Hazardous Waste Management System; Identification and Listing of Hazardous Waste: Petroleum Refining Process Wastes; Land Disposal Restrictions for Newly Identified Wastes; and CERCLA Hazardous Substance Designation and Reportable Quantities

SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing to

amend the regulations for hazardous waste management under the Resource

Conservation and Recovery Act (RCRA) by listing, as hazardous wastes,

three residuals from petroleum refining processes because certain

disposal practices may present a risk to human health or the

environment. EPA is also proposing not to list as hazardous eleven

process residuals. This action proposes to add the toxic constituents

found in the wastes to the list of constituents that serves as the

bases for classifying wastes as hazardous.

This action is proposed pursuant to RCRA section 3001(b) and

section 3001(e)(2), which direct EPA to make a hazardous waste listing

determination for ``refining wastes.'' The effect of this proposed

regulation would be to subject these wastes to regulation as hazardous

wastes under Subtitle C of RCRA. Additionally, this action proposes to

designate the wastes proposed for listing as hazardous substances

subject to the Comprehensive Environmental Response, Compensation, and

Liability Act (CERCLA), and to adjust the one-pound statutory

reportable quantities (RQs) for these substances.

In support of the Agency's regulatory reinvention efforts, this

action also proposes changes to the RCRA regulations to promote the

environmentally sound recycling of oil-bearing residuals. Specifically,

the Agency is proposing to broaden the existing exemption for certain

wastes from the definition of solid waste. These include oil-bearing

residuals from specified petroleum refining sources inserted into the

petroleum refining process, and spent caustic from liquid treating

operations when used as a feedstock. Today's proposal also would exempt

from the definition of hazardous waste mixtures of clarified slurry oil

(CSO) storage tank sediment and/or in-line filter/separation solids

with tank wastewaters, provided that the waste is discharged to the oil

recovery sewer before primary oil/water/solids separation, and ceramic

support media separated from spent hydrotreating/hydrorefining

catalysts.

Finally, EPA is proposing to apply universal treatment standards

(UTS) under the Land Disposal Restrictions program to the Petroleum

Refining Wastes proposed for listing in this rulemaking.

DATES: EPA will accept public comments on this proposed rule until

February 20, 1996. Comments postmarked after this date will be marked

``late'' and may not be considered. Any person may request a public

hearing on this proposal by filing a request with Mr. David Bussard,

whose address appears below, by December 4, 1995.

ADDRESSES: The official record of this rulemaking is identified by

Docket Number F-95-PRLP-FFFFF. The public must send an original and two

copies (and a voluntary copy on a computer diskette) of their comments

to: EPA RCRA Docket Clerk (5305W), U.S. Environmental Protection

Agency, 401 M Street, SW., Washington, D.C. 20460. Place the docket

number F-95-PRLP-FFFFF on your comments. Through November 13, 1995,

copies of materials relevant to this proposed rulemaking are located in

the docket at the address listed above. The Agency plans to relocate

the docket on November 14, 1995, and the docket will be physically

closed from November 14, 1995 to November 26, 1995. Special

arrangements for reviewing docket materials during this time can be

made by calling (202) 260-9327. The Agency will be issuing a separate

Federal Register notice explaining this change.

Starting November 27, 1995, the EPA RCRA Docket will be located at

Crystal Gateway #1, 1st Floor, 1235 Jefferson Davis Highway, Arlington,

VA. Comments may be delivered to that location. The docket is open from

9:00 a.m. to 4:00 p.m., Monday through Friday, excluding Federal

holidays. The public can make an appointment to review docket materials

by calling (202) 260-9327. Starting November 27, 1995, the new

telephone number for the docket will be (703) 603-9230. The public may

copy 100 pages from the docket at no charge; additional copies are

$0.15 per page.

Requests for a hearing should be addressed to Mr. David Bussard at:

Hazardous Waste Identification Division, Office of Solid Waste (5304),

U.S. Environmental Protection Agency, 401 M Street, SW., Washington,

D.C. 20460.

FOR FURTHER INFORMATION CONTACT: The RCRA/Superfund Hotline, toll-free,

at (800) 424-9346 or at (703) 920-9810. The TDD Hotline number is (800)

553-7672 (toll-free) or (703) 486-3323 in the Washington, D.C.

metropolitan area. For technical information on the RCRA hazardous

waste listings, contact Maximo Diaz, Jr., Office of Solid Waste (5304),

U.S. Environmental Protection Agency, 401 M Street, SW, Washington,

D.C., 20460, (202) 260-4786.

For technical information on the CERCLA aspects of this rule,

contact: Mr. Jack Arthur, Response Standards and Criteria Branch,

Emergency Response Division (5202G), U.S. Environmental Protection

Agency, 401 M Street, SW, Washington, D.C. 20460, (703) 603-8760.

SUPPLEMENTARY INFORMATION: The contents of the preamble to this

proposed rule are listed in the following outline:

I. Legal Authority

II. Background

A. Schedule Suit

B. Existing Petroleum Refining Listings and Other Relevant

Agency Actions

1. Listings

2. Definition of Solid Waste Exemptions

C. EPA's Hazardous Waste Listing Determination Policy

III. Today's Action

A. Summary of Today's Action

1. Summary of Listing Determinations

[[Page 57748]]

2. Summary of Definition of Solid Waste and Other Exemptions

Proposed in Today's Notice

B. Description of the Industry

C. Overview of EPA's Information Collection Activities

1. Field Investigations and Sampling

2. RCRA Sec. 3007 Survey

D. Description of the Process Residuals in Comparison With the

Consent Decree Language

E. Hazardous Oil-bearing Residuals Returned to Refinery

Processes

1. Background

2. Proposed Amendments to Address Hazardous Residuals Returned

to the Refining Process

F. Description of Health and Risk Assessments

1. Human Health Criteria and Effects

2. Risk Analysis

3. Consideration of Uncertainty in Listing Determinations

4. Peer Review

G. Waste-specific Listing Determination Rationales

1. Crude Oil Storage Tank Sediment

2. Clarified Slurry Oil (CSO) Tank Sediment and/or In-line

Filter/Separation Solids

3. Catalyst from Hydrotreating

4. Catalyst from Hydrorefining

5. Catalyst from Sulfuric Acid Alkylation

6. Spent Caustic from Liquid Treating

7. Off-specification Product and Fines from Thermal Processes

8. Catalyst and Fines from Catalytic Cracking

9. Sludge from Hydrofluoric Acid Alkylation

10. Sludge from Sulfur Complex and H2S Removal Facilities

11. Catalyst from Sulfur Complex and H2S Removal Facilities

12. Unleaded Gasoline Storage Tank Sediment

13. Catalyst from Reforming

14. Sludge from Sulfuric Acid Alkylation

H. Request for Comments on Options for Conditional Exemptions

1. Legal Basis for Conditional Exemptions

2. Improvements in Risk Assessment Methodology

3. Options for Conditional Exemptions

I. Impacts on Idled Units

J. Third Party Regeneration/Reclamation of Spent Petroleum

Catalyst

1. Exemption under Sec. 266.100(b)

2. Catalyst Support Media

3. Residuals Generated from Petroleum Catalyst Regeneration/

Reclamation

K. Headworks Exemption

IV. Waste Minimization

A. Crude Oil Storage Tank Sediment

B. Clarified Slurry Oil (CSO) Tank Sediment and/or In-line

Filter/Separation Solids

C. Catalyst from Hydrotreating

D. Catalyst from Hydrorefining

V. Applicability of the Land Disposal Restrictions Determinations

A. Request for Comment on the Agency's Approach to the

Development of BDAT Treatment Standards

B. Treatment Standards for the Newly Proposed Listed Petroleum

Refining Wastes

1. Identification of Wastes

2. Proposed Treatment Standards

3. Determination of BDAT

C. Capacity Determination for the Newly Proposed Listed

Petroleum Refining Wastes

1. Introduction

2. Capacity Analysis Results Summary

VI. Environmental Justice and Population Risk

A. Applicability of Executive Order 12898

B. Potential Effects

C. Population Risk

1. Results

VII. Compliance Dates

A. Notification

B. Interim Status and Permitted Facilities

VIII. State Authority

A. Applicability of Rule in Authorized States

B. Effects on State Authorizations

IX. CERCLA Designation and Reportable Quantities

A. Reporting Requirements

B. Basis for RQs and Adjustments

C. Alternative Method

X. Regulatory Requirements and Economic Analysis

A. Regulatory Requirements

1. Executive Order 12866

2. The Regulatory Flexibility Act of 1980

3. Paperwork Reduction Act

4. Unfunded Mandates Reform Act

B. Economic Impact Analysis

1. Costs of Compliance

2. Economic Impact Analysis

3. Cost Effectiveness of Individual Risk Reduction

4. Cost Effectiveness of Population Risk Reduction

5. Other Benefits Considered

XI. Paperwork Reduction Act

I. Legal Authority

Today's regulations are being proposed under the authority of

sections 2002(a) and 3001(b)(1) and (e)(2) of the Solid Waste Disposal

Act, as amended, 42 U.S.C. 6912(a), and 6921(b) and (e)(1), (commonly

referred to as RCRA), and section 102(a) of the Comprehensive

Environmental Response, Compensation, and Liability Act of 1980

(CERCLA), 42 U.S.C. 9602(a).

II. Background

A. Schedule Suit

In 1989, the Environmental Defense Fund (EDF) sued the Agency, in

part, for failing to meet the statutory deadlines of section 3001(e)(2)

of RCRA (EDF v. 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

was approved by the court on December 9, 1994. The consent decree sets

out an extensive series of deadlines for promulgating RCRA rules and

for completing certain studies and reports. Paragraph 1.k of the

consent decree obligates the EPA to promulgate a final listing

determination on or before October 31, 1996, for the following

petroleum refining process residuals: clarified slurry oil sludge

1 from catalytic cracking, crude storage tank sludge, catalyst

from catalytic hydrotreating, process sludge from sulfur complex and

H2S removal facilities, off-spec product and fines from thermal

processes, catalyst from catalytic reforming, unleaded storage tank

sludge, catalyst from catalytic hydrorefining, catalyst and fines from

catalytic cracking, catalyst from sulfur complex and H2S removal

facilities, spent caustic from liquid treating, catalyst from

H2SO4 alkylation, sludge from HF alkylation, and sludge from

H2SO4 alkylation. Today the EPA is proposing listing

determinations for these residuals in accordance with the consent

decree's deadline for this rulemaking proposal.

\1\ While the consent decree uses the term ``sludge'' to refer

to any solid, semi-solid, or liquid residual, the term is defined

more narrowly for RCRA Subtitle C (Sec. 260.10). Throughout today's

proposal the Agency has used the term ``sediment'' to denote solid,

semi-solid, or liquid residuals deposited from industrial process

liquids.

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B. Existing Petroleum Refining Listings and Other Relevant Agency

Actions

1. Listings

A number of wastes from petroleum refineries have been previously

listed as hazardous. The Agency notes that today's proposal does not

affect the scope of the existing hazardous waste listings (described

below) or the applicability of CERCLA to these wastes. EPA is not

soliciting comments concerning these listings and does not intend to

respond to any such comments received.

