examine toxic responses following chronic or subchronic 
exposures. The proposed alternative approach, in which the TEF is 
assigned based in the mean of the relative potency values, ignores the 
weighting scheme and places a relative potency for biochemical 
alterations in vitro equal to that for relative potencies based on 
toxic responses following subchronic exposures in vivo. While the 
statistical approach recommended by the commenters provides an estimate 
of the variability, it ignores biological phenomena that influence the 
relative potencies of these chemicals. In contrast, the use of expert 
opinion provides a TEF that is based on endpoints of concern and 
considers biological factors that influence the relative potency of 
these chemicals. In the development of the TEF methodology, the use of 
expert opinion to provide an estimate of the variability of the TEF has 
not been applied. However, the data base that the expert panel uses to 
derive the TEF is available from the WHO and does present the range of 
relative potencies.
    Finally, the commenter describes the present TEFs as overly 
conservative based on comparison to the geometric mean of the REPs. It 
is unclear what the commenter means by ``overly conservative.'' The 
true relative potency of these chemicals in humans is uncertain. 
Because the true value is uncertain, it is difficult to determine if 
the TEF values are over estimates of the potency or if they 
underestimate the true potency of these chemicals. For the chemicals 
described, 2,3,4,7,8-PeCDF and 1,2,3,4,7,8-HxCDF, the TEF is based on 
giving greater consideration to studies using the most relevant dosing 
regimen and examining toxic endpoints. Use of the geometric mean down 
plays the importance of the more relevant studies and provides greater 
weight to acute and in vitro studies.

ii. Chloroform

    One commenter claimed that, as was the case for TCDD, EPA's unit 
risk of 2.3 x 10<SUP>-5</SUP> (ug/m<SUP>3</SUP>)<SUP>-1</SUP> for 
chloroform was calculated using the outdated practice of scaling dose 
in proportion to body weight raised to the \2/3\ power, rather than to 
the \3/4\ power, as recommended in the 1996 Guidelines (USEPA, 1996). 
The commenter believed that, as a result, the cancer risks attributable 
to chloroform should be adjusted by a factor of 0.52 (calculated in the 
same manner as discussed for TCDD in section VI.A.2.e.i). Another 
commenter asserted that, in evaluating cancer risks due to chloroform 
exposure, EPA failed to consider the EPA Office of Water's (OW) 
reanalysis of chloroform carcinogenicity. The commenter noted that 
EPA's December 16, 1998 rulemaking on disinfection byproducts firmly 
rejected the LMS approach for assessing cancer risks from chloroform 
exposure. The commenter contended that in the preamble for OW's 
rulemaking, EPA concluded specifically that ``the nonlinear cancer 
extrapolation approach is the most appropriate means'' to assess cancer 
risks from chloroform (63 FR 69400). The commenter contended that using 
the nonlinear approach, exposures to chloroform of 0.3 mg/L are 
considered to pose no cancer risk. The commenter believed that, 
therefore, the 0.2 mg/L central tendency concentration for chloroform 
in chlorinated aliphatics wastewater poses no cancer risk.
    In contrast, a third commenter strongly supported the proposal to 
list chlorinated aliphatics wastewaters because of the significant 
risks posed by the hazardous constituents in the waste, including 
chloroform. The commenter pointed out that health risks from chloroform 
are well documented, and noted that chloroform is a recognized human 
carcinogen, as well as ``a suspected toxicant of the following human 
health systems: cardiovascular or blood toxicant; developmental 
toxicant; endocrine toxicant; gastrointestinal or liver toxicant; 
kidney toxicant; neurotoxicant; reproductive toxicant; and respiratory 
toxicant.'' The commenter noted that chloroform is ``more hazardous 
than most chemicals in 11 out of 14 ranking systems and is ranked as 
one of the most hazardous compounds (worst 10%) to ecosystems and human 
health.'' (The commenter referenced ``EDF's Scorecard, www. 
scorecard.org, on chloroform. Scorecard incorporates governmental and 
other authoritative information on chemicals, including their known and 
suspected health effects.'') The commenter believed that EPA is clearly 
justified in listing chlorinated aliphatics wastewaters.
    While EPA acknowledges the concerns of the commenter who 
highlighted chloroform's adverse health effects, EPA agrees with the 
commenter who, based on evaluations conducted by OW, challenged our 
assessment of chloroform carcinogenicity at low doses. Based on mode of 
action considerations, EPA's Science Advisory Board (SAB), WHO, the 
Society of Toxicology, and EPA all strongly endorse the nonlinear 
approach for assessing risks from chloroform. Although OW conducted its 
evaluation of chloroform carcinogenicity for oral exposure, the 
nonlinear approach for low-dose extrapolation cited by the commenter 
would apply to inhalation exposure to chloroform as well, since 
chloroform's mode of action is understood to be the same for both 
ingestion and inhalation exposures. Specifically, tumorgenesis for both 
ingestion and inhalation exposures is induced through cytotoxicity 
(cell death) produced by the oxidative generation of highly reactive 
metabolites (phosgene and hydrochloric acid), followed by regenerative 
cell proliferation (63 FR 15685). As explained in EPA OW's March 31, 
1998, and December 16, 1998, Federal Register notices pertaining to 
chloroform (63 FR 15673 and 63 FR 69389, respectively), EPA now 
believes that ``based on the current evidence for the mode of action by 
which chloroform may cause tumorgenesis, * * * a nonlinear approach is 
more appropriate for extrapolating low dose cancer risk rather than the 
low dose linear approach * * *'' (63 FR 15685). In fact, OW determined 
that given chloroform's mode of carcinogenic action, liver toxicity (a 
noncancer health effect) actually ``is a more sensitive effect of 
chloroform than the induction of tumors'' and that protecting against 
liver toxicity ``should be protective against carcinogenicity given 
that the putative mode of action understanding for chloroform involves 
cytotoxicity as a key event preceding tumor development'' (63 FR 
15686).
    Given the recent evaluations conducted by OW that conclude that 
protecting against chloroform's noncancer health effects protects 
against excess cancer risk, EPA now believes that the noncancer health 
effects resulting from inhalation of chloroform would precede the 
development of cancer and would occur at lower doses than tumor 
(cancer) development. Although EPA has not finalized a noncancer health 
benchmark for inhalation exposure (a reference concentration, RfC), the 
Agency for Toxic Substances and Disease Registry (ATSDR) has developed 
a Minimal Risk Level (MRL) for inhalation exposure to chloroform. An 
MRL is ``an estimate of the daily human exposure to a hazardous 
substance that is likely to be

[[Page 67086]]

without appreciable risk of adverse noncancer health effects over a 
specified duration of exposure [acute, intermediate, or chronic]'' 
(http://www.atsdr.cdc.gov/mrls.html). To evaluate the noncancer hazard 
associated with exposure to chloroform in air, we compared the 
concentration of chloroform that we predicted to occur at a high end 
receptor's point of exposure to the ATSDR MRLs for inhalation exposure 
to chloroform. The high end chloroform exposure point concentration in 
air for chlorinated aliphatics wastewaters, approximately 0.0001 ppm 
(0.74 ug/m\3\), is more than two orders of magnitude below the chronic 
inhalation MRL for chloroform, 0.02 ppm (the chronic MRL is more 
protective than either the acute or intermediate MRLs), indicating that 
there is no concern for adverse noncancer health effects, or, 
therefore, significant increased risk of cancer, resulting from 
inhalation exposure to chloroform derived from chlorinated aliphatics 
wastewaters.
    In response to the commenter who disagreed with EPA's use of a 
slope factor based on animal data that had been adjusted to human 
equivalent doses using body weight raised to the \2/3\ power, EPA notes 
that in OW's comprehensive reevaluation of chloroform carcinogenicity, 
EPA adjusted the animal data to equivalent human doses using body 
weight raised to the \3/4\ power (63 FR 15686), as recommended in EPA's 
1996 Guidelines (USEPA, 1996).
f. Noncancer Dioxin Risks for Adults and Nursing Infants
    One commenter asserted that EPA should have considered dioxin 
noncancer endpoints for adults and for nursing infants in developing a 
dioxin concentration limit that triggers air emission control 
requirements for wastewater tanks. The commenter explained that a 
trigger level based on noncancer endpoints may be higher than the 
cancer-based trigger level, but that EPA should not assume that is the 
case. The commenter said that EPA should approximate and consider a 
trigger level for noncancer endpoints.
    First, we note that the lead option proposed by EPA was a 
`standard' listing for chlorinated aliphatic wastewaters, (i.e., listed 
regardless of dioxin concentration) with the dioxin trigger level 
proposed as an attempt to provide a means to implement tank cover 
requirements more appropriate to the potential risk, particularly 
because our data indicated that dioxin levels varied among generators 
(64 FR at 46503). However, as discussed in section VI.A.3 of today's 
preamble we have made a decision not to list chlorinated aliphatics 
wastewaters based on revised estimates of cancer risk. EPA also does 
not believe there is reason for listing chlorinated aliphatics 
wastewaters based on dioxin noncancer effects, as discussed further 
below. Although the proposed wastewater trigger level to implement tank 
cover requirements is moot because we are not finalizing the listing as 
proposed, we do not believe any increased risk of adverse noncancer 
effects due to dioxin in chlorinated aliphatic wastewaters is of 
concern in any event.
    Typically, EPA calculates a hazard quotient (HQ) to assess the 
noncancer health effects resulting from contaminant exposure. For oral 
exposures, the HQ is the ratio of an individual's average daily 
contaminant dose to the reference dose (RfD \27\) for the contaminant. 
EPA has not established RfDs for any of the dioxin or furan congeners 
(USEPA, 1994 \28\). EPA is awaiting the finalization of the Draft 
Reassessment before formalizing an approach to evaluating noncancer 
risks from dioxin. In recent years EPA's Office of Solid Waste and 
Emergency Response (OSWER) has calculated a modified margin of 
incremental exposure (MOIE) to dioxin on a case-by-case basis (for 
example, see 64 FR 52828, September 30, 1999). The MOIE is a tool for 
evaluating the potential for the occurrence of noncancer health effects 
due to dioxin. The margin of incremental exposure is an expression of 
the additional (increment of) exposure to dioxin that an individual 
receives in excess of background exposure to dioxin. Using this 
approach, we compare the estimated average daily dose attributable to 
chlorinated aliphatic wastewaters to background exposures in the 
general population. As a measure of risk, the MOIE presupposes that if 
exposures are small relative to background, then risks from these 
exposures are likely to have limited significance for human health. 
While the MOIE analysis is not specific to any particular health 
endpoint, it does allow direct comparison of exposures related to 
chlorinated aliphatics wastewaters to background dioxin exposure 
experienced by the general population. Using the high end exposure 
estimates developed for the proposed rule, the high end margin of 
incremental exposure due to chlorinated aliphatic wastewaters would be 
0.17 for an adult farmer and 0.19 for the breast-feeding infant of an 
adult farmer. However, we estimate that exposures attributable to 
chlorinated aliphatics wastewaters are actually lower than we 
originally presented in the proposed rule, due to our reevaluation of 
our air dispersion modeling results, beef intake rates, and air 
emissions modeling assumptions (see section VI.A.3). Therefore, we 
project that the actual high end margin of incremental exposure for 
both the adult farmer and breast-feeding infant of the adult farmer is 
less than 0.1, that is, an order of magnitude or more lower than any 
risk that may be attributable to background exposures (USEPA, 2000b).
---------------------------------------------------------------------------

    \27\ In the preamble to the proposed rule, in an effort to 
present the concept of RfDs and RfCs in plain language, we 
incorrectly characterized RfDs and RfCs as levels that EPA considers 
``acceptable.'' RfDs and RfCs are not by themselves action levels; 
they do not establish acceptable exposures, nor do they establish 
danger levels. RfCs and RfDs are used as tools in establishing 
concern for non-cancer effects resulting from exposure to 
contaminants, and they serve as a common reference point from which 
risk managers can make decisions regarding estimates of exposure.
    \28\ United States Environmental Protection Agency (USEPA). 
1994. Health Assessment for 2,3,7,8-TCDD and Related Compounds. 
Public Review Draft. Office of Research and Development. EPA/600/EP-
92/001a-c. September.
---------------------------------------------------------------------------

3. Rationale for the Final Listing Determination: Summary of the Impact 
of Public Comments on the Proposed Listing Determination for 
Chlorinated Aliphatic Wastewaters
    As discussed above, public commenters presented arguments that 
EPA's high end deterministic risk estimate for the adult farmer was in 
error and overestimated potential risks to human health and the 
environment. After reviewing and carefully considering all information 
provided by commenters, we re-evaluated our risk assessment results for 
air releases of dioxins and chloroform from chlorinated aliphatics 
wastewaters managed in aerated biological treatment tanks. Based on 
information provided by commenters, we decided it was appropriate to 
adjust our risk assessment results to account for cooking and post-
cooking losses for beef, a more realistic size of the pasture 
supporting cattle indirectly exposed to dioxin emissions, and the 
potential for solids removal prior to wastewater treatment in aerated 
biological treatment tanks. After calculating these adjustments to our 
proposed risk assessment results, EPA found that accounting for cooking 
and post-cooking losses for beef would modify the high end risk 
estimate for the adult farmer by a factor of 0.78, and accounting for a 
more reasonable pasture size would modify the risk estimate by a factor 
of 0.50, resulting in an overall risk estimate of 7E-06. This risk 
estimate does not consider the impact of

[[Page 67087]]

assuming solids removal from the wastewater, which could reduce risk to 
an even greater extent, reasonably by an additional factor of 0.67 to 
0.94, such that our final risk estimate could be as low as 4E-06. 
Moreover, our proposed estimate of risk due to emissions of chloroform, 
which we previously believed would be additive to our dioxin risk 
estimate, is no longer valid given recent Agency information regarding 
chloroform's mode of action. Specifically, there is no concern for 
adverse noncancer health effects resulting from inhalation exposure to 
chloroform derived from chlorinated aliphatics wastewaters, therefore, 
there is no concern for increased risk of cancer. Furthermore, the 
noncancer health effects due to dioxin that we characterized in 
response to comments presented above also would be affected by the 
adjustments to our analysis, and would be even less than projected.
    Thus, EPA believes that the risk from this waste is well below 1 
x  10<SUP>-</SUP>\5\. We acknowledge that there is some uncertainty 
associated with the analyses we have conducted in response to the three 
comments we found persuasive--for example, we do not have data to 
support specific conclusions with respect to the percentage of solids 
removed from wastewater by prior to biological treatment. Nonetheless, 
we have been conservative in accounting for the factors raised by the 
comments and believe the risk is unlikely to be higher than our revised 
estimates. In addition, we note that the risk level presented for these 
wastewaters in the proposal (2  x  10<SUP>-</SUP>\5\ as marginal. As we 
have explained, we make listing determinations based on a weight-of-
the-evidence approach, and the result of a decision is not dictated by 
whether the risk calculated for a waste is slightly more or less than 1 
 x  10<SUP>-</SUP>\5\. So, even aside from the specific revised risk 
numbers we have calculated, we would decide not to list this waste 
based on the determination that the already marginal risk level 
presented in the proposal clearly overstates the actual risk associated 
with the waste, and that the actual risk is almost certainly 
considerably below the 1  x  10<SUP>-</SUP>\5\ level.
    Therefore, the Agency concludes that potential air releases from 
wastewaters managed in biological treatment tanks do not present 
significant risk to human health and the environment and do not support 
listing chlorinated aliphatic wastewaters as hazardous wastes. After 
carefully reviewing our analyses and making necessary adjustments to 
our risk estimates based upon arguments and information presented in 
public comments, we estimate that air releases from the management of 
chlorinated aliphatic wastewaters would result in high end cancer risk 
risks less than 1  x  10<SUP>-</SUP>\5\. The Agency therefore is 
finalizing a decision to not list chlorinated aliphatic wastewaters as 
hazardous waste.
4. Waste Management Practices / Scope of Listing Determination for 
Chlorinated Aliphatic Wastewaters
    EPA believes that the rulemaking record for this rule supports a 
decision not to list chlorinated aliphatic wastewaters based on the 
typical management scenario of biological treatment in tanks. As 
mentioned above, and explained in more detail in Listing Background 
Document for the Chlorinated Aliphatics Listing Determination (USEPA, 
1999c),\29\ the majority of chlorinated aliphatic manufacturing 
facilities manage their wastewaters in tank-based wastewater treatment 
systems and either directly discharge treated wastewaters under NPDES 
permits, or discharge the wastewaters to POTWs. However, the Agency is 
aware that two facilities treat their chlorinated aliphatic wastewaters 
on-site and dispose of the wastewaters in on-site UIC wells. In 
addition, the Agency learned from public comments, that one facility 
pipes its wastewaters off-site to a nearby chemical manufacturing 
facility that commingles the chlorinated aliphatic wastewaters with 
other wastewaters, and treats the combined wastewaters in a wastewater 
treatment system that includes surface impoundments.
---------------------------------------------------------------------------

    \29\ U.S. EPA. 1999c. Listing Background Document for the 
Chlorinated Aliphatic Listing Determination (Proposed Rule). Office 
of Solid Waste. July.
---------------------------------------------------------------------------

 a. Wastewaters Managed in Underground Injection Control (UIC) Wells
    With respect to the two facilities that manage their chlorinated 
aliphatic wastewaters in on-site UIC wells, one of the facilities 
already manages its wastewaters as hazardous due to the fact that the 
wastewaters exhibit the toxicity characteristic. This facility manages 
its hazardous wastewaters in covered tanks, pipes the wastewater 
directly to a Class I hazardous UIC well and complies with RCRA and CAA 
(HON) air emissions requirements. Due the fact that this wastewater is 
being managed as a hazardous waste and in full compliance with RCRA 
subtitle C and applicable CAA requirements, we conclude that this 
wastestream does not present significant risk and we believe that our 
decision not to list these wastewaters as hazardous waste will have no 
potential adverse impact in terms of protecting human health and the 
environment.
    In the case of the other chlorinated aliphatic production facility 
that manages its wastewaters by disposing of them in UIC wells, some of 
the facility's wastewaters were, until recently, defined as hazardous 
waste (i.e., derived from previously listed hazardous waste) and 
disposed in a Class I hazardous UIC well and in compliance with a no-
migration petition. Recently, the facility was granted a delisting for 
these wastewaters by the Region VI EPA Regional Administrator. Given 
that the Regional Administrator has evaluated these wastewaters and 
determined that the wastewaters, as generated, do not pose significant 
risks to human health and the environment and warrant the award of a 
delisting, we believe that our decision not to list chlorinated 
aliphatic wastewaters as hazardous waste is appropriate for this 
wastestream and this decision will result in no adverse impact to human 
health and the environment.
    This facility also manages some of its chlorinated aliphatic 
wastewaters as non-hazardous waste and injects the wastewaters into a 
Class I non-hazardous UIC well. Although we did not model this 
management practice in our evaluation of potential risks from the 
management of chlorinated aliphatic wastewaters, we did examine the 
specific waste management requirements governing these wastewaters. Our 
evaluation of the specific management requirements applicable to these 
wastewaters included a comparison of the state requirements governing 
Class I non-hazardous UIC wells and those governing Class I hazardous 
UIC wells. We found that the requirements in Louisiana, where this 
facility is located, for Class I non-hazardous UIC wells are virtually 
identical to those governing Class I hazardous waste UIC wells. EPA 
staff confirmed this conclusion after consulting numerous sources, 
including a direct examination of the state regulations and discussions 
with state authorities and EPA Regional personnel. We also note that in 
our evaluation of these wastewaters, we determined that the levels of 
constituents in the wastewaters are equivalent to the levels for which 
the facility's other wastewaters were recently delisted. This indicates 
that these wastewaters will not pose risk when managed in Class I UIC 
wells at this specific facility. Given these conclusions, we think this 
practice is protective and believe that our decision not to list 
chlorinated

[[Page 67088]]

aliphatic wastewaters will have no adverse impact on human health and 
the environment due to the management of this facility's wastewaters in 
non-hazardous UIC wells.
 b. Wastewaters Managed in Surface Impoundments
    At the time EPA published the proposed listing determination for 
chlorinated aliphatic production wastes, the Agency was not aware that 
any chlorinated aliphatic wastewaters were managed in surface 
impoundments. EPA noted in the preamble to the proposed rule that 
although information available to the Agency, at the time of the 
proposed rule, indicated that surface impoundments had been used in the 
past, available information indicated that chlorinated aliphatic 
wastewaters are not managed in surface impoundments today. However, as 
a result of public comments to the proposed rule, the Agency obtained 
information indicating that a single facility, which is not a 
chlorinated aliphatics manufacturing facility, accepts wastewaters from 
a chlorinated aliphatic manufacturer and treats the chlorinated 
aliphatic wastewater stream after commingling it with other wastewaters 
generated at the chemical manufacturing facility. The commingled 
wastewaters are treated in a wastewater treatment system that includes 
biological treatment in surface impoundments.
    After receiving information indicating that one facility was 
managing chlorinated aliphatic wastewaters in surface impoundments, the 
Agency conducted additional research to determine if other chlorinated 
aliphatic wastewaters were being managed in impoundments. The results 
of this research are that the Agency could identify no other facilities 
managing chlorinated aliphatic wastewaters in surface impoundments.
    As a result of comments received in response to the proposed rule 
indicating that one facility treats chlorinated aliphatic wastewaters 
in surface impoundments, EPA did a screening analysis of potential 
risks from these wastewaters when managed in an impoundment. That risk 
screening analysis was based on very conservative assumptions that 
result in an overestimate of risk, given that the Agency assumed there 
would be no dilution of the wastewater in the environment and that an 
individual would drink the wastewater directly from the impoundment. 
The screening analysis suggested that wastewaters might pose risks in 
impoundments under the very conservative (and unrealistic) assumptions 
used in the screening analysis (that is, it may not be safe to drink 
the wastewaters as generated in the impoundment). However, given the 
overly protective nature of that screening assessment, the ``screening 
analysis'' does not provide meaningful information about any risks 
actually associated with this waste management practice and, therefore, 
it does not provide a basis for listing the wastewaters as hazardous.
    EPA has to make the best decision it can with the information and 
analysis it has at the time of its evaluation. EPA has decided at this 
time not to list as hazardous chlorinated aliphatic wastewaters, 
regardless of how the wastewaters are managed. We are finalizing this 
no list determination, given that the data and analysis before us, 
while indicating some potential for risks from the management of 
wastewaters in surface impoundments, does not warrant a decision to 
list these wastewaters as hazardous. Simply put, EPA was unable, in the 
time afforded under the consent decree, to perform a full risk 
assessment for this waste management practice and to subject that 
decision to public comment, and the screening assessment that EPA was 
able to do was indeterminate. Although EPA cannot rule out the 
possibility that this practice may present some risk to human health 
and the environment, EPA has fully assessed the risk presented by the 
predominant mode of waste management and made the determination that it 
does not present a substantial hazard. In fact, of the 23 chlorinated 
aliphatic manufacturing facilities that generate wastes effected by 
this rulemaking, only 3 facilities manage wastewaters in non-tank based 
systems. Under these circumstances, EPA has concluded that it is 
appropriate to make a final decision based on the information and 
analyses with respect to all the units and practices other than this 
impoundment.
    This conclusion is based in part on our interpretation of our 
obligation under RCRA section 3001(e)(2). Under that provision, 
Congress required that EPA make final listing determinations for 17 
different waste categories in 15 months. In view of the scope of the 
task and the tightness of the timeframe established, Congress could not 
have intended that EPA conduct an in-depth review of every unit 
managing any amount of waste within the categories. Rather, Congress 
must have intended that EPA make the best reasoned judgment it can 
based on analyses and information that are reasonably representative of 
the waste categories. In practice, EPA has gone well beyond this in its 
listing decisions and generally has tried to account for all the waste 
management practices and units of which it is aware. However, in this 
rulemaking, EPA was faced with the choice of continuing this practice--
which would have meant diverting time from completing the rulemaking to 
attempt to negotiate a further extension of the consent decree--or 
completing the rulemaking on schedule. Although EPA could always 
perform more complete and rigorous analysis given more time on any 
rule, at some point it is appropriate to move toward finalizing a 
decision and cut off further analysis. In view of the length of time 
already devoted to this rulemaking and the number of extensions 
previously negotiated to the consent decree, and the fact that only one 
waste management unit was unaccounted for in our analysis, EPA decided 
to issue a final determination not to list aliphatics wastewaters 
without accounting for this unit.
    EPA is not deferring a decision for chlorinated aliphatics 
wastewaters; it is making a final decision not to list the wastewaters. 
Of course, EPA can always consider additional information and analyses 
in the future and make further regulatory decisions based on that. In 
addition, should EPA learn that the management of waste at this 
impoundment presents a threat to human health and the environment, EPA 
could consider taking site-specific action to abate the threat without 
listing the waste, e.g., an action under RCRA Section 7003.

B. Wastewater Treatment Sludges From the Production of EDC/VCM

    EPA is listing as hazardous sludges generated from treating 
wastewaters associated with the manufacture of ethylene dichloride and 
vinyl chloride monomer. This wastestream meets the criteria set out at 
40 CFR 261.11 (a)(3) for listing a waste as hazardous and is capable of 
posing a substantial present or potential hazard to human health or the 
environment when managed in land treatment units. EPA is finalizing a 
conditional listing for this waste, based upon the Agency's 
determination that the waste does not pose a substantial risk when 
disposed of in a landfill.

    K174  * * *  Wastewater treatment sludges from the production of 
ethylene dichloride or vinyl chloride monomer (including sludges 
that result from commingled ethylene dichloride or vinyl chloride 
monomer wastewater and other wastewater), unless the sludges meet 
the following conditions: (i) they are disposed of in a subtitle C 
or non-hazardous landfill licensed or permitted by the state or 
federal

[[Page 67089]]

government; (ii) they are not otherwise placed on the land prior to 
final disposal; and (iii) the generator maintains documentation 
demonstrating that the waste was either disposed of in an on-site 
landfill or consigned to a transporter or disposal facility that 
provided a written commitment to dispose of the waste in an off-site 
landfill. Respondents in any action brought to enforce the 
requirements of subtitle C must, upon a showing by the government 
that the respondent managed wastewater treatment sludges from the 
production of vinyl chloride monomer or ethylene dichloride, 
demonstrate that they meet the terms of the exclusion set forth 
above. In doing so, they must provide appropriate documentation 
(e.g., contracts between the generator and the landfill owner/
operator, invoices documenting delivery of waste to landfill, etc.) 
that the terms of the exclusion were met.

1. Summary of the Agency's Listing Decision for EDC/VCM Wastewater 
Treatment Sludges
    EPA evaluated potential risks from the management of wastewater 
treatment sludges generated by producers of ethylene dichloride (EDC) 
and vinyl chloride monomer (VCM). This waste grouping consists of all 
sludges generated from the treatment of EDC/VCM wastewaters, excluding 
sludge generated from the treatment of VCM-A wastewaters (discussed 
elsewhere in today's rule). EPA estimates, based upon 1996 data, that 
approximately 104,600 metric tons of wastewater treatment sludges are 
generated annually by facilities that produce EDC and/or VCM.
    EDC/VCM wastewater treatment sludges are generated by 12 
facilities. Most facilities manage these sludges by disposing of them 
either in a hazardous waste landfill or a non-hazardous waste landfill. 
However, one facility manages its EDC/VCM sludges in an on-site land 
treatment unit. To assess the potential human health risks associated 
with EDC/VCM sludges, EPA evaluated potential risks from managing this 
waste in an off-site non-hazardous waste (unlined) landfill and an on-
site land treatment unit. The highest risk estimates were calculated 
for an adult farmer who ingests beef and dairy products containing 
dioxin derived from airborne releases and erosion/runoff from the land 
treatment unit. The proposed high end and central tendency risk results 
for the farmer exposed to dioxin from the land treatment unit were 2E-4 
and 4E-6, respectively. The Agency also concluded in the proposal that 
the management of EDC/VCM wastewater treatment sludges in landfills 
does not present risks of sufficient concern to support a decision to 
list the sludges as hazardous waste when managed in this manner. 64 FR 
46476; 64 FR 49052 (September 9, 1999 Federal Register).
    Issues raised by commenters, and data provided in comments received 
in response to the proposed rule, caused the Agency to reevaluate the 
risk analyses that were the basis of our proposed risk estimates. After 
careful consideration of information provided by commenters, we lowered 
the estimated risk associated with the management of EDC/VCM sludges in 
a land treatment unit. While the Agency's proposed high-end 
deterministic risk estimate for the land treatment unit (2E-4) was at a 
level at which the Agency presumes a waste poses sufficient risk to be 
listed (i.e., 1E-4 or greater), the revised risk estimate (7E-5) falls 
within the range of risks where the Agency may decide to list the waste 
as hazardous (i.e., between 1E-4 and 1E-6), upon consideration of 
additional factors. 59 FR at 66077. More specifically, EPA has 
previously stated that where risk estimates are within the 1E-4 to 1E-6 
range, there is a ``presumption of candidacy for either listing (risk 
>1E-5) or no listing (risk  1E-5).'' 59 FR at 66077. Applying that 
approach in this instance, the risk estimate for the land treatment 
unit of 7E-5 is not only greater than 1E-5, it is in the upper end of 
the range between 1E-5 and 1E-4. Comments received on the Agency's 
proposed risk analysis for the landfill waste management scenario did 
not result in the Agency modifying the risk estimate for the landfill. 
High-end deterministic risk estimates for the landfill scenario were 
all well within the presumptive no-list range (i.e., less than 1E-6) 
with the exception of arsenic, the groundwater risk for which was 
estimated at 3E-5. (The Agency's discussion of additional factors that 
led EPA to decide that the arsenic risk estimate alone did not support 
listing EDC/VCM wastewater treatment sludges managed in landfills is 
presented below in Section VI.B.2.b.v. of this preamble.)
    The Agency is therefore listing as hazardous EDC/VCM wastewater 
treatment sludges (using a conditional listing approach as proposed) 
based upon EPA's consideration of the risk estimates and additional 
factors. The Agency's decision was influenced by the fact that dioxin 
has been heavily studied, and the dioxin concentrations and volumes of 
EDC/VCM sludge have been well characterized in EPA's study of this 
industry (and, along with the toxicity \30\ of dioxin, were 
incorporated into the risk assessment). Additionally, there was 
evidence that the land application unit where these wastes are 
currently managed had releases of other constituents to the 
environment, which indicates that there may not be adequate coverage by 
other regulatory programs.\31\ Because industrial solid waste land 
treatment is a plausible management scenario for these wastes, EPA is 
concerned about EDC/VCM sludges managed in this manner where dioxin (a 
chemical that is persistent over the long term) is the constituent of 
concern.
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    \30\ Dioxin has the highest slope factor (an indicator of 
carcinogenic potency) of any chemical in the EPA IRIS database.
    \31\ See Appendix A.--Environmental Release Descriptions, in 
Hazardous Waste Characteristics Scoping Study U.S. EPA, November 15, 
1996, pp. A-28 and A-29.
---------------------------------------------------------------------------

    Finally, the EPA's concern is that not only is the application of 
dioxin-containing wastes in a land treatment unit plausible, it is in 
fact occurring. No commenter provided evidence that absent a decision 
to list the waste, there is other regulatory authority that would 
assure that the risks the Agency estimates for this practice would not 
continue, either at the facility currently utilizing this practice, or 
at a different facility.
    The Agency concludes, based upon the estimated risk for dioxin of 
7E-5, and after considering other relevant factors described above, 
that EDC/VCM wastewater treatment sludges pose a substantial hazard 
when managed in land treatment units. In addition, the Agency concludes 
that this waste does not pose a substantial hazard when managed in 
landfills. Based on these conclusions the Agency is promulgating a 
conditional listing for this waste. EPA is listing EDC/VCM wastewater 
treatment sludges as hazardous waste, unless the sludges are managed in 
landfills. The conditional listing promulgated today also requires that 
EDC/VCM wastewater treatment sludges not be placed on the land prior to 
disposal. In addition, generators must be able to demonstrate that the 
sludges are managed in accordance with the conditions for being 
excluded from the hazardous waste listing.
2. Response to Major Comments Received on Proposed Rule for EDC/VCM 
Wastewater Treatment Sludges
    EPA received comments on a number of issues concerning the data and 
analyses EPA used to arrive at our listing decisions for EDC/VCM 
wastewater treatment sludges. In addition, one commenter asserted that 
many of the comments on EPA's analysis of dioxin risks from the 
management of chlorinated aliphatics

[[Page 67090]]

wastewaters (for example, comments relating to the dioxin cancer slope 
factor) also apply to EPA's analysis of dioxin risks from the 
management of EDC/VCM wastewater treatment sludges in a land treatment 
unit. The comments we received may be generally divided into nine 
categories: (1) Comments on EPA's waste management assumptions; (2) 
comments on the exposure scenarios we evaluated in our risk assessment; 
(3) comments on how we calculated exposure point concentrations in the 
risk assessment; (4) comments on EPA's exposure assessment; (5) 
comments on EPA's toxicity assessment for dioxin; (6) comments on how 
we characterized risks associated with arsenic; (7) comments on 
demonstrating compliance with the listing description; (8) comments on 
the status of EDC/VCM sludges that are managed in ways other than land 
treatment or landfilling; and (9) comments on whether or not a 
contingent management approach to the listing is appropriate. The 
comments, and the Agency's responses to these comments, are described 
below.
a. Waste Management Assumptions
    Eleven facilities manage EDC/VCM wastewater treatment sludges by 
disposing of them either in a hazardous waste landfill or a non-
hazardous waste landfill. One facility manages this waste in an on-site 
land treatment unit. As a result of public comment, the Agency has 
learned that one facility generates and manages EDC/VCM wastewater 
treatment sludges in surface impoundments.
    In 1996, approximately 104,561 metric tons of wastewater treatment 
sludges were generated in wastewater treatment systems used to treat 
process wastewaters from the manufacture of EDC/VCM. Of this volume, 
approximately 6,574 metric tons is attributable to the production of 
EDC/VCM. The remaining sludge volumes are associated with the treatment 
of other process wastewaters that are commingled with EDC/VCM process 
wastewaters and treated in the same wastewater treatment system.

