67068 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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.

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:

elliott.ross@epamail.epa.gov, (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?

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67069

1USEPA. 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.

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.

SUMMARY OF ENTITIES POTENTIALLY AFFECTED BY THE RCRA K174/K175 FINAL RULE

Item

Economic sector classification Number entities potentially affected

SIC NAICS Description Targeted Induced Incidental Total

1 ............. 2869 32511 Industrial organic chemical manufacturers* (waste

generators).

18 0 21 39

2 ............. 4953 562211 Hazardous waste treatment & disposal (waste handlers).0404

3 ............. 9511 92411 State government environmental departments (public

administration).

0 49 0 49

4 ............. 9511

9611

9621

92411

92611

92612

Federal government offices (environmental, economic

& transportation public administration).

0 11 1 12

5 ............. 8742 54161 Management consulting services (non-governmental

organizations).

0 0 12 12

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:

∑ 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.

∑ If waste remediation is required, such entities may be affected (SIC 4959, NAICS 56291).

67070 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

2Now known as Environmental Defense.

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.

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:

• 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),

• Process wastewaters from the

production of vinyl chloride monomer

using mercuric chloride catalyst in an

acetylene-based process,

• Wastewater treatment sludges from

the production of methyl chloride, and

• 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67071

generally below, are directly

incorporated into EPA’s completion of a

risk assessment for the wastestreams of

concern:

• Toxicity (§ 261.11(a)(3)(i)) is

considered in developing the health

benchmarks used in the risk assessment

modeling.

• Constituent concentrations and

waste quantities (§§ 261.11(a)(3)(ii) and

261.11(a)(3)(viii)) are used to define the

initial conditions for the risk evaluation.

• Potential to migrate, persistence,

degradation, and bioaccumulation of the

hazardous constituents and any

degradation products

(§§ 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

(§§ 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-pdioxin (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

67072 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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., nonhazardous 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-pdioxin (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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67073

3EPA. 1995. Guidance for Risk Characterization.

U.S. Environmental Protection Agency Science

Policy Council. February.

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-tetrachlorodibenzop-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 longterm 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-pdioxin; 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-pdioxin (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

67074 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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.

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

1×10¥6 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 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 reconsider 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, tankbased wastewater treatment systems

prior to direct discharge of the

wastewaters in accordance with facilityspecific NPDES permits or discharge to

an off-site POTW. As explained in the

67076 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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 sitespecific approach to assessing risks from

management of chlorinated aliphatic

wastewaters, and presented general

arguments why EPA should adopt a sitespecific 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 sitespecific 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 sitespecific 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 sitespecific information regarding waste

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67077

4USEPA. 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.

5The 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).

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.

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 homegrown root vegetables, 33 percent homegrown 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.

67078 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

6U.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.

7U.S. EPA. 1999a. Risk Assessment Technical

Background Document for the Chlorinated

Aliphatics Listing Determination. Office of Solid

Waste. July.

8The 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). 9The 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). 10The 1987–1988 NFCS data on intake of homeproduced 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.

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.

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.

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 homeproduced food items. As one would

expect, the data in the Exposure Factors

Handbook indicate that farm

households consume more homeproduced 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.

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 homeproduced 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67079

consumption of home-produced beef. In the

Northeast, nearly 40 percent of farm

households report consuming homeproduced 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

67080 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

11Metcalf & Eddy, Inc. 1991. Wastewater

Engineering: Treatment, Disposal, and Reuse.

Revised by G. Tchobanoglous and F. Burton. Irwin

McGraw-Hill, Boston. 1334 pp.

12 12 U.S. EPA. 2000b. Risk Assessment

Technical Background Document for the

Chlorinated Aliphatics Listing Determination,

Addendum. Office of Solid Waste. September.

13Rice, 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.

14Stevens, J.B. and Gerbec, E.N. 1988. Dioxin in

the agricultural food chain. Risk Analysis. 8(3):329–

335.

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.

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).

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.

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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67081

15We 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).

16USEPA. 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.

17Boone, 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.