In addition, EPA-classified listed hazardous wastes are hazardous

substances under the Comprehensive Environmental Response,

Compensation, and Liability Act of 1980 (CERCLA), as amended. CERCLA

hazardous substances are listed in Table 302.4 at 40 CFR 302.4 along

with their reportable quantities (RQs), and include the listed

hazardous wastes from petroleum refining in Table II-1.

[[Page 57749]]

Table II-1.--List of Currently Regulated RCRA Wastes and CERCLA

Hazardous Substances and Reportable Quantities

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

Statutory

Hazardous substance RQ pounds Final RQ

(kg) pounds (kg)

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

K048--Dissolved air flotation (DAF) float from

the petroleum refining industry.............. 1(.454) 10(4.54)

K049--Slop oil emulsion solids from the

petroleum refining industry.................. 1(.454) 10(4.54)

K050--Heat exchange bundle cleaning sludge

from the petroleum refining industry......... 1(.454) 10(4.54)

K051--API separator sludge from the petroleum

refining industry............................ 1(.454) 10(4.54)

F037--Petroleum refinery primary oil/water/

solids sludge................................ 1(.454) 1(.454)

F038--Petroleum refinery secondary

(emulsified) oil/water/solids separation

sludge....................................... 1(.454) 1(.454)

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

2. Definition of Solid Waste Exemptions

The jurisdictional boundaries of RCRA are established primarily by

the definition of solid waste, i.e., materials are subject to

regulation under RCRA only if they meet the regulatory definition of

solid waste. Secondary materials, including those EPA today is

proposing to list as hazardous, may be excluded from the definition of

solid waste and therefore from regulation under RCRA if they are

recycled in certain ways. Today's notice describes how each material is

typically managed. The notice also discusses existing regulatory

exclusions that may apply to a particular refining residual, depending

on how that residual is managed.

It is important to note that EPA is currently evaluating the

existing RCRA regulatory program, with emphasis on the need to clarify

RCRA jurisdiction, particularly as it applies to secondary materials

destined for recycling. Additionally, the Agency plans to develop a

simpler, more streamlined approach to regulating hazardous waste

recycling. One of the Agency's goals in revising the RCRA regulations

is to address outstanding jurisdictional issues that specifically

affect the petroleum refining industry. The petroleum industry poses

unique regulatory issues largely because existing exclusions from the

definition of solid waste generally do not apply to secondary materials

used to produce fuels, the primary product of the refining industry.

The current definition of solid waste at 40 CFR 261.2 classifies

secondary materials destined for recycling as solid wastes if the

recycling is a form of waste management. Conversely, if the materials

are recycled as part of an ongoing manufacturing process, they are not

solid wastes. Accordingly, the existing rules specifically exclude

secondary materials from the definition of solid waste that are: used

directly (i.e., without reclamation) as ingredients in manufacturing

processes to make new products; used directly as effective substitutes

for commercial products; or returned directly to the original process

from which they are generated as a substitute for raw material feed

stock. These exclusions do not apply to materials that are either

contained in, or used to produce fuels, however, and therefore do not

generally apply to secondary materials recycled as part of the

petroleum refining process. Petroleum industry representatives have

long argued that oil-bearing secondary materials used as ingredients in

the petroleum refining process to make fuel should be excluded from

regulation under RCRA.

Today's proposal, which deals specifically with petroleum

residuals, gives EPA the opportunity to address some larger,

longstanding issues involving where the boundaries of RCRA should be

drawn regarding jurisdiction over the petroleum industry. Therefore, in

addition to addressing specific regulatory issues that may arise as a

result of a decision to list an individual petroleum wastestream, the

Agency is proposing more comprehensive revisions to the RCRA

regulations relating to materials that are generated by and recycled

within the petroleum industry. (See Section III.E.)

C. EPA's Hazardous Waste Listing Determination Policy

Today's listing determination proposal follows the elements of the

Agency's hazardous waste listing determination policy. That policy was

presented in the dyes and pigments listing determination proposal (59

FR 66072, December 22, 1994). Readers are referred to that notice for a

description of EPA's listing policy. Also, Section III.F.2., ``Risk

Analysis,'' contains a discussion of how elements of EPA's listing

policy were applied in today's listing determination.

III. Today's Action

A. Summary of Today's Action

1. Summary of Proposed Listing Determinations

In today's notice, EPA is proposing to add three wastes generated

during petroleum refining operations to the list of hazardous wastes in

40 CFR 261.32. A summary of the waste groupings proposed for listing

are provided below with their proposed corresponding EPA Hazardous

Waste Numbers.

K170--Clarified slurry oil storage tank sediment and/or in-line

filter/separation solids from petroleum refining operations.

K171--Spent hydrotreating catalysts from petroleum refining

operations (As discussed in III.A.2 below, this listing does not

include ceramic support media.)

K172--Spent hydrorefining catalysts from petroleum refining

operations (As discussed in III.A.2 below, this listing does not

include ceramic support media.)

EPA is proposing to list certain wastes in this rule because these

materials meet the criteria set out in 40 CFR 261.11(a)(3) for listing

a waste as hazardous. EPA assessed and considered the factors contained

in these criteria primarily by incorporating them as elements in a risk

assessment. Based on this assessment, EPA is proposing to list those

wastes that pose a substantial present or potential hazard to human

health or the environment when improperly managed.

Upon promulgation of these proposed listings, all wastes meeting

the listing descriptions would become hazardous wastes and would

require treatment, storage, or disposal at RCRA Subtitle C permitted

facilities. Residuals from the treatment, storage, or disposal of the

wastes included in this proposed listing also would be classified as

hazardous wastes pursuant to the ``derived-from'' rule (40 CFR

261.3(c)(2)(I)). For example, ash or other residuals from treatment of

the listed wastes would be subject to RCRA Subtitle C hazardous

[[Page 57750]]

waste regulations. Also, 40 CFR 261.3(a)(2)(iv) (the ``mixture'' rule)

provides that, with certain limited exceptions, any mixture of a listed

waste and a solid waste is itself a RCRA hazardous waste.

However, when these materials are recycled as described in 40 CFR

261.2(e)(1)(iii) or 261.4(a)(8), they are not solid wastes and are not

subject to hazardous waste regulations. For example, if a material is

collected and returned in a closed-loop fashion to the same process, it

is not regulated. As discussed further in Section III.E of this notice,

the Agency is proposing some modifications to these recycling

exemptions.

This action also proposes not to list as hazardous eleven residuals

generated from petroleum refining operations:

Crude oil storage tank sediment.

Unleaded gasoline storage tank sediment.

Off-specification product and fines from thermal

processes.

Catalyst from reforming.

Catalyst from H2SO4 alkylation.

Sludge from H2SO4 alkylation.

HF alkylation sludge.

Spent caustic from liquid treating.

Catalyst and fines from catalytic cracking.

Catalyst from sulfur complex and H2S removal

facilities.

Sludge from sulfur complex and H2S removal

facilities.

The Agency requests comments on the proposal not to list the above

wastes. While the agency is proposing not to list crude oil storage

tank sediment, the Agency specifically requests comment on the merits

of listing this waste. Crude oil storage tank sediment could be

finalized as a listing in response to comment. The Agency also requests

comment on the data used in this proposal, the methodology and

assumptions used in the risk assessment, the waste groupings chosen by

the Agency, and other information and analyses supporting the proposed

listings.

2. Summary of Definition of Solid Waste and Other Exemptions Proposed

in Today's Notice

While the primary purpose of today's proposal is to present the

Agency's findings with respect to the hazards posed by the 14 residuals

identified in the consent decree, the Agency also conducted a parallel

effort to analyze the applicability of the definition of solid waste to

these residuals, and to identify appropriate exemptions to the proposed

listings that reflect the Agency's investigation (i.e., the appropriate

scope of the proposed listings) and that encourage responsible

recycling activities. The proposed exemptions and scope limitations are

summarized below and discussed in detail in the following sections.

a. Hazardous Petroleum Refinery Residuals Returned to Refinery

Processes. The Agency is proposing to broaden the existing exemption in

40 CFR 261.4(a)(12) for oil-bearing residuals from specified petroleum

refining sources that are inserted into the petroleum refining process.

If finalized, the existing exemption would be expanded to allow for

reinsertion of a broader array of residuals into more parts of the

refinery, including the coking process. The exemption would continue to

be limited to situations where inappropriate storage or accumulation

does not occur, and to processes that do not result in coke products

that exhibit any of the characteristics of hazardous waste. A detailed

discussion of this proposal is provided in Section III.E.

b. Use of Spent Caustics as Feedstocks. Section III.G.6 describes

the Agency's findings with respect to spent caustic from liquid

treating operations and its status as a solid waste when used as a

feedstock. A significant management practice for this residual is off-

site use as a feedstock in the manufacture of naphthenic or cresylic

acids. The Agency proposes an exclusion from the definition of solid

waste in Section III.G.6, clarifying that spent liquid treating

caustics from petroleum refineries and used as feedstock in the

manufacture of naphthenic and cresylic acid products are not solid

wastes.

c. Third Party Recycling of Spent Petroleum Catalysts. Section

III.J describes the Agency's rationale for proposing an exclusion from

the 40 CFR 266 Subpart H boiler and industrial furnace standards for

spent hydrotreating and hydrorefining catalyst recovery furnaces. Spent

hydrotreating and hydrorefining catalysts, two of the petroleum

refining residuals proposed today for listing, are frequently

regenerated for reuse or reclaimed off-site to recover nonprecious

metals such as nickel, molybdenum, cobalt, and vanadium and other

compounds sold as products (i.e., aluminum sulfate derived from the

alumina substrate material).

d. Wastewaters. The turnaround of both crude oil storage tanks and

clarified slurry oil storage tanks may result in the generation of

process wastewaters. The scope of the Agency's listing determinations

for crude oil storage tank sediment and CSO storage tank sediment and/

or in-line filter/separation solids, as described in Section III.G.1

and 2, respectively, does not include these wastewaters. These sections

also describe the limitation of the scope of the listings to sediments

generated from tanks that are directly associated with petroleum

refining operations, reflecting the Agency's lack of data regarding the

nature of sediments generated from tankage at facilities that are not

petroleum refineries.

In section III.K., the Agency proposes to exclude from the

definition of hazardous waste mixtures of crude oil storage tank

sediment (if listed) or of CSO storage tank sediment with tank

wastewaters, provided the waste waters are discharged to the oil-

recovery sewer before primary oil/water/solids separation.

e. Catalyst Support Balls. Upon removal from catalyst beds and/or

during catalyst regeneration or reclamation, spent catalysts are

separated from the support media that is used in the catalytic reactors

to optimize mixing and flow within the reactor beds. The scope of the

Agency's listing determinations for hydrotreating and hydrorefining

catalysts, as described in Section III.J, does not include these

ceramic support media.

f. Application of Existing Exemptions to the Residuals of Concern.

Section III.G.5 describes EPA's findings with respect to spent sulfuric

acid used as a catalyst in refinery alkylation processes. The Agency

concluded that this residual is already managed in a way that is

virtually exempt from the definition of solid waste under 40 CFR

261.4(a)(7).

B. Description of the Industry

Petroleum refineries are defined as ``establishments primarily

engaged in the production of gasoline, distillate fuel oils, residual

fuel oils, naphtha, liquefied refinery gases, and lubricants through

the integration of fractionation and/or straight distillation of crude

oil, re-distillation of unfinished petroleum derivatives, cracking, or

other processes'' (Office of Management and Budget, 1987).