i. Waste Volumes

    One commenter questioned whether EPA used the correct assumption 
with regard to waste volume in the risk assessment, given that the 
production of EDC/VCM may be increasing in the United States. The 
commenter cited information provided in the Agency's Economics 
Background Document for the proposed rule. The commenter asserted that 
had EPA assumed a larger waste volume, based upon increased future 
production capacity, the result would be an increase in the predicted 
level of risk associated with the management of EDC/VCM sludges in 
landfills. The same commenter questioned whether or not the Agency had 
accounted for the likelihood that EDC/VCM wastewater treatment sludges 
generated by different facilities may be co-disposed in the same 
landfill.
    In response to the commenter's concerns regarding co-disposal of 
sludges, the Agency wishes to clarify that we did, in fact, account for 
co-disposal of EDC/VCM sludges where information provided in the RCRA 
3007 questionnaire responses showed that multiple generators dispose of 
the sludges in the same off-site landfill. As documented in the Listing 
Background Document (USEPA, 1999c, USEPA, 2000e), the Agency accounted 
for two instances where sludges generated by two generators are 
disposed in the same landfill.\32\ In both cases, the Agency used the 
combined sludge volume in assessing the quantities of sludges managed 
in off-site landfills.
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    \32\ See page 56 of ``Listing Background Document for the 
Chlorinated Aliphatics Listing Determination'' (USEPA, 1999c).
---------------------------------------------------------------------------

    In response to other concerns raised by the commenter, the Agency 
reviewed the sensitivity analyses for the landfill analyses that were 
presented in the July 1999 Risk Assessment Technical Background 
Document. Our conclusion is that predicted risk levels are not very 
sensitive to changes in waste volume. As shown in Table H.3.3 in 
Appendix H of the Risk Assessment Technical Background Document (USEPA 
1999a), we found that increasing waste volume from the central tendency 
value of approximately 15,000 m\3\ to the high end value of 
approximately 51,000 m\3\ increases the maximum 9-year average receptor 
well concentration, thus risk, by only a factor of 1.6 in the 10,000 
year time period that we modeled. This means that if waste volumes more 
than tripled, the risk estimate would be expected to increase by only a 
factor of 1.6 (that is, to 5E-05). Such an increase in production and 
waste generation, which results in a relatively small change in 
potential risk, would not cause the Agency to change its listing 
decision. The Agency also points out that there may be significant 
uncertainties in projecting changes in the volume of waste generated, 
based upon increased production capacity, due to uncertainties in the 
relationship between production rates and waste generation rates and 
the effects that technology changes, types of facility expansions 
(i.e., increased production capacity at existing facilities versus 
building new facilities) and the impact of potential (and simultaneous) 
adoption of waste minimization activities.

ii. Interpretation of Analytical Results

    A commenter questioned the Agency's use of analytical results from 
``dedicated'' sludge samples in its risk analysis and the commenter 
indicated that some of the ``non-dedicated'' sludge samples appear to 
have higher dioxin concentrations than the dedicated samples. As 
explained in the preamble to the proposed rule (see 64 FR 46483), 
``dedicated'' wastes are those wastes attributable only to the 
production of EDC/VCM and do not include wastes derived from the 
production of other chlorinated aliphatic wastes and commingled with 
EDC/VCM sludges. In our risk analysis, EPA used analytical information 
from samples of dedicated sludges only to isolate the risks from 
constituents attributed to those wastes generated from the production 
of the chlorinated aliphatic chemicals of concern to this listing 
determination. Given the commenter's concerns, the Agency did review 
the dioxin concentrations in the sludge samples not included in the 
risk analysis. The Agency found that on the basis of dioxin TEQs, the 
highest dioxin concentration in the ``non-dedicated'' samples (those 
not included in our analysis) was less than one fourth of the highest 
concentration of dioxins (on a TEQ basis) found in the samples used in 
the analysis. Therefore, had the Agency used the analytical results 
from the non-dedicated samples in its analysis, the use of the dioxin 
concentrations would not have caused an increase in the risk estimate.
    A commenter also questioned EPA's use of TCLP analytical results to 
predict leachate concentrations of contaminants from landfill disposal 
of EDC/VCM wastewater treatment sludges. The commenter questioned why 
EPA's data showed that lead and chromium are not detected using the 
TCLP, given that these constituents were found in the total constituent 
analysis of the sludges. The commenter suggested that high iron content 
in the sludges may affect the concentration of lead predicted by the 
TCLP analysis, citing data in a previous EPA rulemaking (Phase IV Land 
Disposal Restrictions, or LDR, proposed rule) that suggests high iron 
content effects lead. EPA believes that the commenter is referring to 
an issue first raised in the Phase III LDR proposed rule and 
subsequently finalized in the Phase IV LDR final rule on May 26, 1998 
(63 FR 28556). In the Phase IV LDR final rule, EPA determined that the 
addition

[[Page 67091]]

of iron filings to lead-containing hazardous wastes was not a 
legitimate form of treatment, and was in fact impermissible dilution, 
because the iron filings can interfere with the TCLP test used to 
determine whether the waste has been effectively treated (40 CFR 
268.3(d)). The commenter stated that EPA should determine whether the 
non-detects for lead in the sludge samples are an artifact of the TCLP, 
and if so, that EPA should instead use partitioning equations rather 
than TCLP data in the landfill modeling.
    In response, the Agency notes it has consistently relied on the 
results of TCLP leach tests in estimating the leaching potential of 
wastes for making listing determinations, although more recently this 
use in listing determinations has narrowed to evaluation of leaching 
potential of wastes actually or plausibly being managed in Municipal 
Solid Waste (MSW) landfills (see for example, 65 FR 55684, September 
14, 2000 Federal Register). As presented elsewhere in today's preamble, 
the Agency modeled an unlined, MSW landfill for EDC/VCM sludges, which 
is not only plausible but is actually occurring as well (see section 
below on landfill controls).
    In addition, after reviewing the information related to the LDR 
rulemakings referenced by the commenter, and the analytical data for 
the EDC/VCM sludge samples EPA used in the landfill analysis, EPA does 
not believe there would be potential risks from groundwater even if all 
of the lead leached out of the samples EPA used in the landfill 
modeling, therefore the screening analysis performed was quite adequate 
to conclude that no significant risks would be posed by the lead in the 
EDC/VCM sludges. For further information the reader is referred to the 
Response to Comments Document for today's rule.

iii. Landfill Controls

    Two commenters questioned why EPA assumed, in its risk assessment 
for EDC/VCM sludges managed in landfills, that non-hazardous waste 
landfills are covered daily and have runoff and runon controls. The 
commenters stated that some states do not require industrial, non-
hazardous waste, landfills to apply daily cover and/or install runon 
and runoff control systems. The Agency contacted state agency officials 
in states where generators of EDC/VCM wastewater treatment sludges are 
located and where landfills identified in the RCRA 3007 questionnaires 
as accepting EDC/VCM wastewater treatment sludges are located. 
Officials in each state indicated that either industrial landfills are 
required to have daily cover and runon/runoff controls, or in the case 
of one state, although state regulations do not require these controls, 
the controls are generally required and enforced through permits. In 
addition, EPA called the owner/operators of each of the landfills 
identified in the RCRA 3007 questionnaires as accepting EDC/VCM 
wastewater treatment sludges for disposal. In every case, the owner/
operators indicated that daily cover is applied and that the facility 
is equipped with runon/runoff controls. In addition, all but one of the 
landfills contacted accepts municipal solid waste. Therefore, Federal 
and state regulations require these landfills to apply daily cover and 
be equipped with runon and runoff controls. In addition, we expect that 
state agencies will continue to require these technical standards in 
future. Given that all landfills currently accepting EDC/VCM wastewater 
treatment sludges currently are applying daily cover and are equipped 
with runon/runoff controls and given that state agencies in states 
where EDC/VCM sludges currently are generated and managed require these 
controls, the Agency concludes that the commenters' concerns are 
unfounded.
b. Risk Assessment Exposure Scenarios, Contaminant Fate and Transport 
Modeling, Exposure Assessment, and Toxicity Assessment
    EPA received comments on several aspects of the landfill and land 
treatment unit risk assessments that we conducted to support the EDC/
VCM wastewater treatment sludge listing determination. EPA received two 
specific comments concerning the exposure scenarios that we evaluated 
in the landfill risk assessment: 1) that we did not evaluate 
particulate emissions from landfills, and 2) that we failed to consider 
``non-routine'' exposures. EPA also received a comment on the 
contaminant fate and transport modeling that was conducted for the 
groundwater pathway analysis under the landfill scenario. EPA uses 
contaminant fate and transport modeling to estimate the contaminant 
concentrations at the receptor's point of exposure. Commenters 
contended that we had not correctly evaluated groundwater pathway risk 
for the landfill because we assumed that leaching of the landfill did 
not begin until after landfill closure. Lastly, we received a general 
comment that we believe applies to several aspects of our land 
treatment unit risk assessment: the exposure scenarios evaluated, the 
contaminant fate and transport modeling, and the exposure and toxicity 
assessments. This comment asserted that ``much of the same type of over 
conservatism'' present in the risk assessment for the chlorinated 
aliphatic wastewaters also was present in the risk assessment for EDC/
VCM sludges managed in a land treatment unit.

i. Particulate Emissions From Landfills

    Based upon information provided in responses to the RCRA Sec. 3007 
questionnaires, EPA evaluated the risks associated with the management 
of EDC/VCM wastewater treatment sludges in unlined municipal landfills 
and in a land treatment unit. We determined that releases from 
landfills could occur through the release of vapor emissions to the air 
and through leaching of the waste into the subsurface. One commenter 
was concerned that EPA had not considered the risks due to exposure to 
particulate emissions from landfills in which EDC/VCM wastewater 
treatment sludges are disposed. The commenter acknowledged that the 
Agency did not evaluate particulate emissions because the Agency 
assumed that the moisture content of the waste would prevent the 
release of particulates. The commenter indicated that the assumption 
that sludges would have sufficient moisture content to prevent 
particulate emissions was ``not well founded, given possible climate 
and wind conditions (for example, location of a landfill in an arid 
climate with high wind).''
    The Agency disagrees with the commenter. As explained in the 
proposed rule (64 FR 46484), data collected by the Agency in support of 
the listing determination indicate that the EDC/VCM sludges have a high 
moisture content. Samples analyzed by the Agency had moisture contents 
of between 41 and 74 percent, which should prevent generation and 
release of particulates to the air during the time between placement of 
the waste in the landfill and the application of daily cover (or the 
application of new waste). Moreover, based on the results of our risk 
analyses for the land treatment unit, we do not think that particulate 
emissions from landfills, even if they did occur, would present 
significant risk. Under the land treatment unit scenario, dioxins were 
the only contaminants for which we identified significant risks due to 
air releases, and only 8 percent of the dioxin risk was due to particle 
phase air releases, while 92 percent of the risk was due to vapor phase 
air releases (Table 5-8; USEPA, 1999a). Under the landfill scenario, 
the vapor pathway dioxin risk was estimated to be 4E-10 (Appendix 
H.3.1,

[[Page 67092]]

Table H.3-1c; USEPA, 1999a). Even though we did not calculate risks 
from particle emissions, we expect they would be even less than 4E-10, 
based on the relative risks from land treatment units.

ii. ``Non-Routine'' Exposures

    One commenter claimed that virtually the entire risk modeling 
effort was confined to long-term chronic risk exposures, that is, 
primarily indirect exposures offsite of a management facility. The 
commenter believed that EPA ignored activities at the waste management 
unit itself, and therefore ignored risks to workers and others at the 
waste management facilities. The commenter believes EPA also should 
consider acute exposure risks through accidents and other ``non-
routine'' waste management conditions. Examples of such conditions 
provided by the commenter include high winds (40--60 mph) on dry days, 
drought or arid conditions, heavy rainfall, and hurricanes. The 
commenter stated that heavy rainfall and hurricane conditions could 
cause substantial amounts of dioxin-laden solids to be moved over land 
and into streams if the wastes were disposed in an unbermed area. The 
commenter expressed concern that during windy and arid conditions, 
dioxin-laden particulates may be dispersed from the landfill and beyond 
the unit boundaries. The commenter argued that the analysis of non-
routine exposures is appropriate because of the toxicity and 
persistence of dioxin relative to other contaminants.
    The commenter was concerned that EPA did not evaluate acute 
exposure to dioxins under scenarios involving workers, extreme 
climatological events, or accidents. EPA agrees that it can be 
appropriate to assess acute exposure scenarios or accidents in certain 
cases. However, in the case of chlorinated aliphatic sludges, we did 
not believe that such scenarios merited explicit analysis because the 
sludges, which result from the treatment of wastewaters, do not contain 
the very high concentrations of dioxins that we believe would be 
necessary to result in estimates of significant acute risk or hazard. 
For example, the highest TCDD TEQ concentration reported for dedicated 
EDC/VCM wastewater treatment sludges, 0.907 ug TCDD TEQ/kg, is below 
EPA's Superfund soil action level of 1 ug TCDD TEQ/kg which was 
developed to be protective of direct long term exposure to dioxins in 
residential soils and therefore clearly would be protective of shorter 
term exposure (OSWER Directive 9200.4-26, April 13, 1998).

iii. Delay of Landfill Leaching Until After Closure

    In evaluating releases to groundwater from the landfill used to 
manage EDC/VCM sludge, EPA made a simplifying assumption that 
contaminant leaching from the landfill does not occur until after the 
landfill closes (that is, after 30 years). As we explained in the 
proposed rule, we made this assumption because of the complexities 
associated with linking the output of our landfill partitioning 
equations and our groundwater model, EPACMTP (EPA's Composite Model for 
Leachate Migration with Transformation Products). Two of the public 
commenters and all three of the peer reviewers questioned the 
appropriateness of our assumption, suggesting that it would lead to an 
underestimate of risk. One commenter noted that during the period when 
the landfill is open and the waste is exposed directly to storm water, 
``leachate migration of contaminants is at its highest level.''
    In retrospect, we realize that we were not completely clear 
concerning how our landfill modeling approach considers the production 
of leachate over the life of the landfill. Because of the way our 
landfill model is constructed, the application of daily cover and a 
final cap only limits the release of air emissions from the landfill, 
daily cover and final cap do not limit the production of landfill 
leachate. This is because the infiltration rate that we use for the 
landfill during its active life is the same as the infiltration rate 
that we use for the landfill once it is closed--we assume that the 
infiltration through the daily cover and final cap is the same as the 
infiltration through the exposed waste. Our basis for assuming that the 
cap will not reduce infiltration is that we predict that over the long 
term a cap will fail, and will cease to function effectively. 
Consequently, the effect of delaying leaching of the landfill until 
after closure is only to ``offset'' the arrival of the peak contaminant 
concentration at the groundwater receptor well by 30 years. For the 
sole contaminant of concern for the landfill, arsenic, the peak arrival 
time was estimated to be 8800 years. Reducing this time estimate by 30 
years is clearly insignificant.

iv. Overly Conservative Land Treatment Unit Risk Analysis

    One commenter maintained that ``much of the same type of over 
conservatism'' that was present in the risk assessment for the 
chlorinated aliphatic wastewaters also was present in the risk 
assessment for EDC/VCM sludges managed in a land treatment unit. The 
commenter contended that ``[f]or the same reasons articulated'' for 
wastewaters, ``EPA should reevaluate and adjust risk assessment 
parameters as necessary before proposing to list such wastes, even 
under a land treatment scenario.''
    Although the commenter was not specific regarding which aspects of 
their comments on the wastewater risk analysis they felt applied to the 
Agency's evaluation of EDC/VCM sludges managed under a land treatment 
unit scenario, we reviewed the risk assessment comments for wastewaters 
to determine which could be relevant to the land treatment unit 
analysis. The comments that we focused on are discussed below. Section 
VI.B.3 summarizes how the comments influence the proposed risk estimate 
for EDC/VCM sludges managed in a land treatment unit.

Cooking and Post-Cooking Losses for Beef

    The commenter claimed that the intake rates that EPA used for beef 
should have been adjusted downward to account for cooking and post-
cooking weight loss, as recommended in the Exposure Factors Handbook 
(USEPA, 1997). As was the case for wastewaters (see section VI.A.2.d.), 
EPA agrees that we should have accounted for cooking and post-cooking 
losses of beef in our exposure analysis for the land treatment unit.

Assessment of the Toxicity of Dioxins and Furans

    In our evaluation of the comments on wastewaters, we disagreed with 
the commenter's claim that we should modify the cancer slope factor 
that we used for TCDD and that our TEFs represent upper-bound values. 
Our responses to these comments are provided in section VI.A.2.e.i. 
Although we also disagree with the commenter's assertions that we 
should use the IRIS slope factor for HxCDD mixtures in our risk 
assessment (see section VI.A.2.e.i.), eliminating the 1,2,3,6,7,8- and 
1,2,3,7,8,9-congeners of HxCDD from the land treatment unit risk 
analysis completely would have the impact of modifying the high end 
risk estimate for the adult farmer only by a factor of 0.97, which 
would not significantly change the results of the risk analysis.

EPA Should Have Evaluated Site-Specific Exposure Scenarios

    The commenter maintained that EPA should have used a site-specific 
approach to assessing risks from

[[Page 67093]]

management of chlorinated aliphatics wastewaters (see section 
VI.A.2.b). The commenter suggested that such an approach would 
recognize that EPA's assumption that a farmer lives at the same 
location within 300 meters of a chlorinated aliphatics facility for 
48.3 years, and raises fruits, exposed vegetables, root vegetables, 
beef cattle, and dairy cattle within this distance, is unrealistic. In 
addition, the commenter challenged the amounts of home-produced beef, 
dairy products, vegetables, and fruits that EPA assumed were consumed 
by the farmer.
    Although the Agency's response to these comments is presented in 
our discussion of chlorinated aliphatics wastewaters in section 
VI.A.2.b, there are a few additional points that we can make with 
regard to the exposure scenario we considered in our evaluation of the 
risk associated with management of EDC/VCM wastewater treatment sludges 
in a land treatment unit. Although our land treatment unit analysis was 
inherently more site-specific than our analysis of wastewaters (since 
only one facility uses a land treatment unit to manage EDC/VCM 
sludges), we do not believe, for the reasons presented in section 
VI.A.2.b.i, that it would have been appropriate to conduct facility-
specific risk analyses for chlorinated aliphatics wastes.
    In response to concerns regarding the likelihood that a farmer 
would raise fruits and vegetables for home consumption, in addition to 
producing beef and dairy products, EPA refers to Table 5-8 of the Risk 
Assessment Technical Background Document (USEPA, 1999a) that shows that 
only 4 percent of the high end risk for the adult farmer was due to 
ingestion of home grown fruits and vegetables. As was the case for 
wastewaters, even though EPA believes it is plausible that a 
subsistence or hobby farmer would raise fruits and vegetables for home 
consumption, the validity of EPA's risk estimate depends almost 
entirely on the validity of our assumption that a farmer might consume 
both beef and dairy products from cattle raised on a farm located near 
a chlorinated aliphatics production facility. While we responded to 
this comment in our previous discussion of wastewaters, EPA notes that 
even in the specific case of the facility where the existing land 
treatment unit is located, there is evidence of the potential close 
proximity of grazing cattle. First, the most recently available 
agricultural census data (1997) indicate that both beef and dairy 
cattle were reported as being raised in the parish in which the land 
treatment unit is located. Second, although the potential proximity of 
cattle farming operations to chlorinated aliphatics facilities was 
confirmed by commenters on the wastewater risk analysis, EPA notes 
that, in addition, a land use map depicts the location of the facility 
that operates the land treatment unit as adjacent to land described as 
cropland and pasture (USEPA, 2000b). In addition, in a 1994 aerial 
photograph of the facility (located in the docket for the final rule), 
areas adjacent to the facility are depicted as being used for 
agriculture. Third, a 1986 RCRA Facility Assessment (RFA) conducted at 
the facility at which the land treatment unit is located noted the 
following for a landfarm/land treatment area at the facility: ``* * * 
the State issued a violation to the facility for allowing cows to graze 
in this area.''

EPA Incorrectly Evaluated the Contribution of Feed to Dioxin Levels in 
Dairy and Beef

    The commenter raised several issues related to how EPA evaluated 
the contribution of feed to dioxin levels in dairy and beef. The 
Agency's responses to most of these concerns are addressed in section 
VI.A.2.c.ii. As was the case for wastewaters, we reviewed our 
methodology for estimating the concentrations of dioxins in beef and 
dairy products. The dioxins in the beef and dairy products result 
primarily from the cattle's intake of forage and soil that are 
contaminated by air emissions and runoff/erosion from the modeled land 
treatment unit--minor levels of dioxins are contributed to cattle as a 
result of the cattle's ingestion of grain or silage (USEPA, 2000b). 
Consequently, all that is required for the adult farmer to realize the 
risk that EPA presented in the proposed rule is that the farmer consume 
beef and dairy products derived from cattle that consume forage and 
incidentally ingest soil from the farmer's pastureland/field. That is, 
it is not necessary that the farmer consume home-grown fruits and 
vegetables, or that the farmer produce grain or silage for use as 
cattle feed. As was the case for wastewaters, we felt that we likely 
should have considered how the concentrations of dioxins in air vary 
over a wider areal extent that would be more consistent with the area 
of a pasture where cattle graze. Similar to wastewaters, we calculated 
what the impact would be to the risk estimate if we accounted for a 
more reasonable pasture/field size (USEPA, 2000b). In addition, in 
response to comments from peer reviewers, we also reviewed the method 
by which we evaluated risk attributable to the runoff/erosion pathway 
to ensure that we appropriately characterized the dioxin concentrations 
in feed, thus the concentrations in dairy and beef. In subsequently 
evaluating the land treatment unit dioxin mass balance, we determined 
that, due to limitations of the available model, we overestimated the 
amount of dioxin-contaminated soil lost from the land treatment unit 
due to erosion over long durations (USEPA, 2000b). The revised risk 
estimate that considers these modifications is presented in section 
VI.B.3.

v. Characterization of Arsenic Risk Results

    Several commenters were concerned that although EPA found risks 
from arsenic that are within its discretionary range for listing EDC/
VCM wastewater treatment sludges, EPA did not include arsenic as a 
basis for the listing determination and the contingent management 
listing for EDC/VCM wastewater treatment sludges allows this waste to 
be managed in landfills despite our risk assessment results for 
arsenic.
    EPA evaluated potential risks from arsenic resulting from both 
landfill management of EDC/VCM wastewater treatment sludges and 
management of the waste in a land treatment unit. In the case of the 
landfill scenario, risk assessment results showed a high-end risk from 
arsenic from a groundwater ingestion exposure pathway, to be 3E-05. 
However, this potential risk level is predicted to occur only after a 
very significant period of time. Our modeling results indicate that, 
after a period of 8,800 years, the disposal of EDC/VCM sludge in an 
unlined landfill would result in an increase in the concentration of 
arsenic in groundwater in a down gradient well (102 meters from the 
landfill) by only 1.4 ug/L and would add approximately 2 ug/day of 
arsenic to the average daily exposure level (about 20 ug/day) for the 
highly exposed individual.
    Given these predicted circumstances, we conclude that the risks 
from arsenic for the landfill scenario are not significant for several 
reasons. The predicted risks levels are associated with a peak arsenic 
concentration in a receptor well that is estimated to occur only after 
a very long period of time. In addition, the predicted high-end arsenic 
concentration at a receptor well (1.4 ppb) is very close to the median 
arsenic background concentration of 1.0 ppb found in groundwater in 
Texas and Louisiana.\33\ The predicted high-end

[[Page 67094]]

arsenic concentration also is well below the current maximum 
contaminant level (MCL) allowed for arsenic in drinking water and below 
the revised MCL for arsenic recently-proposed by EPA's Office of Ground 
Water and Drinking Water. The current MCL for arsenic is 50 ppb, the 
revised MCL proposed by EPA is 5 ppb (65 FR 38888).
---------------------------------------------------------------------------

    \33\ Focazio, M.J., Welch, A.H., Watkins, S.A., Helsel, D.R., 
and Horn, M.A., 1999, A Retrospective Analysis on the Occurrence of 
Arsenic in Ground-water Resources of the United States and 
Limitations in Drinking-Water-Supply Characterizations: U.S. 
Geological Survey Water-Resources Investigation Report 99-4279, 21 
p.
---------------------------------------------------------------------------

    Given that the estimate of potential risk for arsenic is within the 
range of risk levels in which the Agency exercises discretion with 
regard to a listing decision (i.e., predicted risk levels are less that 
1E-04), the Agency's established policy provides that it may take into 
account other factors affecting the potential risk associated with the 
waste in making its listing determination. The risk estimate for 
arsenic in EDC/VCM wastewater treatment sludges managed in landfills is 
the result of predicted concentrations of arsenic that are close to 
background levels, do not exceed the MCL in the modeled receptor well, 
and the result of a peak arsenic concentration in a receptor well that 
is predicted to occur only after a period of 8,800 years. Given that 
there are uncertainties associated with our risk estimates we do not 
think it makes sense to impose requirements now to address a marginal 
risk that may be realized so far in the future. In addition, even if 
the arsenic concentrations predicted to occur very far in the future 
were to occur now, these concentrations are not at levels of concern, 
given that the peak concentration of arsenic in groundwater is 
predicted to be below the current (and all recently proposed) MCL(s). 
Therefore, EPA concludes that EDC/VCM wastewater treatment sludges do 
not pose a significant risk due to the presence of arsenic when managed 
in landfills.
    In the case of the potential risks associated with arsenic in EDC/
VCM wastewater treatment sludges managed in a land treatment unit, we 
found that arsenic may present some risk from potential releases to 
groundwater from the land treatment unit. However, we conclude that the 
estimated level of potential risk is not significant for the very same 
reasons we concluded that the risk from arsenic in a landfill scenario 
is not significant (i.e., predicted concentrations of arsenic in 
groundwater wells is close to background levels, and is the result of a 
peak arsenic concentration in a receptor well that is predicted to 
occur only after a long period of time). The Agency concludes that the 
risk posed from potential releases of arsenic in this wastestream does 
not warrant listing the waste as hazardous. However, in the case of the 
land treatment unit scenario, the Agency determined that the waste 
should be listed as a hazardous waste based upon the potential risks 
associated with dioxin concentrations found in the waste. The Agency 
therefore is listing EDC/VCM wastewater treatment sludges based solely 
on the presence of dioxin and the potential risk associated with dioxin 
when this waste is managed in a land treatment unit.

vi. Regulatory Compliance Demonstration

    Two commenters were concerned that the proposed conditional listing 
approach for EDC/VCM wastewater treatment sludges would be burdensome 
to generators due to commenters' view that the proposal required 
generators to document their ``intent'' to properly manage and dispose 
of the waste. In response, the Agency notes that we are not imposing 
any new paperwork requirements as part of the conditional listing. In 
the final listing determination, the Agency is requiring that 
generators and other handlers of EDC/VCM wastewater treatment sludges 
merely be able to demonstrate that past and on-going waste management 
practices are in compliance with the conditions of the contingent 
management listing approach. Our intent in describing potential types 
of records or contracts that could fulfill the demonstration 
requirement was merely to provide examples of appropriate 
demonstrations, and not to impose stringent or specific paperwork 
requirements. As explained above, the Agency is finalizing, as part of 
the listing description, a flexible performance standard similar to the 
documentation requirement provided in 40 CFR 261.2(f) for documenting 
claims that materials are not solid wastes, when managed in certain 
ways. Generators and other handlers of EDC/VCM wastewater treatment 
sludge that claim the waste is not a hazardous waste must merely 
demonstrate that the generator or handler has handled the waste or 
intends to handle the waste in compliance with the conditions of the 
conditional listing. One manner in which this demonstration may be made 
is by presenting a copy of a signed contract between the generator and 
a state-licensed landfill under which the landfill agrees to accept the 
EDC/VCM waste. Again, in cases where such a contract does not exist, 
other documentation of past and on-going disposal practices such as 
signed non-hazardous waste manifests, shipping papers, and/or invoices 
may provide an appropriate demonstration of proper management. The 
Agency points out that a generator's or handler's ability to 
demonstrate recent and/or on-going shipments of EDC/VCM wastewater 
treatment sludges to appropriate disposal facilities will serve as 
sufficient demonstration of their intent to continue such management 
practices for wastes being appropriately stored on-site (i.e., stored 
in a manner that does not involve direct placement of the waste on the 
land) prior to off-site disposal and not yet offered for off-site 
shipment.

vii. Status of EDC/VCM Sludges Managed by Methods Other Than Land 
Treatment and Landfilling

Incineration

    Several commenters requested that EPA include incineration of EDC/
VCM wastewater treatment sludges as a contingent management option for 
this waste. Commenters argued that incineration should be allowed to 
occur without the sludge falling within the scope of the listing 
description (i.e., commenters requested that EPA allow the incineration 
of EDC/VCM wastewater treatment sludges as non-hazardous wastes).
    The Agency disagrees with the commenters. First, the Agency notes 
that commenters provided no information indicating that incineration of 
presently non-hazardous EDC/VCM sludges is occurring and indicated only 
that they were considering the practice. Some commenters stated 
specifically that they currently do not incinerate presently non-
hazardous EDC/VCM wastewater treatment sludges. Information available 
to the Agency during development of the proposed rule indicated that 
there were no facilities presently incinerating non-hazardous forms of 
the waste, and EPA did not evaluate potential risks from on-site or 
off-site incineration of EDC/VCM wastewater treatment sludges in non-
hazardous waste incinerators. EPA bases listing determinations on an 
assessment of plausible (and worst-case) management scenarios. It is 
not practicable for EPA to evaluate every possible management scenario, 
and particularly not those management practices that are found not to 
be plausible (or are hypothetical). This is consistent with the 
Agency's mandate to evaluate determine whether or not to list wastes, 
and not management practices. EPA does carve out particular

[[Page 67095]]

waste management practices in certain circumstances (e.g., here, where 
there is a widespread practice we have modeled fully), but we cannot 
possibly evaluate every practice, particularly hypothetical practices, 
that any commenter says they might employ.
    Our policy with regard to hazardous waste listings is that in cases 
where we have identified one plausible management practice that 
presents a significant risk to human health and the environment (in 
this case, land treatment), the waste warrants being listed as a 
hazardous waste. However, since the Agency identified another plausible 
management approach (landfill), evaluated the risk from this management 
approach, and determined that the second management approach does not 
present a significant risk to human health and the environment, the 
Agency determined that it is appropriate to exclude the waste from the 
hazardous waste listing, when managed in this particular manner. 
Without evaluating potential risks from additional management 
approaches, the Agency cannot determine whether or not the waste, when 
managed in a different manner, warrants being excluded from the 
hazardous waste listing. Given that EDC/VCM wastewater treatment 
sludges currently are not managed in non-hazardous waste incinerators, 
we have not used the limited time and resources we have for the 
rulemaking to conduct an analysis of potential risks associated with 
this potential management practice. Therefore, we do not have a basis 
to exclude sludges managed in this manner from the listing description. 
Should the Agency receive information in the future indicating that 
non-hazardous waste incineration is occurring, the Agency may re-visit 
the decision to preclude the management of these sludges in non-
hazardous waste incinerators. However, given that these sludges contain 
dioxin, EPA would want to carefully consider the potential risks of 
managing these wastes in non-hazardous waste incinerators, before 
concluding that this practice does not pose a risk.
    The final rule, as promulgated in today's notice, provides that 
EDC/VCM wastewater treatment sludges are listed hazardous wastes, 
unless the sludges are disposed in a subtitle C landfill or a non-
hazardous waste, state-licensed landfill and are not placed on the land 
prior to final disposal in a landfill. Under the conditional listing, 
the incineration of EDC/VCM wastewater treatment sludges in a non-
hazardous waste incinerator and the disposal of the ash in a landfill 
does not meet the conditions of the listing. EDC/VCM wastewater 
treatment sludges destined for incineration are hazardous wastes (i.e., 
are K174).