18Shor, 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.

19NAS. 1987. Predicting Feed Intake of FoodProducing Animals. National Research Council,

Committee on Animal Nutrition. National Academy

Press, Washington, D.C.

20For 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)

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.

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 2, 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 2 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 (2×10 ¥5) by

a factor of 0.50 (USEPA, 2000b).

67082 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

21The 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 postcooking 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.

22USEPA. 1996. Proposed Guidelines for

Carcinogen Risk Assessment. 61 FR 17960.

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. Beefspecific 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 (0.73×0.76).21

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 homeproduced 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 (HXCDD)

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:

• 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 lowdose 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.

• 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)¥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 doseresponse), 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67083

23Byrd 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.

24ATSDR. 1998. Toxicological Profile for

Chlorinated Dibenzo-p-Dioxins (Update). U.S.

Department of Health and Human Services.

December.

25USEPA. 1985. Health Assessment Document

for Polychlorinated Dibenzo-p-Dioxins. Office of

Health and Environmental Assessment. EPA/600/8–

84/014F. September.

26The 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/kgday)¥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.

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.

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.

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)¥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)¥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.

67084 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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/kgday)¥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)¥1 and a TEF value

of 0.1, yielding an effective cancer slope

factor of 15,600 (mg/kg-day)¥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)¥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 doseresponse 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)¥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 congenerspecific 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, shortterm 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

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

2.3×10¥5 (ug/m3)¥1 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

67086 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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.

28United 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.

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/m3), 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-bycase 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 breastfeeding 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).

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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67087

29U.S. EPA. 1999c. Listing Background

Document for the Chlorinated Aliphatic Listing

Determination (Proposed Rule). Office of Solid

Waste. July.

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 × 10¥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 × 10¥5 as marginal. As we

have explained, we make listing

determinations based on a weight-ofthe-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 × 10¥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 × 10¥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 ×

10¥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.

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 nomigration 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 nonhazardous 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 nonhazardous 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

67088 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

aliphatic wastewaters will have no

adverse impact on human health and

the environment due to the management

of this facility’s wastewaters in nonhazardous 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67089

30 Dioxin has the highest slope factor (an

indicator of carcinogenic potency) of any chemical

in the EPA IRIS database.

31See Appendix A.—Environmental Release

Descriptions, in Hazardous Waste Characteristics

Scoping Study U.S. EPA, November 15, 1996, pp.

A–28 and A–29.

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.

Finally, the EPA’s concern is that not

only is the application of dioxincontaining 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

67090 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

32See page 56 of ‘‘Listing Background Document

for the Chlorinated Aliphatics Listing

Determination’’ (USEPA, 1999c).

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 codisposal 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.

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 m3 to the high

end value of approximately 51,000 m3

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 nondedicated 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

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

67092 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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 SiteSpecific Exposure Scenarios

The commenter maintained that EPA

should have used a site-specific

approach to assessing risks from

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67093

33Focazio, 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 GroundContinued

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 homeproduced 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 sitespecific 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 dioxincontaminated 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

67094 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

water Resources of the United States and

Limitations in Drinking-Water-Supply

Characterizations: U.S. Geological Survey WaterResources Investigation Report 99–4279, 21 p.

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).

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 nonhazardous 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 onsite (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 nonhazardous 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 nonhazardous forms of the waste, and EPA

did not evaluate potential risks from onsite or off-site incineration of EDC/VCM

wastewater treatment sludges in nonhazardous 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

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

67096 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

34RCRA § 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).

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 nomigration 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 nonhazardous 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.

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

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

67098 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

35The 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.

36As 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. 37 (0.05)(0.041 mg/L) = 0.002 mg/L

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).

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.

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.

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67099

38The 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.

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:

• 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.

• 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 m2

does not represent a realistic landfill size,

since industrial landfills are typically on the

order of 50,000 to 100,000 m2. Moreover, a

landfill of the size modeled by BCP (6m3)

would not be large enough to contain the

quantity of sludge that we estimate BCP

generates in 1 year, 109m3), let alone the

quantity we estimate BCP might generate

over a 30 year period (3,273m3)

.