The refineries use a complex combination of interdependent

operations to produce these petroleum-derived products. Depending upon

the type of crude being processed, the type of product to be produced,

and the process units present at a refinery, various combinations of

processes may be employed to effect the separation of crude fractions.

Petroleum refining operations and processes include desalting of crude,

atmospheric and vacuum distillation, hydrotreating, catalytic cracking,

thermal processing and upgrading of residual fuel oil, light

[[Page 57751]]

hydrocarbon processing, hydrocracking, catalytic reforming, alkylation,

extraction, isomerization, processing of lubricating oil, removal of

sulfur, and blending of products. Additional processes may also be

employed to produce additives or other desired products.

Today's proposal is based on the Agency's analysis of data

characterizing the industry in 1992. In 1992, 185 operating refineries

were reported by the U.S. Department of Energy's Petroleum Supply

Annual, with a total distillation capacity of 15 million barrels of

crude oil per calendar day.

C. Overview of EPA's Information Collection Activities

OSW's listing determination for the petroleum refining industry has

been underway since 1992 and can be characterized in terms of two major

avenues for information collection: field work and survey evaluation.

1. Field Investigations and Sampling

As part of the Agency's field work, engineering site visits,

familiarization sampling, and record sampling were conducted. Twenty-

five refineries were randomly selected for evaluation in the field

program. The industry was stratified into large and small refineries

and the 25 refineries were selected randomly (and proportionately) from

the two strata so that any differences in waste generation and

management practices could be observed. Engineering site visits were

conducted at each of the targeted refineries, at which time the Agency

conducted extensive discussions with the facilities and representatives

of the American Petroleum Institute (API) to certify each of the

potential sampling locations would result in samples that were

representative of normal operating conditions and typical industry

practices.

Sixty three record samples of the listing residuals of concern were

collected and analyzed. All sample volumes were obtained in duplicate

for the purpose of providing API with sample splits. Of the 63 samples

collected, 46 were split directly with API; the remaining 17 were

either split with the refinery (12 samples) or only collected as single

EPA aliquot (5 samples). Of the 46 split samples, the analytical data

for 31 were compared directly to the API data. The results of the

comparison indicated good agreement. The sampling and analysis plans

and analytical data reports that are not Confidential Business

Information (CBI) are available in the docket for this rule (see

ADDRESSES section), and provide detailed discussions regarding the

identification and collection of samples. The Listing Background

Document available in the docket provides additional information on the

Agency's field program, including a more detailed discussion of EPA's

site selection process.

EPA's approach to sample analysis is described generally in its

Quality Assurance Project Plan (QAPjP), dated October 21, 1992

(describing the familiarization phase of this investigation) and

September 22, 1993 (describing the record sampling phase of this

investigation) available in the docket of today's rule. Target analytes

were identified by compiling lists of target constituents used in

previous OSW investigations, including the petroleum refining listing

investigation conducted in the 1980s, the 1984 ``Skinner List''

(guidance issued by OSW for the characterization of wastes derived from

petroleum refinery wastewater treatment sludge), and the Delisting

Program. Additional constituents were added to reflect waste-specific

concerns such as amines from sulfur-removal residuals, and fluorides

from HF alkylation residuals. The Agency's contracted laboratory

confirmed its ability to reliably and adequately quantify the target

analytes during the analysis of six familiarization samples collected

during the engineering site visits. Upon completion of the

familiarization sample analysis effort, EPA finalized the target

analyte list and QAPjP with a list of more than 180 target

constituents. In addition, during both familiarization and record

sampling and analysis, the Agency quantified the ten most abundant

nontarget volatile and the 20 most abundant nontarget semi-volatile

organics in each sample.

The Agency believes that the samples collected and analyzed under

its field investigations are generally representative of residuals

typically generated throughout the industry. This belief is based on

(1) the extensive discussions between the Agency, the targeted

facilities and API regarding the sampling protocol and sample

representativeness; (2) the Agency's broader understanding of the

residuals and the industry's array of management practices developed

during extensive review of the industry-wide survey (described below);

and (3) the fact that the toxicants that ultimately were found through

risk assessment modeling to show significant risk and serve as the

proposed basis for listing in today's notice are all common refinery

constituents of concern (e.g., benzene, arsenic, polynuclear aromatic

hydrocarbons (PAHs)) that are found in virtually all crudes and thus

reasonably are expected to be present in refinery residuals across the

Nation.

2. RCRA Section 3007 Survey

The survey effort included the development, distribution, and

assessment of an extensive industry-wide section 3007 survey. The

questionnaire covered topics such as crude oil and product information,

facility and unit process flow diagrams, process descriptions, residual

generation and management profiles, residual and contaminated soil and

debris characterization, residual management unit and media

characterization, general facility characterization (focussing on

exposure pathway characterization), source reduction efforts, and

certification.

The survey was distributed in September 1993 to all refineries

identified as active in 1992 in the DOE Petroleum Supply Annual. Of the

185 surveys distributed, completed responses were obtained for 172

refineries. The remaining refineries notified EPA that they had stopped

operations at some point in or after 1992 and thus were unable to

complete the survey.

The Agency entered the completed surveys into a relational database

known as the 1992 Petroleum Refining Database (PRDB). An exhaustive

engineering review of each facility's response was then conducted,

resulting in follow-up letters to most of the industry which sought

clarifications, corrections, and additional data where needed. The

responses to the follow-up letters were entered into the database. A

wide variety of additional quality assurance checks were run on the

data, with added emphasis on the listing residuals, to ensure that the

residuals of concern were characterized as completely and accurately as

possible. Follow-up telephone interviews were conducted as necessary to

address remaining data issues. After extensive review, the Agency

believes that the data are reliable and represent the industry's

current residual generation and management practices.

D. Description of the Process Residuals in Comparison With the Consent

Decree Language

The consent decree identifies fourteen residuals for which the

Agency must make proposed listing determinations in this rulemaking.

Upon investigation of the categories identified in the consent decree,

the Agency determined that several of the categories should be split

into distinct subcategories to allow the

[[Page 57752]]

Agency to differentiate between unique residuals. For example, the

consent decree identified as one residual catalysts from sulfur complex

and H2S removal facilities. There are two major subcategories of

catalysts used in refinery sulfur removal facilities: Claus catalysts

(an alumina bauxite catalyst) and tail gas treating catalysts

(typically a cobalt/molybdenum catalyst). These wastes are inherently

different in their composition, application, and management, and thus

were assessed separately in the Agency's risk assessment.

Table III-1 identifies the residuals in the consent decree,

describes their coverage in the listing determinations proposed in

today's rulemaking, and the action proposed.

Table III-1.--Consent Degree Residuals

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

Residuals identified in the consent decree Coverage in today's rulemaking

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

Crude oil storage tank sludge.......................... Crude oil storage tank sediment.

Unleaded storage tank sludge........................... Unleaded gasoline storage tank sediment.

Clarified slurry oil sludge from catalytic cracking.... Clarified slurry oil (CSO) storage tank sediment and/or

in-line filter/separation solids.

Catalyst from catalytic hydrotreating.................. Non-precious metal hydrotreating catalysts.

Catalyst and fines from catalytic cracking............. Equilibrium catalysts and catalyst fines were evaluated

as individual subcategories based on differences in

particle sizes and management practices.

Catalyst from catalytic hydrorefining.................. Non-precious metal hydrorefining catalysts.

Catalyst from catalytic reforming...................... Includes spent catalysts and fines.

Catalyst from H2SO4 alkylation......................... Spent sulfuric acid.

Sludge from H2SO4 alkylation........................... Same.

Sludge from HF alkylation.............................. Neutralization sludges.

Off-spec product and fines from thermal processes...... Same.

Spent caustic from liquid treating..................... Same.

Process sludge from sulfur complex and H2S removal Sludges from amine-based sulfur removal systems,

facilities. including turnaround sludges and filter cartridges.

Catalyst from sulfur complex and H2S removal facilities Claus catalyst, an alumina-based sulfur conversion

catalyst.

SCOT-like catalyst, a cobalt/molybdenum

tailgas treating catalyst.

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

E. Hazardous Oil-Bearing Residuals Returned to Refinery Processes

EPA is today proposing to exclude from the definition of solid

waste oil-bearing residuals from specified petroleum industry sources

that are inserted into the petroleum refining process (including the

petroleum coker) along with normal process streams, if these materials

are not stored in a manner involving placement on the land, or

accumulated speculatively before being so recycled, and if the

resulting coke product does not exhibit one or more of the

characteristics of hazardous waste.

1. Background

a. January 8, 1988 Proposal. On January 8, 1988, EPA proposed rules

to implement a decision by the District of Columbia Circuit Court

regarding EPA's statutory authority to regulate recycled materials. See

53 FR 519, January 8, 1988. In its decision in American Mining Congress

v. EPA, 824 F. 2d1177 (D.C. Cir. 1987) (AMC I), the D.C. Circuit Court

held that EPA's rules defining the statutory term ``solid waste'' (RCRA

Section 1004(27)) exceeded the Agency's statutory authority to the

extent that the rules asserted jurisdiction over ``materials that are

recycled and reused in an ongoing manufacturing or industrial

process.'' Id. at 1186 (emphasis original). The court held that

``Because these materials have not yet become part of the waste

disposal problem,'' Id., they are not yet ``discarded'' within the

meaning of Section 1004(27) and so cannot be considered to be ``solid

wastes.''

In its January 1988 proposal, EPA responded to the AMC I decision

specifically as it applied to petroleum refining industry operations.

The Agency proposed to exclude from the regulatory definition of solid

waste oil bearing petroleum residuals that are returned for further

refining ``as part of one continuous and ongoing process.'' (53 FR 525,

January 8, 1988.) More specifically, EPA proposed to exclude oil-

bearing residues from the refining process when those residues are

generated on-site and reinserted on-site into the petroleum refining

process (including the coker), provided that the residues were not

speculatively accumulated or stored in a manner involving land

placement.

Subsequent decisions have established that the decision in AMC I is

relatively narrow. In particular, courts have rejected the argument

that ``potential reuse of a material prevents the Agency from

classifying it as 'discarded'.'' American Mining Congress v. EPA, 907

F. 2d 1179, 1186 (D.C. Cir. 1990) (AMC II). The proper test as to when,

as a matter of law, the Agency is foreclosed from classifying a

material as a solid waste is when a material is ``destined for

immediate reuse in another phase of the industry's ongoing production

process'' and that ``have not yet become part of the waste disposal

problem.'' Id. at 1186. EPA retains considerable discretion in

ascertaining how to apply this standard. For example, secondary

materials generated by one industry and sent to another industry for

reclamation could be classified as solid wastes (although EPA retains

discretion as to whether to make that determination). (American

Petroleum Inst. v. EPA, 906 F. 2d 726, 740-41 (D.C. Cir. 1990); Ilco v.