EDC/VCM Wastewater Treatment Sludges Derived From the Management of 
Chlorinated Aliphatic Wastewaters in Surface Impoundments

    As mentioned above, at the time of the proposed rule EPA was not 
aware that any chlorinated aliphatic production facility was managing 
chlorinated aliphatic wastewaters in surface impoundments, or 
potentially generating EDC/VCM wastewater treatment sludges in surface 
impoundments. However, the Agency received information from public 
comments indicating that one chlorinated aliphatic manufacturing 
facility produces VCM and sends its process wastewaters to an adjacent 
facility, where the VCM wastewater is combined with other non-
chlorinated aliphatic wastewaters for treatment in surface 
impoundments. The commenter described the type of treatment occurring 
in these impoundments to include biological treatment followed by 
clarification; therefore, we presume wastewater treatment sludges are 
generated in these impoundments. Because these wastewater treatment 
sludges are the result of treating wastewaters from the production of 
VCM, they will meet the definition of today's K174 hazardous waste 
listing on the effective date of today's rule.
    The listing description for EDC/VCM wastewater treatment sludges 
finalized in today's rulemaking includes sludges that are placed on the 
land prior to final disposal in a landfill. EPA's long-standing policy 
under RCRA subtitle C is that wastes generated in surface impoundments 
are subject to regulation while actively managed in the impoundment 
(not just when the sludges are removed from the unit) (see 45 FR at 
72024; 55 FR 39409; 55 FR 46380). Therefore, sludges resulting from 
treating wastewaters from the production of EDC/VCM after the effective 
date of today's rule, when actively managed in surface impoundments in 
which they are generated, fall within the scope of today's listing 
determination for EDC/VCM wastewater treatment sludges (K174).
    With regard to the regulatory status of surface impoundments used 
to treat EDC/VCM wastewaters prior to the effective date of the today's 
rule, EPA has articulated in prior rulemakings certain circumstances 
where a surface impoundment, in which newly-regulated wastes were 
generated prior to the effective date of the listing, would not become 
subject to subtitle C management standards (see 55 FR 39410 and 55 FR 
46380). In the November 2, 1990 rulemaking finalizing the hazardous 
waste listings for F037 and F038, EPA provided that in cases where 
wastes become defined as hazardous as a result of new listing 
determinations, if the wastes are removed from the impoundment prior to 
the effective date of the rule defining them as hazardous, then the 
impoundment does not become subject to Subtitle C.
    In the Federal Register notice published on September 27, 1990, EPA 
clarified the regulatory status of surface impoundments containing 
sludges newly defined as hazardous that were deposited in an 
impoundment prior to the effective date of the rule defining the waste 
as hazardous, and where the impoundment ceased to receive hazardous 
wastes on or before the effective date of the rule. In that notice, EPA 
stated: If (1) the newly identified hazardous waste remains in the 
surface impoundment after the effective date of the rule, and (2) the 
impoundment does not receive or generate any other hazardous wastes 
after the effective date, and (3) the impoundment is the final disposal 
site for the waste, then the impoundment is not subject to RCRA 
subtitle C. Additionally, the Agency clarified that if newly-listed 
wastes are removed from an impoundment as part of a one-time removal, 
including a one-time removal after the date on which the waste becomes 
defined as hazardous, the impoundment will not be subject to RCRA 
subtitle C. The Agency also clarified in the September 27, 1990 
rulemaking that EPA will not view the one-time removal of waste as part 
of a closure as changing the status of the surface impoundment (i.e., 
subjecting the impoundment to RCRA subtitle C), as long as there is no 
ongoing management of the waste in the impoundment after the effective 
date of the hazardous waste listing.
    Therefore, if a facility ceases to manage EDC/VCM process 
wastewater sludge in surface impoundments prior to the effective date 
of today's listing determination, and the facility undertakes a one-
time removal of the newly-listed waste, the surface impoundment will 
not be subject to RCRA subtitle C. The sludges removed from an 
impoundment as part of a one-time removal after the effective date of 
today's listing (that were derived from the previously managed 
chlorinated aliphatic wastewaters), will be defined as K174, unless the 
waste meets the conditions for exclusion from the hazardous waste 
listing. If the sludge does meet these conditions (i.e., it is

[[Page 67096]]

disposed in a subtitle C landfill or a non-hazardous waste landfill 
permitted or licensed by a state, and it is not placed on the land 
other than in such a landfill after it is removed from the 
impoundment), it will be exempt from the listing. After the one-time 
removal of sludge generated from the chlorinated aliphatic wastewaters, 
and as long as no additional chlorinated aliphatic wastewaters are 
managed in the impoundment, sludges generated in the impoundment will 
not meet the listing description for K174. In other words, the 
impoundment would not become regulated. In addition, sludges removed in 
subsequent removals (e.g., as part of routine maintenance activities) 
will not be considered EDC/VCM wastewater treatment sludge (K174), as 
long as chlorinated aliphatic wastewaters were not managed in the 
impoundment after the effective date of the rule.
    The above discussion pertains to facilities that choose to continue 
operating their surface impoundments as non-hazardous waste units after 
the effective date of today's rule. However, a facility could choose to 
continue to manage chlorinated aliphatic wastewaters in surface 
impoundments after the effective date of today's rule. In this case, 
the sludge generated in the impoundments will meet the K174 listing 
description and the surface impoundments will become subject to RCRA 
subtitle C. Any newly listed EDC/VCM wastewater treatment sludges that 
are managed in a newly regulated surface impoundment (i.e., an 
impoundment that becomes subject to RCRA regulation as a result of the 
new waste listing) may continue to be managed in the impoundment for up 
to four years, provided that the impoundment is in compliance with the 
groundwater monitoring requirements of 40 CFR part 265, Subpart F 
within 12 months after promulgation of the new waste listing (40 CFR 
part 268.14).\34\ Surface impoundments also may continue to treat 
wastes that do not meet LDR treatment standards if the surface 
impoundments are in compliance with 40 CFR 268.4 (the surface 
impoundment exemption), or if facilities obtain no-migration variances 
for the units (40 CFR 268.6, 264.221(b), 265.221(c)). Under the surface 
impoundment exemption, owners or operators must follow specific 
sampling and testing, removal, subsequent management, and recordkeeping 
requirements. Some impoundments may be granted a delay of closure (see 
40 CFR 265.113 and 40 CFR 264.113) and thus will be allowed to remain 
in operation, providing that hazardous waste is removed and the 
impoundment is used for non-hazardous wastes (see section VIII.B for a 
discussion of permitting requirements and compliance dates applicable 
to the management of newly-listed wastes). Facilities that currently 
manage EDC/VCM wastewater treatment sludges in surface impoundments 
must meet the terms of these regulations or discontinue their use for 
the management of these sludges prior to the effective date of the 
listing and land disposal restrictions.
---------------------------------------------------------------------------

    \34\ RCRA Sec. 3005(j)(6) provides that facilities managing 
wastes in surface impoundments that are newly brought into the 
subtitle C system by a new listing or characteristic have four years 
to retrofit or close impoundments receiving newly identified or 
listed wastes (and no other hazardous wastes).
---------------------------------------------------------------------------

viii. Contingent Management Approach

    A few commenters asserted that a contingent management approach to 
listing EDC/VCM wastewater treatment sludges is not appropriate. 
Commenters pointed out that such an approach would allow the waste to 
be land disposed without treatment in compliance with the land disposal 
restrictions requirements. One commenter stated that RCRA does not 
provide EPA with the statutory authority to list a waste as hazardous 
on the basis of how the waste is or is not managed. Another commenter 
stated that the management process should not decide whether a waste is 
hazardous or not. The commenter further stated that waste management 
practices only should ensure that the waste is properly treated.
    Given the Agency's finding (discussed in Section VI.B.1. of this 
preamble) that the predominant approach for managing EDC/VCM wastewater 
treatment sludges does not pose a substantial hazard to human health 
and the environment, we see no reason to include sludges managed in 
this manner in the scope of the hazardous waste listing. In fact, the 
Agency knows of only two facilities that manage these sludges in a 
manner other than landfilling. It does not make sense to list the bulk 
of EDC/VCM wastewater treatment sludges managed safely in landfills 
based upon the management approaches used by two facilities. On the 
other hand, we do not believe that it is appropriate to promulgate a 
no-list determination, given the Agency's finding (discussed in Section 
VI.B.1. of this preamble) that EDC/VCM sludges pose a substantial 
hazard to human health and the environment when managed in a land 
treatment unit. Therefore, the Agency is promulgating a contingent 
management listing to ensure that EDC/VCM wastewater treatment sludges 
are managed only in a manner that EPA has shown does not pose a 
substantial hazard to human health and the environment.
    Because the Agency has made a finding that the waste does not pose 
a substantial hazard to human health and the environment if disposed in 
a landfill, without being treated prior to disposal, we do not agree 
with commenters' regarding the necessity of imposing treatment 
requirements under RCRA subtitle C. Our finding that treatment is not 
necessary to insure protection of human health and the environment is a 
major factor supporting the contingent management approach. In 
addition, the land disposal restrictions apply to hazardous wastes 
only. Since the Agency has determined that EDC/VCM wastewater treatment 
sludges, when managed in a landfill, are not hazardous wastes, the 
treatment standards are not necessary to ensure protection of human 
health and the environment.
    A contingent management listing approach is within EPA's statutory 
authority. Section 3001(a) requires the Administrator to promulgate 
criteria for identifying and listing wastes that ``should'' be subject 
to the requirements of RCRA. The word ``should'' in section 3001(a) 
calls for an exercise of judgment and, therefore, confers discretion 
upon EPA to determine whether listing is warranted. RCRA sections 3002, 
3003 and 3004 direct the Agency to issue regulations ``necessary to 
protect human health and the environment.'' Accordingly, the decision 
whether a waste should be regulated under RCRA turns upon EPA's 
assessment of whether such regulation is necessary to protect human 
health and the environment. Because a hazardous waste is by definition 
a solid waste that poses ``a substantial threat to human health and the 
environment when improperly treated, stored, transported, or disposed 
of, or otherwise managed,'' (RCRA section 1004(5)) EPA concludes that 
where a waste might pose a hazard only under limited management 
scenarios, and other regulatory programs already address such 
scenarios, the Agency is not required to list a waste as hazardous.
    The Agency's decision with regard to whether a waste should be 
regulated under subtitle C turns upon EPA's assessment of whether RCRA 
regulation is necessary to protect human health and the environment. In 
particular, in Military Toxics Project v. EPA, 146 F.3d 948 (D.C. Cir. 
1998) the court found that, if EPA concludes that a waste might pose a 
hazard only under limited management scenarios, EPA can reasonably and 
permissibly determine that the waste should be regulated as

[[Page 67097]]

hazardous only under those scenarios. In the Military Toxics Project 
case, EPA reasonably determined that waste munitions would not pose a 
hazard if managed in accordance with existing military munitions 
handling regulations. Similarly, with regard to EDC/VCM wastewater 
treatment sludges in today's rulemaking we have reasonably determined 
that the waste will not pose a hazard if managed in hazardous waste 
landfills or non-hazardous waste landfills licensed or permitted by a 
state. We base this conclusion on the results of the Agency's risk 
assessment and in view of existing state and federal controls for non-
hazardous waste landfills. We note that the finding by the court in 
Military Toxics Project did not hinge upon EPA deferring to a 
comprehensive regulatory program, but only to programs that address the 
appropriate waste management scenarios in a manner that EPA determined 
is necessary to protect health and the environment. Given the results 
of the Agency's risk assessment, we find that the management of these 
wastes in non-hazardous waste landfills licensed or permitted by a 
state is protective of human health and the environment. On the basis 
of this conclusion and in light of the Military Toxics Project 
decision, we conclude that EPA has the authority to promulgate a 
conditional listing for this waste.
3. Rationale for Final Listing Determination: Summary of the Impact of 
Public Comments on the Proposed Listing Determination for EDC/VCM 
Wastewater Treatment Sludges
    The Agency decided to finalize a contingent management listing for 
EDC/VCM wastewater treatment sludges based on the EPA's finding that 
these wastes posed a substantial hazard to human health and the 
environment when managed in a land treatment unit, but did not pose 
this hazard when managed in a landfill. As discussed above, commenters 
argued that EPA's risk estimates for the landfill and land treatment 
unit were in error. After reviewing and carefully considering all 
information provided by commenters, we re-evaluated our risk assessment 
results. Based on information provided by commenters, we decided it was 
appropriate to adjust our proposed risk estimate, 2E-04, for the land 
treatment unit. As mentioned above in response to a commenter's 
concerns regarding the expected productivity of EPA's modeled 
agricultural field, EPA's risk estimate for the land treatment unit 
almost entirely was due to a farmer's ingestion of beef and dairy 
products from cattle that consume dioxin-contaminated forage and 
pasture soil. That is, the risk estimate is 2E-04 even when the portion 
of risk associated with cattle consumption of grain and silage are 
eliminated. Correcting the risk estimate to account for both cooking 
and post-cooking loss of beef and an overestimate of risk attributable 
to the erosion pathway analysis would reduce the risk estimate to 1E-
04. Accounting for a more reasonable pasture size would reduce this 
risk estimate (1E-04) to approximately 7E-05. Moreover, adjusting the 
TCDD slope factor downward as recommended by the commenter, and 
removing 1,2,3,6,7,9- and 1,2,3,7,8,9-HxCDD from the risk assessment 
completely, would reduce this risk estimate only to 5E-05. Although EPA 
does not support making these adjustments to the toxicity values, doing 
so demonstrates that accepting the commenter's recommendation would not 
reduce the risk estimate to a value that, after consideration of other 
factors as described in Section VI.B.1. of this preamble, would change 
the Agency's finding that these wastes pose a substantial hazard to 
human health and the environment. Our analysis of the comments did not 
reveal any justification for modifying our proposed risk estimate for 
the landfill scenario.
    Therefore, the Agency is listing EDC/VCM wastewater treatment 
sludges as EPA Hazardous Waste Number K174, unless the sludges are 
managed in a subtitle C landfill, or a non-hazardous waste landfill 
permitted or licensed by a state. The Agency believes that allowing the 
waste to continue to be managed under a low risk management scenario 
(i.e., non-hazardous waste landfilling) outside of the subtitle C 
system achieves protection of human health and the environment, and 
that little additional benefit would be gained by requiring that all 
EDC/VCM wastewater treatment sludges be managed in accordance with RCRA 
subtitle C management standards. Given the Agency's finding that the 
level of risk posed from managing EDC/VCM wastewater treatment sludges 
in a landfill is not at a sufficient level to support a hazardous waste 
listing determination, the Agency sees no reason to include sludges 
managed in this manner in the scope of the hazardous waste listing. 
Additionally (and after consideration of the predicted risk 
differential between land treatment and landfilling), because only one 
facility employs land treatment for these wastes, this practice is 
somewhat anomalous compared with land disposal. It does not make sense 
to apply a traditional listing approach (i.e., list all wastes 
regardless of management practice) based upon a practice occurring at 
one facility, especially if a more tailored listing can prevent 
potential risks from the practice.
    Under the contingent management listing approach finalized today 
for EDC/VCM wastewater treatment sludges, EDC/VCM sludges will be 
hazardous wastes unless they are disposed in a landfill. EDC/VCM 
wastewater treatment sludges that are handled in compliance with the 
contingent management approach will be considered nonhazardous from the 
point of generation. Such sludges will not be subject to RCRA subtitle 
C management requirements for generation, transport, or disposal 
(including the land disposal restrictions), if the waste is destined 
for disposal in a landfill and is not placed directly on the land prior 
to disposal in a landfill. If the waste is not disposed of in a 
subtitle C landfill or a state-licensed non-hazardous waste landfill, 
then the waste meets the listing description and must be managed in 
compliance with subtitle C management standards from the point of 
generation.
    In addition to requiring that EDC/VCM wastewater treatment sludges 
be disposed in a subtitle C landfill or a state-licensed landfill to 
meet the contingent management listing, the Agency also is restricting 
the placement of EDC/VCM wastewater treatment sludges directly on the 
land prior to disposal in a landfill (e.g., storage in surface 
impoundments, storage in waste piles, spills). EPA wants to ensure that 
these wastes are managed in the manner found to be protective of human 
health and the environment. Under the terms of the listing, storage of 
EDC/VCM wastewater treatment sludge in tanks or containers, or in any 
manner other than direct placement on the land, prior to disposal will 
not constitute a violation of the conditions for exclusion from the 
hazardous waste listing.
    Generators, and other parties involved in the management of EDC/VCM 
wastewater treatment sludges, claiming that their wastes fall outside 
the scope of the hazardous waste listing must be able to document or 
demonstrate that sludges excluded from the listing description are 
being managed in accordance with the conditions for being excluded from 
the listing. This means that parties claiming the waste falls outside 
the scope of subtitle C must be able to demonstrate that (1) previously 
generated and managed waste (which is being claimed as not meeting the 
K174 listing) was disposed of in a landfill; and (2) waste currently

[[Page 67098]]

being managed is not being stored, or otherwise managed, on the land 
(e.g., waste piles, surface impoundments) as well as demonstrate that 
the waste is disposed of in a landfill. We note that the Agency is not 
imposing any specific recordkeeping requirements as part of today's 
final rule. Instead the Agency is finalizing, as part of the listing 
description, a more flexible performance standard similar to the 
documentation requirement provided in 40 CFR 261.2(f) for documenting 
claims that materials are not solid wastes. Generators and other 
handlers of EDC/VCM that claim the waste is not a hazardous waste must 
merely demonstrate that the generator or handler has, and continues to 
handle the waste in compliance with the contingent management 
conditions. One of the simplest ways to make such a demonstration may 
be to provide a compliance or enforcement official, upon request, with 
a copy of a signed contract with a state-licensed landfill. In cases 
where such a contract does not exist, other documentation of past and 
on-going disposal practices such as signed non-hazardous waste 
manifests, shipping papers, and/or invoices should provide an 
appropriate demonstration of proper management. The Agency points out 
that a generator's or handler's ability to demonstrate recent and/or 
on-going shipments of EDC/VCM wastewater treatment sludges to 
appropriate disposal facilities will serve as sufficient demonstration 
of intent to continue such management practices for wastes being stored 
on-site in tanks or containers (or in any other manner other than 
direct placement on the land) and not yet offered for off-site 
shipment.
    The Agency points out that should EDC/VCM wastewater treatment 
sludges meet a listing description for another listed hazardous waste, 
or if the wastewater treatment sludges exhibit one or more of the 
characteristics of hazardous waste, the sludges must be managed as 
hazardous wastes and are not exempt from regulation, due to the fact 
that they may be characterized as EDC/VCM wastewater treatment sludge.

C. Wastewater Treatment Sludges and Wastewaters From the Production of 
VCM-A

1. Wastewater Treatment Sludges From VCM-A Production
    The EPA is listing as hazardous wastewater treatment sludge from 
the production of vinyl chloride monomer using mercuric chloride 
catalyst in an acetylene-based process (VCM-A). This wastestream meets 
the criteria set out at 40 CFR 261.11(a)(3) for listing a waste as 
hazardous because it may pose a substantial or potential hazard to 
human health or the environment. The Agency identified significant 
potential risks to consumers of groundwater due to the release of 
mercury from this waste when managed in a landfill. We are not 
promulgating the proposed alternative option of conditionally listing 
this waste (i.e., listing the waste only if it is not managed in a 
subtitle C landfill) because after reviewing comments we remain 
convinced that the current management practice of disposing of 
untreated forms of this waste in a subtitle C landfill, even after 
taking into account landfill controls, can pose significant risk as 
explained in more detail below.

    K175--Wastewater treatment sludges from the production of vinyl 
chloride monomer using mercuric chloride catalyst in an acetylene-
based process.

    In the August 25, 1999 Federal Register we proposed to list VCM-A 
wastewater treatment sludge due to the potential risk from consuming 
groundwater containing concentrations of mercury, arising from the 
landfill disposal of the VCM-A sludge, that exceed the Maximum 
Contaminant Limit (MCL).\35\ At proposal, we considered risks arising 
from both an unlined landfill disposal and a subtitle C landfill 
disposal management scenario, because at that time we believed both 
scenarios were plausible forms of managing this waste. Under the 
unlined landfill scenario, we used the mercury TCLP analytical results 
for the VCM-A sludge (0.26 mg/L; facility split sample was 0.654 mg/L) 
and calculated a predicted groundwater concentration at a receptor well 
using a dilution and attenuation factor (DAF) of 40.\36\ The predicted 
receptor well groundwater concentration exceeded the mercury MCL by a 
factor of three based on a mercury leachate concentration of 0.26 mg/L 
(obtained from a sample of the waste analyzed by EPA), and by a factor 
of eight using the mercury leachate concentration from the facility's 
split sample of 0.654 mg/L (64 FR at 46510).
---------------------------------------------------------------------------

    \35\ The Maximum Contaminant Level Goal (MCLG) for mercury is 
0.002 mg/L because EPA has determined that drinking water below this 
level of protection would not cause any adverse health effects. The 
MCL for mercury is also 0.002 mg/L, and is an enforceable standard 
set as close to the MCLG as possible, considering the ability of 
public water systems to detect and remove contaminants using 
suitable treatment technologies.
    \36\ As noted at proposal, the DAF of 40 for mercury was 
developed for the 1995 proposed Hazardous Waste Identification Rule 
(60 FR 66344, December 21, 1995) for landfill leachate.
---------------------------------------------------------------------------

    Under the subtitle C landfill scenario, we took into account 
additional information regarding the increased mobility of mercuric 
sulfide (the form of mercury in the VCM-A sludge) under higher pH 
environments, and the degree to which subtitle C landfill controls 
(e.g., liner systems) would have to perform to prevent releases that 
exceed the MCL in groundwater at a modeled receptor well (64 FR at 
46511). We documented that the pH measured in leachate from the 
subtitle C disposal cell where this waste is currently managed is 
greater than 9, which is in all likelihood due to the presence in the 
landfill of alkaline materials commonly used to stabilize many types of 
hazardous wastes. We also cited analytical results from a draft 
treatability study on the VCM-A waste, indicating that mercuric sulfide 
is less stable in a higher pH environment, and that the leachate 
resulting from a constant pH leach test at pH=10 contained 1.63 mg/L of 
mercury. We concluded that mercury in the VCM-A waste would be 
significantly mobilized under the conditions found in the subtitle C 
landfill scenario, and at proposal we said that ``* * * even assuming a 
low probability of [liner] failure * * * there may still be a release 
of mercury that results in an accedence of the MCL. While there are 
uncertainties in this assessment, it still illustrates that the mercury 
concentrations in the receptor well may be close to, and could even be 
higher than the MCL'' (64 FR 46511). In other words, with a leachate 
concentration of 1.63 mg/L at pH=10 and a DAF of 40, the modeled 
receptor well mercury concentration is 0.041 mg/L when no credit is 
given to the liner system (i.e., assuming an unlined landfill). 
Assuming that no mercury is released to groundwater if a liner system 
is 100% effective, one only has to reduce the ``effectiveness'' of the 
subtitle C liner system by a small margin, to 95%, to predict a mercury 
concentration in a modeled receptor well equal to the MCL for 
mercury.\37\ The issue of the uncertainty with engineered liner systems 
is discussed in more detail further below.
---------------------------------------------------------------------------

    \37\ (0.05)(0.041 mg/L) = 0.002 mg/L
---------------------------------------------------------------------------

    Therefore, we presented at proposal two plausible management 
scenarios upon which we based our proposed listing, an unlined landfill 
and a subtitle C landfill. As discussed below in section VI.C.1.a, 
because we received information after proposal indicating that the 
unlined landfill scenario was not plausible, our final decision today 
to list the VCM-A sludge as hazardous is based only upon the subtitle C 
landfill scenario described above.

[[Page 67099]]

a. Response to Major Comments Received on Proposed Rule for VCM-A 
Wastewater Treatment Sludges
    VCM-A sludge is generated by only one facility in the United 
States, Borden Chemical and Plastics (BCP) in Geismar, Louisiana; 
therefore, the industry comments relating directly to this waste stream 
were from BCP. Environmental groups and waste treatment industry 
representatives also commented on the EPA's proposal to list this 
wastestream as hazardous.

i. Risk Assessment Submitted by BCP

    In response to the Agency's proposed decision to list wastewater 
treatment sludges from the production of VCM-A, BCP provided the Agency 
with a groundwater pathway exposure and risk analysis for mercury in 
VCM-A wastewater treatment sludges managed in landfills, conducted by a 
contractor on their behalf. BCP concludes, based upon their risk 
assessment, that there would be no human health risks to consumers of 
groundwater resulting from releases of mercury from VCM-A waste managed 
in a landfill.
    BCP's analysis was designed to parallel the manner in which EPA 
conducts contaminant fate and transport modeling when evaluating 
landfills. Specifically, BCP stated that its ``methods and assumptions 
followed to the extent possible those presented in [EPA's] Chlorinated 
Aliphatics Risk Assessment document when feasible.'' However, rather 
than using EPA's groundwater fate and transport model, EPACMTP, BCP's 
analysis used a simpler analytical groundwater transport model, AT123D. 
This model is not specifically designed to simulate leachate migration 
from land disposal units; although, when used appropriately, AT123D 
should be able to produce results that are protective and comparable to 
those obtained with EPACMTP. However, after carefully reviewing the 
risk assessment submitted by BCP, EPA found that there are significant 
deficiencies associated with certain aspects of the modeling and risk 
assessment and therefore is not persuaded by the conclusions drawn from 
BCP's analysis. These deficiencies are described below:

    <bullet> EPA's most significant concern regarding the way in 
which BCP conducted its groundwater modeling is that BCP limited the 
period of time that the contaminant plume is allowed to migrate to 
70 years from the time mercury was introduced into the groundwater. 
BCP's assumption has the effect of considering only exposure and 
hazard to current receptors and ignores potential hazard to future 
generations. In fact, in the case of release of leachate from a 
landfill, the greatest risk is often to future generations. This is 
because wastes initially are accumulated in landfills for many years 
prior to landfill closure, then, subsequent to landfill closure, 
leachate generation and migration in groundwater can occur for 
additional tens, hundreds, or thousands of years.
    <bullet> EPA disagrees with the way that BCP considered the area 
of the landfill in its modeling efforts. Although the area of the 
waste management unit is not input directly into the AT123D model 
employed by BCP, the model does require an equivalent source length 
and width. In its analysis, BCP modeled an areal source with an area 
of one meter by one meter, and a depth (thickness) of 6 meters. The 
analysis submitted by BCP does not provide the area of the actual 
landfill in which the VCM-A sludge is disposed, but a source area 
equal to 1 m<SUP>2</SUP> does not represent a realistic landfill 
size, since industrial landfills are typically on the order of 
50,000 to 100,000 m<SUP>2</SUP>. Moreover, a landfill of the size 
modeled by BCP (6m<SUP>3)</SUP> would not be large enough to contain 
the quantity of sludge that we estimate BCP generates in 1 year, 
109m<SUP>3)</SUP>, let alone the quantity we estimate BCP might 
generate over a 30 year period (3,273m<SUP>3)</SUP>.
    <bullet> In its AT123D modeling efforts, BCP assumed an aquifer 
hydraulic conductivity of 1E-04 centimeters per second (cm/s). The 
median hydraulic conductivity value that we would have selected to 
correspond to the location of the landfill where BCP disposes of 
their waste is 8E-03 cm/s.\38\ In the context of BCP's analysis, it 
does not appear that the hydraulic conductivity value used was 
protective. On the contrary, BCP's conclusion that: ``* * * in the 
70-year time span evaluated, mercury would move no further than 
between approximately 37-46 meters * * *.'' was supported in part 
through use of a hydraulic conductivity value that was 80 times less 
than the median hydraulic conductivity value that EPA would have 
selected, potentially resulting in an underestimate of the predicted 
groundwater flow rate. This could result in a significant 
underestimation of predicted contaminant migration.
---------------------------------------------------------------------------

    \38\ The source of our hydraulic conductivity data is a database 
prepared by the American Petroleum Institute (Newell, Charles J., 
Loren P. Hopkins, and Philip B. Bedient, 1989. Hydrogeologic 
Database for Ground Water Modeling. API Publication No. 4476, 
American Petroleum Institute, Washington, D.C.). The range of values 
from which the median is derived is 1E-05 to 4E-01 cm/s.
---------------------------------------------------------------------------

    <bullet> The value BCP used for the parameter that defines the 
dispersion of the contaminant plume (the dispersivity) was 
unrealistically large for the transport distances that BCP 
evaluated. Dispersion causes a contaminant plume to spread both 
ahead of the bulk flow of groundwater (longitudinally) and 
perpendicular to the bulk flow of groundwater (transversely and 
vertically). The effect of dispersion is to cause the leading edge 
of the plume to travel more rapidly and spread more widely than the 
bulk (average) groundwater flow. Dispersion also will cause the 
plume to become more diluted due to mixing with ambient 
(uncontaminated) groundwater. This dilution effect will be most 
pronounced at the periphery of the plume. BCP's methodology for 
estimating dispersivity was based on designating where the 
concentration value for the plume will be measured (that is, the 
location of the receptor well) and calculating an appropriate 
dispersivity value for that location, since dispersivity increases 
with distance from the source. Accordingly, BCP calculated 
dispersivity values corresponding to the location of a receptor well 
152 meters from the landfill source. EPA acknowledges that this 
approach is consistent with generally accepted practices, and does 
not disagree with the approach in principle; that is, the 
dispersivity values used in BCP's modeling would have been 
appropriate to characterize the effect of hydrodynamic dispersion on 
plume concentrations at the location of the designated receptor well 
(152m from the source). BCP's error occurred when they elected to 
use the modeled concentration at a distance of 37m (the predicted 
leading edge of the contaminant plume) as the basis for their 
calculation of mercury hazard. BCP did not modify their estimate of 
plume dispersion to correspond to a closer distance to the source. 
By not correctly accounting for distance from the source, BCP's 
groundwater modeling analysis significantly overestimated the effect 
of dispersion at the edge of the plume, and the resulting dilution 
of the plume due to dispersive mixing. Consequently, the mercury 
concentration (and associated hazard) that BCP predicted to 
correspond to the edge of the plume was much lower than it would 
have been had they accurately estimated dispersion. More 
appropriately, BCP should have extended their modeling timeframe, as 
discussed above, such that they could have more accurately predicted 
contaminant concentrations at their designated receptor well 
distance.

    BCP concluded from their analysis that essentially no migration of 
mercury would occur in groundwater, and that mercury concentrations in 
groundwater are below levels of concern. Because BCP limited their 
analysis to the evaluation of current receptors, potentially 
underestimated the hydraulic conductivity of the aquifer, overestimated 
aquifer dispersivity, and grossly underestimated the area of the 
landfill, EPA does not believe BCP's risk analysis can be used to 
support a listing decision for VCM-A sludge.

ii. Plausibility of Unlined Landfill Management Scenario

    In the proposed rule, EPA stated that disposal of Borden's VCM-A 
sludge in a non-hazardous, unlined landfill was plausible, based upon 
gaps in the record, particularly prior to 1990. BCP commented that in 
all of the time it had responsibility for the operation of the VCM-A 
plant (which records indicate is since the early 1980's) Borden always 
managed its VCM-A sludge at a facility that was ``constructed and 
operated in

[[Page 67100]]

accordance with the hazardous waste regulations that existed at the 
time of disposal.'' Upon consideration of BCP's claim that the specific 
inventory of VCM-A waste, cited by EPA as having been stored on site in 
1985, was in fact disposed of as hazardous waste between March and May 
of 1985, there is no evidence the waste has ever been disposed of in an 
unlined, non-hazardous landfill. Moreover, given BCP's record of 
disposal of this waste in a hazardous waste landfill during the 1990's, 
and its comments that this is where BCP will continue to send the waste 
in the future, we see no compelling information to suggest the company 
would do otherwise. Accordingly, we agree that disposal in an unlined 
landfill is not plausible.

iii. Constant pH Leach Results Versus TCLP

    BCP took issue with our overall approach to determining that the 
VCM-A waste poses significant risk when mismanaged. Specifically, BCP 
disagreed with EPA's assertion that the VCM-A waste, which is in the 
form of mercuric sulfide, leaches mercury more readily at higher pH 
conditions. In particular, BCP criticized our reliance on the results 
of a preliminary EPA-sponsored study \39\ indicating (using only one 
sample) a leachate concentration for mercury at 1.63 mg/L at pH=10, and 
that the pH conditions of the landfill cell where this waste is 
presently disposed indicate an elevated pH as well (pH=9.48 to 9.7 as 
reportedly measured in the leachate collected from this landfill cell). 
Furthermore, BCP questioned our application of these analytical results 
to the circumstances surrounding the disposal of the VCM-A waste. BCP 
also argued that it appears that because we stated in the proposed rule 
that the TCLP may not be a reliable indicator of mercury mobility under 
these conditions, that EPA has ``invalidated its own regulatory 
procedures for this particular [waste] stream'' by relying on the 
waste-specific pH results discussed above, instead of relying on the 
existing TCLP method for defining whether or not the VCM-A sludge is 
hazardous. BCP was concerned that EPA's reliance on a waste-specific 
approach to determining the hazard of the VCM-A waste, rather than 
relying instead on the existing toxicity characteristic to determine 
hazardousness, was an ``unconventional method to single out this 
particular waste stream'' and was therefore arbitrary and capricious. 
BCP is arguing that it is inappropriate for EPA to assess the hazard of 
mercury in a waste when there is already an existing toxicity 
characteristic for mercury, and that by doing so for one specific waste 
EPA is selectively ``changing the rules'' for that waste.
---------------------------------------------------------------------------

    \39\ Paul Bishop, Renee A. Rauche, Linda A. Rieser, Markram T. 
Suidan, and Jain Zhang; ``Stabilization and Testing of Mercury 
Containing Wastes,'' Draft, Department of Civil and Environmental 
Engineering, University of Cincinnati, March 31, 1999.
---------------------------------------------------------------------------

    EPA disagrees with BCP's comment that EPA should rely on the 
existing TCLP, and that doing otherwise unfairly or inappropriately 
singles out its waste. First, because EPA has undertaken a listing 
determination for a certain category of wastes (chlorinated aliphatic 
wastewater treatment sludges), and has further identified VCM-A sludge 
as a reasonable subcategory due to the markedly different manufacturing 
process from which the waste is generated, it is entirely reasonable 
for us to assess the hazards of this specific waste in the context of 
this listing determination. The fact that only one facility in the 
United States currently is generating the waste in this subcategory is 
irrelevant to the sound technical conclusion that it merits separate 
consideration. Second, in making a specific listing determination EPA 
is not limited to looking only at whether the waste is hazardous under 
the existing characteristics approach to defining hazardous waste. 
While the listing criteria in 40 CFR 261.11(a)(3)(i) do require EPA to 
consider whether a waste is characteristically hazardous, there are 
other criteria in Sec. 261.11(a)(3) that the EPA also addresses in 
making listing determinations, which include a determination as to 
whether the waste poses significant risk based on a waste-specific 
evaluation.
    Additionally, the toxicity characteristic regulation is a 
regulation of general applicability; that is, it potentially applies to 
all non-exempt solid waste generated. The TCLP leaching test was 
designed to represent likely leaching potential of waste in an MSW 
landfill, which was considered plausible worst-case management 
conditions for industrial solid waste generally. BCP's comments 
expressed concern that the Agency is singling this waste out for 
assessment under an approach different (and more stringent) than that 
applied to other wastes or to evaluation of solid waste under the TC 
regulation. The Agency is considering the pH dependency of mercury 
sulfide solubility, and considering other data on this key waste 
constituent, including both the changes in likely leachability under 
conditions different from the TCLP test but matching those of the 
landfill where the waste is actually disposed. In doing so, the Agency 
is not singling this waste out for more stringent assessment. Rather, 
the Agency is attempting to more fully consider all the scientific data 
on the waste, its constituents, and its actual management conditions, 
and applying these data in an assessment of the likely risks from the 
waste as it is actually managed. The whole point of a listing 
determination is to decide, on a wastestream-specific basis, whether 
the existing characteristics adequately address risks from the waste.
    Regarding BCP's comment questioning the results from the EPA/ORD 
study on mercury mobility, while BCP claims to not necessarily dispute 
the results, it pointed out that the results were from a preliminary 
study that had not yet been peer reviewed, and that any decision EPA 
makes should be based upon peer-reviewed, final analytical reports with 
all QA/QC data available. BCP also commented that it attempted to 
duplicate the extraction of the VCM-A waste at varying pH (6, 8, and 
10) but found very little difference in the resultant mercury leachate 
concentration, and all results were below the TCLP limit of 0.2 mg/L. 
BCP points out that contradicting results cast doubt on EPA's 
conclusions that mercury is more mobile at elevated pH when in the 
mercuric sulfide state.
    EPA continues to believe that available evidence supports the 
conclusion that the solubility of mercuric sulfide increases with 
increasing pH, and that this conclusion is supported by scientific 
literature cited in the proposed rule \40\ as well as additional 
scientific literature and EPA calculations presented below. A recently 
published study on mercury speciation in the presence of polysulfides 
agrees with our finding that there is an increase in the solubility of 
cinnabar (mercury sulfide) in the presence of elemental sulfur, 
particularly at high pH.\41\ This same study also indicated that at a 
pH of 10, mercury can solubilize from mercuric sulfide at 
concentrations very similar to what was reported in the draft EPA/ORD 
study. EPA performed additional calculations using the geochemical 
assessment model MINTEQA2. We calculated the solubility of mercuric