• 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.

• 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

67100 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

39Paul 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.

40H. 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.

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, nonhazardous 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 EPAsponsored 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.

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 § 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 wastespecific 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67101

42Memorandum from John Austin to Ross Elliott,

May 12, 2000.

43EPA 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.

44EPA 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.

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.

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.

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, postclosure 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

67102 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

45See 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.

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 codisposed 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.

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 rephrase 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 acetylenebased 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67103

46Although 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).

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.

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 ‘‘weightof-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 nonhazardous 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

67104 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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 nonhazardous 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67105

47Alkhatib, 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.

48See Table 4–4 of ‘‘Risk Assessment Technical

Background Document for the Chlorinated

Aliphatics Listing Determination,’’ EPA, June 25,

1999a.

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.

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 nonhazardous 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 nonhazardous waste landfills. If these

sludges had been managed in nonhazardous 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 nonhazardous 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)).

67106 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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. § 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¥4 and

10¥6.

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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67107

50Travis, Curtis C., 1987. Environment Science

and Technology, Vol. 21, No. 5.

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.

addressed these factors for EDC/VCM

sludge see Section VI.B.1. of today’s

preamble.

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.

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

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 × 10¥4) 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 × 10¥5 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

67108 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

53Memorandum EPA Regional Waste

Management Division Directors from Elliott P.

Laws, ‘‘Land Use in the CERCLA Remedy Selection

Process,’’ OSWER Directive No. 9355.7–04.

54See ‘‘Risk Assessment Guidance for Superfund

(RAGs), Volume I—Human Health Evaluation

Manual, Part A,’’ (Chapter 6), 1989.

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 timeconsuming cleanups.

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 nonzero 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

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

67110 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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 dioxinlike 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 NewlyListed 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 octachlorinated 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 dioxinlike 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)¥1 and the slope factors for

the 2,3,7,8-substituted hepta dioxin and

furan isomers are effectively 156 (mg/

kg-day)¥1. 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

Common name CAS2 No. Concentration in mg/L1, or

technology code 2

Concentration in mg/kg 3

unless noted as ‘‘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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67111

TABLE I–1.—TREATMENT STANDARDS FOR K174—Continued

Regulated harzardous constituent Wastewaters Nonwastewaters

Common name CAS2 No. Concentration in mg/L1, or

technology code 2

Concentration in mg/kg 3

unless noted as ‘‘mg/L

TCLP’’, or technology code

1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin (OCDD) ......................... 3268–87–9 0.000063 or CMBST 4 ........ 0.005 or CMBST 4

1,2,3,4,6,7,8,9-Octachlorodibenzofuran (OCDF) ............................... 39001–02–0 0.000063 or CMBST 4 ........ 0.005 or CMBST 4

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.

3All 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. 4For 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

67112 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

55See 64 FR at 46510; see also Table 4–14 from

Listing Background Document for Chlorinated

Aliphatics Listing Determination (Proposed Rule)

(USEPA, 1999c).

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.

57Paul 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.

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).

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.

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

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 codisposed 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67113

58Personal communication with SepraDyne

Corporation representatives.

59Memorandum 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.

60See 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.

61Memorandum from John Austin to Ross Elliott,

May 12, 2000.

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.

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

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.

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-pdioxin; 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-pdioxin (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

67114 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

62RCRA Section 3004(m).

63U.S. EPA. 2000f. Background Document for

Capacity Analysis for Land Disposal Restrictions:

Newly Identified Chlorinated Aliphatics Production

Wastes (Final Rule), September.

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

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 octadioxin/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 analysisrelated 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).

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 newlylisted 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67115

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.

65See RCRA § 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 * * * ’’

66Personal communication with Carl Carlson,

Chemical Waste Management Inc.

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.

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

67116 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

wastewater or nonwastewater forms of

K175.