EPA, 996 F. 2d 1126 (11th Cir. (1993); Owen Electric Steel v. Browner,

37 F. 3d 146 (4th Cir. 1994)). So can secondary materials generated on-

site, stored in wastewater treatment impoundments, and reclaimed within

the process which generated them. AMC II. EPA also must normally

justify determinations that a secondary material being recycled is not

a solid waste by showing how the determination is consistent with

RCRA's objective to ``establish a cradle-to-grave regulatory structure

for the safe handling of hazardous wastes.'' API, 906 F. 2d at 741.

b. July 28, 1994 Final Recovered Oil Rule. On July 28, 1994, EPA

finalized parts of the January 8, 1988 proposal pertaining to petroleum

refining industry operations. The proposal was based on the Court's

decision in AMC I. As noted, however, post-AMC I decisions make clear

that the statute

[[Page 57753]]

affords EPA great latitude to set the jurisdictional parameters of

RCRA. As a consequence, the final exclusion is more narrow than the one

proposed: it excludes a more limited set of materials, and imposes

greater restrictions on where the materials can be inserted within the

petroleum refining process.

In its January 1988 proposal, EPA did not distinguish between

recovered oil and oil-bearing hazardous sludges, nor did it distinguish

between the petroleum coker and other petroleum process units in

defining the scope of the proposed petroleum refining exclusion. In

contrast, in the July 28, 1994 rule, EPA limited the exclusion to

recovered oil from petroleum refining, exploration and production that

are inserted into the petroleum refining process prior to distillation

and catalytic cracking. Also, the final exclusion thus does not apply

to recovered oil reinserted into the petroleum coker.

(Sec. 261.4(a)(12)).

(1) Definition of Recovered Oil. Recovered oil, as defined in

Sec. 261.4(a)(12), includes materials that are primarily oil and that

are recovered from any phase of petroleum exploration, refining,

production, and transportation. As explained in the July 28, 1994 rule,

EPA limited the exclusion to recovered oil because recovered oil is

equivalent to the raw materials normally used in the petroleum refining

process in its composition and management.

The exclusion does not apply to hazardous oil-bearing sludges. EPA

reasoned that these materials are typically unlike raw materials

normally used in the petroleum refining process (i.e., crude oil).

First, oil-bearing sludges are not normally composed primarily of oil.

Additionally, the units in which they are managed (e.g., API

separators, DAF units, land treatment units and surface impoundments)

are not parts of the refining process, but instead function as waste

holding and treatment units. Finally, EPA cited damage incidents

associated with management of such materials as confirmation that these

materials can be part of the waste disposal problem.

(2) Limitation on Point of Insertion. The final recovered oil

exclusion does not apply to recovered oil or other hazardous oil-

bearing secondary materials that are inserted into the petroleum coker.

EPA decided not to exclude materials that are recycled in the petroleum

coker because of concerns about the fate of the hazardous constituents

that may be contained in the recovered oil. As stated in the preamble

to the recovered oil rule, the Agency was concerned that toxic

constituents could end up in the coke product in quantities that could

be harmful to human health and the environment when the coke is burned

as a fuel. See 59 FR 38542, July 28, 1994. EPA had limited data on the

composition of hazardous oil-bearing residuals compared to normal coker

feed and was concerned that additional toxic constituents (e.g., heavy

metals) that may be present in these secondary materials could be

discarded by simple incorporation into the coke product, in which case

the coke could be part of the waste disposal problem when burned.

The Agency therefore retained jurisdiction over recovered oil, and

other hazardous oil-bearing secondary materials that are inserted into

the petroleum coker. Cokers that receive hazardous oil-bearing waste as

a feedstock are currently not subject to regulation under RCRA,

however. (59 FR 38542, July 28, 1994.) (See also May 3, 1995 letter to

Ralph J. Colleli, API Counsel, from Michael Shapiro, Director, Office

of Solid Waste).

2. Proposed Amendments To Address Hazardous Residuals Returned to the

Refining Process

a. Summary of Proposed Amendments. In the preamble to the final

recovered oil rule, EPA indicated that the rulemaking was not

necessarily its final disposition of jurisdictional issues relating to

the petroleum industry, and that further exclusions might be warranted

after additional study (59 FR 38536, and 38541, July 28, 1994). Since

promulgation of the recovered oil rule, EPA has received numerous

comments from petroleum industry representatives objecting to the

Agency's decision to narrow the scope of the originally proposed

exclusion. Industry representatives continue to assert that cokers are

an integral part of the petroleum refining process and that the

practice of recycling oil-bearing secondary materials (including

recovered oil) as feed to petroleum cokers, or elsewhere to the

refining process, falls outside of RCRA jurisdiction. In light of these

comments, and as part of its continued efforts to define more clearly

the scope of RCRA jurisdiction within the petroleum industry, EPA has

reviewed its position regarding whether exclusions should apply only to

recovered oil and whether reinsertion into petroleum cokers as well as

earlier parts of the refining process should be excluded.

Accordingly, the Agency has reevaluated existing information on

oil-bearing residuals and their use in the petroleum refining process.

In particular, EPA has reviewed existing information on the composition

of oil-bearing refinery residuals and the fate of toxic constituents

contained in secondary materials that are reinserted into the coker. In

addition, the Agency has obtained more detailed information from the

petroleum refining industry on the coking process itself. The Agency's

analysis, which is discussed in detail below, supports broadening the

existing recovered oil exclusion. Therefore, EPA is today proposing to

expand the recovered oil exclusion to cover all oil-bearing secondary

materials that are generated within the petroleum refining industry and

are reinserted into the petroleum refining process (including

distillation, catalytic cracking, fractionation, or thermal cracking

(i.e., coking)).

Under today's proposal, Sec. 261.4(a)(12) would be revised to

provide that oil-bearing residuals from specified petroleum industry

sources that are inserted into the petroleum refining process

(including the coker) along with normal process streams would be

excluded from the definition of solid waste, if the material is not

stored in a manner involving placement on the land, or accumulated

speculatively before being recycled and (if insertion is into the

coker) if the coke product does not exceed characteristically hazardous

levels. More specifically, today's proposed exclusion would cover oil-

bearing secondary materials that are generated on-site at refineries,

transported intracompany from off-site, or received from any off-site

facilities (intercompany transfers) in the following SIC codes: 1311,

1321, 1381, 1382, 1389 (oil and gas extraction), 2911 (petroleum

refining), 4612 and 4613 (crude oil and refined petroleum pipelines),

4922 and 4923 (natural gas transmission and distribution), 4789

(independent pipeline operators), and 5171 and 5172 (petroleum product

bulk stations and terminals). It should be noted that certain existing

exclusions provided under Sec. 261.6 that pertain specifically to

petroleum refining wastes would become unnecessary as a result of

today's proposal. The Agency will amend these provisions as necessary

in its final rulemaking.

Today's proposal would not effect the current regulatory status of

petroleum refinery wastewaters. EPA considers refinery wastewaters to

be discarded materials and therefore solid wastes potentially subject

to regulation under RCRA (59 FR 38539, July 28, 1994). Likewise,

wastewater treatment systems in which RCRA hazardous wastes are managed

would continue to be subject to regulation as hazardous waste

management units or exempt under 40 CFR 264.1 under today's proposal.

[[Page 57754]]

Today's proposed exclusion would also be expanded to include

recovered oil that is generated from certain organic chemical industry

operations and inserted into a petroleum refining process along with

normal process streams.

b. Rationale for Proposed Amendments. (1) Exclusion for Oil-Bearing

Residuals Returned to Refining Process. Today's proposed exclusion

applies to any oil-bearing residual material from any phase of

petroleum exploration, refining, transport or marketing that is

inserted directly into any part of the refining process. These

materials are most likely to be inserted into the petroleum coker, and

the basis for this proposed exclusion is discussed at length below.

Materials inserted elsewhere into the refining process are likely to

already be recovered oil, and hence to be excluded, or to so closely

resemble recovered oil as to fit the rationale of the existing rule, if

not its exact literal language. Thus, with respect to insertion into

parts of the refining process other than coking, extending the

exclusion to all oil-bearing materials largely avoids unproductive

disputes about what is and is not recovered oil, and leaves refineries

with maximum flexibility as to the best part of the process to reinsert

oil-rich residuals.

(2) Proposed Exclusion for Oil-Bearing Materials Inserted into

Petroleum Coking. Role of the Petroleum Coker in the Petroleum Refining

Process. EPA decided in the July 1994 rule not to exclude hazardous

oil-bearing secondary materials that are inserted into the coking

process until the Agency studied further whether the coker may be

functioning, at least in part, as a waste management unit in these

cases (59 FR 38542, July 28, 1994). A more detailed review of the

coking process has since convinced EPA that the coker is in fact an

integral part of the petroleum refining process and is similar to other

refining processes such as distillation and catalytic cracking. The

coker is normally located on-site and typically processes oil-bearing

materials that are generated on-site. The petroleum coker contributes

significant revenue to the refinery primarily through upgrading of

lower value hydrocarbons into light ends that are used to produce more

valuable product fuels. While coke is a co-product of the coking

process, the primary purpose of the coker is, in fact, to thermally

convert longer-chain hydrocarbons to recover the more valuable middle

and light end hydrocarbons that are used to produce high grade fuels

(e.g., gasoline, kerosene, jet fuel, etc.). The typical coker yield is

about 25%-30% petroleum coke and 70% light hydrocarbons that are

returned to the refining process to produce high grade fuels. The

importance of the coker to the refining process is illustrated by the

fact that the coking operation may determine the economic viability of

the refinery. Given that the coker is a crucial unit in the refining

process, industry representatives assert and the Agency believes that

it is highly unlikely that refinery owners or operators would allow any

incompatible materials to be inserted into the coker for fear of

interfering with proper operation of the coker. It is also significant

that, consistent with EPA's finding that cokers are considered process

units for purposes of today's proposed exclusion, cokers are also

viewed as process units under recently issued Clean Air Act (CAA)

regulations and that emissions from cokers are subject to regulations

under the National Emission Standards for Hazardous Air Pollutants from

Petroleum Refineries (40 CFR 63 Subpart CC; 60 FR 43244, August 18,

1995).

Hazardous Oil-bearing Residuals Compared to Normal Coker Feed. EPA

also initially decided not to exclude recovered oil and other oil-

bearing hazardous materials used to produce petroleum coke because of

concerns that toxic metals contained in these materials are being

disposed of by incorporation into a coke product. At the time the

recovered oil rule was published, the Agency had only limited data

indicating that oil-bearing hazardous residuals do not contain

significantly different amounts of toxic constituents from the heavy

petroleum residuals that are normally fed to the petroleum coker, but

was uncertain of the representativeness of the information. The Agency

has since received some additional data on the composition of oil-

bearing hazardous sludges relative to crude oil residuals that are

typically fed to the coker which supports industry's claim that oil-

bearing sludges generated during the refining process are substantially

similar to normal coker feedstock material.2 At this time, all of

the data in EPA's possession indicates that the recycling of oil-

bearing residuals can be accomplished without raising hazardous

constituent (e.g., heavy metal) concentrations to levels of concern in

the final coke product. To guard against this possibility, the Agency

is limiting this exclusion to the production of coke which does not

exhibit the characteristics of a hazardous waste. This is consistent

with the thrust of RCRA Sec. 3004(q)(2)(A) which subjects certain

petroleum refinery wastes converted into petroleum coke to regulation

if the resulting coke exhibits a characteristic.

\2\ See October 8, 1993 and October 13, 1993 letters from Mark

A. Smith (Unocal) to James R. Berlow.

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

Another significant consideration bearing on today's proposal is

the fact that hazardous oil-bearing sludges constitute only a very

small fraction of the total residual materials that are generated by

the petroleum refining process and inserted back into the refinery for

further processing. Due to process limitations, hazardous oil-bearing

materials comprise only about 1-3% of the total amount of refining

residuals that are routinely fed to the coker according to industry

representatives.