[[Page 67101]]

sulfide using conditions reported for the VCM-A waste (e.g., pH 
reported for subtitle C landfill leachate where waste is disposed, 
sulfide concentration of VCM-A waste) and found the calculated mercury 
solubility agreed well with the mercury concentration data for the 
landfill leachate (originally included in the docket to the proposed 
rule). This further supports our assertion that sulfide and pH are 
controlling factors in the solubility of mercuric sulfide, and that 
this conclusion reasonably can be applied to the VCM-A waste as 
well.\42\ Therefore, while we did indicate at proposal that the EPA/ORD 
study was preliminary, we believed it was important to present these 
results as evidence because they represented direct studies on the 
instant waste being evaluated for listing. EPA has received no specific 
information in comment that effectively contradicts this evidence, and 
has identified specific information in the scientific literature that 
supports it.
---------------------------------------------------------------------------

    \40\ H. Lawrence Clever, Susan A. Johnson, and M. Elizabeth 
Derrick, The Solubility of Mercury and Some Sparingly Soluble 
Mercury Salts in Water and Aqueous Electrolyte Solutions, J. Phys. 
Chem. Ref. Data, Vol. 14, No. 3, 1985, page 652.
    \41\ Jenny Ayla Jay, Francois M. M. Morel, and Harold F. Hemond, 
Mercury Speciation in the Presence of Polysulfides, Environmental 
Science and Technology, 2000, Vol. 34, No. 11, pages 2196-2200.
    \42\ Memorandum from John Austin to Ross Elliott, May 12, 2000.
---------------------------------------------------------------------------

    Regarding the results from BCP's own leach testing experiment, 
which BCP claims did not show a strong correlation between pH and 
mercury solubility, BCP stated that it had attempted to replicate EPA's 
study ``in the absence of any information regarding how the EPA 
contractor samples were extracted.'' \43\ While EPA does not have any 
information on BCP's experiment (other than a summary of the findings) 
to explain why there might be differences between Borden's results and 
those from the EPA study, EPA's results are consistent with literature 
sources regarding the relationship between pH and mercury solubility 
from the mercuric sulfide form; therefore EPA does not agree that BCP's 
results indicate that EPA's conclusions are invalid.\44\ Again, even 
absent the draft EPA/ORD study, the effect of pH on the solubility of 
mercury in mercuric sulfide is established independently in the 
scientific literature, as discussed above.
---------------------------------------------------------------------------

    \43\ EPA notes that there was a summary description of the 
constant pH leaching procedure in Section 4.4 of the draft EPA 
report, which was part of the proposed regulatory docket.
    \44\ EPA also points to data in the proposed rule record from 
BCP's analysis of their mercuric sulfide sludge at three different 
pH values, which were all above the current TCLP limit and did vary 
with pH. See Appendix 1, Reclassification Petition Submitted to 
LDEQ, September 1987.
---------------------------------------------------------------------------

iv. Liner Effectiveness

    EPA requested comment on the basis for listing as hazardous the 
VCM-A waste that is presently being disposed in a lined subtitle C 
landfill. BCP stated that EPA's reliance on some degree of liner 
failure as part of predicting the release of mercury to groundwater 
from a subtitle C landfill amounts to a ``repudiation of existing 
standards for * * * landfill management of hazardous waste.'' BCP 
argues that EPA's statement that there is ``inherent uncertainty'' 
associated with liner integrity in a subtitle C landfill is no greater 
with respect to its VCM-A waste than it is for any other waste 
currently disposed in C landfills. BCP continues by making numerous 
arguments that subtitle C liner systems are designed to be compatible 
with the wastes being disposed, and that the regulatory requirements 
applicable to these systems (e.g., groundwater monitoring, leak 
detection, leachate collection, post-closure care and maintenance, 
etc.) are all designed to ensure system integrity in both the short- 
and long-term.
    EPA has acknowledged the uncertainty associated with liner systems 
in the past. Taking this uncertainty into account when evaluating the 
potential risk from this specific waste stream is in no way a 
repudiation of EPA's reliance on liner systems overall. Indeed, the 
premise of the statutory land disposal restrictions requirements--one 
of the core features of RCRA--is precisely that liners and other 
containment systems, no matter how well designed, are inherently 
uncertain and cannot be relied upon alone to fully mitigate threats 
posed by hazardous wastes. In general, we believe releases from 
landfills are significantly reduced by well-constructed, monitored, and 
maintained liner and cap systems. However, we recognize that there is 
still uncertainty associated with liner performance, both in the near 
term as well as in the long term. While some studies indicate that 
engineering properties of liners may last for many (perhaps several 
hundred) years, there are a variety of factors that may influence 
longevity and performance, such as poor construction, installation, or 
geologic movement below the liner that can cause holes, tears, or 
larger failures. Some defects are likely to have little to moderate 
effect on the leakage rate. Other defects may have a significant effect 
and may necessitate corrective action (64 FR at 31582).
    We are only considering this uncertainty to the extent that, as 
discussed previously in section VI.C.1, even if a liner system is 
capable of preventing 95% of releases over the long-term, the waste 
likely will present substantial risk to consumers of groundwater due to 
a release of mercury from the landfill unit (i.e., exceedance of the 
MCL). We are not saying we believe that liners will necessarily fail. 
What we are saying is that given the specific evaluation we have made 
of the VCM-A waste, a liner system can be 95% effective and we still 
would predict a release to groundwater that potentially poses risk 
(exceedance of the mercury MCL at a modeled receptor well). We think 
that over the long term such a change in effectiveness is sufficiently 
plausible to merit consideration in this listing decision. We emphasize 
that this assessment is specific to a waste containing a highly toxic, 
very persistent constituent coupled with the possibility of a small 
degree of liner degradation, and does not mean that EPA would choose to 
list any wastes voluntarily put into a subtitle C landfill.
    Despite the uncertainty noted above on predicting how well liners 
will perform over periods of say, 100, 1000, or 10,000 years, and the 
fact that the oldest subtitle C units are less than 30 years old, EPA 
is nevertheless obligated in this listing determination to make a 
judgment whether waste disposed of in these units ``is capable of 
posing a substantial present or potential hazard to human health and 
the environment.'' Given that landfill controls would have to be 95% 
effective forever to prevent substantial risks from this highly 
concentrated, toxic, and persistent waste, EPA concludes that the waste 
is capable of posing a substantial hazard. While EPA cannot say how 
effective these units will be over the long term, we believe it is 
plausible that at least some will not be 95% effective forever. The 
alternative course would be for EPA to conclude the waste is not 
capable of posing a substantial hazard, by concluding that a Subtitle C 
landfill will most likely be 95% effective forever. But, we conclude 
that that is an unreasonable and unsupportable conclusion and are 
acting upon what seems like the more reasonable conclusion under the 
circumstances.
    EPA also points out that under RCRA, the subtitle C management 
standards provide that hazardous wastes that are land disposed must be 
treated to reduce the risk of hazardous constituents being released to 
the environment as well as be disposed in landfills equipped with 
liners and leak detection. The existing standards for the safe 
management of hazardous wastes rest on more than the landfill 
management requirements, or liner integrity. The legislative history to 
RCRA 3004(m) states that this section of the statute ``makes 
Congressional intent clear that land disposal without prior treatment 
of these wastes with significant concentrations of highly persistent, 
bioaccumulative constituents

[[Page 67102]]

is not protective of human health and the environment.'' (130 Cong. 
Rec. S 9178; daily ed. July 25, 1984). Mercury is exactly the type of 
``highly persistent, bioaccumulative constituent'' to which Congress 
was directing this statutory mandate.

v. pH Conditions of Disposal Environment

    BCP questioned EPA's conclusions that the disposal conditions at 
the subtitle C landfill cell where the VCM-A waste is presently 
disposed are at elevated pH levels, based upon the recorded pH 
measurements EPA obtained for the leachate collected from this same 
cell. BCP also cited several factors that it stated led to the 
conclusion that the VCM-A waste will not be subjected to elevated pH 
conditions when disposed in the subtitle C cell where it currently is 
sent. BCP described several factors that would limit the influence of 
other co-disposed wastes on the VCM-A waste (and thus, BCP appears to 
be saying, reduce the likelihood of the VCM-A waste being subject to 
elevated pH conditions). BCP points out that the volume of the VCM-A 
waste disposed in the cell since 1985, which is relatively minor, 
compared with the large volume of other hazardous wastes in the 
disposal cell, the supposed absence of free liquids in a subtitle C 
landfill, the lower pH and resultant buffering capacity of the VCM-A 
waste, and the fairly solid nature of the VCM-A waste, all reduce the 
influence that other co-disposed wastes may have on the potential for 
mercury to leach from the disposed VCM-A sludge.
    EPA disagrees that these factors would change the conclusion that 
is drawn from the measured elevated pH of the leachate removed from 
this landfill cell. In addition to the leachate pH measurements cited 
in the proposed rule for the same cell where BCP's VCM-A sludge is 
disposed, additional information from the landfill facility confirms 
these leachate pH measurements are consistent with the nature of the 
landfill leachate for this facility.\45\ In fact, to the extent that 
these factors affect the pH of the landfill environment, we believe it 
is reasonable to conclude that the measured leachate pH provided by the 
landfill operator reflects the sum total of these various factors. 
Borden's comments give us no reason to believe that the leachate 
collected from this cell is not indicative of elevated pH conditions 
within the unit. We thus conclude that BCP's waste, while in the same 
disposal cell and coming into contact with leachate, would be exposed 
to the type of alkaline conditions that result in higher mercury 
mobility when in the sulfide form.
---------------------------------------------------------------------------

    \45\ See Memorandum from Ross Elliott, U.S. EPA Office of Solid 
Waste, to RCRA Docket, ``Summary of Phone Call Between EPA and Carl 
Carlsson, Chemical Waste Management Inc.,'' July 12, 2000.
---------------------------------------------------------------------------

vi. Other Comments

    BCP commented that should EPA decide to list the VCM-A waste as 
hazardous, we should select the alternative option proposed which would 
result in the VCM-A waste only being listed if sent anywhere other than 
to a subtitle C landfill (and provided the waste does not exhibit the 
toxicity characteristic for mercury). EPA proposed this alternative 
option in the event that we received comment persuading us that our 
assumptions were incorrect regarding mercury being more mobile in the 
presence of sulfides in a higher pH environment, or that our assessment 
of liner uncertainty is insufficient to predict a risk to consumers of 
groundwater. As discussed above, EPA remains convinced that mercuric 
sulfide is less stable under the elevated pH conditions of disposal in 
a subtitle C landfill, and that a liner system can be 95% effective and 
we still would predict a release to groundwater that potentially poses 
risk.
    BCP also requested that should EPA proceed with a decision to list 
the VCM-A waste as hazardous, that we re-phrase the K175 listing 
description so it only applies to mercuric sulfide forms of sludge. The 
commenter said that this was so future technologies could be developed 
that are ``better'' and the sludge would no longer meet the listing if 
these changes are employed. Aside from suggesting that the reference to 
mercuric sulfide be removed, the commenter did not provide any specific 
potential changes that might occur, or how these changes would make the 
wastewater treatment sludge significantly different or less risky. The 
listing description proposed refers to the manufacturing process that 
uses mercuric chloride catalyst, and the commenter did not suggest 
changing that part of the listing; therefore EPA concludes that the 
commenter would still be faced with a wastewater treatment sludge 
containing very high levels of total mercury (to comply with regulatory 
limits on the amount of mercury in the discharged wastewater). Absent 
any specific examples, EPA can think of one possible change that could 
result in a sludge that could pose a greater potential risk. It is 
possible that the facility could continue to use the mercuric chloride 
catalysts (as is currently the case for the acetylene-based process), 
but alter the wastewater treatment process to produce a mercuric oxide 
sludge, in order to make the sludge more amenable to retorting for 
mercury recovery. Sludge from such a process might pose a greater risk, 
because the mercury would be more soluble than the current sulfide. We 
believe that the current listing description is appropriate, because it 
appropriately describes the waste subject to our evaluation.
b. Summary
    In conclusion, EPA is listing as hazardous the VCM-A wastewater 
treatment sludge described above because this wastestream meets the 
criteria set out at 40 CFR 261.11(a)(3) for listing a waste as 
hazardous. Our analysis that showed potential risk to consumers of 
groundwater due to a predicted exceedance of the MCL takes into account 
the toxicity and concentration of mercury in the waste (criteria at 40 
CFR 261.11(a)(3)(i) and (ii)). This is because the mercury MCL is based 
upon toxic human health effects from ingestion of mercury, and because 
the high mercury concentration in the waste results in the predicted 
MCL at the modeled receptor well. We also determined that the potential 
of mercury to migrate from the waste into the environment under a 
plausible disposal scenario (criteria at 40 CFR 261.11(a)(3)(iii) and 
(vii)) and mercury's persistence and lack of degradation into non-
harmful constituents (criteria at 40 CFR 261.11(a)(3)(iv) and (v)) also 
supported a decision to list this waste. This is because there is 
increased solubility of mercury in this waste at the elevated pH 
conditions in the landfill cell where the waste is disposed, and only a 
relatively small degradation of liner performance results in 
unacceptable risk to potential groundwater consumers. In addition, 
mercury is a persistent contaminant and therefore will not degrade 
before any predicted impact to groundwater occurs.
    Listing criteria that the EPA considered but which did not form the 
basis for listing this waste include the ability of mercury to 
bioaccumulate in ecosystems, the nature and severity of human health or 
environmental damage from improper management of these wastes, and 
actions taken by other governmental agencies or regulatory programs. 
(40 CFR 261.11(a)(3)(vi), (ix), and (x)). Bioaccumulation of mercury is 
not relevant to the exposure pathway EPA assessed (ingestion of 
groundwater). Although no documented damage incidents were found for 
this particular waste, EPA believes that on balance this fact alone 
does not

[[Page 67103]]

persuade us to make a finding that this waste should not be listed, 
when weighed against the other criteria described in this section that 
support a decision to list this wastestream. No governmental or 
regulatory actions \46\ were identified that would lead EPA to decide 
to list this waste or conclude that waste was already sufficiently 
controlled to render further regulation moot.
---------------------------------------------------------------------------

    \46\ Although we noted at proposal that the facility had 
obtained a ``reclassification'' of the waste as non-hazardous from 
the State of Louisiana, this determination did not appear to be a 
blanket exemption from hazardous waste requirements, for example, 
should a process change result in a waste that fails the toxicity 
characteristic for mercury, the waste would have to be handled as 
hazardous waste).
---------------------------------------------------------------------------

    Finally, EPA did consider certain ``other factors as may be 
appropriate'' together with the quantities of this waste generated 
(criteria at 40 CFR 261.11(a)(3)(xi) and (viii)) in a ``weight-of-
evidence'' approach to reach a decision to list this waste as 
hazardous. As discussed in the Land Disposal Restrictions section of 
today's preamble (section VI.I.3), EPA believes that this waste can be 
disposed in a manner that helps ensure the mercury is more stable and 
less likely to leach. Because this waste is already being sent to a 
hazardous waste landfill, one important effect of today's listing is 
the assurance that the waste is properly treated (or otherwise meets 
specific standards as generated) and is disposed in a manner to reduce 
the likelihood of mercury releases to groundwater, releases that may 
result in unacceptable risk to consumers of groundwater. Given the 
reported amount of this waste generated per year (120 metric tons), and 
the high total concentration of mercury in the waste (approximately one 
percent mercury by weight), the total loading to the landfill is 
approximately one metric ton of mercury per year. Ensuring that this 
amount of mercury is disposed of in a form that minimizes releases of 
mercury was considered by EPA when making its final listing decision.
2. Wastewaters From VCM-A Production
a. Summary of Agency's Listing Determination for VCM-A Wastewaters
    The EPA is not listing as hazardous wastewaters generated from the 
production of vinyl chloride monomer using mercuric chloride catalyst 
in an acetylene-based process (VCM-A). This wastestream does not meet 
the criteria set out at 40 CFR 261.11(a)(3) for listing a waste as 
hazardous, for the reasons described below.
b. Discussion of Agency's Listing Determination
    As discussed above, only one facility in the United States operates 
an acetylene-based VCM production process, which uses mercuric chloride 
catalysts in the production of VCM. The management of spent mercuric 
chloride catalyst used in the VCM-A production process results in the 
generation of a wastewater containing mercuric chloride, as well as 
vinyl chloride. EPA proposed not to list this wastewater due to the 
fact that the wastewater already is identified as hazardous waste. As 
explained in the preamble to the proposed rule, the wastewater exhibits 
the toxicity characteristic for mercury and vinyl chloride. EPA 
received only one comment addressing the Agency's proposed decision not 
to list VCM-A wastewaters. This comment favored EPA's proposed 
decision.
    The Agency bases its decision not to list VCM-A wastewaters as 
hazardous on the fact that the wastewaters already are identified as 
hazardous wastes under the toxicity characteristic. In fact, the 
concentration of mercury in a sample of this wastestream analyzed by 
EPA was over 40 times above the TC regulatory limit for mercury. 
Therefore, it is highly probable that the wastewater routinely contains 
levels of mercury which cause this wastestream to be defined 
consistently as characteristically hazardous waste. Therefore, EPA 
concludes that the TC adequately defines this wastestream as hazardous.
    Additionally, the facility's dedicated wastewater treatment system 
is designed and optimized expressly for the removal of mercury, the 
source of which is the mercuric chloride catalysts, to comply with 
regulations promulgated under the Clean Water Act. The criteria in 40 
CFR 261.11(a)(3) for evaluating whether or not a solid waste is a 
hazardous waste provide that EPA should consider how the waste (and 
potential risk) is affected by other regulatory programs (i.e., 
261.11(a)(3)(x)). In the case of the VCM-A wastewaters, EPA notes that 
the Agency's decision not to list this wastewater as hazardous is based 
on the fact that the waste already is defined as a hazardous waste 
because it exhibits the toxicity characteristic and the potential risks 
posed by the wastestream are regulated both under RCRA and other 
programs. With respect to the discharge of the wastewater, the facility 
treats and discharges the wastewater in compliance with the conditions 
of a NPDES permit issued under the authority of the Clean Water Act. 
Regarding any air emissions of vinyl chloride from these wastewaters, 
vinyl chloride is a hazardous air pollutant; therefore the facility is 
subject to the National Emissions Standards for Hazardous Air 
Pollutants (NESHAP) requirements specific to vinyl chloride emissions 
(40 CFR 61.65), as well as the Hazardous Organic NESHAP for the 
synthetic and organic chemical manufacturing industry sector (40 CFR 
Part 63, subpart G)(59 FR 19468, April 22, 1994).
    Given that this waste currently is regulated as hazardous because 
it exhibits the TC and given the fact that management of the 
wastestream is adequately regulated under a number of environmental 
regulatory programs, the Agency is promulgating a decision not to list 
VCM-A wastewaters as hazardous waste.

D. Wastewater Treatment Sludges from the Production of Methyl Chloride

1. Summary of Agency's Listing Determination for Methyl Chloride 
Wastewater Treatment Sludges
    EPA is not listing as hazardous sludges from the treatment of 
wastewaters generated from methyl chloride production processes. The 
Agency has determined that this wastestream does not meet the criteria 
set out at 40 CFR 261.11(a)(3) for listing a waste as hazardous.
2. Discussion of Agency's Listing Determination
    Only one facility generates a non-hazardous wastewater treatment 
sludge from the production of methyl chloride. The facility generates 
less than 800 metric tons of the sludge annually and disposes of the 
sludge in an on-site landfill. As discussed in the preamble to proposed 
rule (64 FR 46516), EPA conducted a risk assessment of this waste, 
modeling one management scenario (the on-site landfill). The Agency's 
analysis of potential risks due to volatile emissions from the landfill 
found negligible risks (i.e., estimated risks less than 1E-6) to 
individuals in the surrounding area. The Agency also conducted a 
bounding (i.e., worst case) risk analysis to estimate potential risks 
to groundwater consumers. This analysis used the leachate concentration 
measured from a sample of the facility's methyl chloride wastewater 
treatment sludge, and assumed the direct ingestion of this leachate by 
an adult for a period of 58 years. This bounding analysis resulted in a 
risk of 5E-5 for one constituent, arsenic. This estimate of individual 
risk, together with additional factors described below in

[[Page 67104]]

EPA's response to specific comments, led the Agency to conclude that 
this waste did not pose a substantial risk to human health and the 
environment.
3. Response to Major Comments Received on the Proposed Listing 
Determination for Methyl Chloride Wastewater Treatment Sludges
    Two commenters questioned why the Agency proposed not to list the 
wastewater treatment sludges from methyl chloride production as 
hazardous, given that the individual cancer risk level from arsenic, 
via the groundwater pathway, is within the range of risk values that 
EPA generally associates with potential candidacy for listing the waste 
as hazardous. The commenters argued that EPA should not ignore the 
potential risks from the arsenic in the wastewater treatment sludges 
and should list the waste as hazardous.
    EPA did not ignore the potential risk from arsenic. The estimated 
risk described by the commenter was the result of the Agency conducting 
a bounding analysis using worst case assumptions. Given that the 
Agency's assumptions were very conservative (i.e., an adult receptor 
would drink leachate generated from the disposal of the methyl chloride 
wastewater treatment sludges for 58 years), and taking into account 
additional factors described below, the Agency determined that there is 
no substantial hazard to human health and the environment on which to 
base a decision to list the waste as hazardous.
    As described in more detail in Section VI.B.1. of this preamble, 
EPA's policy for listing wastes as hazardous (originally outlined in 
the in 1994 Dyes and Pigments proposal, 59 FR 66077) is that 
wastestreams with risks in the range of 1E-6 to 1E-4 may be either 
listed or not listed after taking into account additional factors. 
Generally, our benchmark level for listing is the middle of the range 
(1E-05), but, as described in the preamble to the Dyes and Pigments 
proposal, we use a ``weight of evidence'' approach that considers other 
factors. In the case of our listing determination for methyl chloride 
wastewater treatment sludges, these additional factors include the 
conservative assumptions that resulted in the groundwater risk estimate 
for arsenic, along with additional information available to the Agency 
regarding the manner in which the waste is currently managed (i.e., in 
a landfill). We also evaluated our risk assessment results in 
conjunction with additional information available to the Agency with 
regard to the constituent of concern (i.e., arsenic).
    If the Agency assumes a less direct pathway of ingestion (i.e., 
taking into account some dilution and attenuation expected with a 
landfill scenario, so that a person drinks groundwater contaminated 
with leachate, rather than the leachate directly), and applying a DAF 
of 5 (which would be a reasonable assumption for an unlined landfill), 
the predicted risk becomes 1E-5. However, the Agency also notes that 
assuming a DAF of 5 (as was described in the proposed rule) is likely 
too conservative, given that the landfill in which the methyl chloride 
sludge is disposed has a 24-inch clay liner and a leachate collection 
system. Therefore, the actual risk from arsenic in this waste will be 
much lower than the risk level predicted by the bounding analysis, 
given that the landfill currently used by the single facility 
generating this waste is lined and has a leachate collection system.
    To further illustrate why assuming a DAF of 5 would be a very 
conservative assumption, in our assessment of risk from the EDC/VCM 
wastewater treatment sludge presented elsewhere in today's rule, 
arsenic was an initial constituent of potential concern. To support our 
analysis of potential groundwater risks from the landfilling of EDC/VCM 
wastewater treatment sludges, we modeled arsenic releases and obtained 
estimates of DAFs for arsenic (assuming an unlined landfill) of 13 for 
the high-end risk estimate, and a DAF of 93 for the central tendency 
estimate. Thus, even if the Agency does not take into account the liner 
and leachate collection system in the one landfill where currently non-
hazardous methyl chloride sludge is managed, applying reasonable 
estimates of DAFs lowers the estimated risk to the lower end of the 
range of risks where the Agency may or may not list a waste; and upon 
consideration of the very conservative approach used in generating the 
arsenic risk estimate, the Agency concludes that the potential risk 
associated with arsenic in the waste is well below the range in which 
the Agency would deem the waste to pose a substantial hazard to human 
health and the environment. Therefore, EPA is finalizing a no list 
determination for wastewater treatment sludges from the production of 
methyl chloride.

E. Wastewater Treatment Sludges From the Production of Allyl Chloride

1. Summary of Agency's Listing Determination for Allyl Chloride 
Wastewater Treatment Sludges
    EPA is not listing as hazardous waste sludges from the treatment of 
wastewaters generated from allyl chloride production processes. The 
Agency has determined that this wastestream does not meet the criteria 
set out at 40 CFR 261.11(a)(3) for listing a waste as hazardous. The 
Agency identified no risks of concern associated with the current 
management of this waste.
2. Discussion of Agency's Listing Determination
    As discussed in the proposal, currently non-hazardous wastewater 
treatment sludges from allyl chloride production are generated at a 
single facility. The sludges are generated from the facility's 
centralized wastewater treatment system in which the facility manages 
wastewaters from multiple production processes and facilities. 
Wastewaters from the production of allyl chloride contribute less than 
two percent to the system's total sludge loading. According to the RCRA 
Section 3007 survey response from the one facility generating a non-
hazardous allyl chloride sludge, the sludge generated from the 
facility's wastewater treatment system is incinerated on site in a non-
hazardous waste incinerator.
    As described in the proposed rule, during the investigations 
undertaken in support of the listing determinations EPA collected one 
sample of sludge from the facility's combined wastewater treatment 
system. Two duplicate TCLP analyses were performed using the sample 
collected. The TCLP analyses indicated the presence of no TCLP 
constituents above regulatory levels. The sample also was analyzed for 
total constituent concentrations including arsenic and dioxins and 
furans. The total arsenic concentration in the waste was 11.7 mg/kg, 
and the total dioxin (TEQ/TCDD) concentration was 11.79 ng/kg.
    The Agency did not assess risks by modeling management practices 
and exposure pathways, since both the total arsenic level and the total 
dioxin level detected in the sludge are below levels of concern and 
well within the range of background levels of those constituents

[[Page 67105]]

in soils.\47\ \48\ In addition, the waste is generated by a single 
facility and currently is not managed in a manner other than non-
hazardous waste incineration.
---------------------------------------------------------------------------

    \47\ Alkhatib, Eid, and O'Connor, Timothy, ``Background Levels 
of Priority Pollutant Metals in Soil, American Environmental 
Laboratory, Vol. 10, No. 3, April, 1998.
    Hunter, Philip M., ``Air-Force Wide Background Concentrations of 
Inorganics Occurring in Ground Water and Soil,'' Proceedings from 
the Fourteenth Annual Waste Testing and Quality Assurance Symposium, 
Pp. 73-77, 1998.
    Welch, Alan H., Lico, Michael S., and Hughes, Jennifer L., 
``Arsenic in Ground Water of the Western United States,'' Ground 
Water, Vol. 26, No. 3, May/June, 1988.
    \48\ See Table 4-4 of ``Risk Assessment Technical Background 
Document for the Chlorinated Aliphatics Listing Determination,'' 
EPA, June 25, 1999a.
---------------------------------------------------------------------------

    Given that wastewater treatment sludges from allyl chloride 
production are generated by a single facility, that the sludge 
generated is the product of a facility-wide non-dedicated (i.e., not 
process-specific) wastewater treatment system, and that the waste 
contains no constituents of concern at concentrations of concern, the 
Agency concludes that no significant risks are posed by the waste. The 
Agency is finalizing a determination not to list this waste as 
hazardous.
3. Response to Major Comments Received on the Proposed Listing 
Determination for Allyl Chloride Wastewater Treatment Sludges
    One commenter questioned whether EPA had considered the fact that 
the one facility generating wastewater treatment sludges from the 
production of allyl chloride may manage this waste in a manner other 
than on-site combustion in the future. The commenter suggested that EPA 
should have conducted a risk analysis of managing the waste both in a 
non-hazardous waste incinerator and in an unlined landfill.
    Given that the one facility generating this waste is managing the 
waste in an on-site incinerator and that the Agency has no information 
indicating that the facility has or intends to manage the waste in a 
manner other than on-site incineration, we believe that landfill 
management is not plausible for this wastestream. In the case of a 
waste that is generated by a single facility, we would not project a 
change in management practices without information or cause. EPA 
evaluated information provided by the facility regarding current 
management practices to project plausible scenarios. The Agency 
concluded that the facility has sufficient on-site capacity to continue 
to treat the waste in its non-hazardous waste incinerator. The total 
arsenic and total dioxin concentrations in the waste are below levels 
of concern.
    A commenter suggested that the analytical work performed on the 
wastewater treatment sludge generated from allyl chloride production 
was inadequate, given that only one sample of the sludge was collected 
and analyzed by EPA.
    The commenter did not provide any specific information as to why 
the allyl chloride sample collected by EPA was inadequate, other than 
it was one sample. As noted in Table 2-10 of the Listing Background 
Document (USEPA, 1999c), the Agency sampled 100% of the facilities 
producing allyl chloride, that is, EPA visited and sampled the one 
facility that produces this chlorinated aliphatic chemical. As 
discussed above and in the proposed rule, EPA is not listing this 
facility's allyl chloride wastewater treatment sludge because the 
chlorinated aliphatic production process at this facility contributes 
less than two percent of the total wastewater volume to the wastewater 
treatment process from which the sludges are generated. Given that 
there is only one generator of this waste and that the wastewaters from 
the allyl chloride production process contribute a relatively small 
portion to the facility's wastewater treatment system, EPA believes 
that our data, though perceived as limited by the commenter, is 
adequate to support the listing determination.

F. What is the Status of Landfill Leachate Derived-From Newly-Listed 
K175?

    At the time of the proposed rule, information available to EPA 
indicated that wastewater treatment sludges from the production of VCM-
A may have been managed previously in non-hazardous waste landfills. If 
these sludges had been managed in non-hazardous waste landfills, and if 
the leachate and gas condensate generated at such landfills is actively 
managed after the effective date of today's rule, the landfill leachate 
and gas condensate derived from the newly-listed VCM-A waste in such 
landfills could be classified as K175. As explained in the preamble to 
the proposed rule and in the final rule for leachate derived from 
newly-listed petroleum wastes (64 FR 6806), in such circumstances, we 
would be concerned about the potential disruption in current leachate 
management that could occur, and the possibility of redundant 
regulation (under RCRA and CWA) due to the application of the 
``derived-from'' rule to the leachate. In the case of non-hazardous 
waste landfills receiving newly-listing hazardous wastes prior to the 
effective date of the listing decision, the leachate that is collected 
and managed from the landfills would be classified as hazardous, due to 
the application of the waste code for the newly-listed K175 to the 
leachate. As noted by a commenter in response to proposed petroleum 
listing determination, this could lead to vastly increased treatment 
and disposal costs without necessarily any environmental benefit.
    In the chlorinated aliphatics proposed listing determination, EPA 
requested comment on whether or not VCM-A wastewater treatment sludges 
were previously disposed in non-hazardous waste landfills. Information 
provided to the Agency by the one generator of this waste indicates 
that this waste was not previously managed in non-hazardous waste 
landfills. The generator stated that they have always disposed of the 
VCM-A sludge in a subtitle C landfill. Since EPA has no evidence that 
this waste has been disposed of in non-hazardous waste landfills, the 
Agency sees no reason at this time to finalize the proposed temporary 
deferral for landfill leachate and gas condensate derived from newly-
listed VCM-A wastes. Therefore, today EPA is not finalizing the 
proposed temporary deferral for landfill leachate as was proposed.
    Although the Agency is not finalizing the proposed temporary 
deferral for applying the new K175 waste code to leachate from non-
hazardous waste landfills that previously accepted K175, should the 
Agency, in the future, receive information indicating that one or more 
non-hazardous waste landfills did accept this waste prior to the 
effective date of today's rulemaking, we may re-consider our decision 
not to finalize the proposed deferral. The Agency notes that the 
proposed regulatory language for the temporary deferral, as published 
in the August 25, 1999 Federal Register, inadvertently included both 
the K174 and K175 waste codes. The regulatory language in the proposal 
only should have included the K175 waste code. Given that the Agency is 
finalizing the conditional listing approach for K174 (and thus EDC/VCM 
sludge disposed in a licensed landfill will not be listed hazardous 
waste) there is no reason to include (nor did EPA intend to include at 
proposal) the K174 waste code in the temporary deferral for the 
application of waste codes to leachate from non-hazardous waste 
landfills that previously accepted newly-listed wastes (40 CFR 
261.4(b)(15)).