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 newlylisted 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-bycase 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 (§ 268.48)

and the list of regulated constituents in

F039 (§ 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

Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations 67117

67U.S. EPA. 2000a. Economics Background

Document. Office of Solid Waste. September. 68U.S. EPA. 2000g. Response to Public Comments

on Proposed Listing Determination for Chlorinated

Aliphatic Wastes. Office of Solid Waste. September.

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.

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.

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.

67118 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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

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

67120 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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 nonHSWA, 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.

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

Waste Constituent

Max.

concentration

(ppm (mg/kg))

RQ (lb)

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,

67122 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

69For 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 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.

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-toKnow 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

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

farmer.sandy@epamail.epa.gov, 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.

67124 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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 costeffective 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

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

67126 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

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:

§ 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

§ 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 § 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:

§ 261.32 Hazardous waste from specific

sources.

Industry and EPA

hazardous waste No. Hazardous waste Hazardouscode

*******

Organic chemicals:

*******

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 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.

T

K175 ................... Wastewater treatment sludges from the production of vinyl chloride monomer using mercuric chloride

catalyst in an acetylene-based process.

T

*******

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

EPA hazardous waste

no. Hazardous constituents for which 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:

Common name Chemical abstracts name

Chemical

abstracts

No.

Hazardous

waste No.

*******

Octachlorodibenzo-p-dioxin (OCDD) ................................. 1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin ..................... 3268–87–9 ....................

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:

§ 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 § 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

§ 268.44;

(4) Hazardous debris has met the

treatment standards in § 268.40 or the

alternative treatment standards in

§ 268.45; or

(5) Persons have been granted an

extension to the effective date of a

prohibition pursuant to § 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 § 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 codisposed are at pH≤6.0.

9. In § 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:

§ 268.40 Applicability of treatment

standards.

* * * * *

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*******

Footnotes to Treatment Standard Table 268.40

1The 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. 2CAS 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. 3Concentration standards for wastewaters are expressed in mg/L and are based on analysis of composite samples.

4All 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. 5Except 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.

*******

11For 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≤6.0.

* * * * *

10. In § 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.)

§ 268.48 Universal treatment standards.

(a) * * *

UNIVERSAL TREATMENT STANDARDS

[Note: NA means not applicable]

Regulated constituent common name CAS1

number

Wastewater

standard

Nonwastewater

standard

Concentration in

mg/L2

Concentration in

mg/Kg3 unless

noted as ‘‘mg/L

TCLP’’

*******

1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8–HpCDD) .................................... 35822–46–9 0.000035 0.0025

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

*******

*******

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.

3Except 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 § 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.

§ 271.1 Purpose and scope.

* * * * *

(j) * * *

67132 Federal Register / Vol. 65, No. 217 / Wednesday, November 8, 2000 / Rules and Regulations

TABLE 1.—REGULATIONS IMPLEMENTING THE HAZARDOUS AND SOLID WASTE AMENDMENTS OF 1984

Promulgation date Title of regulation Federal Register reference Effective date

*******

September 29, 2000 ..................... Listing of Hazardous Wastes

K174 and K175.

65 FR 67132 May 7, 2001.

*******

TABLE 2.—SELF IMPLEMENTING PROVISIONS OF THE SOLID WASTE AMENDMENTS OF 1984

Effective date Self-implementing provision RCRA citation Federal Register reference

*******

May 7, 2001 .................................. Prohibition on land disposal of

K174 and K175 wastes, and

prohibition on land disposal of

radioactive waste mixed with

K174 and K175 wastes, including soil and debris..

3004(g)(4)(C) and 3004(m) ........... November 8, 2000.

65 FR 67132.

*******

* * * * *

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 § 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:

§ 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]

Hazardous substance CASRN Regulatory synonyms

Statutory Final RQ

RQ Code † RCRA

waste No. Category Pounds(KG)

*******

K174f ....................................................... ........... .................................. 1* 4 K174 X 1(0.454)

*******

K175f ....................................................... ........... .................................. 1* 4 K175 X 1(0.454)

† Indicates the statutory sources as defined by 1, 2, 3, and 4 below.

1 *—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.

fSee 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:

§ 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:

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

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