Additionally, EPA has found that hazardous oil-bearing refinery

sludges are managed in much the same way as are non-regulated crude oil

residuals prior to insertion into the petroleum coker. In a typical

petroleum refinery operation, refinery residuals (e.g., K048-52) that

are inserted into petroleum cokers are transferred from wastewater

treatment tanks to the coker via a closed system. The wastewater

treatment tanks in which the residuals are initially stored are exempt

from Subtitle C regulation. (See 40 CFR 264.1(g)(6).) The residuals are

typically transferred from exempt wastewater treatment tanks via hard

pipe or tank trucks to stationary tanks or containers where oil is

recovered and/or the secondary materials are prepared for insertion

into the coker. Since the residuals are not ordinarily stored in stand

alone storage tanks but are instead transferred directly to process

tanks and containers (i.e., centrifuge systems, desorption units, etc.)

EPA does not believe that storage of the residuals prior to reinsertion

into the refining process poses hazards to human health or environment.

In addition, American National Standard Institute (ANSI) standards

governing design, construction, operation, maintenance and inspection

of petroleum terminal and tank facilities help to ensure

environmentally protective management storage of the in-process

residuals prior to reinsertion into the coker or other parts of the

refinery.

Furthermore, data on the composition of the coke product indicate

that use of oil-bearing secondary materials has little, if any, impact

on the quality and/or properties of the resulting coke. In particular,

EPA has information which indicates that levels of toxic metals in coke

produced from oil-bearing sludges are comparable to those found in coke

[[Page 57755]]

produced strictly from crude oil residuum.3

\3\ See February 2, 1993 data submission from Mobil Oil

Corporation.

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

Finally, coke product is subject both to regulatory requirements

and certain limited industry product specifications, a fact that serves

to ensure the quality of the coke product. The statute and existing

regulations provide that coke product derived from a hazardous waste

which exhibits a hazardous characteristic (as determined by application

of the Toxicity Characteristic Leaching Procedure) is subject to

regulation as hazardous waste under RCRA. See RCRA Sec. 3004(q)(2)(A)

and 40 CFR 261.6(a)(3)(vii). EPA would retain this provision under

today's proposal as a means of ensuring that reinsertion of these

materials is not part of the waste disposal problem. See generally AMC

II, supra. Coke is also subject to product standards established by the

American Society for Testing of Materials' (ASTM) for volatile matter

and ash content. Taken together, these controls help to ensure that

coke product does not contain unsafe levels of toxic contaminants.

Restrictions on Land Placement and Speculative Accumulation.

Today's proposed exclusions do not apply to oil-bearing hazardous

secondary materials that are placed in land-based hazardous waste

management units such as surface impoundments or land treatment units.

The Agency considers materials placed in such units to be discarded,

and hence solid wastes. Land-based units that contain hazardous oil-

bearing residuals would remain subject to Subtitle C requirements under

today's proposal. AMC II, 907 F. 2d at 1186-87. In addition, any

material that spills from tanks and containers and is not expeditiously

retrieved for reinsertion is a solid waste and, if listed or

characteristic, a hazardous waste. See Sec. 261.33(d) and 55 FR 22671,

June 1, 1990.

Today's proposed exclusion also does not apply to oil-bearing

secondary materials that are accumulated speculatively (as defined in

Sec. 261.1(c)(8)) before being recycled into a petroleum refining

process. Under RCRA, secondary materials that are accumulated

speculatively are considered to be discarded and hence solid waste. EPA

applies this standard condition to otherwise excluded secondary

materials to prevent risks from prolonged storage of the material

before recycling. See 50 FR 634-635, 658-661, Jan. 4, 1985.

Restrictions on Petroleum Coke Produced From Hazardous Oil-Bearing

Secondary Materials. Under the current regulations, petroleum coke

produced from hazardous oil-bearing refinery wastes is excluded from

regulation under RCRA provided that the resulting coke product does not

exceed one or more of the characteristics of hazardous waste in part

261, Subpart C (Sec. 261.6(a)(3)(vii)). Under today's proposal, EPA

would continue to regulate coke that exhibits a characteristic as

hazardous if the coke is produced from oil-bearing residuals that are

excluded from regulation because they are reinserted into the refining

process, but are otherwise regulated as hazardous waste. In addition,

EPA is proposing to condition the exclusion for oil-bearing residuals

that are inserted into the coker on the requirement that coke produced

from these materials not exceed characteristic levels. In other words,

the exclusion would not apply to secondary materials that, if recycled,

would result in coke that exhibits a characteristic. To do otherwise,

as noted, would lead to situations where management of oil-bearing

residues becomes part of the waste management problem by tainting the

coke. EPA thus is proposing these conditions to ensure that coke

produced from otherwise excluded oil-bearing secondary materials will

not contain toxic constituents in quantities that could be harmful to

human health and the environment when the coke is burned so as to

assure that the proposed exclusion does not undermine RCRA's cradle-to-

grave purpose. API, 906 F.2d at 741; RCRA Sec. 3004(q)(2)(A). EPA

requests comment on the adequacy of the TCLP for this purpose.

Materials That Are Deemed To Be Inherently Waste-Like. The existing

regulations provide EPA with authority to designate as solid wastes

materials that are inherently waste-like regardless of the mode of

recycling. (See Sec. 261.2(d).) Under current regulations, the Agency

may designate materials as inherently waste-like either because they

are typically disposed of or incinerated on an industry-wide basis or

they contain toxic constituents not normally found in the raw materials

or products for which they are being substituted (50 FR 637, January 4,

1985). Therefore, while EPA is proposing to generally exclude hazardous

oil-bearing refinery residuals that are returned to the petroleum

refining process, the Agency retains the authority to regulate specific

waste-streams as ``inherently waste-like'' if it finds that particular

petroleum refining residuals contain high levels of toxic constituents

that are not ordinarily found in the normal coker feed and do not

contribute to the product.

Regulatory Status of Petroleum Refinery Wastewater and Wastewater

Treatment Operations. Under today's proposal petroleum refining

wastewaters would continue to be subject to regulation as solid wastes

under RCRA. Petroleum industry representatives have argued in public

comments submitted in response to both the January 8, 1988 proposal and

the July 28, 1994 final recovered oil rule, that plant wastewaters

containing oil are not solid wastes. Industry representatives contend

that primary wastewater treatment operations in which oil is skimmed

and oil-bearing sludges are separated from plant waters are part of the

ongoing refining process.

EPA has considered this argument but does not agree for the

following reasons. First, petroleum refining wastewaters differ from

both recovered oil and oily sludges that are separated from the

wastewaters in that, unlike these secondary materials, the wastewaters

themselves are not analogous in composition to normal petroleum

refining feedstock material and consequently are not reinserted into

the petroleum refining process to produce petroleum products. Instead,

petroleum refining wastewaters from which oily materials have been

removed are discharged, and are thus not eligible for exclusion as a

petroleum refining process feed.

Second, as explained in the preamble to the recovered oil rule,

primary wastewater treatment operations exist to treat plant

wastewater. The main purpose of wastewater treatment is to purify

discarded wastewaters from the refining process so that they can

ultimately be discharged pursuant to Clean Water Act requirements, not

to recover secondary materials for recycling back into an ongoing

manufacturing or industrial process. See 59 FR 38539, July 28, 1994.

A final and equally important consideration in EPA's decision not

to exclude refinery wastewaters from regulation is that regulation of

these wastewaters ensures treatment of hazardous constituents in

characteristic wastestreams that are managed in wastewater treatment

impoundments (e.g., impoundments in which biological treatment occurs)

in accordance with the land disposal restriction (LDR) requirements of

Part 268. See 59 FR 38540.

Recovered Oil From Co-Located Petroleum Refineries and

Petrochemical Facilities. EPA is also today proposing to add an

exclusion at Sec. 261.12(a)(13) for recovered oil that is generated by

certain

[[Page 57756]]

organic chemical industry operations and inserted into petroleum

refining processes provided that the conditions discussed above are met

(i.e., provided that the recovered oil is not stored in a manner

involving placement on the land, or accumulated speculatively before

being recycled and that (if insertion is into the coker) coke product

does not exceed characteristically hazardous levels).

The final recovered oil exclusion does not currently apply to

recovered oil from organic chemical industry operations except in cases

where petrochemical and petroleum refining operations share a common

wastewater treatment system (where wastewater from petrochemical

processing units typically comprises only small percentage of the total

refinery wastewater volume). In these cases, given the predominance of

petroleum refining wastewater, the Agency believes that the recovered

oil exclusion appropriately applies to oil recovered from shared

petrochemical/petroleum refining wastewater treatment systems.4

The Agency did not more broadly exclude recovered oil from organic

chemical operations in its final recovered oil rule because of concerns

about additional toxic constituents that may be present in oil

recovered from petrochemical processing residuals (i.e., the exclusion

is provided on the premise that the oil-rich materials in question

contain the same constituents as normal refining process streams).

\4\ May 3, 1995 letter from Michael Shapiro (EPA) to Ralph J.

Colleli, Jr. (API).

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

EPA is aware, however, that some petrochemical facilities recover

oil separately from their process streams and send it to petroleum

refineries for insertion into the refining process. This practice

typically occurs between petroleum refineries and chemical operations

that are either co-located or owned by the same company. The oil

recovered from petrochemical operations typically comes from ``dry''

process streams, i.e., hydrocarbon streams with little or no water

content that are recovered outside of wastewater treatment systems. It

is generally composed of hydrocarbons that originate from, or are

derived from, feedstocks supplied by the petroleum industry.

Since promulgation of the final recovered oil rule in July 1994,

the Agency has received compelling information from the chemical

manufacturing industry indicating that the recovered oil from these

organic chemical industry operations is comparable to oil recovered

from petroleum refining operations.5 Based on this information,

which is described in detail below, the Agency is proposing to exclude

oil that is recovered from petrochemical operations and inserted into

co-located or commonly owned petroleum refining operations.

\5\ September 13, 1995 letter to Becky Daiss (Office of Solid

Waste) from Michael W. Steinberg (Morgan, Lewis & Bockius and July

31, 1995 letter to Steven E. Silverman (U.S. EPA, Office of General

Counsel) from Michael W. Steinberg (Morgan, Lewis & Bockius).

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

The specific reasons for the proposed petrochemical exclusion are

as follows. First, chemical industry representatives have argued and

EPA agrees that the need to closely control petroleum product quality

makes it unlikely that the recovered oil from the dry organic chemical

plant streams covered by the proposed exclusion would contain toxic

contaminants not otherwise found in petroleum feedstock. The presence

of non-hydrocarbon contaminants in the recovered oil can jeopardize the

integrity of the refined product. Product quality problems (e.g.,

solids or potential gum-forming problems in automobile fuel injection

or carburetor systems) can, in turn, have a widespread impact both on

customers and the refiners because of the extensive distribution

network in the industry. In addition, quality of the recovered oil

feedstock is important to the integrity of the refining process itself

(e.g., some chemicals and metals can cause equipment fouling and costly

downtime at refineries).