[[Page 67106]]

G. Population Risks

    As discussed previously, our proposed and final listing 
determinations were based upon estimates of individual risk. For the 
EDC/VCM wastewater treatment sludges, the projected population risks 
are low. We relied on individual risk estimates (excess lifetime cancer 
risk), and not population risk estimates, because we are concerned 
about risks to individuals who are exposed to releases of hazardous 
constituents. EPA concludes that, under certain waste management 
practices, these wastes are capable of posing a substantial present or 
potential hazard to human health or the environment. We have determined 
that using individual risk as a basis for this listing determination, 
which is consistent with past practices, also is appropriate because 
the Agency must protect against potential, as well as present hazards 
that may arise due to the generation and management of particular 
wastestreams. EPA acknowledges that in cases where small populations 
are exposed to particular wastes and waste management practices, 
population risk estimates may be very small. EPA finds it is important 
to address the current or potential substantial hazards to individuals 
living in small communities. Where individuals may be subject to 
substantial risks, EPA finds that such individuals deserve protection. 
In promulgating the final listing determinations for EDC/VCM and VCM-A 
wastewater treatment sludges, it is the increased risk for currently or 
potentially exposed individuals, regardless of how few individuals are 
exposed, against which EPA is reasonably protecting.
    In the proposed rule, in addition to presenting the results of our 
risk assessments estimating individual risks, we also discussed the 
potential risk posed to populations from the management of chlorinated 
aliphatic wastewaters managed in tanks, and EDC/VCM sludges managed in 
land treatment units and landfills. We requested comment on whether or 
not it is appropriate to give weight to population risk in making our 
final listing determinations. We also invited comment on the effect of 
such an approach with respect to the Agency's environmental justice 
goals, including our goal of protecting human health in rural areas.
    In response to the proposal, we received comments both supporting 
the use of population risk estimates in making listing determinations, 
and comments against this approach. Several commenters stated that the 
population risks estimated by EPA do not justify a decision to list as 
hazardous the wastes proposed for listing (chlorinated aliphatic 
wastewaters, EDC/VCM wastewater treatment sludges, VCM-A wastewater 
treatment sludges). Commenters argued that consideration of the risks 
posed by the management of these wastes to the entire population 
potentially exposed would lead to the conclusion that these residuals 
do not pose substantial hazards to human health. Therefore, the wastes 
should not be listed as hazardous. Commenters argued that EPA's failure 
to give serious consideration to the low levels of population risk is 
at odds with the RCRA statute, the listing criteria, and regulatory 
precedent within the federal government. Some commenters claimed that, 
due to the low population risk estimates, EPA cannot conclude that any 
of the residuals ``is capable of posing a substantial present or 
potential hazard to human health or the environment,'' as required in 
40 CFR 261.11, and therefore EPA should not list any of the residuals.
    In response, EPA notes that the use of ``population risk'' is not 
explicitly required nor prohibited in either the RCRA statute or the 
hazardous waste listing criteria in 40 CFR 261.11. EPA does not believe 
it is appropriate to allow contamination from waste management units to 
potentially cause substantial hazards to nearby residents simply 
because there are few individuals or wells in the immediate area. As 
stated above, our decision to list EDC/VCM and VCM-A wastewater 
treatment sludges is based on our concern about the present and 
potential hazards to those individuals who may be significantly 
exposed, even if there are few of them. In addition, the regulations 
clearly state that wastes are to be listed as hazardous, if they are 
``capable of posing a substantial present or potential hazard'' 
(emphasis added). Therefore, it is the Agency's past and current view 
that as a policy matter, the Agency considers the threats to 
individuals, whether they exist today or in the future. EPA's 
discretion to base its hazardous waste listing decisions upon 
substantial risks to individuals, even if risk to the overall 
population is low or near zero, recently was upheld by the U.S. Court 
of Appeals for the District of Columbia Circuit in American Petroleum 
Institute, et al. v. EPA (No. 94-1683).
    Specific comments received in response to the proposed rule 
included several commenters who argued that the legal standard in the 
RCRA statute for whether a waste is hazardous--that is, that the waste 
poses a ``substantial present or potential hazard to human health or 
the environment''--cannot be met unless EPA establishes that a large 
number of people are likely to have increased cancer risk due to 
exposure to the hazardous constituents in the waste, i.e., the so-
called ``population risk'' is high. We disagree with these commenters. 
EPA concludes in this listing (and has concluded in previous listings) 
that even if relatively few people may be subject to substantial 
hazards, those individuals still deserve protection. Accordingly, 
consistent with our past practice, we have based the EDC/VCM hazardous 
waste listing determination on the substantial hazard to currently or 
potentially exposed individuals, rather than on the increased number of 
cancer cases in the population at-large. The D.C. Circuit Court in 
American Petroleum Institute, et al., v. EPA upheld EPA's practice in a 
previous listing decision to base the decision on its concern for 
substantial risks to individuals.
    EPA points out that the use of the word ``substantial'' in the RCRA 
statute (i.e., ``* * * substantial present or potential hazard * * *'') 
need not be restricted to a quantitative meaning or applied exclusively 
to population risk. In the case of the wastes being listed as hazardous 
wastes today, we have determined that risks to individuals are 
``substantial.'' The estimated increased risk of cancer for the exposed 
individual is greater than 1 in 100,000. Consistent with EPA policy 
(see 59 FR 66072, at 66077), wastestreams for which the calculated 
high-end individual cancer risk level is 1 in 100,000 or higher 
generally are considered initial candidates for a listing decision. 
Wastestreams for which these risks are calculated to be 1 in 10,000 or 
higher will generally be listed as hazardous waste, although even for 
some of these wastestreams, there can be in some cases factors which 
could mitigate the high hazard presumption. Listing determinations for 
wastestreams with calculated high-end individual lifetime cancer risks 
falling into the range of 1 in 10,000 and 1 in 1,000,000 are also 
potentially listable but always involve an assessment of additional 
factors.\49\ For specific discussion of how EPA

[[Page 67107]]

addressed these factors for EDC/VCM sludge see Section VI.B.1. of 
today's preamble.
---------------------------------------------------------------------------

    \49\ ``The Superfund program has always designed its remedies to 
be protective of all individuals * * * that may be exposed at a 
site.'' 55 F.R. 8666, 8710 (Mar. 8, 1990). EPA's Superfund 
regulations at 40 C.F.R. Sec. 300.430(e)(2)(i)(A)(2) establish 
remediation goals at levels that represent an excess upper bound 
lifetime cancer risk to an individual cancer risk to an individual 
at between 10<SUP>-4</SUP> and 10<SUP>-6</SUP>.
---------------------------------------------------------------------------

    In addition to comments arguing the legality of basing hazardous 
waste listing decisions on estimated risks to individuals, rather than 
population risks, we received comments claiming that the individual 
risk approach used by EPA was ``overly conservative and unrealistic.'' 
These commenters stated that EPA needs to use population risk estimates 
as a ``reality check'' on individual risk estimates. Two commenters 
also said that we should use individual central tendency risk estimates 
as a more meaningful or realistic estimate of potential risk.
    EPA disagrees with commenters' assertions that the highly-exposed 
individual risk approach used in the risk assessment supporting today's 
listing determinations was overly conservative and unrealistic. In 
today's notice, as well as in the Response to Comment Document 
accompanying today's rule, we address specific comments regarding the 
risk assessment. Even though our listing decisions in today's rule are 
based upon predicted risks to highly-exposed individuals, we believe 
that these risks are within the distribution of risks that could 
reasonably be expected to exist in the population. In support of this 
conclusion, we note that as part of the analyses to support the notice 
of proposed rulemaking, we also conducted probabilistic modeling to 
more directly evaluate the anticipated distribution of risk levels. The 
high end deterministic risk estimate for the adult farmer under the 
EDC/VCM land treatment unit scenario fell at the 95th percentile of the 
probabilistic distribution. EPA's Guidance For Risk Characterization 
(USEPA, 1995) states: ``Conceptually, high end exposure means exposure 
above about the 90th percentile of the population distribution, but not 
higher than the individual in the population who has the highest 
exposure.''
    One commenter cited a 1987 study of 13 regulatory determinations 
where low population risk was cited as a reason not to regulate, and 
noted that the study suggests that EPA should not establish regulatory 
controls on the management of wastes, if the population burden is less 
than one cancer in 100 years.\50\ The commenter described where the 
individual risk levels in the proposed chlorinated aliphatics listings 
fell in comparison to the individual risk levels in these other 
regulatory decisions.
---------------------------------------------------------------------------

    \50\ Travis, Curtis C., 1987. Environment Science and 
Technology, Vol. 21, No. 5.
---------------------------------------------------------------------------

    EPA does not find this study leads it to change today's listing 
decisions. As already noted, the Agency has the discretion to base its 
listing decisions on the substantial hazard to highly exposed 
individuals, even if there is only a small number of them, as upheld by 
the U.S. Court of Appeals for the D.C. Circuit in American Petroleum 
Institute v. EPA. The study itself, however, has a number of flaws 
which lead EPA to reject its use. It deals with no RCRA decisions, but 
instead deals with a number of other statutes that have different 
mandates. This study also is outdated in that it was conducted a number 
of years ago when Agency risk assessment was less sophisticated than it 
is now. In particular, the study notes that at the time federal 
agencies overestimated risk assuming maximum exposures. Since issuance 
of EPA's 1992 ``Guidance on Risk Characterization for Risk Managers and 
Risk Assessors,\51\ EPA has modified its risk assessment approach to 
determine a plausible high-end exposure analysis, which is intended not 
to overestimate risks to highly exposed individuals. Moreover, EPA's 
current guidance acknowledges that in situations where small 
populations are exposed ``individual risk estimates will usually be a 
more meaningful parameter for decision-makers.'' \52\
---------------------------------------------------------------------------

    \51\ 1992 Memorandum from the then Deputy Administrator F. Henry 
Habicht, ``Guidance on Risk Characterization for Risk Managers and 
Risk Assessors.''
    \52\ 1995 Guidance for Risk Characterization (section III.C.2), 
page 17.
---------------------------------------------------------------------------

    The study merely presents a listing of decisions made by various 
federal agencies under different statutory requirements. It does not 
suggest any rationale for the regulatory decisions other than the fact 
that they occurred. It seems to suggest that, because we decided 
against specific regulations in the past that coincided with a 
particular individual risk level (e.g., 1  x  10<SUP>-4)</SUP> and low 
numbers of cancer cases avoided, we are somehow obligated to make that 
same decision now. The commenter does not offer any other rationale for 
determining at what point the number of cancer cases avoided would 
support an Agency decision to list a waste as hazardous.
    For several additional reasons, EPA disagrees with the suggestion 
that the Agency base today's listing decisions on total population risk 
or total number of cancer cases. In the first place and as previously 
noted, we believe we should not ignore substantial risks to 
individuals, if that might consign individuals to substantial risks, 
simply because only a few individuals potentially will be exposed. In 
addition, risk estimates alone do not dictate any particular listing 
decision. Even if EPA finds an individual risk of 1  x  10<SUP>-5</SUP> 
or greater, for example, the Agency considers other factors and may 
decide to list or not list a waste as hazardous, based upon the 
consideration of all relevant factors. In finalizing today's listing 
determinations, the Agency is basing its decisions on the listing 
policy described in the December, 1994 proposed listing determination 
for dyes and pigment industry wastes (59 FR 66072). Furthermore, the 
Agency does not think that it is adequate to base a hazardous waste 
listing determination upon a comparison of potential risks posed by 
wastes covered by one rulemaking relative to risks posed by other 
wastes and potentially unrelated rulemakings. The Agency considers 
relevant factors particular to a waste and the plausible management 
practices affected when making each regulatory decision. As we have 
discussed thoroughly in this preamble and in the accompanied background 
documents, in this case we think the individual risk estimates and our 
consideration of other factors provide an adequate justification for 
listing both EDC/VCM and VCM-A wastewater treatment sludges as 
hazardous wastes.
    Other comments received by the Agency include comments that stated 
that society does not have unlimited resources to address risks unless 
they are ``clearly substantial,'' as indicated by population risk. We 
point out however that the regulations state that EPA may list a waste 
if it is ``capable'' of posing a hazard and the underlying RCRA 
statutory language states that hazardous wastes are those that ``may * 
* * pose'' a hazard. Thus, the Agency disagrees that risks must be 
``clearly'' substantial to be subject to RCRA regulation. Further, EPA 
disagrees that ``clearly substantial'' risk (or even a risk that 
``may'' occur) must be indicated by a high population risk estimate. 
The statutory standard for listing a waste is ``substantial hazard.'' 
Where EPA finds that a waste poses a substantial hazard to highly 
exposed individuals, EPA will list the waste to protect those 
individuals potentially exposed.
    Other commenters supported the Agency's use of individual risk 
estimates as the appropriate criteria for making hazardous waste 
listing determinations. For example, one commenter said that EPA should 
weigh individual risk more than population risk because the commenter 
believes there is greater uncertainty in population risk estimates than 
in

[[Page 67108]]

individual risk estimates. No information was provided by the commenter 
as to why this would necessarily be the case. EPA agrees with the 
commenter that individual risk is an appropriate decision parameter, 
for the reasons already stated above.
    Another commenter who supports the use of individual risk over 
population risk, argued that EPA is not compelled by governing 
regulation or statue to define ``substantial hazard'' in terms of 
population risk. The commenter also stated that EPA should take into 
account risks to populations from more than just the industry under 
study, since populations are potentially impacted by risks from many 
different facilities. For example, in parts of the country concerns 
have been raised previously about certain minority and poor populations 
bearing a disproportionate amount of risk for a variety of industries 
and wastes.
    We agree that we are not compelled by governing regulation or 
statue to define ``hazard'' in terms of population risk. We may define 
``hazard'' on the basis of substantial risk to individuals even when 
population risk estimates are low. Although population risk is one of 
many factors that has been considered in some Agency decisions, there 
are numerous precedents where the Agency has taken action, for example 
at Superfund sites and in previous listing determinations, when there 
are relatively few people potentially affected. Superfund is a 
particularly apt example since it, like RCRA, deals with protecting 
human health and the environment from harm arising from the 
mismanagement of waste. The D.C. Circuit Court particularly noted the 
consistency with Superfund in American Petroleum Institute et al., v. 
EPA described above. While a different statute, the Agency has stated 
that the key objective of the CERCLA National Contingency Plan (NCP) is 
to protect individuals at contaminated sites (see 55 FR at 8710), and 
rejected using population risk as the point of departure for setting 
clean-up levels (see 55 FR at 8718). In addition, the CERCLA 
regulations (see 300.430(e)(2)(I)(A)(2), and 55 FR at 8848) direct EPA 
to establish preliminary remediation goals for carcinogens based on 
``cancer risks to an individual.''
    The Agency disagrees with the commenter's claim that potential 
risks from other industries should be estimated or accounted for in 
estimating potential risks from a particular wastestream generated by 
one specific industry. The benefits of this listing are the risks 
avoided from management of the newly-listed wastes. The Agency has no 
reason to factor in risks from other industrial wastes, unless a 
synergetic effect can be identified, which the commenter does not 
claim.
    The Agency is committed to addressing environmental justice 
concerns and does consider risks to minority and disadvantaged 
populations in its decision making. Our goal is to ensure that no 
segment of the population bears a disproportionally high risk as a 
result of our decision making. The hazardous waste listing 
determinations promulgated today are based upon analyses conducted with 
a goal of protecting all potentially exposed individuals. No segment of 
the overall population will be placed at a disadvantage as a result of 
today's rulemaking.
    Finally, the Agency is also concerned that land use patterns can 
change over time. For example, when evaluating a waste that adversely 
impacts groundwater, the Agency also is concerned about the potential 
contamination of future drinking water supplies, and of groundwater 
which may have other uses (e.g., livestock watering, irrigation, 
aquaculture). If regulatory decisions were based solely on population 
risks at a particular point in time, beneficial uses could be precluded 
or, if the future users were unaware of the contamination, unacceptable 
risks could occur. This same objective, the protection of reasonably 
anticipated land use is an integral part of the Agency's Superfund 
remedy selection process.\53\ Under Superfund, it is not sufficient 
only to consider potential risks to populations surrounding a 
particular site at the time of contamination or remediation; reasonably 
anticipated future land use patterns and future populations (i.e., 
future receptors) are considered in risk assessments supporting remedy 
decision making and in selecting the final remedy.\54\ In fact, the 
extensive experience with the Superfund program bears out these 
concerns. There are Superfund sites, for example, where residential 
developments were placed over former landfills that have turned out to 
be dangerous to the new populations, leading not only to risks to the 
population but expensive and time-consuming cleanups.
---------------------------------------------------------------------------

    \53\ Memorandum EPA Regional Waste Management Division Directors 
from Elliott P. Laws, ``Land Use in the CERCLA Remedy Selection 
Process,'' OSWER Directive No. 9355.7-04.
    \54\ See ``Risk Assessment Guidance for Superfund (RAGs), Volume 
I--Human Health Evaluation Manual, Part A,'' (Chapter 6), 1989.
---------------------------------------------------------------------------

H. Which Constituents Are Being Added to Appendix VIII to 40 CFR Part 
261?

1. Summary of Agency's Decision To Add Two Constitutents to Appendix 
VIII
    Two of the constituents of concern that are present in the EDC/VCM 
wastewater treatment sludges (K174) that will be designated as listed 
hazardous wastes as a result of today's rule do not currently appear on 
the list of hazardous constituents at 40 CFR part 261, Appendix VIII. 
Therefore, EPA is adding these two constituents, octachlorodibenzo-p-
dioxin (OCDD) and octachlorodibenzofuran (OCDF), to Appendix VIII.
2. Discussion of Agency's Decision To Add Constituents to Appendix VIII
    OCDD and OCDF are members of the large family of polychlorinated 
dioxins and furans. Certain of these compounds, most notably, 2,3,7,8 -
TCDD, have been shown to be toxic. The Agency found substantial hazard 
associated with the presence of dioxins in EDC/VCM wastewater treatment 
sludges, when these sludges are managed in land treatment units. In our 
risk assessment, dioxin/furan risk was reported on a TCDD TEQ basis. As 
previously discussed in today's final rule, as well as in the proposal, 
TCDD TEQ concentrations are calculated by multiplying each 2,3,7,8 
substituted congener by the appropriate TEF, and then summing the 
resultant concentrations to come up with a TCDD TEQ value. OCDD and 
OCDF are included in this calculation.
    Several studies, as noted in the response to comments below, show 
that OCDD and OCDF have toxic effects on life forms. Therefore, we have 
concluded, based upon the results presented in these scientific 
studies, that OCDD and OCDF should be added to Appendix VIII of 40 CFR 
part 261.
3. Response to Major Comments Addressing Agency's Decision To Add 
Constituents to Appendix VIII
    One commenter opposed the addition of OCDD and OCDF to Appendix 
VIII of 40 CFR part 261 on the basis that OCDD and OCDF contribute very 
little to the actual risk attributable to dioxin compounds. The 
commenter also contended that the assignment of non-zero TEFs to OCDD 
and OCDF cannot form the basis for a regulatory decision to list the 
compounds as hazardous constituents, since TEFs are intended only to be 
used as a tool to aid risk managers in thinking about potential health 
risks associated with the compounds. The commenter argued that

[[Page 67109]]

TEFs are not intended to provide a scientific basis for drawing the 
conclusion that OCDD or OCDF are toxic, carcinogenic, mutagenic, or 
tetratogenic. The commenter also argued that OCDD and OCDF do not meet 
the criteria in 40 CFR 261.11(a) for listing a substance on the 
Appendix VIII hazardous constituent list.
    The commenter contends that the 1988 study by Couture, Elwell, and 
Birnbaum, although it led to a raising of the TEF for OCDD/OCDF to 
0.001 by NATO/CCMS, does not support a non-zero TEF for OCDD/OCDF. A 
reevaluation of the study resulted in a downgrading of the TEF to 
0.0001 by the World Health Organization. The commenter further contends 
that few statistically significant physiological effects have been 
observed in the study and that they are transitory in nature and are of 
uncertain toxicological significance. The commenter also points out 
that a longer-term subchronic study has been reported which 
dramatically demonstrates that dioxin-like effects are not produced by 
OCDD in animals even at high dose levels.
    The commenter concludes that an extensive body of data exists that 
does not support the conclusion that OCDD is a toxicant, carcinogen, 
mutagen, or teratogen. In addition, the commenter states that 
essentially no toxicological data has been published for OCDF 
supporting the listing of the compound in Appendix VIII.
    EPA disagrees with the commenter's arguments for several reasons. 
First, the Agency notes, in response to issues raised by the commenter, 
that as a preliminary matter, dioxin TEFs are irrelevant to EPA's 
decision to list OCDD and OCDF in Appendix VIII. The criteria in 40 CFR 
261.11(a) for listing a substance on the list of hazardous constituents 
in Appendix VIII are that the constituents be ``shown in scientific 
studies to have toxic, carcinogenic, mutagenic or teratogenic effects 
on humans or other life forms.'' The Agency has determined that OCDD 
and OCDF meet these criteria, independent of any TEF calculation.
    There are data from subchronic studies for both OCDD and OCDF which 
demonstrate dioxin-like effects (Couture et al., 1988; DeVito et al., 
1997). Couture et al. (1988) is one of the best studies of OCDD and 
describes not only the effects but the importance of study design in 
examining the effects of OCDD. Couture et al. (1988) demonstrate toxic 
response of OCDD following subchronic exposures. In addition, this 
study also provides tissue concentrations at which these effects are 
observed. Couture et al. (1988) demonstrate that the absorption of OCDD 
is dependent upon both dosing volume and concentration of the solution. 
The higher the concentration the lower the absorption and the larger 
the volume (up to 5 ml/kg) the greater the absorption. Hence, high dose 
single exposures are unlikely to induce significant effects due to the 
limited absorption of OCDD. In contrast, low dose repeated exposures 
will allow for the bioaccumulation of OCDD, which eventually leads to 
biological effects. This is clearly demonstrated in the Couture et al. 
study (1988). The repeated exposure to 1 ug/kg of OCDD in a dose volume 
of 5 ml/kg produces time dependent effects that also are associated 
with increasing tissue accumulation of OCDD. OCDD induces hepatic 
CYP1A1 activity and increases CYP1A1 and CYP1A2 protein. Induction of 
CYP1A1 occurred as early as two weeks after treatment, and this 
response increased with time and with hepatic OCDD accumulation. 
Induction of CYP1A1 is a dioxin-like effect and is indicative of 
activation of the Ah receptor. Hepatic cytoplasmic vacuolization in the 
livers was also induced in a time dependent manner, first occurring 
after 40 doses and increasing in incidence and severity after 65 does 
of OCDD.
    The Agency disagrees with the commenter's argument that these 
effects are transitory or of uncertain toxicological significance. 
First, the cytoplasmic vacuolization (lesions) in the liver increased 
in incidence and severity in a time dependent manner. The increased 
incidence and severity of these lesions were associated with increasing 
hepatic concentrations of OCDD. Animals at the last time point examined 
in the study of Couture et al. (1988) demonstrated the highest 
incidence and severity of these lesions; it is difficult to describe 
them as ``transitory'' as the commenters suggest, given that the 
effects worsened over the last five weeks of the study. Indeed, 
hepatotoxicity can be considered as part of a continuum of events 
leading to necrosis or carcinogenicity. Demonstration of events early 
in this continuum, such as cytoplasmic vacuolization, are cause for 
concern. The commenter also attributes the liver effects to 
``nutritional, metabolic or hormonal imbalances.'' Indeed, dioxins are 
endocrine disruptors and hormonal imbalances are expected to be induced 
by OCDD and other dioxins. These hormonal imbalances should be 
considered adverse responses based on our understanding of the 
endocrine disrupting actions of these chemicals.
    The commenter neglects to mention that not only was enzyme activity 
induced by OCDD in the rats, but CYP1A1 and CYP1A2 protein were also 
increased as demonstrated by western blot analysis (Couture et al., 
1988). These proteins have been implicated in playing important roles 
in oxidative damage and porphyria (Sinclair et al., 2000). According to 
Nebert and colleagues ``metabolism of endogenous and exogenous 
substrates by perhaps every P450 enzyme, but certainly CYP1A1 and 
CYP1A2 (which are located, in part, in the mitochondrion), have been 
shown to cause reactive oxygenated metabolite (ROM)-mediated oxidative 
stress'' (Nebert et al., 2000). Ames and colleagues have clearly 
demonstrated the role of CYP1A1 in oxidative stress (Park et al., 
1996).
    The commenter cites a number of studies which suggest that OCDD is 
not toxic, in contrast to the studies of Couture et al. The studies 
cited are generally inadequately designed to address the toxicity of 
OCDD. Several studies have demonstrated that, while OCDD is poorly 
absorbed in biological systems (Norback et al. Birnbaum and Couture, 
1988; Couture et al., 1988) it can bioaccumulate through repeated 
exposures to low concentrations. In addition, in the Couture et al., 
study, it took at least 40 doses over approximately nine weeks before 
enough of the chemical could accumulate to produce alterations in liver 
histology. Acute, single exposures to high concentrations of OCDD are 
unlikely to result in significant accumulation to induce a toxic 
response since very little of the dose shall be absorbed. In fact, this 
is one of the conclusions in the McConnell et al. study (1978). Hence, 
the acute studies on the effects of OCDD demonstrated none of the 
typical signs of dioxin-like toxicity due to the limited absorption of 
the chemical. Other studies have to a lesser or greater degree 
attempted subchronic exposures. However, these studies either are too 
short (Holsapple et al. (1986)) or use too concentrated a dosing 
solution (Norback et al., 1975). In either case, too little OCDD was 
absorbed to induce effects.
    The commenter cites a study by Wermelinger et al. (1990) as 
evidence that OCDD does not induce dioxin-like effects. The USEPA 
strongly disagrees with this conclusion. This manuscript was published 
as an extended abstract from the dioxin meetings (Organohalogen 
Compounds, 1:221-224). These data clearly demonstrate that both OCDD 
and OCDF administered in the diet result in clear dioxin-like activity. 
Both OCDD and OCDF resulted

[[Page 67110]]

in dose dependent increases in CYP1A1 activity and decreases in thymic 
atrophy. These responses are clearly the hallmark of dioxin-like 
effects in experimental animals. The Wermelinger et al. study clearly 
supports the finding of Couture et al., that repeated low dose 
administration of OCDD results in dioxin-like effects. In addition, 
both Wermelinger et al. and Couture et al. provide similar estimates of 
the relative potency of OCDD, further supporting the inclusion of these 
chemicals in the TEF methodology.
    The commenter cites a study by the National Toxicology Program in 
which a two year feeding study of OCDD produced no effects. We could 
not locate any reports of this study in the NTP databases. After 
contacting the NTP, it was determined that the study of OCDD was halted 
due to uncertain technical difficulties and no reports were ever 
prepared on any study of OCDD by the NTP. It is unclear where the 
commenter obtained its information, since a citation for the report was 
not provided.
    The effects of OCDF are not as well studied as those of OCDD. 
Recent studies do document that subchronic exposure to OCDF 
demonstrates dioxin-like activities in mice (DeVito et al., 1997). The 
subchronic exposure resulted in EROD induction in liver, lung and skin 
(DeVito et al., 1997) and hepatic porphyrin accumulation (van Birgelen 
et al., 1996) in these mice. These studies demonstrate that OCDF also 
possesses dioxin-like properties.

I. What Are the Land Disposal Restrictions Standards for the Newly-
Listed Wastes?

1. What Are EPA's Land Disposal Restrictions (LDRs)?
    The RCRA statute requires EPA to establish treatment standards for 
all wastes destined for land disposal. These are the so called ``land 
disposal restrictions'' or LDRs. For any hazardous waste identified or 
listed after November 8, 1984, EPA must promulgate LDR treatment 
standards within six months of the date of identification or final 
listing (RCRA Section 3004(g)(4), 42 U.S.C. 6924(g)(4)). RCRA also 
requires EPA to set as these treatment standards ``* * * levels or 
methods of treatment, if any, which substantially diminish the toxicity 
of the waste or substantially reduce the likelihood of migration of 
hazardous constituents from the waste so that short-term and long-term 
threats to human health and the environment are minimized.'' RCRA 
Section 3004(m)(1), 42 U.S.C. 6924(m)(1). Once a hazardous waste is 
prohibited, the statute provides only two options for legal land 
disposal: meet the treatment standard for the waste prior to land 
disposal, or dispose of the waste in a land disposal unit that 
satisfies the statutory no migration test. A no migration unit is one 
from which there will be no migration of hazardous constituents for as 
long as the waste remains hazardous. RCRA Sections 3004 (d), (e), (f), 
and (g)(5).
5. What Are the LDR Standards for K174?
    In today's rule, we are adopting treatment standards for several 
forms of dioxins and furans as well as a treatment standard for 
arsenic. With respect to the dioxins and furans being regulated, our 
standard requires either treatment by means of combustion (denoted as 
CMBST in the 40 CFR 268.40 Table) or that the specified types of 
dioxins and furans meet numerical standards prior to land disposal.
    For most of the specified types of dioxins and furans (e.g., the 
hexa, penta, and tetra classes of congeners) as well as arsenic, we are 
adopting the existing universal treatment standards and no significant 
issues have been encountered. However, the setting of congener-specific 
numerical standards for 3 hepta and 2 octa forms of dioxin/furan 
warrants some additional discussion. In previous rulemakings, we have 
not adopted treatment standards for these isomers. Several reasons 
convince us that we should do so in today's rule.
    First, with the K174 waste, our risk analysis indicates that, 
should this waste be mismanaged in a land treatment unit, the hepta- 
and octa-chlorinated dioxin and furan isomers present high-end 
deterministic risks that, as described in Section VI.B.1. of today's 
rule, form the basis for EPA's decision to list this waste as 
hazardous. Second, studies have attributed dioxin-like toxicity to both 
the hepta and octa isomers. Based on the TCDD cancer slope factor and 
TEFs used in the risk analysis for this rule, the slope factors for 
OCDD and OCDF are effectively 15.6 (mg/kg-day)<SUP>-1</SUP> and the 
slope factors for the 2,3,7,8-substituted hepta dioxin and furan 
isomers are effectively 156 (mg/kg-day)<SUP>-1</SUP>. These are by 
comparison 10 and 100 times, respectively, the slope factor for 
arsenic, an Appendix VIII constituent and known carcinogen.
    The carcinogenicity and risk levels of the 5 hepta and octa isomers 
and their potential conversion to even more toxic isomers by 
dechlorination or photolytic mechanisms lead us to conclude that 
adopting specific treatment standards (i.e., numerical or CMBST) for 
these isomers is warranted for the K174 wastes. Because we typically 
include the same standards for new listings into those for F039 
(multisource leachate) to maintain equivalence within the LDR 
regulatory structure, we are also adding the same treatment standards 
in the F039 section of the 268.40 table (see section below on 
conforming changes).
    In summary, today, we are promulgating as final the numerical 
standards that were proposed for the constituents of concern in the 
K174 wastewater treatment sludges from the production of ethylene 
dichloride and vinyl chloride monomer. We are finalizing the numerical 
standards based on the data received and analyzed at proposal. No 
comments or additional data were received regarding the achievability 
of the proposed standards so, therefore, we are adopting the same 
numerical standards as final. In addition we also are promulgating the 
option of complying with the technology standard of combustion (CMBST) 
for the organic constituents present in K174. The final treatment 
standards are presented in the following table.

                                                        Table I-1.--Treatment Standards for K174
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Regulated harzardous constituent                                Wastewaters                                   Nonwastewaters
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Concentration in mg/L\1\, or technology code     Concentration in mg/kg \3\ unless noted as
               Common name                   CAS \2\ No.                         \2\                             ``mg/L TCLP'', or technology code
--------------------------------------------------------------------------------------------------------------------------------------------------------
1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin      35822-39-4  0.000035 or CMBST \4\.........................  0.0025 or CMBST \4\
1,2,3,4,6,7,8-Heptachlorodibenzofuran....      67562-39-4  0.000035 or CMBST \4\.........................  0.0025 or CMBST \4\
1,2,3,4,7,8,9-Heptachlorodibenzofuran....      55673-89-7  0.000035 or CMBST \4\.........................  0.0025 or CMBST \4\
HxCDDs (All Hexachlorodibenzo-p-dioxins).      34465-46-8  0.000063 or CMBST \4\.........................  0.001 or CMBST \4\
HxCDFs (All Hexachlorodibenzofurans).....      55684-94-1  0.000063 or CMBST \4\.........................  0.001 or CMBST \4\

[[Page 67111]]

 
1,2,3,4,6,7,8,9-Octachlorodibenzo-p-            3268-87-9  0.000063 or CMBST \4\.........................  0.005 or CMBST \4\
 dioxin (OCDD).
1,2,3,4,6,7,8,9-Octachlorodibenzofuran         39001-02-0  0.000063 or CMBST \4\.........................  0.005 or CMBST \4\
 (OCDF).
PeCDDs (All Pentachlorodibenzo-p-dioxins)      36088-22-9  0.000063 or CMBST \4\.........................  0.001 or CMBST \4\
PeCDFs (All Pentachlorodibenzofurans)....      30402-15-4  0.000035 or CMBST \4\.........................  0.001 or CMBST \4\
TCDDs (All tetrachlorodi-benzo-p-doxins).      41903-57-5  0.000063 or CMBST \4\.........................  0.001 or CMBST \4\
TCDFs (All tetrachlorodibenzofurans).....      55722-27-5  0.000063 or CMBST \4\.........................  0.001 or CMBST \4\
Arsenic..................................       7440-36-0  1.4...........................................  5.0 mg/L TCLP
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CAS means Chemical Abstract Services. When the waste code and/or regulated constituents are described as a combination of a chemical with its salts
  and/or esters, the CAS number is given for the parent compound only.
\2\ Concentration standards for wastewaters are expressed in mg/L and are based on analysis of composite samples.
\3\ All treatment standards expressed as a Technology Code or combination of Technology Codes are explained in detail in 40 CFR 268.42 Table 1--
  Technology Codes and Descriptions of Technology-Based Standards.
\4\ For these wastes, the definition of CMBST is limited to: (1) Combustion units operating under 40 CFR 266, (2) combustion units permitted under 40
  CFR Part 264, Subpart O, or (3) combustion units operating under 40 CFR 265, Subpart O, which have obtained a determination of equivalent treatment
  under 268.42(b).