Precautions are therefore taken to ensure that recovered oil from

petrochemical plants does not contain contaminants that may adversely

affect the quality of refinery products or cause equipment and catalyst

fouling process unit downtime within refineries. Recovered oil from

organic chemical operations is segregated from other by-product or

waste streams generated by petrochemical plants. In addition, the

petrochemical recovered oil streams, which are generally aggregated on-

site, are routinely analyzed before being sent to the petroleum

refinery for use as a feedstock to ensure that the recovered oil does

not include toxic contaminants beyond those found in normal petroleum

refining process streams. Recovered oil quality parameters include bulk

solids and water content, bromine number (an indicator of olefin

content and potential fouling due to polymerization) and specific

gravity.

Second, the Agency has received sampling and analytical data that

supports industry's premise that recovered oil from petrochemical and

petroleum refining operations is similar in composition and that,

consequently, petrochemical recovered oil is suitable for insertion

into the petroleum refining process. The data provides a comparison

between recovered oil samples from co-owned petrochemical and petroleum

refining operations on key parameters including specific gravity,

distillation temperature ranges, flash point, hydrocarbon type, and

sulfur, ash, and total chlorine content. The analysis indicates that

the petrochemical recovered oil is comprised essentially of

hydrocarbons that are within a refinery's distillation range and

hydrocarbon type. The refinery and chemical plant recovered oil samples

were also compared against the Agency's used oil fuel specification.

The used oil specification includes levels for arsenic, cadmium,

chromium, lead, and flash point. Used oil that is within the specified

limits is considered by EPA to be comparable to crude oil for

regulatory purposes. The analysis of all recovered oil samples

indicates that arsenic, cadmium, chromium, lead and total halogen

levels are well below the used oil fuel specification. The

petrochemical recovered oil samples were below detection limits for the

specified contaminants. Flash points of both types of recovered oil

were also well below the used oil specification minimum.

EPA requests comment on today's proposed exclusion for recovered

oil that is generated by organic chemical plants and inserted into co-

located or commonly owned petroleum refining processes along with

normal refining process streams. Today's proposal is based on a very

limited set of data. To ensure that the data are representative of the

industry, the Agency is soliciting additional data on the composition

of recovered oil from petrochemical operations that is typically sent

to petroleum refineries. Additionally, EPA may consider broadening the

proposed exclusion to include recovered oil from plastic materials and

resins manufacturers (SIC Code 2821), synthetic rubber manufacturers

(SIC Code 2822), and cyclic crude and intermediate producers (SIC Code

2865) if the Agency receives sufficient analytical data to support such

an extension. Finally, EPA also solicits additional information on

refinery limitations that serve to preclude introduction of toxic

constituents from recovered oil from chemical manufacturing operations.

F. Description of Health and Risk Assessments

In determining whether wastes generated from petroleum refining

[[Page 57757]]

operations meet the criteria for listing a waste as hazardous as set

out at 40 CFR 261.11, the Agency evaluated the potential toxicity and

intrinsic hazard of constituents present in the wastes, the fate and

mobility of these chemicals, the likely exposure routes, and the

current waste management practices. A quantitative risk assessment was

conducted for those wastes where the available information made such an

assessment possible.

1. Human Health Criteria and Effects

The Agency uses health-based levels, or HBLs, as a means for

evaluating the level of concern of toxic constituents in various media.

In the development of HBLs, EPA first must determine exposure levels

that are protective of human health and the environment, then apply

standard exposure assumptions to develop media-specific levels. EPA

uses the following hierarchy for evaluating human health effects data

and health-based standards in establishing chemical specific HBLs:

The Maximum Contaminant Level (MCL) is used as the HBL for

the ingestion of the constituent in water, when it exists. MCLs are

promulgated under the Safe Drinking Water Act (SDWA) of 1974, as

amended in 1986, and consider technology and economic feasibility as

well as health effects.

Agency-verified Reference Doses (RfDs) or Reference

Concentrations (RfCs) are used in calculating HBLs for noncarcinogens

and verified carcinogenic slope factors (CSFs) in calculating HBLs for

carcinogens. Agency-verified RfDs, RfCs, and CSFs and the bases for

these values are presented in the EPA's Integrated Risk Information

System (IRIS).

RfDs, RfCs, or CSFs are used which are calculated by

standard methods but not verified by the Agency. These values can be

found in a number of different types of Agency documents and EPA used

the following hierarchy when reviewing these documents: Health Effects

Assessment Tables (HEAST); Human Health Assessment Group for

Carcinogens; Health Assessment Summaries (HEAs) and Health and

Environmental Effects Profiles (HEEPs); and Health and Environmental

Effects Documents (HEEDs).

Use RfDs or CSFs that are calculated by alternative

methods, such as surrogate analyses, including structure activity

analysis, and toxicity equivalency.

a. 1,3,5-Trimethylbenzene. 1,3,5-Trimethylbenzene was identified in

the record samples. EPA has adequate toxicological information to

develop a provisional health benchmark (i.e., RfD). The Agency has

developed a provisional RfD of 0.05 mg/kg/day for 1,3,5-

trimethylbenzene using a subchronic oral rat study, along with other

toxicological studies. In addition, the Agency has determined that the

provisional RfD developed for 1,3,5-trimethylbenzene is an appropriate

benchmark for 1,2,4-trimethylbenzene. These studies and the Agency's

supporting analysis for the provisional RfD can be found in the docket

supporting this rule. The Agency has conducted limited external peer

review of the provisional RfD and it is therefore subject to change.

A number of assumptions and extrapolations are used to derive the

provisional RfD, including extrapolating from short-term animal studies

to a chronic human exposure, and the selection of the critical study on

which to develop a health benchmark. The Agency requests comments on

the appropriateness of the provisional RfD and requests any additional

data on the toxicity of 1,3,5-trimethylbenzene.

b. Use of Structure-Activity Relationships. There are 15

constituents identified in the record samples for which EPA has found

no reliable health effects data to calculate health benchmarks for

carcinogenic and noncarcinogenic chemicals. Because of the lack of

health effects data on these constituents, the Agency used a structure-

activity analysis to identify surrogate chemicals, where possible, that

have reliable health benchmarks for use in the risk assessment. The

approach involves identifying a surrogate chemical that has similar

chemical structure, physical properties, and health effects information

as that of the constituent for which human health data and animal data

are either lacking or inadequate. The Agency used the surrogate health

benchmarks in the risk analysis to assess the potential impacts of the

constituents without benchmarks found in the wastestreams for the

following five constituents: 1-methylnaphthalene; t-butylbenzene;

butylbenzene; sec-butylbenzene; and 2-hexanone. The risk analysis did

not include an evaluation of potential impacts from the following

constituents because no appropriate surrogates with health benchmarks

could be found: indene; 2-methylnaphthalene; n-propylbenzene;

bromobenzene; dibenzofuran; aluminum (+3); cobalt; magnesium hydroxide;

magnesium oxide; and iron oxide. Based on this assessment none of these

constituents were of concern in any of the listing decisions in today's

proposal. Further discussion of this approach can be found in the

docket supporting this rule. The Agency is planning to conduct a peer

review of the surrogate analysis and, therefore, the health benchmark

is subject to change. See ADDRESSES section. The Agency requests

comment on this approach, and any additional toxicity information on

these compounds.

c. Use of Relative Potencies for Polynuclear Aromatic Hydrocarbons

(PAHs). The Agency has a verified cancer slope factor available for

only one PAH, benzo(a)pyrene. For the remaining PAHs evaluated in the

risk assessment supporting this rule, the Agency used two methods to

quantitatively estimate the relative potencies of other PAHs. The first

method, developed by EPA's Office of Health and Environmental

Assessment, is interim guidance for the quantitative risk assessment of

six PAHs. This guidance uses data from mouse studies to develop

relative carcinogenic potency estimates relative to benzo(a)pyrene. A

detailed description of the methodology and resulting rankings can be

found in ``Provisional Guidance for Quantitative Risk Assessment of

Polycyclic Aromatic Hydrocarbons,'' included in the docket supporting

today's rule. The second method the Agency used for the risk assessment

is a semi-quantitative scoring exercise organized by the Office of

Pesticides, Pollution Prevention and Toxic Substances. In this method,

experts independently reviewed available data and reached consensus

scoring on an additional 101 PAHs in terms of the compound's relative

potency using benzo(a)pyrene as the reference compound. The Agency

seeks comments on the uncertainties and limitations of both methods. A

more detailed discussion of the two methods can be found in the docket

supporting today's rule.

All HBLs and their bases for this listing determination are

provided in a document entitled ``Assessments of Risks from the

Management of Petroleum Refining Waste: Background Document,'' which

can be found in the RCRA docket for this rule at EPA Headquarters (see

ADDRESSES section).

2. Risk Analysis

a. Risk Characterization Approach. The risk characterization

approach follows the EPA Guidance on Risk Characterization (Habicht,

1992), and Guidance for Risk Assessment (EPA Risk Assessment Council,

1991), and Guidance for Risk Characterization (EPA Science Policy

Council, 1995). These guidance documents specify that EPA risk

assessments will be expected to include (1) the central tendency and

high-end portions of the risk

[[Page 57758]]

distribution, and (2) important subgroups of the populations such as

highly susceptible groups or individuals, if known, and (3) population

risk. In addition to the presentation of results, these guidance

documents also specifies that the results portray a reasonable picture

of the actual or projected exposures with a discussion of

uncertainties. These documents are available in the public docket for

this action (see ADDRESSES section).

b. Individual Risk. Individual risk descriptors are intended to

convey information about the risk borne by individuals within a

specified population and subpopulations. These risk descriptors are

used to answer questions concerning the affected population, and the

risk for individuals within a population of interest. The approach used

in this analysis for characterizing baseline individual risk included:

(1) identifying and describing the population of concern for an

exposure route; (2) determining the sensitivity of the model parameters

used in the risk estimation; (3) estimating central tendency and high-

end values for the most sensitive parameters in the risk estimation

procedures; and (4) calculating individual risk for likely exposure

pathways that provides a characterization of the central tendency and

high-end risk descriptor.

Descriptors of population risk are intended to convey information

about the risk borne by the population or population segment being

studied. These risk descriptors are used to answer questions concerning

the number of cases of a particular health effect that could occur

within the population during a given time period, the number of persons

or percent of the population above a certain risk level or health

benchmark (e.g., RfD or RfC), and risk for a particular population

segment.

The Agency performed a population risk analysis for impacts to the

affected community surrounding the refineries across the country. The

results of the analysis are discussed in Section VI.C.

c. Risk Assessment. The results of the risk assessment are

presented in waste-specific risk tables in each of the basis for

listing sections (Section III.G). The risk tables include the following

information: constituents of concern; estimated human health central

tendency and high-end risk for each constituent of concern associated

with the management scenarios; high, low, and average concentrations of

constituents found in this waste; the number of samples in which the

constituent was detected; and notes regarding potential sources of

uncertainty. In addition to assessing the risks associated with the

individual constituents found in the waste, the Agency presents the

combined potential risk of constituents that coexist in the waste, as

described in ``The Risk Assessment Guidelines of 1986,'' found in the

docket supporting today's rule. However, where sampling data or the

exposure analysis show compelling evidence that the constituents cannot

or do not occur together in the waste stream or at the receptor, the

Agency considered only the risk associated with the individual

constituent.

In addition to those compounds presented in the waste-specific risk

tables, the Agency's characterization data include other constituents

found in these wastes. The risk tables presented in this preamble

contain only those constituents which had adequate data for

quantitative risk assessment and which were found to present a risk of

concern. The complete list of constituents found in each of the wastes

generated from petroleum refining operations, an explanation of the

risk analysis process, and an explanation of EPA's development of the

target analyte list are presented in the background documents for this

rule, which are located in the RCRA Docket for this rulemaking (see

ADDRESSES section).

(1) Selection of Waste Management Scenarios. EPA's regulations at

261.11(a)(3)(vii) require the Agency to consider the risk associated

with ``the plausible types of improper management to which the waste

could be subjected'' because exposures to wastes (and therefore the

risks involved) will vary by waste management practice. The choice of

which ``plausible management scenario'' (or scenarios) to use in a

listing determination depends on a combination of factors which are

discussed in general terms in EPA's general policy statement on

hazardous waste listing determinations (59 FR 24530, December 22,

1994). EPA generally employed the elements of the policy in this

listing determination.

The following discussion explains the selection of plausible

management scenarios for the petroleum listing determination. The

Agency requests comment on its choice of plausible management scenarios

and on the possibility of using alternative plausible management

scenarios.

EPA's basic approach to selecting which waste management scenarios

to model for risk analysis in listing determinations is to examine

current management practices and assess whether or not other practices

are available and are reasonably expected to be used. Where a practice

is actually reported used, that practice is generally considered

``plausible'' and may be considered for potential risk. EPA then

evaluates which of these current or projected management practices for

each wastestream are likely to pose significant risk based on an

assessment of exposure pathways of concern associated with those

practices. There are common waste management practices, such as

landfilling, which the Agency generally presumes are universally

plausible for solid wastes and will assess it for risk. There are other

practices which are less common, such as land treatment, where EPA will

consider them plausible only where the disposal methods have been

reported to be practiced. In some situations, potential trends in waste

management for a specific industry suggest the Agency will need to

project ``plausible'' mismanagement even if it is not currently in use

in order to be protective of potential changes in management and

therefore in potential risk. Finally, there may be situations where

analysis shows no need to model any scenarios because, although

considered plausible management, no exposure potential exists.

In its study of the petroleum refining industry, EPA was able to

develop a comprehensive database of existing waste management

practices. All U.S. refineries that EPA was aware of were sent a RCRA

section 3007 questionnaire and all the active ones responded. This

allowed the Agency to conduct a careful analysis of how wastestreams

were managed in 1992. Based on discussions with industry, the Agency

also was able to project potential changes in these practices and thus

determine whether or not to include unused or little used practices in

the risk assessment.

Overall, the Agency found the reported waste management practices

for the industry to be numerous and varied. This required an assessment

of the existing (and potential) management of each wastestream to

determine which of those practices should be modeled for that

particular residual. Some wastestreams had special considerations

(e.g., rarity of practice, volumes managed, existing regulatory

coverage) associated with their management that had to be included in

the decision-making process. The description of such considerations is

included in the listing determination section for that wastestream.

Given the extensive amount of data collected for this industry, EPA

did not find it necessary to quantitatively model all currently used

waste management practices. Furthermore, for the reported management

practices that were

[[Page 57759]]

assessed for risk, EPA conducted risk analysis based on the volumes of

wastes reported to be managed by those practices in 1992. This is a

modification of EPA's general policy to consider plausible (and model)

all reported waste management practices. The reasons for the

modification, discussed in more detail later in this section, are:

1. Some practices involve very small volumes or very few generators

with a correspondingly low potential to cause unacceptable risk.

2. Some practices have proved in past listing determinations to

pose less risk than those more common practices (e.g., landfilling)

that were modeled. Therefore the modeled practices act as surrogates to

the less common, less risky alternatives.

3. Most of the reported management practices selected for modeling

are less expensive than other plausible alternatives (industry will

usually select and continue to use the less costly option) and

therefore there was no need to assess practices not currently used or

only rarely used.

4. The Agency was unable to model every reported management

practice for every metric ton of waste due to time and resource

constraints. However, EPA believes it has evaluated the practices

likely to be of most concern.

EPA's data show that the overwhelming volume of the wastestreams

that were actually disposed of (as opposed to being recycled or

reclaimed) involved three specific waste management practices:

discharge to a wastewater treatment plant, landfilling, and land

treatment. Each of these was reported to be currently in use by a

number of refineries.

(2) Disposal in Wastewater Treatment Plants. Exposure pathways and

potential risks associated with disposal of wastes to wastewater

treatment plants, which in this industry generally represents combined

wastestream treatment in tanks, are largely covered by regulation under

the NPDES or air permit programs. Furthermore, sludges generated by

refinery wastewater treatment systems, which could be affected by the

discharge of the wastestreams of concern in this listing, are already

listed hazardous wastes F037, F038, K048, and K051. The exception is

activated biological treatment (ABT) sludge and sludges generated

downstream of ABT units. These sludges can be disposed of in various

ways, including surface impoundments. However, activated biological

treatment sludge is not one of the residuals under consideration in

this listing. In addition, the volumes managed in the wastewater

treatment system of the residuals under consideration in this listing

are relatively small in comparison to the volumes typically handled in

refinery wastewater treatment systems. In addition, unlike most

refinery process wastewaters, these volumes are generated on an

intermittent (e.g., once a year) basis. The wastestreams of concern for

this listing would be considerably diluted by the other wastestreams

sent to the plant. Further, EPA has proposed that the risk associated

with disposal of these ABT and downstream sludges be covered by the

Phase IV Land Disposal Restrictions treatment requirements (60 FR

43654, August 22, 1995). For these reasons, discharge of wastes covered

by the consent decree to wastewater treatment systems, although a

practiced management scenario, was not modeled for risk.

(3) Disposal in Landfills and Land Treatment Units. The principal

waste management practices chosen for modeling the residuals in this

listing determination were off-site and on-site Subtitle D landfilling

and treatment in off-site and on-site land treatment units (LTUs).

These disposal practices were reported in the Section 3007

questionnaire survey to be in use by a large percentage of refineries

and for a large proportion of the total volume discarded. Therefore,

EPA modeled both direct and indirect exposure pathways associated with

these two waste management practices.

For on-site landfills and LTUs, the Agency used the data submitted

by industry in the Section 3007 questionnaire to characterize the units

in terms of the waste quantities disposed, surface area of disposal

units, and distances to receptors. For off-site landfills and LTUs, the

Agency used characteristics based on a statistical analysis of existing

Subtitle D land treatment facilities, from the Agency's ``Industrial

Subtitle D Facility Study'' (October 20, 1986).

The Agency modeled the releases from the disposal of wastes in on-

site and off-site land treatment units by partitioning the constituents

of concern between several fate and transport processes. These releases

include the following: volatilization to the air, leaching to ground

water, erosion of soil and runoff of dissolved constituents to nearby

land and surface water bodies, and biodegradation. For the screening or

bounding estimates, the Agency assumed that no partitioning or

biodegradation occurred, thus maximizing releases to all media; for

example, for the groundwater pathway's bounding analysis, TCLP results

were used as model inputs. For the central and high-end estimates of

risk, the Agency modeled the partitioning of these releases from the

land treatment units to derive annual concentrations in the media.

Biodegradation losses were calculated using data on constituent half-

life in the environment. The Agency's groundwater risk analysis used

the estimated leaching concentrations from this analysis, instead of

TCLP data, as the starting concentration in which to estimate

groundwater concentrations at a receptor well. The TCLP data that the

Agency collected estimate the concentration of the constituents

leaching from the waste samples in a landfill management scenario. The

Agency evaluated the land treatment scenario on a soil/waste mixture

for which the Agency did not have TCLP data and, therefore, relied on

the results of the partitioning analysis. A more detailed discussion of

the release processes for land treatment units is presented in the

``Assessment of Risks From the Management of Petroleum Refining Wastes:

Background Document'' in the docket supporting today's proposal.

(4) Other Disposal Practices Reported. There were other, less

commonly employed waste management practices reported in the petroleum

refining industry. Several residuals had ten or more different

management practices reported as ``in use.'' For most of them, EPA has

concluded that although they are used in the petroleum refining

industry, they are not management scenarios that need to be assessed

for risk. For example, there were ten reported management practices for

HF alkylation sludge. Four of these (representing 75% of the reported

waste volume) involved land treatment or disposal in a landfill and

were modeled for risk. One practice was on-site recovery in the coking

unit (12% of reported waste volume), two others involved practices

since terminated (10% of reported waste volume), and the remainder of

management practices involved discharge to the wastewater treatment

plant. These latter practices were not modeled. The factors the Agency

considered in deciding whether or not the less common disposal

practices should be modeled are:

i. Coverage of the characterization program. The comprehensive

nature of EPA's petroleum refining database allowed the Agency to

develop an in depth knowledge of the amounts of waste generated and the

final management practices employed by the petroleum refining industry.

In

[[Page 57760]]

particular, a very high percentage (more than 80 percent of the total

volume) of these wastestreams either were reused, reclaimed, or

recycled or were disposed of using landfilling or land treatment (more

than 50 percent of the remaining volume), suggesting that there are

financial and practical incentives to handle wastes using the methods

reported. These incentives were assumed to be constraints.

Moreover, the information indicated that aside from recycling,

landfilling, and land treatment, most reported management practices

involved low volumes of waste that would be of significantly less

concern in terms of risk. If possible given the potential risks

involved, EPA tries not to base listing determinations on disposal

practices employed by a very small segment of an industry producing low

volumes of waste as this can penalize unnecessarily, without a

concomitant benefit in actual risk reduction, the vast majority of

generators who dispose of the bulk of the wastes generated in less

risky ways. For example, if one plant reported one metric ton of a

wastestream as used as dust suppressant, but thousands of tons of that

wastestream were reported as landfilled by a number of other plants,

EPA would likely conclude that dust suppression, although nominally in

use, is not a practice that should be assessed for risk. In fact, EPA

was unable, due to resource and time constraints, to cover all waste

volumes reported with the plausible management scenarios selected for

modeling. Therefore, there are some reported management practices that

were not formally evaluated using predictive risk assessment models

after EPA judged them unlikely to be significant. Less formal

projections of potential risk were made for some management scenarios.

Also, experience in previous listings has indicated some waste

management practices show more risk than others. Therefore, if EPA

calculates risk for the usually more risky management scenario, the

risk from other scenarios will probably be lower.

ii. Effect of other regulatory programs. For some wastestreams and

their reported waste management practices, EPA concluded that existing

regulatory programs provided a level of regulatory coverage that

rendered further assessment of risk unnecessary. Many of these

wastestreams are often characteristically hazardous. In fact, the

Agency concluded that many of the wastestreams that were disposed of in

Subtitle C management facilities were sent there specifically because

they were characteristically hazardous wastes. Therefore, EPA believes

that the volumes sent to Subtitle C facilities would continue to be

handled in that way.

iii. Management costs. Where one management practice is generally

more expensive than another, cost becomes a factor in EPA's assessment

of whether or not that practice should be considered plausible. In this

industry, the Agency generally found that the lower cost management

option was currently the one employed and that factor further suggested

existing management practices would not change. The principal example

is incineration, which is a higher cost option than landfilling or land

treating. Little direct incineration of wastestreams was reported by

the industry. EPA concluded there was a negative cost incentive for the

industry to switch to incineration of these wastestreams. Additionally,

the petroleum refining industry reported little disposal of these

wastestreams in surface impoundments. Due to the industry's heavy

investment in wastewater treatment tanks, there appears to be little

incentive to switch to surface impoundments to treat and dispose of

wastestreams. Therefore, EPA only modeled surface impoundments in its

risk assessment for one wastestream.