    Regarding the use of combustion (CMBST) for the regulated organic 
constituents, commenters requested that we allow combustion as an 
alternative to the proposed (and now final) numerical treatment 
standards. This is consistent with the approach taken for F024, a set 
of previously listed chlorinated aliphatic wastes (62 FR 26000-3, May 
12, 1997). We agree and are promulgating the requested change. As a 
consequence, facilities treating K174 wastes will have the option of 
complying with either the numerical standards promulgated or the 
technology standard of CMBST for the regulated organic constituents.
    Adopting combustion as an alternative to the numerical standards 
serves a general LDR programmatic interest as well. We typically 
promulgate numerical performance standards to allow facilities maximum 
flexibility in determining for themselves how best to achieve 
compliance with the LDR treatment standards. If we promulgate a 
technology-specific treatment standard (such as combustion) instead, 
this flexibility is lost. In today's rule, by promulgating combustion 
as an alternative compliance option, we are not disturbing the degree 
of flexibility afforded to facilities; rather, we are maintaining or 
enhancing it.
    However, when we specify a treatment technology like CMBST as the 
LDR standard, the analytical elements of compliance change. Typically, 
when we specify a method of treatment (like CMBST), no testing and 
analysis of treatment residuals is required because we are confident 
that use of the specified technology will reduce the level of target 
constituents (organics in the case of CMBST) to levels that minimize 
threats to human health and the environment. For K174, the regulated 
organic constituents of concern are dioxin/furan congeners, which, if 
combustion is used for treatment, will not be individually analyzed in 
the treatment residue (e.g., the ash).
    Several factors suggest that such individual constituent analysis 
is not necessary and that specifying CMBST is appropriate. First, if 
combustion in well designed and operated units is used to treat K174, 
the structural features of dioxin/furan congeners (e.g., the presence 
of the oxygen in the ring formation) suggest that all dioxins and 
furans in K174 should be substantially destroyed by the high 
temperature combustion process that would have to be used.
    Second, we ensure that combustion will occur in well designed, 
operated, and highly regulated units. Part of the CMBST standard itself 
(as modified in today's rule for K174 waste) is that combustion of K174 
must occur either in units subject to the standards in 40 CFR part 264 
subpart O or 40 CFR part 266, subpart H, or in interim status 
incinerators where the owner/operator has made a specific demonstration 
that the unit can operate in a manner equivalent to a part 264 or part 
266 combustion unit. The type of facilities that can combust K174 is 
thereby restricted to highly-regulated RCRA units (or, after the 
current transition period, Clean Air Act permitted units subject to 
MACT standards). This will ensure that combustion is done only in a 
closely-regulated facility and in a manner that provides protection for 
human health and the environment. More specifically, combustion will 
occur only in units subject to the recently upgraded dioxin/furan 
emission standards of the MACT Hazardous Waste Combustion Rule as well 
as standards for other hazardous air pollutants, such as metals (64 FR 
52828, September 30, 1999). Given this level of regulation and 
permitting oversight, we do not find the need to impose additional and, 
with respect to other dioxin/furan congeners, unique analytical burdens 
on the regulated community regarding these 5 hepta and octa congeners.
    Of course, K174 does have metal constituents of concern, which 
would not be treated by the combustion process and that would remain in 
the combustion treatment residuals (e.g., ash and scrubber water). We 
therefore are retaining metal treatment standards for all 
circumstances, i.e., whether or not the treatment used by a facility 
involves combustion. When combustion is used to treat the organics to 
achieve LDR compliance, facilities still will need to conduct 
compliance testing and analysis for all regulated metal constituents in 
the combustion treatment residuals prior to disposal. This approach is 
patterned after EPA's promulgation of a similar alternative treatment 
standard for F024 (wastes from production of chlorinated aliphatics) 
and also for F032 (wastes from wood preserving processes). See 55 FR 
22580-22581, June 1, 1990. See also 62 FR 26000-26003, May 12, 1997.
    Another issue warranting brief discussion concerns a related, but 
in reality quite different, issue. Commenters, in general, oppose the 
regulation of the additional congeners individually, and state that the 
existing dioxin and furan congeners covered under UTS standards are 
sufficient to serve as surrogates for the effective treatment of the 5 
hepta and octa

[[Page 67112]]

congeners. These commenters would omit the 5 hepta and octa congeners 
entirely from list of regulated hazardous constituents for which LDR 
treatment standards are set.
    We do not agree with this approach. Absent a specific requirement 
that hepta and octa congeners be treated (i.e., by including them as 
regulated hazardous constituents for K174 in the table in 268.40), 
generators would not be obliged to determine the presence of these 
congeners. Without such a determination, it is certainly possible that 
generators would not engage in any organic-oriented treatment at all. 
For example, if the other dioxin/furans are below treatment levels, 
generators would not have to combust the K174 waste. Given our concern 
about the potential threats posed to human health and the environment 
by dioxins and furans, we are choosing to require treatment wherever 
harmful congeners are present above the treatment standard. Also, the 
formation pathways for dioxins and furans are highly waste specific, 
such that we have no way of knowing the concentration of one isomer 
based on the presence or absence of another.
    We conclude that a surrogate approach without compliance testing 
for the 5 hepta and octa isomers, such as that which would be the 
consequence of the commenters' views, would not be adequate. Therefore, 
with today's rule, we are promulgating treatment standards for each of 
the 5 hepta and octa dioxin and furan isomers identified in the 
proposal.
3. What Are the LDR Treatment Standards for K175?
    We proposed two options for establishing treatment standards under 
the LDRs for the mercury-bearing waste to be listed as K175 (64 FR 
46521). The first option would have included three treatment standards 
that would essentially be the same as those for other mercury-bearing 
wastes. These standards are:

(1) for K175 wastes containing greater than 260 mg/kg total mercury, 
the treatment would be recovery of the waste's mercury content via 
roasting and retorting (RMERC);
(2) for K175 RMERC residues containing less than 260 mg/kg total 
mercury, the residues would have to meet a numerical standard of 0.2 
mg/L TCLP mercury prior to land disposal; and
(3) for K175 wastes and non-RMERC treatment residues containing less 
than 260 mg/kg total mercury, these wastes and treatment residues 
would have to meet a numerical standard of 0.025 mg/L TCLP mercury 
prior to land disposal

We also proposed that wastes and residues in this last category be 
treated so that a pH of 6.0 or less is achieved prior to land disposal, 
and that disposal of these wastes and residuals be restricted to 
landfill cells where only wastes with similar pH properties are co-
disposed.
    Because of the potential difficulty in roasting and retorting K175 
waste, the Agency requested performance data, and solicited comment on 
a second treatment standard option. This option would require that K175 
waste exhibit no more than 0.025 mg/L TCLP mercury for disposal without 
any requirement that the waste be roasted or retorted.
    The K175 wastes are typically much greater than 260 mg/kg mercury, 
ranging from approximately 3,000 to 17,700 mg/kg mercury, and are 
greater than one percent in total organic constituents.\55\ As noted in 
the proposal (64 FR at 46521), when these wastes (high mercury and 1% 
or more organics) exhibit the toxicity characteristic, they would 
already be subject to requirements of either RMERC (roasting and 
retorting) or IMERC (incineration in units operated in accordance with 
RCRA incinerator standards).
---------------------------------------------------------------------------

    \55\ See 64 FR at 46510; see also Table 4-14 from Listing 
Background Document for Chlorinated Aliphatics Listing Determination 
(Proposed Rule) (USEPA, 1999c).
---------------------------------------------------------------------------

    Commenters questioned the ability and willingness of commercial 
retorting and roasting treatment facilities to accept K175 wastes, 
citing two factors. First, with a K175 mercury content of approximately 
one percent, commercial retorters may not recover enough mercury to be 
cost-effective, and second, most commercial retort facilities may not 
be able to accept wastes in excess of 500 ppm Appendix VIII organics 
and still comply with their RCRA permitting limits (USEPA, 1999c).\56\ 
This information suggests that adopting an RMERC standard for K175 may 
present significant practical difficulties that could not be overcome 
in the near term.
---------------------------------------------------------------------------

    \56\ In accordance with 40 CFR 266.100, a ``metals recovery'' 
unit such as a commercial mercury retorter is conditionally excluded 
from most RCRA permit requirements provided that the facility 
complies with certain operating restrictions, one being a 
prohibition against accepting wastes in excess of 500 ppm Appendix 
VIII organics.
---------------------------------------------------------------------------

    In addition to the practical points made by commenters, no roasting 
and retorting performance information for the subject waste or even a 
similar waste was submitted in comment. Since the Agency itself lacks 
data on the properties of the subject waste following roasting and 
retorting, we are not able to persuasively conclude that this type of 
treatment technology can achieve the level of mercury removal desired. 
In addition, we have no firm basis for determining whether the RMERC 
residues from treating K175 could meet the existing 0.2 mg/L TCLP total 
mercury standard so that the RMERC residues could be land disposed. We 
are therefore disinclined to adopt a K175 treatment standard that 
involves mandatory roasting and retorting.
    Conversely, with respect to the second option proposed for K175 
treatment standards, several factors suggest that this is a better 
approach to adopt. First, as discussed above, the commercial roasting 
and retorting alternatives may not exist. Second, the physical 
properties of the waste indicate that the waste can readily achieve 
0.025 mg/L TCLP mercury. Testing conducted for EPA shows the waste 
sample tested readily achieved 0.025 mg/L TCLP mercury, as the sample 
tested leached only 0.0027 and 0.0058 mg/L total mercury at pH 4 and 6 
respectively.\57\
---------------------------------------------------------------------------

    \57\ Paul Bishop, Renee A. Rauche, Linda A. Rieser, Markram T. 
Suidan, and Jain Zhang; ``Stabilization and Testing of Mercury 
Containing Wastes,'' Department of Civil and Environmental 
Engineering, University of Cincinnati, March 31, 1999.
---------------------------------------------------------------------------

    Third, at this point in time, the Agency is reviewing the 
appropriateness of thermal treatment and recovery of mercury in all 
forms of hazardous waste, not solely K175. See 64 FR 28949, May 28, 
1999. Therefore, requiring RMERC for K175 at this juncture may prove to 
be somewhat premature even if adequate data and assurance of commercial 
treatment capacity were to exist. Because we have an acceptable and 
effective treatment alternative, we are able to postpone having to make 
a policy judgment about promoting or requiring mercury recovery and 
recycling in today's rule (which would just apply to K175) until we are 
better prepared to resolve the longer term issues of mercury recovery 
in a comprehensive and more environmentally effective manner.
    Based on all these factors, the Agency has selected stabilization 
as the appropriate technology upon which to base our K175 treatment 
standard, and is setting 0.025 mg/L TCLP mercury together with control 
of the pH of co-disposed wastes (as discussed below) as the land 
disposal restrictions for K175. This standard may be achieved by any 
technology (other than impermissible dilution), and does not prohibit 
roasting/retorting should it be shown to achieve the performance 
standard. While no data were provided in response comment on this 
proposal, subsequently a vendor has indicated a willingness to 
demonstrate that the

[[Page 67113]]

waste could be retorted successfully.\58\ Should subsequent testing 
demonstrate that retorting produces a waste form better suited for 
stabilization and having less potential for long-term mercury release, 
the standards promulgated today could potentially be adjusted as part 
of the ongoing re-evaluation of mercury waste treatment technologies. 
See 64 FR 28949, May 28, 1998. Any modification of today's promulgation 
would be the subject of a future proposal.
---------------------------------------------------------------------------

    \58\ Personal communication with SepraDyne Corporation 
representatives.
---------------------------------------------------------------------------

    Other comments focused upon the proposed requirement that disposal 
of K175 wastes and treatment residues which are less than 260 mg/kg 
total mercury be restricted to landfill cells into which disposal of 
wastes in excess of pH 6.0 is prohibited. Commenters noted that the 
waste could readily be treated to a pH 6.0 but stated that, given the 
relative small quantity of waste generated, monofill disposal of K175 
or co-disposal only with similar wastes would not be feasible. One 
commenter suggested macroencapsulation of the K175 waste as is 
currently performed for debris would provide a viable alternative to 
achieve isolation of the waste from surrounding, potentially adverse 
landfill conditions. Subsequent discussions with Chemical Waste 
Management Inc. confirm that acidic wastes make up only a small portion 
of hazardous wastes and that it would not be feasible to manage a small 
cell for only K175 or for K175 and only similar wastes of pH 6.0.\59\
---------------------------------------------------------------------------

    \59\ Memorandum from Ross Elliott, U.S. EPA Office of Solid 
Waste, to RCRA Docket, ``Summary of Phone Call Between EPA and Carl 
Carlsson, Chemical Waste Management Inc.,'' July 12, 2000.
---------------------------------------------------------------------------

    Control of the disposal site conditions is essential to ensure that 
the mercury present in this waste remains immobile so that long-term 
threats to human health and the environment are minimized. The 
solubility measurements conducted on the waste for EPA are consistent 
both with results found in the mercury literature \60\ as well as with 
calculations from a geochemical stability model for mercury sulfide 
complexes.\61\ The testing and subsequent solubility calculations 
confirm that above pH 6.0, increased mobility of mercury as mercuric 
sulfide/hydrogen sulfide complexes occurs with increasing pH and 
sulfide concentration.
---------------------------------------------------------------------------

    \60\ See 64 FR at 46522. See also Jenny Ayla Jay, Francois M. M. 
Morel, and Harold F. Hemond, Mercury Speciation in the Presence of 
Polysulfides, Environmental Science and Technology, 2000, Vol. 34, 
No. 11, pages 2196-2200.
    \61\ Memorandum from John Austin to Ross Elliott, May 12, 2000.
---------------------------------------------------------------------------

    Therefore, we find that to minimize the potential future threats 
from mercury mobilization, our treatment standard must ensure that pH 
is maintained at 6.0 or less for K175 waste. Because we agree with the 
commenter's suggestion about the practical advantages of 
macroencapsulation in some situations, we are finalizing treatment 
standards that require, prior to land placement: (1) Wastes to be at pH 
6.0 or less, and placement is restricted to landfill cells in which 
disposal of other wastes in excess of pH 6.0 is prohibited; or (2) 
wastes to be at pH 6.0 or less, and macroencapsulation per the 
requirements of 40 CFR 268.45. The pH restriction in the latter 
standard is to ensure that mercury is not in a mobile form should the 
macroencapsulation vessel fail over time. This additional level of 
protection is part of the best demonstrated and available treatment 
(BDAT) needed to minimize the threats posed by potential mobilization 
of the mercury within a landfill over the long-term. Furthermore, 
macroencapsulation itself is not viewed as BDAT (except in unusual 
cases such as debris) because it merely isolates the waste from the 
environment for a period of time and does not actually effect any 
treatment. We have amended the regulations promulgated today 
accordingly.
    Affected parties and other stakeholders should note that we may 
revisit the requirement for macroencapsulation should we determine, at 
some future date, that the generation rate of materials requiring 
disposal at low pH has increased to the point where maintaining a 
separate cell for these wastes is an operationally feasible option for 
a landfill.
    We did not pursue to regulatory conclusion other potential avenues 
by which mercury mobilization could be affected for a number of 
reasons. Two avenues would be to regulate the sulfide content of the 
waste itself or the sulfide concentration in the disposal environment, 
or both. These approaches are fraught with technical and implementation 
difficulties. For example, chemical and biological processes within the 
disposal unit may reduce sulfate to sulfide at varying rates depending 
on in situ conditions. Also, current test methods do not readily 
distinguish free sulfide from that bound as mercuric sulfide in the 
waste. Hence, adopting sulfide limits on incoming K175 wastes or 
mandating in situ sulfide levels would likely not be reliable or 
implementable means of ensuring mercury immobility. On the other hand, 
pH can readily be determined using the existing procedure SW-846 Method 
9045C. Thus, practical considerations also favor limitation of waste pH 
at the time of disposal as a more viable option to control potential 
mobilization of mercury once the wastes are disposed.
    In summary, for K175 waste, we are finalizing a treatment standard 
requiring that, prior to land disposal: (1) The waste must meet a TCLP 
leachate concentration of 0.025 mg/L mercury or less, (2) the waste 
must be at or below a pH 6.0 when disposed, and (3) the wastes must be 
macroencapsulated or, if not, placement is restricted to landfill cells 
in which disposal of other wastes in excess of pH 6.0 is prohibited. We 
are promulgating these land disposal restriction requirements for K175 
to ensure the long term protection of human health and the environment.
4. What Are the Conforming Changes to F039 and Universal Treatment 
Standards?
    We proposed that the constituents 1,2,3,4,6,7,8-heptachlorodibenzo-
p-dioxin; 1,2,3,4,6,7,8-heptachlorodibenzofuran; 1,2,3,4,7,8,9-
heptachlorodibenzofuran; 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin 
(OCDD); and 1,2,3,4,6,7,8,9-octachlorodibenzofuran (OCDF) be added to 
the list of regulated constituents in hazardous waste F039 multisource 
leachate. The F039 waste code applies to hazardous waste landfill 
leachates in lieu of the original waste codes when multiple waste codes 
would otherwise apply. F039 wastes are subject to numerical treatment 
standards equivalent to UTS. We proposed these additions to the 
constituents regulated by F039 to maintain the implementation benefits 
of having one waste code for multisource leachate.
    Commenters correctly noted that the Agency did not add the 
constituents of the carbamate waste listing to F039 (61 FR 15566), an 
issue not directly within the purview of this rulemaking. As a result, 
multisource F039 leachates that also contain one of the listed 
carbamate wastes must be treated to comply with carbamate hazardous 
waste codes to meet the 40 CFR 268.48(c) requirement for treatment to 
achieve the lowest treatment standard for constituents of concern. 
Therefore, such wastes would be subject to multiple codes; the very 
situation F039 sought to eliminate. The Agency's intent upon 
promulgating F039 was that the single F039 waste code would replace the 
multiple codes to which such wastes were then subject (52 FR 22619, 
June 1, 1990). To limit

[[Page 67114]]

any further proliferation of circumstances where treatment standards in 
addition to F039 may apply, we are promulgating the additional K174 
dioxin and furan constituents of concern as proposed. Resources 
permitting, conforming changes may be proposed for the carbamate waste 
constituents at some future date.
    We also proposed that the numerical standards derived for 
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8-
heptachlorodibenzofuran; 1,2,3,4,7,8,9-heptachlorodibenzofuran; OCDD; 
and OCDF be added to the Table of Universal Treatment Standards (UTS) 
at 40 CFR 268.48. These constituents contribute to the overall risks 
that formed the basis for EPA's decision the EDC/VCM sludges pose a 
substantial risk to human health and the environment, as shown in the 
risk assessment accompanying this rule. Their presence in other 
hazardous wastes should be mitigated by effective treatment to avoid 
similar risks after land disposal. By adding these numerical standards 
for five dioxin and furan congeners, we are ensuring that treatment of 
hazardous waste addresses these risks.
    Following the adoption of today's rule, all characteristic wastes 
that have these constituents as underlying hazardous constituents above 
the UTS levels will require treatment of these additional constituents 
before land disposal. This is in direct accord with our mandate under 
the LDR treatment program to ``substantially diminish the toxicity of 
the waste or substantially reduce the likelihood of migration of 
hazardous constituents from the waste so that short-term and long-term 
threats to human health and the environment are minimized.'' \62\
---------------------------------------------------------------------------

    \62\ RCRA Section 3004(m).
---------------------------------------------------------------------------

    Commenters in general objected to changes to UTS because of their 
perceived cost of the analysis and concerns over available treatment 
capacity, which will be discussed in the following section. We were not 
persuaded by the commenters' arguments. Waste generators must already 
comply with treatment requirements for tetra-, penta-, and hexa- 
chlorinated dibenzo-p-dioxin and dibenzofuran congeners. Much of the 
labor and cost of analysis of the currently regulated congeners can not 
be separated from the costs associated solely with the hepta and octa 
congeners because the analysis of these 5 additional isomers is 
accomplished intrinsically as part of the overall method and is not 
separable. Hence, sample preparation, labor, and instrument time are 
not increased by including these 5 additional congeners.
    Commenters also suggest that treatment and control of the existing 
regulated dioxin/furan congeners provides adequate protection against 
potential risks associated with the hepta and octa congeners. 
Commenters appear to recognize that the hepta- and octa-dioxin/furan 
congeners contribute significantly to the overall carcinogenicity of 
K174 wastes and waste treatment residues, and that they also must be 
controlled if human health and the environment are to be protected. In 
essence, these commenters would have us make broad assumptions for all 
situations about the ancillary impacts of treating and controlling 
certain dioxin and furan congeners, but not others that nevertheless 
present significant risks to human health and the environment.
    We are not in a position to make such broad assumptions regarding 
our degree of control over dioxin and furan congeners that present 
significant risks. We have chosen to take a more conservative tack, 
providing treatment standards that, when met, ensure that long-term 
threats to human health and the environment are minimized (RCRA Section 
3004(m)). For reasons noted earlier (e.g., carcinogenicity of these 
congeners, dechlorination or photolytic changes to more toxic 
congeners, and assuring treatment if these congeners are present), we 
conclude that direct control of these 5 hepta and octa congeners is 
warranted.
    For these reasons, the Agency is promulgating the proposed 
additions to the Table of Universal Treatment Standards (UTS) at 40 CFR 
268.48 and to the list of regulated constituents for F039, multisource 
leachate from hazardous waste, in 40 CFR 268.40.

J. Is There Treatment Capacity for the Newly-Listed Wastes?

1. Introduction
    Under the land disposal restrictions (LDR) determinations, the 
Agency must demonstrate that adequate commercial capacity exists to 
manage listed hazardous wastes in compliance with BDAT standards before 
the Agency can restrict the listed waste from further land disposal. 
The Agency performs capacity analyses to determine the effective date 
of the LDR treatment standards for the proposed listed wastes. This 
section summarizes the results of EPA's capacity analysis for the 
wastes covered by today's rule. For a detailed discussion of capacity 
analysis-related data sources, methodology, and detailed responses to 
comments for each waste covered in this rule, see USEPA, 2000f \63\ 
(i.e., the Capacity Background Document).
---------------------------------------------------------------------------

    \63\ U.S. EPA. 2000f. Background Document for Capacity Analysis 
for Land Disposal Restrictions: Newly Identified Chlorinated 
Aliphatics Production Wastes (Final Rule), September.
---------------------------------------------------------------------------

    EPA's decisions on whether to grant a national capacity variance 
are based on the availability of alternative treatment or recovery 
technologies capable of achieving the prescribed treatment standards. 
Consequently, the methodology focuses on deriving estimates of the 
quantities of newly-listed hazardous waste that will require either 
commercial treatment or the construction of new on-site treatment or 
recovery as a result of the LDRs. The resulting estimates of required 
commercial capacity are then compared to estimates of available 
commercial capacity. If adequate commercial capacity exists, the waste 
is restricted from further land disposal unless it meets the LDR 
treatment standards prior to disposal. If adequate capacity does not 
exist, RCRA Section 3004(h)(2) authorizes EPA to grant a national 
capacity variance for the waste for up to two years or until adequate 
alternative treatment capacity becomes available, whichever is sooner.
    2. Capacity Analysis Results for Newly Identified Wastes
    In conducting the capacity analysis for the wastes newly-listed by 
today's rule, EPA examined data on waste characteristics and management 
practices gathered for the purpose of the chlorinated aliphatics 
hazardous waste listing determinations and on available treatment or 
recovery capacity for these wastes. The data sources for the analyses 
are primarily the 1992 RCRA Section 3007 survey, the follow-up survey 
specific to these wastes conducted in 1997 (see the docket for this 
rule for more information on these survey instruments), the available 
treatment capacity data submission that was collected in the mid-
1990's, and the 1997 Biennial Report (BR). EPA analyzed the capacity-
related information from these data sources, reviewed the public 
comments received in response to the proposed rule, and corresponded or 
met with several commenters to obtain more specific information.
    We identified the following annual quantities of the newly-listed 
wastes that are generated and therefore the quantities of waste that 
potentially could require commercial treatment. Information available 
to the Agency indicates that up to 6,100 tons of K174 per year could 
potentially require

[[Page 67115]]

commercial treatment capacity. The Agency notes, however, that because 
EPA is finalizing a conditional listing approach for the K174 
wastewater treatment sludges under which these wastes are not hazardous 
if disposed of in a subtitle C or a non-hazardous waste landfill, it is 
possible that little or no hazardous waste treatment capacity will be 
required for this waste. In addition, approximately 130 tons of K175 
are generated annually and potentially could require commercial 
treatment capacity. EPA has determined that there is adequate 
commercial treatment or recovery capacity available to treat both of 
these wastes.
    For wastewaters from chlorinated aliphatic production processes 
(proposed as K173), some commenters requested a national capacity 
variance for this waste in response to the proposed rule. Since EPA is 
finalizing a decision not to list wastewaters from chlorinated 
aliphatic production processes as hazardous (as discussed in section 
VI.A), there is no need for a capacity variance determination for this 
waste stream.
    EPA proposed not to grant a capacity variance for K174 waste (EDC/
VCM wastewater treatment sludge). No comments were received regarding 
the variance determination, available treatment or disposal capacity, 
or the quantity of the waste potentially requiring treatment, either in 
nonwastewater or wastewater forms. As described in section VI.I above, 
we are finalizing the proposed numerical treatment standards as well as 
an alternative treatment standard of hazardous waste combustion. We 
estimate that the commercially available sludge and hazardous waste 
combustion capacity is at least 300,000 tons per year (see details in 
the Capacity Background Document) and therefore sufficient to treat any 
K174 hazardous wastes that could require treatment.
    As discussed earlier in this preamble, EPA has identified (as a 
result of public comments) that one facility may generate K174 in a 
surface impoundment as a result of today's rule. The facility may 
remove K174 waste before the effective date of the new listing and 
therefore may not be subject to LDR requirements.\64\ The impoundment 
can also be retrofitted, closed, or replaced with tank systems. If the 
impoundment continues to be used to actively manage K174 waste, the 
unit will be subject to subtitle C requirements. In addition, any 
hazardous wastes that are actively managed in an impoundment (other 
than wastes removed from an impoundment as part of a one-time removal) 
after the effective date of today's rule are subject to the land 
disposal prohibitions.\65\ EPA expects that the one facility currently 
managing chlorinated aliphatic wastewaters in surface impoundments (and 
which therefore may potential manage EDC/VCM sludges in impoundments 
after the effective date of today's rule) will cease to do so before 
the effective date of this rule.
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    \64\ If the waste is actively managed in unretrofitted 
impoundments (i.e., impoundments not satisfying the minimum 
technology requirements specified in RCRA sections 3004(o) and 
3005(j)(11)) after the effective date of today's rule, it would be 
land disposed in a prohibited manner.
    \65\ See RCRA Sec. 3004(m)(1) ``Simultaneously with the 
promulgation of regulations under subsection (d), (e), (f), or (g) 
prohibiting one or more methods of land disposal of a particular 
hazardous waste * * * promulgate regulations specifying those levels 
or methods of treatment * * * ''
---------------------------------------------------------------------------

    However, as described earlier in this preamble (see section 
VI.B.2.b.vii) regarding the listing determination for EDC/VCM 
wastewater treatment sludges, this facility (or others) could manage 
newly-listed K174 in surface impoundments, provided they are in 
compliance with the appropriate standards for impoundments (40 CFR 
parts 264 and 265 subpart K) and the special rules regarding surface 
impoundments (40 CFR 268.14). EPA notes that those provisions require 
(by reference) basic groundwater monitoring (40 CFR parts 264 and 265 
subpart F), management, and recordkeeping, but are afforded up to 48 
months to retrofit to meet minimum technological requirements (see RCRA 
Section 3005(j)(6)(A)).
    Based on the foregoing, EPA concludes that sufficient treatment or 
disposal capacity is available to manage K174 waste generated after the 
effective date of the LDR treatment standards either on site or 
offsite, even if generators seek offsite management for all K174 wastes 
in a permitted subtitle C disposal or treatment unit. Therefore, EPA is 
finalizing its decision not to grant a capacity variance for wastewater 
and nonwastewater forms of K174.
    With respect to K175 waste, several commenters raised issues with 
regard to permitting requirements and constraints of commercial 
treatment facilities, including the ability of commercial facilities to 
accept nonwastewater forms of K175 waste and comply with the proposed 
land disposal restrictions of RMERC. As discussed earlier, EPA is 
finalizing a numerical treatment standard for this waste (in 
conjunction with other pH-related restrictions and macroencapsulation), 
which has been demonstrated to be achievable using stabilization. 
Sufficient commercial stabilization, pH, and macrocapsulation treatment 
capacity exists to treat and dispose of mercury-containing wastes and 
to meet the final treatment standards adopted today. In addition, the 
one facility generating K175 uses a sulfide precipitation technology 
and therefore may be able to meet the numerical mercury concentration 
standard upon generation of the waste. Depending on their ability to 
control pH and to perform on-site macrocapsulation, no other commercial 
treatment might be necessary prior to off-site hazardous waste 
landfilling. EPA notes that generators can use any treatment technology 
(except impermissible dilution) to meet the numerical mercury 
concentration and pH standards promulgated today.
    EPA proposed that the K175 waste (about 130 tons per year) be co-
disposed in a landfill with other wastes with similar pH (6.0 or less). 
Commenters did not indicate the existence of any technical difficulties 
in meeting the additional pH requirement. Furthermore, they did not 
provide any data or information on the issue of available monofill 
disposal capacity for this waste or landfill co-disposal with similarly 
acidic (pH 6.0 or less) wastes. Based on previous activities in the 
commercial sector as well as the lack of adverse comment, we find no 
reason to doubt that owners of commercial landfills can and at some 
point will create a special cell based on customer's needs, compliance 
conditions, and contract negotiation.
    However, as noted earlier, we understand from one stakeholder that 
facilities with hazardous commercial landfill capacity may not have 
sufficient volumes of similarly acidic wastes to make it cost-effective 
to designate an entire unit or cell for disposal of only low pH wastes. 
We have therefore adopted an alternative that allows land disposal in 
other types of landfill cells following macroencapsulation of the waste 
(assuming the waste meets other applicable standards, such as Hg 
concentration and pH 6.0 or less). Based on a discussion with a 
hazardous waste management facility,\66\ we find that 
macroencapsulation of K175 waste can be made readily available for K175 
waste. Based on available data and analyses, EPA has therefore 
determined that sufficient commercial treatment and disposal capacity 
exists to manage K175 waste to meet the LDR standards, and we are today 
finalizing our decision not to grant a capacity variance for

[[Page 67116]]

wastewater or nonwastewater forms of K175.
---------------------------------------------------------------------------

    \66\ Personal communication with Carl Carlson, Chemical Waste 
Management Inc.
---------------------------------------------------------------------------

    In summary, we conclude that sufficient capacity exists for the 
management of both wastewater and nonwastewater forms of K174 and K175. 
For K174 and K175 wastes, the customary time period of six months is 
sufficient to allow facilities to determine whether their wastes are 
affected by this rule, to identify onsite or commercial treatment and 
disposal options, and to arrange for treatment or disposal capacity if 
necessary. LDR treatment standards thus will become effective when the 
listing determinations become effective for the wastes covered under 
this rule--the earliest possible date. This conforms to RCRA section 
3004(h)(1), which indicates that land disposal prohibitions must take 
effect immediately when there is sufficient treatment or disposal 
capacity available for the waste.
    Further, for soil and debris contaminated with the newly-listed 
wastes, EPA proposed not to grant a national capacity variance. EPA 
received no comments regarding this issue. We expect that the majority 
of contaminated soil and debris will be managed on-site and therefore 
would not require substantial off-site commercial treatment capacity. 
Therefore, EPA is not granting a national capacity variance for 
hazardous soil and debris contaminated with the newly listed wastes 
covered under this rule. LDR treatment standards for K174 and K175 
hazardous soil and debris will therefore become effective when these 
listing determinations become effective.
    Based on the 1992 RCRA section 3007 questionnaire and the 1997 
updated responses, there were no data showing underground injection of 
the newly-listed wastes or indicating that the newly-listed wastes are 
mixed with radioactive wastes or with both radioactive wastes and soil 
or debris. EPA did not receive comments indicating that these wastes 
are underground injected or that they are mixed with radioactive wastes 
or with both radioactive wastes and soil or debris. Therefore, EPA is 
not granting a national capacity variance for K174 and K175 wastes that 
might be underground injected, mixed with radioactive wastes, or mixed 
with both radioactive wastes and soil or debris. LDR treatment 
standards for K174 and K175 underground injected and mixed wastes (if 
any exists) will therefore become effective when these listing 
determinations become effective.
    Finally, EPA may consider a case-by-case extension to the effective 
date based on the requirements outlined in 40 CFR 268.5, which includes 
a demonstration that adequate alternative treatment, recovery, or 
disposal capacity for the petitioner's waste cannot reasonably be made 
available by the effective date due to circumstances beyond the 
applicants' control, and that the petitioner has entered into a binding 
contractual commitment to construct or otherwise provide such capacity.
3. Available Treatment Capacity for Other Wastes Subject to Revised UTS 
and F039 Standards
    Several commenters expressed concern that EPA did not adequately 
consider the need for alternative treatment capacity for other 
hazardous wastes subject to the proposed revisions to the UTS and F039 
(multiple source leachate) standards. Such additional treatment would 
be necessary to meet the treatment standards for the five additional 
dioxin and furan congeners being added to the UTS table (Sec. 268.48) 
and the list of regulated constituents in F039 (Sec. 268.40). 
Commenters noted that EPA must consider the potential need for national 
capacity variances by determining what fraction of the hazardous wastes 
are required to meet these new requirements, the appropriate means of 
treatment (if any), and the sufficiency of national treatment capacity 
for these wastes.
    When changing the treatment requirements for wastes already subject 
to LDR (including F039 and characteristic wastes), EPA no longer has 
authority to use RCRA section 3004(h)(2) to grant a capacity variance 
to these wastes. However, EPA is guided by the overall objective of 
section 3004(h), namely that treatment standards which best accomplish 
the goal of RCRA section 3004(m) (to minimize threats posed by land 
disposal) should take effect as soon as possible, consistent with 
availability of treatment capacity. Our task is therefore to balance 
the points raised by commenters against the clear statutory direction 
that treatment standards, such as those at issue here, should be 
imposed in the shortest feasible time provided capacity is available.
    With respect to the issue of capacity availability, we find first 
that only a limited quantity of hazardous waste leachate is expected to 
be generated from the disposal of newly-listed K174 and K175 wastes and 
added to the generation of leachates from other multiple restricted 
hazardous wastes already subject to LDR. Absent any data from 
commenters suggesting to the contrary, we have no reason to delay 
imposition of the LDRs on this ground.
    Second, with respect to the other, and potentially much larger 
volumes of, wastes that would be affected, we evaluated the universe of 
wastes that could be impacted by today's revisions to the lists of 
regulated constituents for F039 and UTS. Commenters themselves did not 
supply any information on these volumes in support of their generalized 
claims of insufficient capacity or their views that delaying the 
effective date of these treatment standards is warranted. However, 
based on 1997 Biennial Report data and some assumptions of waste 
compositions and their potential for land disposal, we were able to 
estimate the potential need for additional treatment. For example, EPA 
estimated an upper bound of 68,000 tons per year of the nonwastewaters 
mixed with other waste codes, the F039 leachate from which would be 
potentially impacted by the revisions to the F039 treatment standards. 
In a similar fashion, we estimated that no more than 130,000 tons per 
year of characteristic nonwastewaters potentially could be affected by 
the promulgated changes to the UTS.
    Of course, these upper bound estimates are most likely very 
overstated since only a portion of each estimated waste volume may 
contain one or more of the five congeners at concentrations above the 
numerical concentrations specified in the UTS table and the F039 list. 
Available hazardous waste landfill leachate characterization data from 
EPA's Office of Water indicate that only one of 15 samples analyzed 
shows leachate concentration of OCDD exceeding the numerical UTS level 
adopted today. Any concentrations below these numerical standards would 
not trigger any treatment obligation or the concomitant need for 
treatment capacity. (See the Capacity Background Document for detailed 
analysis.) Furthermore, EPA does not anticipate that waste volumes 
subject to treatment for F039 or characteristic wastes would 
significantly increase because waste generators already are required to 
comply with the treatment requirements for tetra-, penta-, and hexa-
chlorinated dioxin/furan congeners. The volumes of wastes for which 
additional treatment is needed solely due to the addition of the five 
new congeners to the F039 and UTS lists is therefore expected to be 
very small. Both of these factors indicate the highly conservative 
nature of our volume estimates.
    However, even though our volume estimates are highly conservative 
and overstated, we find that there still would be no shortage of 
treatment capacity. Based on data submittals in the mid-1990's and the 
1997 Biennial

[[Page 67117]]

Report, EPA has estimated that approximately 37 million tons per year 
of commercial wastewater treatment capacity are available, and well 
over one million tons per year of liquid, sludge, and solid commercial 
combustion capacity are available. These are well above the quantities 
of wastewater and nonwastewater forms of F039 or characteristic wastes 
potentially requiring treatment for the 5 hepta and octa isomers even 
under the conservative screening assumptions described above. We find 
therefore that there is sufficient treatment capacity for these wastes 
to ensure that the wastes meet today's revisions to the UTS and F039 
treatment standards. For this reason, EPA is finalizing its decision 
not to delay the effective date for adding the five hepta-and octa-
dioxin and furan congeners to the lists of constituents for F039 and 
UTS. As with the other treatment standards being promulgated today, 
these revised F039 and UTS standards will become effective six months 
after the date of promulgation, the same date on which the K174 and 
K175 listing will become effective. This will provide sufficient time 
to allow facilities to determine whether their wastes are affected by 
this rule, to identify onsite or commercial treatment and disposal 
options, and to arrange for treatment or disposal capacity if 
necessary.

VII. What Is the Economic Analysis of Today's Final Rule?

A. What Is the Purpose of the Economic Analysis?

    In 1999, the EPA presented an initial economic analysis (in the 
form of both a preamble discussion, and a supplementary ``Economics 
Background Document'(USEPA, 1999b), for public review in support of the 
RCRA K173/K174/K175 listing proposed rule (64 Federal Register, 46517-
46519, August 25, 1999). The primary purpose of the 1999 economic 
analysis was to estimate regulatory compliance costs associated with 
the proposed rule. Secondary purposes were to provide (1) descriptive 
information about the economic sectors (i.e. the chemical industry) and 
other types of facilities potentially affected by the proposed rule, 
and (2) descriptive information about the economic activities involving 
chlorinated aliphatic hydrocarbon chemicals (CAHCs).
    As a result of both public comments and changes to the rule, EPA 
revised the 1999 ``Economics Background Document'' (USEPA 1999b). In 
comparison to the 1999 economic analysis, the primary objectives of 
this final economic analysis are: (1) to present and respond to the 
public comments received about the economic analysis for the 1999 
proposed rule, and (2) to estimate the impacts of the final rule. The 
findings for each objective are summarized below.
    The Economics, Methods, and Risk Assessment Division (EMRAD) of 
EPA's Office of Solid Waste (OSW) conducted the economic analyses for 
both the 1999 proposed rule, and for this final rule. The ``Economics 
Background Document'' (USEPA, 2000a) \67\ in support of this final 
rule, is available to the public from the EPA's RCRA Docket (refer to 
the introduction to this preamble for instructions on how to obtain a 
copy). References to statements below pertaining to facts, data, 
assumptions and other types of information, are identified in the final 
rule background document.
---------------------------------------------------------------------------

    \67\ U.S. EPA. 2000a. Economics Background Document. Office of 
Solid Waste. September.
---------------------------------------------------------------------------

B. How Did the Public Participate in the Economic Analysis?

    In conjunction with the 1999 proposed rule (64 FR 46517), EPA 
requested public comment on the following eleven specific information 
elements pertaining to the data, assumptions, design, accuracy, 
representativeness and completeness of the initial ``Economic 
Background Document'' (dated 30 July 1999, 127pp., which is available 
over the Internet at http://www.epa.gov/epaoswer/hazwaste/id/chlorali/economic.pdf): (1) Economic study design, (2) industry facility 
universe, (3) affected waste volumes/sources, (4) industry sector 
profile, (5) baseline (current) waste management practices, (6) 
regulatory compliance waste management, (7) compliance facility process 
modifications, (8) waste management costs, (9) regulatory impact 
financial benchmarks, (10) economic analysis data sources, and (11) 
other impact considerations. As described elsewhere in this preamble, 
EPA received a total of 20 sets of public comments on the 1999 proposed 
rule, of which 14 commenters offered a total of 61 remarks on the 1999 
economic analysis. EPA presents and addresses each comment in the 
``Response to Public Comments'' background document (USEPA, 2000g) 
\68\, also available from the EPA RCRA Docket.
---------------------------------------------------------------------------

    \68\ U.S. EPA. 2000g. Response to Public Comments on Proposed 
Listing Determination for Chlorinated Aliphatic Wastes. Office of 
Solid Waste. September.
---------------------------------------------------------------------------

    For purpose of summary here, the 61 remarks made by the 14 
commenters who targeted the 1999 economic analysis may be grouped 
according to six topics: (1) K173 compliance cost estimates, (2) K174 
compliance cost estimates, (3) K175 compliance cost estimates, (4) 
economic analysis framework, (5) overall magnitude of rule cost, and 
(6) industry characterization. Many of the commenters made remarks 
about multiple economic analysis topics (as well as about other aspects 
of the proposed rule, such as preamble language and risk analysis). 
Forty-two of the 61 remarks were directed at the EPA's K173 compliance 
cost estimate, stating that EPA's 1999 estimate was too low for a 
variety of reasons, including lack of complete descriptive information 
about all possible wastewater tanks affected, as well as incomplete 
assessment of all potential costs involved in retrofitting wastewater 
tanks with covers and tank air emission control devices. However, 
because the K173 listing is dropped from the final rule, EPA has 
dropped the K173 cost estimate from the economic analysis, rather than 
revise it. Otherwise, EPA has incorporated into the final rule economic 
analysis, information contained in other public comments addressing the 
K174 listing, K175 listing, economic analysis framework, and industry 
characterization. Four of the comments also contained remarks about the 
K174 listing, questioning the magnitude of its associated recordkeeping 
burden, and claiming that EPA did not consider other impacts arising 
from RCRA's ``mixture and derived-from'' clause. One commenter 
challenged EPA's assertion of the current market availability of K175 
waste retorting treatment. The 14 commenters made nineteen remarks 
questioning the industrial scope of the listing, whether the rule would 
impact other types of facilities/wastes, and the appropriateness of 
EPA's cost annualization and future industry waste generation 
parameters. The 14 commenters also offered thirty-three remarks about 
the cost-effectiveness of the rule, the total industry cost of the 
rule, and challenged EPA's assertion that the proposed rule was not 
economically ``significant'' according to the $100 million annual 
effect threshold established in Executive Order 12866 (30 September 
1993). Finally, commenters offered seven remarks raising questions 
about EPA's count of the affected number of facilities, EPA's 
characterization of the size of wastewater tanks in the affected 
industry, and EPA's characterization of the affected industry's annual 
sales and growth rate.

[[Page 67118]]

C. What Are the Expected Economic Impacts of This Final Rule?

    As of the late 1990s, 39 facilities in the US manufacture 
chlorinated aliphatic hydrocarbon chemicals. Eighteen of these are 
potentially subject to the rule, 17 as generators of K174 waste, and 
one as a generator of K175 waste. None of these 18 facilities are owned 
by small-sized companies. The 21 remainder facilities do not currently 
manufacture the types of chemicals and associated industrial wastes 
which are listed as RCRA ``hazardous'' industrial wastes by the rule.
    The anticipated economic impacts associated with the final rule 
primarily consist of industry compliance costs, likely to be incurred 
by three of the 18 relevant waste generators (two K174 and one K175), 
and by four commercial waste handlers.
    Because of the facts that: (1) Many of the CAHC manufacturing 
facilities and commercial industrial waste handlers are currently 
regulated under RCRA (via the existing RCRA F024 and F025 wastecodes, 
among others), (2) some CAHC manufacturing facilities currently manage 
some wastewater sludges as hazardous waste, (3) the K174 listing is 
targeted upon a subset of chlorinated aliphatic production processes, 
and/or (4) the K174 final rule is ``conditional'' upon only certain 
waste management practices, the incremental impact of this listing is 
expected to be substantially less than it otherwise would be if all 
waste generators fitting the listing descriptions, or if all 39 
chemical class manufacturers, were affected. Consequently, the 
incremental impact of the final rule is expected to be less than it 
otherwise could be (e.g., impacts could be higher under a listing 
affecting all facilities across the industry sector, rather than the 
final targeted and ``conditional'' listing approach which affects only 
a few facilities).
    EPA estimates that the average annualized national cost of this 
rule will be between $0.42 and $4.05 million per year (consisting of 
$0.53 to $7.21 million in initial costs and $0.35 to $3.25 million in 
recurring annual costs), if one generator of EDC/VCM wastewater 
treatment sludge (K174) is able to make arrangements for the apparent 
lower-cost option for managing its affected industrial wastewaters. But 
if that generator is not able to make the appropriate waste management 
arrangements prior to the effective date for the final rule, such that 
the one facility might find it cannot make arrangements for a lower 
cost means of managing its affected wastewater (from which the EDC/VCM 
wastewater treatment sludges are derived), then it could face 
relatively high monthly costs for temporarily transporting its 
wastewater offsite to a commercial hazardous waste management facility, 
until it can complete an alternative (and lower-cost) waste management 
arrangement for its wastewaters. For the purpose of reflecting EPA's 
uncertainty about this facility's actual cost impacts, as well as other 
cost estimation parameters, EPA included other higher cost waste 
management options and industry compliance cost contingencies (such as 
possible surface impoundment corrective action costs) in the economic 
analysis for the final rule (Economics Background Document USEPA 
2000a). Inclusion of all of these high-cost assumptions results in an 
upper-end EPA cost estimate of $23.37 million in average annualized 
cost (which includes up to 22 months of temporary offsite transport for 
the generator of EDC/VCM wastewater treatment sludge currently managing 
its wastewaters in a surface impoundment). EPA notes that total costs 
also include minor impacts on EPA regional offices and states with 
authorized RCRA programs to implement the new rule, as well as other 
``incidental effects.'' The reader is referred to the ``Economics 
Background Document'' for additional details about all cost items 
included in EPA's estimate of national cost.

VIII. When Must Regulated Entities Comply With Today's Final Rule?

A. Effective Date

    The effective date of today's rule is May 7, 2001.

B. Section 3010  Notification

    Pursuant to RCRA section 3010, the Administrator may require all 
persons who handle hazardous wastes to notify EPA of their hazardous 
waste management activities within 90 days after the wastes are 
identified or listed as hazardous. This requirement may be applied even 
to those generators, transporters, and treatment, storage, and disposal 
facilities (TSDFs) that have previously notified EPA with respect to 
the management of other hazardous wastes. The Agency has decided to 
waive this notification requirement for persons who handle wastes that 
are covered by today's hazardous waste listings and already have (1) 
notified EPA that they manage other hazardous wastes, and (2) received 
an EPA identification number. The Agency has waived the notification 
requirement in this case because it believes that most, if not all, 
persons who manage the wastes listed as hazardous in today's rule 
already have notified the Agency and received an EPA identification 
number. However, any person who generates, transports, treats, stores, 
or disposes of these newly listed wastes and has not previously 
received an EPA identification number must obtain an identification 
number pursuant to 40 CFR 262.12 to generate, transport, treat, store, 
or dispose of these hazardous wastes by February 6, 2001.

C. Generators and Transporters

    Persons who generate newly identified hazardous wastes may be 
required to obtain an EPA identification number if they do not already 
have one (as discussed in section VIII.B, above). If generating or 
transporting these wastes after the effective date of this rule, 
generators of the wastes listed today will be subject to the generator 
requirements set forth in 40 CFR Part 262. These requirements include 
standards for hazardous waste determination (40 CFR 262.11), compliance 
with the manifest (40 CFR 262.20 through 262.23), pretransport 
procedures (40 CFR 262.30 through 262.34), generator accumulation (40 
CFR 262.34), record keeping and reporting (40 CFR 262.40 through 
262.44), and import/export procedures (40 CFR 262.50 through 262.60). 
We note that the generator accumulation provisions of 40 CFR 262.34 
allow generators to accumulate hazardous wastes without obtaining 
interim status or a permit only in certain specified units; the 
regulations also place a limit on the maximum amount of time that 
wastes can be accumulated in these units. If these wastes are actively 
managed in surface impoundments or other units that are not tank 
systems, containers, drip pads, or containment buildings as outlined in 
40 CFR 262.34, accumulation of these wastes is subject to the 
permitting requirements of 40 CFR Parts 264 and 265, and the generator 
is required to obtain interim status and seek a permit (or modify 
interim status or a permit, as appropriate). Also, persons who 
transport newly identified hazardous wastes will be required to obtain 
an EPA identification number (if they do already have one) as described 
above and will be subject to the transporter requirements set forth in 
40 CFR Part 263. [NOTE: Generators of EDC/VCM wastewater treatment 
sludge who manage the waste in compliance with the requirements of the 
conditional listing (i.e., dispose of the waste in a landfill and do 
not store the waste directly on the land prior to landfilling, are not 
subject to the hazardous waste

[[Page 67119]]

generator requirements at 40 CFR Part 262.]

D. Facilities Subject to Permitting

    Today's rule is issued pursuant to HSWA authority. Therefore, EPA 
will regulate the management of the newly identified hazardous wastes 
until states are authorized to regulate these wastes. EPA will apply 
Federal regulations to these wastes and to their management in both 
authorized and unauthorized states.
1. Facilities Newly Subject to RCRA Permit Requirements
    Facilities that treat, store, or dispose of wastes that are subject 
to RCRA regulation for the first time by this rule (that is, facilities 
that have not previously received a permit pursuant to Section 3005 of 
RCRA and are not currently operating pursuant to interim status), might 
be eligible for interim status (see Section 3005(e)(1)(A)(ii) of RCRA). 
To obtain interim status based on treatment, storage, or disposal of 
such newly identified wastes, eligible facilities are required to 
comply with 40 CFR 270.70(a) and 270.10(e) by providing notice under 
Section 3010 and submitting a Part A permit application no later than 
May 7, 2001. Such facilities are subject to regulation under 40 CFR 
Part 265 until a permit is issued.
    In addition, under Section 3005(e)(3) and 40 CFR 270.73(d), not 
later than November 8, 2001, land disposal facilities newly qualifying 
for interim status under section 3005(e)(1)(A)(ii) also must submit a 
Part B permit application and certify that the facility is in 
compliance with all applicable groundwater monitoring and financial 
responsibility requirements. If the facility fails to submit these 
certifications and a permit application, interim status will terminate 
on that date.
2. Existing Interim Status Facilities
    Pursuant to 40 CFR 270.72(a)(1), all existing hazardous waste 
management facilities (as defined in 40 CFR 270.2) that treat, store, 
or dispose of the newly identified hazardous wastes and are currently 
operating pursuant to interim status under section 3005(e) of RCRA, 
must file an amended Part A permit application with EPA no later than 
the effective date of today's rule (i.e., May 7, 2001). By doing this, 
the facility may continue managing the newly listed wastes. If the 
facility fails to file an amended Part A application by that date, the 
facility will not receive interim status for management of the newly 
listed hazardous wastes and may not manage those wastes until the 
facility receives either a permit or a change in interim status 
allowing such activity (40 CFR 270.10(g)).
3. Permitted Facilities
    Facilities that already have RCRA permits must request permit 
modifications if they want to continue managing newly listed wastes 
(see 40 CFR 270.42(g)). This provision states that a permittee may 
continue managing the newly listed wastes by following certain 
requirements, including submitting a Class 1 permit modification 
request by the date on which the waste or unit becomes subject to the 
new regulatory requirements (i.e., the effective date of today's rule), 
complying with the applicable standards of 40 CFR Parts 265 and 266 and 
submitting a Class 2 or 3 permit modification request within 180 days 
of the effective date.
    Generally, a Class 2 modification is appropriate if the newly 
listed wastes will be managed in existing permitted units or in newly 
regulated tank or container units and will not require additional or 
different management practices than those authorized in the permit. A 
Class 2 modification requires the facility owner to provide public 
notice of the modification request, a 60-day public comment period, and 
an informal meeting between the owner and the public within the 60-day 
period. The Class 2 process includes a ``default provision,'' which 
provides that if the Agency does not reach a decision within 120 days, 
the modification is automatically authorized for 180 days. If the 
Agency does not reach a decision by the end of that period, the 
modification is permanently authorized (see 40 CFR 270.42(b)).
    A Class 3 modification is generally appropriate if management of 
the newly listed wastes requires additional or different management 
practices than those authorized in the permit or if newly regulated 
land-based units are involved. The initial public notification and 
public meeting requirements are the same as for Class 2 modifications. 
However, after the end of the 60-day public comment period, the Agency 
will grant or deny the permit modification request according to the 
more extensive procedures of 40 CFR part 124. There is no default 
provision for Class 3 modifications (see 40 CFR 270.42(c)).
    Under 40 CFR 270.42(g)(1)(v), for newly regulated land disposal 
units, permitted facilities must certify that the facility is in 
compliance with all applicable 40 CFR part 265 groundwater monitoring 
and financial responsibility requirements no later than May 7, 2001. If 
the facility fails to submit these certifications, authority to manage 
the newly listed wastes under 40 CFR 270.42(g) will terminate on that 
date.
4. Units
    Units in which newly identified hazardous wastes are generated or 
managed will be subject to all applicable requirements of 40 CFR part 
264 for permitted facilities or 40 CFR part 265 for interim status 
facilities, unless the unit is excluded from such permitting by other 
provisions, such as the wastewater treatment tank exclusions (40 CFR 
264.1(g)(6) and 265.1(c)(10)) and the product storage tank exclusion 
(40 CFR 261.4(c)). Examples of units to which these exclusions could 
never apply include landfills, land treatment units, waste piles, 
incinerators, and any other miscellaneous units in which these wastes 
may be generated or managed.
5. Closure
    All units in which newly identified hazardous wastes are treated, 
stored, or disposed after the effective date of this regulation that 
are not excluded from the requirements of 40 CFR parts 264 and 265 are 
subject to both the general closure and post-closure requirements of 
Subpart G of 40 CFR parts 264 and 265 and the unit-specific closure 
requirements set forth in the applicable unit technical standards 
Subpart of 40 CFR part 264 or part 265 (e.g., Subpart N for landfill 
units). In addition, EPA promulgated a final rule that allows, under 
limited circumstances, regulated landfills, surface impoundments, or 
LTUs to cease managing hazardous waste but to delay subtitle C closure 
to allow the unit to continue to manage non-hazardous waste for a 
period of time prior to closure of the unit (see 54 FR 33376, August 
14, 1989). Units for which closure is delayed continue to be subject to 
all applicable 40 CFR 264 and 265 requirements. Dates and procedures 
for submittal of necessary demonstrations, permit applications, and 
revised applications are detailed in 40 CFR 264.113(c) through (e) and 
265.113(c) through (e).

IX. How Will This Rule Be Implemented at the State Level?

A. Applicability of Rule in Authorized States

    Under section 3006 of RCRA, EPA may authorize qualified States to 
administer the RCRA hazardous waste program within the State. See 40 
CFR part 271 for the overall standards and requirements for 
authorization. Following authorization, the State

[[Page 67120]]

requirements authorized by EPA apply in lieu of equivalent Federal 
requirements and become Federally enforceable as requirements of RCRA. 
EPA maintains independent authority to bring enforcement actions under 
RCRA sections 3007, 3008, 3013, and 7003. Authorized States also have 
independent authority to bring enforcement actions under State law. A 
State may receive authorization by following the approval process 
described under 40 CFR part 271.
    After a State receives initial authorization, new Federal 
requirements promulgated under RCRA authority existing prior to the 
1984 Hazardous and Solid Waste Amendments (HSWA) do not apply in that 
State until the State adopts and receives authorization for equivalent 
State requirements. The State must adopt such requirements to maintain 
authorization.
    In contrast, under RCRA section 3006(g) (42 U.S.C. 6926(g)), new 
Federal requirements and prohibitions imposed pursuant to HSWA 
provisions take effect in authorized States at the same time that they 
take effect in unauthorized States. Although authorized States are 
still required to update their hazardous waste programs to remain 
equivalent to the Federal program, EPA carries out HSWA requirements 
and prohibitions in authorized States, including the issuance of new 
permits implementing those requirements, until EPA authorizes the State 
to do so.
    Authorized States are required to modify their programs only when 
EPA promulgates Federal requirements that are more stringent or broader 
in scope than existing Federal requirements. RCRA section 3009 allows 
the States to impose standards more stringent than those in the Federal 
program. See also 40 CFR 271.1(i). Therefore, authorized States are not 
required to adopt Federal regulations, both HSWA and non-HSWA, that are 
considered less stringent.

B. Effect on State Authorizations

    EPA is promulgating this rule (with the exception of the changes to 
Part 302) pursuant to sections 2002(a), 3001(b), 3001(e)(2), and 
3007(a) of the Solid Waste Disposal Act, which are HSWA provisions. We 
will add the new requirements to Table 1 at 40 CFR 271.1, which 
identifies Federal program requirements promulgated pursuant to HSWA. 
Because this rule is promulgated pursuant to the HSWA, after its 
effective date EPA will implement it rule in all States, including 
authorized States. Once authorized States modify their programs to 
adopt equivalent rules and receive authorization for such rules from 
EPA, those rules will become RCRA subtitle C requirements that apply in 
that States in lieu of the equivalent federal requirements.
    Because this rule is promulgated pursuant to HSWA, a State 
submitting a program modification may apply to receive either interim 
or final RCRA authorization under RCRA 3006(g) or (b) on the basis that 
State regulations are, respectively, substantially equivalent or fully 
equivalent to EPA's regulations. The procedures and schedule for State 
programs modifications for either interim or final authorization are 
described in 40 CFR 271.21 and 271.24. Note that all HSWA interim 
authorizations will expire on January 1, 2003 (see 40 CFR 271.24(c)).

X. What Are the Reportable Quantity Requirements for Newly-Listed 
Wastes (K174 and K175) Under the Comprehensive Environmental 
Response, Compensation, and Liability Act (CERCLA)?

A. What Is the Relationship Between RCRA and CERCLA?

    CERCLA defines the term ``hazardous substance'' to include RCRA 
hazardous wastes. When EPA lists a hazardous waste under RCRA, the 
waste is also a hazardous substance pursuant to CERCLA 101(14), and the 
Agency adds the waste to the table of CERCLA hazardous substances in 
the CFR. EPA establishes a reportable quantity or RQ for each CERCLA 
hazardous substance. EPA provides a list of the CERCLA hazardous 
substances along with their RQs in Table 302.4 at 40 CFR 302.4. If you 
are the person in charge of a vessel or facility that releases a CERCLA 
hazardous substance in an amount that equals or exceeds its RQ, then 
you must report that release to the National Response Center (NRC). You 
also may have to notify State and local authorities.

B. Is EPA Adding Chlorinated Aliphatic Wastes to the Table of CERCLA 
Hazardous Substances?

    Yes. Today, EPA is adding the newly listed chlorinated aliphatic 
wastes (K174 and K175) to the list of CERCLA hazardous substances. As 
discussed below, EPA also is finalizing adjusted RQs for these wastes.

C. How Does EPA Determine Reportable Quantities?

    Under CERCLA, all new hazardous substances generally have a 
statutory one-pound RQ. EPA adjusts the RQ of a newly added hazardous 
substance based on an evaluation of its intrinsic physical, chemical, 
and toxic properties. These intrinsic properties--called ``primary 
criteria''--are aquatic toxicity, mammalian toxicity (oral, dermal, and 
inhalation), ignitability, reactivity, chronic toxicity, and potential 
carcinogenicity. EPA evaluates the data for a hazardous substance for 
each primary criterion. To adjust the RQs, EPA ranks each criterion on 
a scale that corresponds to an RQ value of 1, 10, 100, 1,000, or 5,000 
pounds. For each criterion, EPA establishes a tentative RQ. A 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, EPA further evaluates 
substances for their susceptibility to certain degradative processes. 
These are secondary adjustment criteria. The natural degradative 
processes are biodegradation, hydrolysis, and photolysis (BHP). If a 
hazardous substance, when released into the environment, degrades 
rapidly to a less hazardous form by one or more of the BHP processes, 
EPA generally raises its RQ (as determined by the primary RQ adjustment 
criteria) by one level. Conversely, if a hazardous substance degrades 
to a more hazardous product after its release, EPA assigns an RQ to the 
original substance equal to the RQ for the more hazardous substance.
    The standard methodology used to adjust the RQs for RCRA hazardous 
waste streams differs from the methodology applied to individual 
hazardous substances. The procedure for assigning RQs to RCRA waste 
streams is based on the results of an analysis of the hazardous 
constituents of the waste streams. The constituents of each RCRA 
hazardous waste stream are identified in 40 CFR part 261, Appendix VII. 
EPA first determines an RQ for each hazardous constituent within the 
waste stream using the methodology described above. The lowest RQ value 
of these constituents becomes the adjusted RQ for the waste stream. 
When there are hazardous constituents of a RCRA waste stream that are 
not CERCLA hazardous substances, the Agency develops an RQ, called a 
``reference RQ,'' for these constituents in order to assign an 
appropriate RQ to the waste stream (see 48 FR 23565, May 25, 1983). In 
other words, the Agency derives the RQ for waste streams based on the 
lowest RQ of all of the hazardous constituents, regardless of whether 
they are CERCLA hazardous substances.

[[Page 67121]]

D. When Do I Need To Report a Release of K174 or K175 Under CERCLA?

    Today, EPA is promulgating adjusted statutory RQs for newly-listed 
hazardous wastes K174 and K175 waste streams of one pound based on 
their hazardous constituents. EPA also is adjusting the RQ at one pound 
for K174 based on its hazardous constituents, chlorinated dibenzo-p-
dioxins (CDDs) and chlorinated dibenzofurans (CDFs). EPA is 
promulgating an adjusted RQ of one pound for newly-listed waste K175 
based on its hazardous constituent, mercury. However, in determining 
when to report a release of K174 or K175, EPA will allow you to apply 
the mixture rule, codified in 40 CFR 302.6, using the maximum observed 
concentrations of the hazardous constituents within the respective 
waste streams.
    The mixture rule provides that when you know the quantities of all 
hazardous constituents of a mixture or solution, you must notify of 
releases of an RQ or more of such constituents (40 CFR 302.6). 
Therefore, if you know the concentration of the hazardous constituents 
of a hazardous waste, you can calculate the amount of waste released 
needed to reach the RQ for the constituents. By using the maximum 
observed concentration that EPA is promulgating today, you may apply 
the mixture rule, even if you do not know the concentration of 
constituents released. That is, if you are the person in charge, you 
must immediately report the release as soon as you know that you have 
released K174 or K175 in an amount that will reach the RQ for any of 
the hazardous constituents. This approach is reasonable and 
conservative because the sampling data presented in the Listing 
Background Document (USEPA, 1999c) accurately identify the maximum 
observed concentrations of the hazardous constituents in the 
chlorinated aliphatics waste streams. Table X-1 below identifies the 
hazardous constituents for each waste stream, their maximum observed 
concentrations in parts per million (ppm), and their constituents' RQs 
or reference RQs.

   Table X-1.--Maximum Observed Concentration and Corresponding RQ for
  Hazardous Constituents That Are Basis for Newly-Listed K174 and K175
------------------------------------------------------------------------
                                                    Max.
      Waste               Constituent           concentration    RQ (lb)
                                                (ppm (mg/kg))
------------------------------------------------------------------------
K174.............  2,3,7,8-TCDD.............          0.000039         1
                   1,2,3,7,8-PeCDD..........         0.0000108         1
                   1,2,3,4,7,8-HxCDD........         0.0000241         1
                   1,2,3,6,7,8-HxCDD........          0.000083         1
                   1,2,3,7,8,9-HxCDD........          0.000062         1
                   1,2,3,4,6,7,8-HpCDD......           0.00123         1
                   OCDD.....................            0.0129         1
                   2,3,7,8-TCDF.............          0.000145         1
                   1,2,3,7,8-PeCDF..........         0.0000777         1
                   2,3,4,7,8-PeCDF..........          0.000127         1
                   1,2,3,4,7,8-HxCDF........          0.001425         1
                   1,2,3,6,7,8-HxCDF........          0.000281         1
                   1,2,3,7,8,9-HxCDF........           0.00014         1
                   2,3,4,6,7,8-HxCDF........          0.000648         1
                   1,2,3,4,6,7,8-HpCDF......            0.0207         1
                   1,2,3,4,7,8,9-HpCDF......            0.0135         1
                   OCDF.....................             0.212         1
K175.............  Mercury..................              9200         1
------------------------------------------------------------------------

    For example, if K174 is released from your facility and you do not 
know the actual concentrations of its constituents, you may assume that 
the concentrations are those identified in Table X-1. Thus, if K174 is 
released from your facility and you do not know the actual 
concentrations of its constituents, you may apply the mixture rule to 
the assumed maximum concentrations indicated in the table. You would 
have to release 4,716,981 pounds of K174 to reach the RQ for this waste 
(based on the maximum observed concentration of OCDF). If K175 is 
released from your facility and you do not know the actual 
concentration of mercury, you may assume that the concentration is 9200 
ppm. Applying the mixture rule, you would have to release 108.7 pounds 
of K0175 to reach the RQ.

E. What if I Know the Concentration of the Constituents in My Waste?

    If you know the concentration levels of all the hazardous 
constituents in a particular chlorinated aliphatic waste, you may apply 
the mixture rule (see 40 CFR 302.6(b)) to the actual concentrations. 
You would need to report a release of either waste when an RQ or more 
of any of their respective hazardous constituents is released.

F. How Did EPA Determine the RQs for K174 and K175 and Their Hazardous 
Constituents?

    The hazardous constituents identified as the basis for listing K174 
as hazardous waste include chlorinated dibenzo-p-dioxins (CDDs) and 
chlorinated dibenzofurans (CDFs). Previously, EPA had established an 
adjusted RQ of one pound for 2,3,7,8-TCDD (see 54 FR 33426). EPA has 
not established adjusted RQs for the other CDD and CDF congeners. 
However, EPA recognizes that a number of these congeners exhibit 
dioxin-like toxicity and has established ``reference RQs'' of one pound 
for these congeners to support the development of the adjusted RQs for 
K174.
    The adjusted RQ for 2,3,7,8-TCDD was established as one pound based 
on potential carcinogenicity, considering the weight of evidence that 
this substance is carcinogenic, and considering its estimated 
carcinogenic potency. To establish reference RQs for the other CDD and 
CDF congeners in the waste stream, EPA applied the toxicity equivalency 
factors (TEFs) established for dioxin-like compounds to the potency 
factor used as the basis for the adjusted RQ for 2,3,7,8-TCDD. Of the 
210 CDD and CDF congeners, only those with chlorine substitutions in, 
at least,

[[Page 67122]]

the 2, 3, 7, and 8 positions (a total of 17 CDD and CDF congeners) are 
considered to have dioxin-like toxicity. Applying the TEFs established 
for these 17 congeners to the potency factor established for 2,3,7,8-
TCDD indicates that all of the congeners fit into RQ Potency Group 1 
with a corresponding reference RQ of one pound.\69\ Therefore, because 
each of the hazardous constituents has an RQ or reference RQ of one 
pound, EPA is promulgating an adjusted RQ of one pound for K174.
---------------------------------------------------------------------------

    \69\ For an explanation of how potency factors are calculated 
and potency groups and RQs are established, see the Technical 
Background Document to Support Rulemaking Pursuant to CERCLA Section 
102, Volume 3, July 27, 1989. This document can be viewed by calling 
the EPA Superfund Docket Center, 703-603-8917, and requesting 
document number 102 RQ 273C.
---------------------------------------------------------------------------

    The hazardous constituent identified as the basis for listing as 
hazardous VCM-A wastewater treatment sludges (K175) is mercury. 
Previously, EPA had established an adjusted RQ of one pound for mercury 
(see 50 FR 13456, April 4, 1985). Because the hazardous constituent 
used as the basis for listing K175 has an RQ of one pound, EPA is 
promulgating an adjusted RQ of one pound for this waste.

G. How Do I Report a Release?

    To report a release of K174 or K175 (or any other CERCLA hazardous 
substance) that equals or exceeds its RQ, you must immediately notify 
the National Response Center (NRC) as soon as you have knowledge of 
that release. The toll-free telephone number of the NRC is 1-800-424-
8802; in the Washington, DC, metropolitan area, the number is (202) 
267-2675.
    You also may have to notify State and local authorities. The 
Emergency Planning and Community Right-to-Know Act (EPCRA) requires 
that owners and operators of certain facilities report releases of 
CERCLA hazardous substances and EPCRA extremely hazardous substances 
(see list in 40 CFR part 355, Appendix A) to State and local 
authorities. After the release of an RQ or more of any of those 
substances, you must report immediately to the community emergency 
coordinator of the local emergency planning committee for any area 
likely to be affected by the release, and to the State emergency 
response commission of any State likely to be affected by the release.

H. Is CERCLA Reporting Required for Spills of EDC/VCM Wastewater 
Treatment Sludge That (Prior to the Spill) Does Not Meet the Listing 
Description for K174?

    Commenters to the proposed rule asked whether spills of EDC/VCM 
wastewater treatment sludge, where prior to being spilled the sludge 
does not meet the K174 listing because of the manner in which it is 
being managed, would have to be reported in compliance with the CERCLA 
RQ reporting requirements. The Agency notes that we are finalizing a 
contingent management listing for EDC/VCM wastewater treatment sludges 
under which these sludges would be regulated as K174 wastes unless they 
are destined for management in a subtitle C landfill or a non-hazardous 
waste landfill licensed or permitted by a state. As part of the listing 
description, once the EDC/VCM wastewater treatment sludge is placed on 
the land it meets the listing description. Therefore, contrary to the 
commenter's suggestion, spills of EDC/VCM sludges would not be excluded 
from the K174 listing. A spill of EDC/VCM wastewater treatment sludges 
would constitute the release of a CERCLA hazardous substance, and 
provided that an amount equal to or exceeding the RQ had been released, 
would be subject to CERCLA notification requirements.

I. What Is the Statutory Authority for This Program?

    Section 101(14) of CERCLA defines the term hazardous substance by 
referring to substances listed under several other environmental 
statutes, as well as those substances that EPA designates as hazardous 
under CERCLA section 102(a). In particular, CERCLA section 101(14)(C) 
defines the term hazardous substance to include ``any hazardous waste 
having the characteristics identified under or listed pursuant to 
section 3001 of the Solid Waste Disposal Act.'' CERCLA section 102(a) 
gives EPA authority to establish RQs for CERCLA hazardous substances. 
CERCLA section 103(a) requires any person in charge of a vessel or 
facility that releases a CERCLA hazardous substance in an amount equal 
to or greater than its RQ to report the release immediately to the 
federal government. EPCRA section 304 requires owners or operators of 
certain facilities to report releases of CERCLA hazardous substances 
and EPCRA extremely hazardous substances to State and local 
authorities.

XI. What Are the Administrative Assessments?

A. Executive Order 12866

    Under Executive Order 12866 (September 30, 1993), EPA must 
determine whether a regulatory action is ``significant'' and, 
therefore, subject to OMB review and the other provisions of the 
Executive Order. A significant regulatory action is defined by 
Executive Order 12866 as one 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 rights and obligations or 
recipients thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
Executive Order 12866.

    Pursuant to the terms of Executive Order 12866, EPA has determined 
that this rule is a ``significant regulatory action'' because of point 
four (4) above: The rule includes a novel legal or policy issue arising 
out of legal mandates, the President's priorities, or the principles 
set forth in this Executive Order. Today's final rule, which includes 
an alternative listing approach for one of the newly-listed 
wastestreams, deviates from the Agency's standard or historic listing 
approach in that the Agency is listing as hazardous only those 
quantities of the waste that are managed in a manner that reflects 
unacceptable risks. This differs from the Agency's traditional approach 
to listing a waste as hazardous, in which the listing determination 
captures the entire quantity of a targeted wastestream that poses 
unacceptable risks to human health and the environment when managed in 
one or more particular manners.
    Due to the Agency's decision to promulgate a listing approach that 
deviates from our historical hazardous waste listing approach, the 
Agency is deeming today's action to be ``significant.'' Prior to 
finalizing today's rule, EPA submitted this proposed policy change to 
OMB for review. Changes made to the Agency's proposal in response to 
OMB suggestions or recommendations are documented in the public record.
    Although today's final rule is not ``economically significant,'' 
the Agency prepared an Economics Background

[[Page 67123]]

Document (USEPA 1999b) in support of today's rule. The Agency's 
economic assessment addresses, among other factors, industry compliance 
costs, industry financial impacts, and potential for small entity 
impacts. A summary of findings from our economic assessment is 
presented in Section VII. The complete Economics Background Document 
(USEPA 1999b) is available for public review from the RCRA docket, 
according to instructions provided in the introduction to this 
preamble.
    EPA anticipates that the final rule will primarily affect three of 
the 18 known US generators of K174 and K175 hazardous wastes, causing 
these three facilities to modify current waste management practices, 
according to the terms and conditions of the final rule. None of these 
18 facilities are owned by small-sized companies. The 15 remainder 
chemical plants will incur relatively minor annual costs for 
documentation of current waste management practices. In addition, EPA 
anticipates that four industrial waste management operators will be 
affected by either increased or decreased annual volumes and business 
revenues associated with the management of wastes from the three 
affected chemical plants. EPA also anticipates that states with 
authorized RCRA programs will be affected as they will be required to 
implement and enforce the final rule. Finally, EPA anticipates that 
other Federal agencies and non-governmental organizations may be incur 
relatively minor costs associated with reading and propagating the 
final rule.
    EPA estimates that the national average annual cost of the final 
rule will be between $0.42 to $4.05 million. Under broader cost 
estimation uncertainty assumptions which allow for temporary offsite 
trucking of affected wastes by one facility if it requires additional 
time beyond the final rule six-month compliance deadline to modify its 
current waste management practices, the upper-bound of this cost 
estimate increases to $23.37 million in average annual cost.

B. Regulatory Flexibility Act

    Pursuant to the 1980 Regulatory Flexibility Act (RFA)(5 U.S.C. 601 
et seq., as amended by the Small Business Regulatory Enforcement 
Fairness Act (SBREFA) of 1996), whenever an agency is required to 
publish a notice of rulemaking for any proposed or final rule, it must 
prepare and make available for public comment, a regulatory flexibility 
analysis that describes the effect of the rule on small entities (i.e., 
small businesses, small organizations, and small governmental 
jurisdictions). However, a regulatory flexibility analysis is not 
required if the head of an agency certifies that the rule will not have 
a ``significant'' economic impact on a substantial number of small 
entities.
    SBREFA amended the Regulatory Flexibility Act to require Federal 
agencies to provide a statement of the factual basis for certifying 
that a rule will not have a ``significant'' economic impact on a 
substantial number of small entities. The following discussion explains 
EPA's determination.
    EPA has examined this rule's potential effects on small entities as 
required by the RFA/SBREFA, and has determined that this action will 
not have a significant economic impact on a substantial number of small 
entities. This is evidenced by the fact that only one of the 
potentially affected, parent companies determined to be producers of 
chlorinated aliphatic products in the U.S., may be classified as a 
``small business,'' according to the U.S. Small Business 
Administration's employee size standards (i.e., less than or equal to 
1,000 employees) and according to that company's primary Standard 
Industrial Classification (SIC) code (SIC 2869).
    I hereby certify that this rule will not have a significant 
economic impact on a substantial number of small entities. This rule, 
therefore, does not require a regulatory flexibility analysis.

C. Paperwork Reduction Act

    The information collection requirements in this final rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An 
Information Collection Request (ICR) document was prepared by EPA (ICR 
No. 1924.01) and a copy may be obtained from Sandy Farmer by mail at OP 
Regulatory Information Division; U.S. Environmental Protection Agency 
(2137); 1200 Pennsylvania Avenue NW.; Washington, DC 20460, by E-mail 
at <a href="/cdn-cgi/l/email-protection#8bedeaf9e6eef9a5f8eae5eff2cbeefbeae6eae2e7a5eefbeaa5ece4fd"><span class="__cf_email__" data-cfemail="98fef9eaf5fdeab6ebf9f6fce1d8fde8f9f5f9f1f4b6fde8f9b6fff7ee">[email protected]</span></a>, or by calling (202) 260-2740. A copy 
also may be downloaded off the Internet at 
http://www.epa.gov/icr.
    This final rule includes new information collection requirements 
subject to OMB review under the Paperwork Reduction Act of 1995, 44 
U.S.C. 3501 et seq. In addition to complying with the existing subtitle 
C recordkeeping and reporting requirements for the newly listed waste 
streams, EPA is requiring that facilities generating EDC/VCM wastewater 
treatment sludges be able to document their compliance with the 
conditions provided for exclusion from the scope of the conditional 
hazardous waste listing promulgated today. This requirement is 
necessary to ensure that EDC/VCM wastewater treatment sludges are 
managed in a manner that is safe for human health and the environment. 
In addition, EPA is requiring disposal facilities that manage VCM-A 
wastewater treatment sludges to maintain records documenting that these 
sludges are co-disposed only with other wastes that have a pH level of 
6.0 or lower. This requirement is necessary to ensure that the mercury 
contained in the waste does not leach from the waste after disposal.
    The Agency estimated the burden associated with complying with the 
requirements in this proposed rule. Included in the ICR are the burden 
estimates for the following requirements for industry respondents: 
reading the regulations; keeping records documenting compliance with 
conditions for exclusion from hazardous waste listings; and keeping 
records documenting compliance with landfill waste disposal 
requirements for the disposal of VCM-A wastewater treatment sludges. 
Included also are the burden estimates for State respondents for 
applying for State authorization. The Agency determined that all of 
this information is necessary to ensure compliance with today's final 
rule.
    To the extent that this rule imposes any information collection 
requirements under existing RCRA regulations promulgated in previous 
rulemakings, those requirements have been approved by the Office of 
Management and Budget (OMB) under the Paperwork Reduction Act, 44 
U.S.C. 3501 et seq., and have been assigned OMB control numbers 2050-
0009 (ICR No. 1573, Part B Permit Application, Permit Modifications, 
and Special Permits); 2050-0120 (ICR No. 1571, General Facility 
Hazardous Waste Standards); 2050-0028 (ICR No. 261, Notification of 
Hazardous Waste Activity); 2050-0034 (ICR No. 262, RCRA Hazardous Waste 
Permit Application and Modification, Part A); 2050-0039 (ICR No. 801, 
Requirements for Generators, Transporters, and Waste Management 
Facilities under the Hazardous Waste Manifest System); 2050-0035 (ICR 
No. 820, Hazardous Waste Generator Standards); and 2050-0024 (ICR No. 
976, 1997 Hazardous Waste Report).
    EPA estimates that the projected annual hour burden for industry 
respondents will be 93 hours, and the annual cost associated with the 
additional paperwork burden will be $5,254. Total estimates over three 
years are 279 hours and $15,762.

[[Page 67124]]

    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and use 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations are listed in 40 CFR part 9 and 48 CFR chapter 15.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Pub. 
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 by State, local, and tribal governments, in 
the aggregate, or by 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. The rule would not impose any 
federal intergovernmental mandate because it imposes no enforceable 
duty upon state, tribal or local governments. States, tribes and local 
governments would have no compliance costs under this rule. It is 
expected that states will adopt similar rules, and submit those rules 
for inclusion in their authorized RCRA programs, but they have no 
legally enforceable duty to do so. For the same reasons, we determined 
that this rule contains no regulatory requirements that might 
significantly or uniquely affect small governments, and thus, is not 
subject to the requirements of sections 202 and 205 of UMRA. In 
addition, EPA has determined that this rule does not contain a Federal 
mandate that may result in expenditures of $100 million or more for 
State, local, and tribal governments, in the aggregate, or the private 
sector in any one year.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
The Executive Order defines ``policies that have federalism 
implications'' to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    This final rule does not have federalism implications. It will not 
have substantial direct effects on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in Executive Order 13132. This proposed rule directly 
affects the chlorinated aliphatics industry. States and local 
governments will not incur direct compliance costs under this rule. It 
is expected that states will adopt similar rules, and submit those 
rules for inclusion in their authorized RCRA programs, but they have no 
legally enforceable duty to do so. Thus, Executive Order 13132 does not 
apply to this rule.

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

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

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

    Executive Order 13045, ``Protection of Children from Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997), applies 
to any rule that: (1) is determined to be ``economically significant'' 
as defined under E.O. 12866, and (2) concerns an environmental health 
or safety risk that EPA has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, the Agency must evaluate the environmental health or 
safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective

[[Page 67125]]

and reasonably feasible alternatives considered by the Agency. This 
rule is not subject to the Executive Order because it is not 
economically significant as defined in E.O. 12866, and because the 
Agency does not have reason to believe the environmental health or 
safety risks addressed by this action present a disproportionate risk 
to children.
    The topic of environmental threats to children's health is growing 
in regulatory importance as scientists, policy makers, and village 
leaders continue to recognize the extent to which children are 
particularly vulnerable to environmental hazards. Recent EPA actions 
have been in the forefront of addressing environmental threats to the 
health and safety of children. Today's final rule further reflects our 
commitment to mitigating environmental threats to children.
    A few significant physiological characteristics are largely 
responsible for children's increased susceptibility to environmental 
hazards. First, children eat proportionately more food, drink 
proportionately more fluids, and breathe more air per pound of body 
weight than do adults. As a result, children potentially experience 
greater levels of exposure to environmental threats than do adults. 
Second, because children's bodies are still in the process of 
development, their immune systems, neurological systems, and other 
immature organs can be more easily and considerably affected by 
environmental hazards.
    Today's rule will reduce risks posed by the hazardous constituents 
found in the listed waste streams by requiring more appropriate and 
safer management practices. EPA considered risks to children in its 
risk assessment. The more appropriate and safer management practices 
promulgated in this rule are projected to reduce risks to children 
potentially exposed to the constituents of concern.

H. National Technology Transfer and Advancement Act of 1995

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Pub L. No. 104-113, section 12(d) (15 U.S.C. 
272 note) directs EPA to use voluntary consensus standards in its 
regulatory activities, unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. The NTTAA directs EPA 
to provide Congress, through OMB, explanations when the Agency decides 
not to use available and applicable voluntary consensus standards.
    This rulemaking does not involve technical standards. Therefore, 
EPA is not considering the use of any voluntary consensus standards.

I. Executive Order 12898: Environmental Justice

    Under Executive Order 12898, ``Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations,'' as well as through EPA's April 1995, ``Environmental 
Justice Strategy, OSWER Environmental Justice Task Force Action Agenda 
Report,'' and National Environmental Justice Advisory Council, EPA has 
undertaken to incorporate environmental justice into its policies and 
programs. EPA is committed to addressing environmental justice 
concerns, and is assuming a leadership role in environmental justice 
initiatives to enhance environmental quality for all residents of the 
United States. The Agency's goals are to ensure that no segment of the 
population, regardless of race, color, national origin, or income, 
bears disproportionately high and adverse human health and 
environmental effects as a result of EPA's policies, programs, and 
activities.
    Today's rule is intended to reduce risks from the generation and 
management of hazardous wastes and to benefit all populations. As such, 
this rule is not expected to cause any disproportionately high and 
adverse impacts to minority or low-income communities versus non-
minority or affluent communities.
    In making hazardous waste listing determinations, we base our 
evaluations of potential risk from the generation and management of 
solid wastes on an analysis of potential individual risk. In conducting 
risk evaluations, our goal is to estimate potential risk to any 
population of potentially exposed individuals (e.g., home gardeners, 
adult farmers, children of farmers, anglers) located in the vicinity of 
any generator or facility handling a waste. Therefore, we are not 
putting poor, rural, or minority populations at any disadvantage with 
regard to our evaluation of risk or with regard to how the Agency makes 
its proposed hazardous waste listing determinations.
    In promulgating decisions to list two wastes as hazardous (i.e., 
EDC/VCM wastewater treatment sludges managed in land treatment units, 
and VCM-A wastewater treatment sludges), all populations potentially 
exposed to these wastes or potentially exposed to releases of the 
hazardous constituents in the wastes will benefit from the listing 
determinations. In addition, listing determinations are effected at the 
national level. The wastes proposed to be listed as hazardous will be 
hazardous regardless of where they are generated and regardless of 
where they may be managed. Although the Agency understands that the 
listing determinations may affect where these wastes are managed in the 
future (in that hazardous wastes must be managed at subtitle C 
facilities), the Agency's decision to list these wastes as hazardous is 
independent of any decisions regarding the location of waste generators 
and the siting of waste management facilities.
    Similarly, in cases where the Agency is not listing a solid waste 
as hazardous because the waste does not meet the criteria for being 
identified as a hazardous waste, these decisions are based upon an 
evaluation of potential individual risks located in proximity to any 
facility handling the waste. In the case of wastewater treatment 
sludges from the production of allyl chloride and methyl chloride and 
in the case of EDC/VCM wastewater treatment sludges managed in 
landfills, we believe the potential risk levels associated with the 
wastes are safe for all populations potentially exposed to the wastes 
and their constituents.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A Major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2). This rule will be effective May 7, 2001.

List of Subjects

40 CFR 148

    Administrative practice and procedure, Hazardous waste, Reporting 
and recordkeeping requirements, Water supply.

[[Page 67126]]

40 CFR 261

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

40 CFR Part 268

    Environmental protection, Hazardous materials, Waste management, 
Reporting and recordkeeping requirements, Land disposal restrictions, 
Treatment standards.

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 recordkeeping 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, Hazardous 
materials transportation, Hazardous substances, Hazardous waste, 
Intergovernmental relations, Natural resources, Reporting and 
recordkeeping requirements, Superfund, Waste treatment and disposal, 
Water pollution control, Water supply.

    Dated: September 29, 2000.
Carol M. Browner,
Administrator.

    For the reasons setforth in the preamble, title 40, chapter I of 
the Code of Federal Regulations is amended as follows:

PART 148--HAZARDOUS WASTE INJECTION RESTRICTIONS

    1. The authority citation for part 148 continues to read as 
follows:

    Authority: Sec. 3004, Resource Conservation and Recovery Act, 42 
U.S.C. 6901 et seq.


    2. Section 148.18 is amended by adding paragraphs (j) and (k) to 
read as follows:


Sec. 148.18  Waste-specific prohibitions--newly listed and identified 
wastes.

* * * * *
    (j) Effective May 8, 2001, the wastes specified in 40 CFR 261.32 as 
EPA Hazardous Waste Numbers K174 and K175 are prohibited from 
underground injection.
    (k) The requirements of paragraphs (a) through (j) of this section 
do not apply:
    (1) If the wastes meet or are treated to meet the applicable 
standards specified in subpart D of 40 CFR part 268; or
    (2) If an exemption from a prohibition has been granted in response 
to a petition under subpart C of this part; or
    (3) During the period of extension of the applicable effective 
date, if an extension has been granted under Sec. 148.4 of this part.

PART 261--IDENTIFICATION AND LISTING OF HAZARDOUS WASTE

    3. The authority citation for part 261 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6912(a), 6921, 6922, 6924(y), and 
6938.


    4. In Sec. 261.32, the table is amended by adding in alphanumeric 
order (by the first column) the following waste streams to the subgroup 
``Organic Chemicals'' to read as follows:


Sec. 261.32  Hazardous waste from specific sources.

------------------------------------------------------------------------
  Industry and EPA hazardous
          waste No.              Hazardous waste       Hazardous code
------------------------------------------------------------------------
 
*                  *                  *                  *
                  *                  *                  *
Organic chemicals:
 
*                  *                  *                  *
                  *                  *                  *
    K174.....................  Wastewater          T
                                treatment sludges
                                from the
                                production of
                                ethylene
                                dichloride or
                                vinyl chloride
                                monomer
                                (including
                                sludges that
                                result from
                                commingled
                                ethylene
                                dichloride or
                                vinyl chloride
                                monomer
                                wastewater and
                                other
                                wastewater),
                                unless the
                                sludges meet the
                                following
                                conditions: (i)
                                they are disposed
                                of in a subtitle
                                C or non-
                                hazardous
                                landfill licensed
                                or permitted by
                                the state or
                                federal
                                government; (ii)
                                they are not
                                otherwise placed
                                on the land prior
                                to final
                                disposal; and
                                (iii) the
                                generator
                                maintains
                                documentation
                                demonstrating
                                that the waste
                                was either
                                disposed of in an
                                on-site landfill
                                or consigned to a
                                transporter or
                                disposal facility
                                that provided a
                                written
                                commitment to
                                dispose of the
                                waste in an off-
                                site landfill.
                                Respondents in
                                any action
                                brought to
                                enforce the
                                requirements of
                                subtitle C must,
                                upon a showing by
                                the government
                                that the
                                respondent
                                managed
                                wastewater
                                treatment sludges
                                from the
                                production of
                                vinyl chloride
                                monomer or
                                ethylene
                                dichloride,
                                demonstrate that
                                they meet the
                                terms of the
                                exclusion set
                                forth above. In
                                doing so, they
                                must provide
                                appropriate
                                documentation
                                (e.g., contracts
                                between the
                                generator and the
                                landfill owner/
                                operator,
                                invoices
                                documenting
                                delivery of waste
                                to landfill,
                                etc.) that the
                                terms of the
                                exclusion were
                                met.
    K175.....................  Wastewater          T
                                treatment sludges
                                from the
                                production of
                                vinyl chloride
                                monomer using
                                mercuric chloride
                                catalyst in an
                                acetylene-based
                                process.
 
*                  *                  *                  *
                  *                  *                  *
------------------------------------------------------------------------


[[Page 67127]]


    5. Appendix VII to Part 261 is amended by adding the following 
wastestreams in alphanumeric order (by the first column) to read as 
follows:

Appendix VII To Part 261--Basis for Listing Hazardous Waste

------------------------------------------------------------------------
                                        Hazardous constituents for which
        EPA hazardous waste no.                      listed
------------------------------------------------------------------------
 
*                  *                  *                  *
                  *                  *                  *
K174..................................  1,2,3,4,6,7,8-Heptachlorodibenzo-
                                         p-dioxin (1,2,3,4,6,7,8-HpCDD),
                                         1,2,3,4,6,7,8-
                                         Heptachlorodibenzofuran
                                         (1,2,3,4,6,7,8-HpCDF),
                                         1,2,3,4,7,8,9-
                                         Heptachlorodibenzofuran
                                         (1,2,3,6,7,8,9-HpCDF), HxCDDs
                                         (All Hexachlorodibenzo-p-
                                         dioxins), HxCDFs (All
                                         Hexachlorodibenzofurans),
                                         PeCDDs (All Pentachlorodibenzo-
                                         p-dioxins), OCDD
                                         (1,2,3,4,6,7,8,9-
                                         Octachlorodibenzo-p-dioxin,
                                         OCDF (1,2,3,4,6,7,8,9-
                                         Octachlorodibenzofuran), PeCDFs
                                         (All Pentachlorodibenzofurans),
                                         TCDDs (All tetrachlorodi-benzo-
                                         p-dioxins), TCDFs (All
                                         tetrachlorodibenzofurans).
K175..................................  Mercury
------------------------------------------------------------------------

Appendix VIII to Part 261--Hazardous Constituents

    6. Appendix VIII to Part 261 is amended by adding in alphabetical 
order of common name the following entries:

----------------------------------------------------------------------------------------------------------------
                                                                                          Chemical
                  Common name                           Chemical abstracts name          abstracts    Hazardous
                                                                                            No.       waste No.
----------------------------------------------------------------------------------------------------------------
 
      *                   *                   *                   *                   *                   *
                                                           *
Octachlorodibenzo-p-dioxin (OCDD).............  1,2,3,4,6,7,8,9-Octachlorodibenzo-p-      3268-87-9  ...........
                                                 dioxin.
Octachlorodibenzofuran (OCDF).................  1,2,3,4,6,7,8,9-Octachlorodibenofuran.   39001-02-0  ...........
 
      *                   *                   *                   *                   *                   *
                                                          *
----------------------------------------------------------------------------------------------------------------

PART 268--LAND DISPOSAL RESTRICTIONS

    7. The authority citation for part 268 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6912(a), 6921, and 6924.

Subpart C--Prohibitions on Land Disposal

    8. Section 268.33 is revised to read as follows:


Sec. 268.33  Waste specific prohibitions--chlorinated aliphatic wastes.

    (a) Effective May 8, 2001, the wastes specified in 40 CFR part 261 
as EPA Hazardous Wastes Numbers K174, and K175, soil and debris 
contaminated with these wastes, radioactive wastes mixed with these 
wastes, and soil and debris contaminated with radioactive wastes mixed 
with these wastes are prohibited from land disposal.
    (b) The requirements of paragraph (a) of this section do not apply 
if:
    (1) The wastes meet the applicable treatment standards specified in 
subpart D of this part;
    (2) Persons have been granted an exemption from a prohibition 
pursuant to a petition under Sec. 268.6, with respect to those wastes 
and units covered by the petition;
    (3) The wastes meet the applicable treatment standards established 
pursuant to a petition granted under Sec. 268.44;
    (4) Hazardous debris has met the treatment standards in Sec. 268.40 
or the alternative treatment standards in Sec. 268.45; or
    (5) Persons have been granted an extension to the effective date of 
a prohibition pursuant to Sec. 268.5, with respect to these wastes 
covered by the extension.
    (c) To determine whether a hazardous waste identified in this 
section exceeds the applicable treatment standards specified in 
Sec. 268.40, the initial generator must test a sample of the waste 
extract or the entire waste, depending on whether the treatment 
standards are expressed as concentrations in the waste extract or the 
waste, or the generator may use knowledge of the waste. If the waste 
contains regulated constituents in excess of the applicable levels of 
subpart D of this part, the waste is prohibited from land disposal, and 
all requirements of part 268 are applicable, except as otherwise 
specified.
    (d) Disposal of K175 wastes that have complied with all applicable 
40 CFR 268.40 treatment standards must also be macroencapsulated in 
accordance with 40 CFR 268.45 Table 1 unless the waste is placed in:
    (1) A Subtitle C monofill containing only K175 wastes that meet all 
applicable 40 CFR 268.40 treatment standards; or
    (2) A dedicated Subtitle C landfill cell in which all other wastes 
being co-disposed are at pH<ls-thn-eq>6.0.

    9. In Sec. 268.40, the Table is amended by adding entries to F039 
in alphabetical order, by adding in alphanumeric order new entries for 
K174 and K175, and by adding footnote 12 to read as follows:


Sec. 268.40  Applicability of treatment standards.

* * * * *

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    *                  *                  *                  *        
          *                  *                  *
    Footnotes to Treatment Standard Table 268.40
    \1\ The waste descriptions provided in this table do not replace 
waste descriptions in 40 CFR Part 261. Descriptions of Treatment/
Regulatory Subcategories are provided, as needed, to distinguish 
between applicability of different standards.
    \2\ CAS means Chemical Abstract Services. When the waste code 
and/or regulated constituents are described as a combination of a 
chemical with its salts and/or esters, the CAS number is given for 
the parent compound only.
    \3\ Concentration standards for wastewaters are expressed in mg/
L and are based on analysis of composite samples.
    \4\ All treatment standards expressed as a Technology Code or 
combination of Technology Codes are explained in detail in 40 CFR 
268.42 Table 1-Technology Codes and Descriptions of Technology-Based 
Standards.
    \5\ Except for Metals (EP or TCLP) and Cyanides (Total and 
Amenable) the nonwastewater treatment standards expressed as a 
concentration were established, in part, based upon incineration in 
units operated in accordance with the technical requirements of 40 
CFR part 264, subpart O or 40 CFR part 265, subpart O, or based upon 
combustion in fuel substitution units operating in accordance with 
applicable technical requirements. A facility may comply with these 
treatment standards according to provisions in 40 CFR 268.40(d). All 
concentration standards for nonwastewaters are based on analysis of 
grab samples.
    *                  *                  *                  *        
          *                  *                  *
    \11\ For these wastes, the definition of CMBST is limited to: 
(1) combustion units operating under 40 CFR 266, (2) combustion 
units permitted under 40 CFR part 264, subpart O, or (3) combustion 
units operating under 40 CFR 265, subpart O, which have obtained a 
determination of equivalent treatment under 268.42(b).
    \12\ Disposal of K175 wastes that have complied with all 
applicable 40 CFR 268.40 treatment standards must also be 
macroencapsulated in accordance with 40 CFR 268.45 Table 1 unless 
the waste is placed in:
    (1) A Subtitle C monofill containing only K175 wastes that meet 
all applicable 40 CFR 268.40 treatment standards; or
    (2) A dedicated Subtitle C landfill cell in which all other 
wastes being co-disposed are at pH<ls-thn-eq>6.0.
* * * * *

    10. In Sec. 268.48 the Table is amended by adding in alphabetical 
sequence the following entries under the heading organic constituents: 
(The footnotes are republished without change.)


Sec. 268.48  Universal treatment standards.

    (a) * * *

                                          Universal Treatment Standards
                                         [Note: NA means not applicable]
----------------------------------------------------------------------------------------------------------------
                                                                                Wastewater       Nonwastewater
                                                                                 standard           standard
                                                                           -------------------------------------
              Regulated constituent common name                    CAS<SUP>1</SUP>                         Concentration in
                                                                  number     Concentration in    mg/Kg<SUP>3</SUP> unless
                                                                                  mg/L<SUP>2</SUP>         noted as ``mg/L
                                                                                                     TCLP''
----------------------------------------------------------------------------------------------------------------
 
                          *         *         *         *         *         *         *
1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8-       35822-46-9           0.000035             0.0025
 HpCDD)......................................................
1,2,3,4,6,7,8-Heptachlorodibenzofuran (1,2,3,4,6,7,8-HpCDF)..   67562-39-4           0.000035             0.0025
1,2,3,4,7,8,9-Heptachlorodibenzofuran (1,2,3,4,7,8,9-HpCDF)..   55673-89-7           0.000035             0.0025
 
                          *         *         *         *         *         *         *
1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin (OCDD)............    3268-87-9           0.000063              0.005
1,2,3,4,6,7,8,9-Octachlorodibenzofuran (OCDF)................   39001-02-0           0.000063              0.005
 
                         *         *         *         *         *         *         *
----------------------------------------------------------------------------------------------------------------
*         *         *         *         *         *         *
<SUP>1</SUP> CAS means Chemical Abstract Services. When the waste code and/or regulated constituents are described as a
  combination of a chemical with its salts and/or esters, the CAS number is given for the parent compound only.
<SUP>2</SUP> Concentration standards for wastewaters are expressed in mg/L and are based on analysis of composite samples.
<SUP>3</SUP> Except for Metals (EP or TCLP) and Cyanides (Total and Amenable) the nonwastewater treatment standards
  expressed as a concentration were established, in part, based upon incineration in units operated in
  accordance with the technical requirements of 40 CFR Part 264, Subpart O, or 40 CFR Part 265, Subpart O, or
  based upon combustion in fuel substitution units operating in accordance with applicable technical
  requirements. A facility may comply with these treatment standards according to provisions in 40 CFR
  268.40(d). All concentration standards for nonwastewaters are based on analysis of grab samples.

* * * * *

PART 271--REQUIREMENTS FOR AUTHORIZATION OF STATE HAZARDOUS WASTE 
PROGRAMS

    11. The authority citation for Part 271 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6912(a), and 6926.

    12. In Sec. 271.1(j) tables 1 and 2 are amended by adding the 
following entries in chronological order by date of publication to read 
as follows.


Sec. 271.1  Purpose and scope.

* * * * *
    (j) * * *

[[Page 67132]]



               Table 1.--Regulations Implementing the Hazardous and Solid Waste Amendments of 1984
----------------------------------------------------------------------------------------------------------------
                                                                    Federal Register
          Promulgation date              Title of regulation           reference              Effective date
----------------------------------------------------------------------------------------------------------------
 
                     *         *         *         *         *         *         *
September 29, 2000...................  Listing of Hazardous             65 FR 67132      May 7, 2001.
                                        Wastes K174 and K175.
 
                     *         *         *         *         *         *         *
----------------------------------------------------------------------------------------------------------------


                  Table 2.--Self Implementing Provisions of the Solid Waste Amendments of 1984
----------------------------------------------------------------------------------------------------------------
                                          Self-implementing                                  Federal Register
            Effective date                    provision              RCRA citation              reference
----------------------------------------------------------------------------------------------------------------
 
                     *         *         *         *         *         *         *
May 7, 2001..........................  Prohibition on land      3004(g)(4)(C) and        November 8, 2000.
                                        disposal of K174 and     3004(m).                65 FR 67132.
                                        K175 wastes, and
                                        prohibition on land
                                        disposal of
                                        radioactive waste
                                        mixed with K174 and
                                        K175 wastes, including
                                        soil and debris..
 
 
 
                     *         *         *         *         *         *         *
----------------------------------------------------------------------------------------------------------------

* * * * *

PART 302--DESIGNATION, REPORTABLE QUANTITIES, AND NOTIFICATION

    13. The authority citation for part 302 continues to read as 
follows:

    Authority: 42 U.S.C. 9602, 9603, and 9604; 33 U.S.C. 1321 and 
1361.

    14. In Sec. 302.4, Table 302.4 is amended by adding the following 
new entries in alphanumeric order at the end of the table to read as 
follows:


Sec. 302.4  Designation of hazardous substances.

* * * * *

                                            Table 302.4--List of Hazardous Substances and Reportable Quantities
                                             [Note: All Comments/Notes Are Located at the End of This Table]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                               Statutory                              Final RQ
                                                                             ---------------------------------------------------------------------------
        Hazardous substance                CASRN         Regulatory synonyms                                                                    Pounds
                                                                                  RQ          Code        RCRA waste No.        Category         (KG)
--------------------------------------------------------------------------------------------<dagger>----------------------------------------------------
 
                   *                  *                  *                  *                  *                  *                  *
K174<SUP>f</SUP>.............................    ................    ..................          1*            4   K174               X                    1(0.454)
 
                   *                  *                  *                  *                  *                  *                  *
K175<SUP>f</SUP>.............................    ................    ..................          1*            4   K175               X                   1(0.454)
--------------------------------------------------------------------------------------------------------------------------------------------------------
<dagger> Indicates the statutory sources as defined by 1, 2, 3, and 4 below.
1 <SUP>*</SUP>--Indicates that the 1-pound RQ is a CERCLA statutory RQ.
4--Indicates that the statutory source for designation of this hazardous substance under CERCLA is RCRA Section 3001.
<SUP>f</SUP> See 40 CFR 302.6(b)(1) for application of the mixture rule to this hazardous waste.


    15. Section 302.6 is amended by revising paragraph (b)(1)(iii) to 
read as follows:


Sec. 302.6  Notification requirements.

* * * * *
    (b) * * *
    (1) * * *
    (iii) For waste streams K169, K170, K171, K172, K174, and K175, 
knowledge of the quantity of all of the hazardous constituent(s) may be 
assumed, based on the following maximum observed constituent 
concentrations identified by EPA:

[[Page 67133]]



------------------------------------------------------------------------
     Waste                     Constituent                    max ppm
------------------------------------------------------------------------
K174..........  2,3,7,8-TCDD.............................      0.000039
                1,2,3,7,8-PeCDD..........................      0.0000108
                1,2,3,4,7,8,-HxCDD.......................      0.0000241
                1,2,3,6,7,8,-HxCDD.......................      0.000083
                1,2,3,7,8,9,-HxCDD.......................      0.000062
                1,2,3,4,6,7,8-HpCDD......................      0.00123
                OCDD.....................................      0.0129
                2,3,7,8-TCDF.............................      0.000145
                1,2,3,7,8-PeCDF..........................      0.0000777
                2,3,4,7,8-PeCDF..........................      0.000127
                1,2,3,4,7,8-HxCDF........................      0.001425
                1,2,3,6,7,8-HxCDF........................      0.000281
                1,2,3,7,8,9-HxCDF........................      0.00014
                2,3,4,6,7,8-HxCDF........................      0.000648
                1,2,3,4,6,7,8-HpCDF......................      0.0207
                1,2,3,4,7,8,9-HpCDF......................      0.0135
                OCDF.....................................      0.212
K175..........  Mercury..................................   9200
------------------------------------------------------------------------

* * * * *
[FR Doc. 00-25928 Filed 11-7-00; 8:45 am]
BILLING CODE 6560-50-P


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