Because of all of these factors, EPA determined it was unnecessary

either to project unreported management scenarios or to model many of

the infrequently reported management practices for this listing

determination. Instead, EPA determined it more appropriate to estimate

risk based on the most plausible, highest risk management practices and

therefore focused risk assessment modeling on landfilling and land

treatment.

During EPA's information collection process, it was pointed out to

the Agency that leaking tanks and refinery piping have been problems

for the petroleum industry and that exposures from such sources should

be modeled. Although such unintentional spills are not management per

se, exposures from such sources could be a concern. For the major

liquid wastestreams evaluated in today's proposal (e.g., spent sulfuric

acid and spent caustic), spills and leaks already fall under the

hazardous waste management system because these wastes are typically

characteristically hazardous. This obviates the need for conducting a

risk assessment for such pathways. For other wastestreams, EPA

concluded that the selection of unlined landfilling as a plausible

management scenario could serve as a surrogate for such sources because

the exposure scenario would be roughly similar. Leaks and spills of

wastestreams would cause exposures similar to those caused by landfills

(for potential groundwater contamination) or land treatment units (for

runoff or windblown dust). Because EPA modeled those management

scenarios, the Agency concluded additional modeling of leaks and spills

is unnecessary. Furthermore, such leaks and spills are typically

intermittent and should not present the long-term exposure potential

presented by land disposal.

The Agency evaluated each of the residuals of concern to determine

whether it was appropriate to model interim storage methods (e.g.,

tanks, containers, etc.) that are typically employed prior to final

management (e.g., landfilling). In most cases, the Agency determined

that the predominant exposure risks were expected to be associated with

long-term final management methods and that it was unnecessary to model

short-term interim storage. For example, many of the residuals of

concern are generated infrequently: the typical generation frequency

for tank sludges is once every ten years per tank and the catalyst

residuals are only generated every 2 to 5 years. For these types of

infrequently generated residuals, the residuals are typically stored

on-site for a period of time comparable to the tank or unit turnaround.

The Agency observed that these turnaround periods are often only 4 to 6

weeks in duration. Several factors contribute to the refineries'

motivation to move the residuals out of short-term storage: (1) the

residuals are often staged in the immediate vicinity of the process

area, impeding movement for continued operations; (2) the containers

used to transport the residuals (e.g., flo-bins, dumpsters, roll-off

bins) are often rented and incur substantial cost during usage; and (3)

turnarounds are often contracted out and the refineries are financially

motivated to minimize the length of time that they must pay for

contractor services and equipment, including storage units.

Because the on-site storage period is so short for many of the

infrequently generated residuals of concern, the Agency felt that it

was more appropriate to focus on assessing risk from long-term

management of these types of residuals. For those residuals, however,

that are generated on a more frequent basis, the Agency did model

certain storage practices. For example, spent caustic is generated on a

continual or frequent basis and is generally stored in tanks prior to

further management. These tanks are in continual usage. The Agency

modeled potential air releases from these spent caustic storage tanks

because of the potential for continual

[[Page 57761]]

toxicant releases. Similarly, sludge from sulfur complex operations can

be generated on a regular basis (e.g., weekly) and the Agency observed

facilities that maintain storage areas in the process units for

dumpsters used to accumulate filter cartridges. This practice also

poses the potential for ongoing air emissions and was modeled in EPA's

risk assessment.

Finally, the Agency notes that residuals from refining are, due to

their very nature, often reusable. They can be recycled, sold, or

transferred to other facilities. The disposition of these reusable

wastes is described in Section III.E. of this preamble. Because these

residuals are currently exempt or are proposed to be excluded from the

hazardous waste management system, exposures associated with their

management were not modeled in this listing determination. However, for

the wastestreams managed in an exempt manner that were assessed in this

listing determination, EPA has done qualitative risk analysis. Those

qualitative risk evaluations are described in the listing decision

rationales for the appropriate individual wastestream. Additionally,

the Agency did model air pathways for certain wastestreams when on-site

storage tanks were projected to be a potential source of air risk.

(5) Exposure Scenarios. The scenarios (i.e., receptors) included in

the risk assessment include adult resident, child resident, subsistence

fisher, recreational fisher, subsistence farmer, home gardener, and

consumers of ground water.

Adult Resident Applicable exposure pathways for the adult resident

include incidental ingestion of contaminated soil and direct inhalation

of vapors and particulates.

Child Resident Exposure pathways for the child resident are

identical to those for the adult resident. The rate of incidental soil

ingestion for the child, however, is twice that for an adult.

Recreational Fisher Applicable exposure pathways for the

recreational fisher include ingestion of contaminated fish, in addition

to exposure pathways of an adult resident (i.e., incidental ingestion

of contaminated soil, and direct inhalation of vapors and

particulates). Risks calculated for the recreational fisher were found

to be predominantly driven by the incidental ingestion of contaminated

soil; risks estimated through the ingestion of contaminated fish were

negligible by comparison. While the results for the recreational fisher

are presented in the risk assessment background document, they are not

presented in the preamble. The Agency is not using the subsistence

fisher scenario to support the listing determination proposed today.

Subsistence Fisher Applicable exposure pathways for the subsistence

fisher include ingestion of contaminated fish, in addition to exposure

pathways of an adult resident (i.e., incidental ingestion of

contaminated soil, and direct inhalation of vapors and particulates).

The rate of ingestion of fish for the subsistence fisher is twice that

for the recreational fisher. Risks calculated for the subsistence

fisher were also found to be predominantly driven by the incidental

ingestion of contaminated soil. The subsistence fisher risk assessment

results are available in the risk assessment background document in the

docket for this rule and are not presented in this preamble. The Agency

is not using the subsistence fisher scenario to support the listing

determination proposed today.

Subsistence Farmer Applicable exposure pathways for the subsistence

farmer include ingestion of home-grown beef and milk, ingestion of

home-grown fruits and vegetables, incidental ingestion of soil, and

direct inhalation of vapors and particulates. The total amount of beef,

milk, fruit, and vegetables that the subsistence farmer consumes is

assumed to be contaminated.

In conducting the subsistence farmer risk assessment, the Agency

determined that there is high uncertainty in the calculated plant-to-

animal (primarily beef and dairy cattle) bioconcentration factors for

the key constituents of concern, polynuclear aromatic hydrocarbons

(PAHs). No empirical data were found for bioaccumulation of PAHs in

mammals by this route; the model uses physical properties of

constituents (Kow) to predict transfer factors. For fish,

empirical data show that using Kow to predict bioconcentration

overestimates fish tissue concentrations by several orders of

magnitude. Based on these very high predicted bioconcentration factors,

the beef and dairy product ingestion pathways are major contributors to

cancer risk estimates for subsistence farmers. Because of the high

uncertainty associated with these bioconcentration factors, the Agency

is not using the subsistence farmer scenario to support the listing

determinations proposed today. The subsistence farmer scenario risk

assessment results are presented in the risk assessment background

document in the docket for this proposal but are not presented in the

preamble; the Agency requests comment and data regarding the

uncertainty associated with the bioconcentration factors of concern.

Home Gardener Applicable exposure pathways for the home gardener

include incidental ingestion of soil, direct inhalation of vapors and

particulates, and ingestion of fruits and vegetables. Forty percent of

the total amount of fruits and vegetables that the home gardener

consumes is assumed to come from their home garden which is assumed to

be contaminated.

Consumers of Ground Water These receptors are exposed only from

ingestion of untreated ground water contaminated by the leaching of

toxic constituents in the wastes being managed in land disposal units.

The Agency used a ground water fate and transport model, the EPACMTP

(EPA's Composite Model for Leachate Migration with Transformation

Products), to project the concentrations reaching the receptor well.

The EPACMTP is described in the background documents available in the

docket for today's proposal. See ADDRESSES section.

Chemicals in the subsurface may be subject to a variety of

biochemical transformation processes. EPACMTP accounts for

transformations due to hydrolysis, however, none of the organic

constituents considered in the present analysis are subject to

breakdown by hydrolysis. Biodegradation may be a significant removal

process for some of the constituents considered in the analysis.

However, the data and parameters associated with biodegradation are

subject to much greater uncertainty, vary over a wide range, and may be

highly site-specific. For these reasons, the Agency developed a

protocol for the determination of nationwide biodegradation rates,

which was published on June 15, 1988 (53 FR 22300). The protocol

requires biodegradation data from six sites that represent different

regions of the country. To date, the Agency has not received a complete

set of biodegradation rates for the constituents of concern

(particularly benzene). Therefore, biodegradation is not considered

directly in the groundwater pathway analysis. However, EPA evaluated

the potential effect of biodegradation using the available information

and best estimates.

Using the limited data available, EPA estimates that the benzene

concentration in well water is reduced by less than a factor of two

(reduction varies from 2 to 44 percent). Details of effects of benzene

biodegradation rates on modeling results for the different waste

streams are presented in

[[Page 57762]]

``Background Document for Groundwater Pathway Analysis'' available in

the docket. The Agency is soliciting comments on these rates and

requesting any biodegradation data, consistent with our protocol, which

can be used for nationwide modeling analyses.

3. Consideration of Uncertainty in Listing Determinations

One of the potential exposures of significant concern for this

rulemaking is erosion of soil from a land treatment unit onto adjacent

areas, including possible vegetable gardens. This type of exposure is

what the Agency refers to as ``indirect'' exposure, meaning that the

receptor (in this case a home gardener) is exposed to contaminants in

the waste after these contaminants have been transported from the waste

management area and have entered another environmental media (in this

case soil and vegetables) at the receptor site.

The Agency has used indirect exposure assessments in a number of

programs over the last several years. Some examples include the

development of the sewage sludge regulations, the development of

proposed standards for land application of paper mill sludge, and the

development of pesticide standards. In the hazardous waste listing

program, the Agency has considered indirect exposures for several

proposed regulations (wood surface protection, carbamate pesticides,

dyes and pigments) but has not based any final listing determinations

on risks from indirect exposures. These examples apply to national

regulations; in addition, the Agency has used indirect exposure

analyses on a site-specific basis in the Superfund program and to

develop hazardous waste combustion permit limits.

Despite its considerable experience with indirect exposure

assessments, the Agency recognizes that there are still significant

uncertainties associated with estimating the risks associated with some

exposure routes. Therefore, the Agency requests comment on how it

should factor in uncertainty in its listing determinations.

For example, if a risk estimate has a high degree of uncertainty

associated with it, should the Agency consider listing the waste in

question only if the calculated risk is near the high end of the risk

range of 10-6 to 10-4? Should the calculated risk estimate be even

higher? These questions imply that greater uncertainty generally

results in making a risk assessment more conservative. Is that

implication accurate? The Agency solicits comment on these questions

and this issue in general.

4. Peer Review

A peer review of the risk assessment for non-ground water pathways

has been performed. (The groundwater model was previously reviewed by

the Agency's Science Advisory Board.) Particular emphasis was placed on

the components that follow:

(1) Confidence in data on biotransfer factors for PAHs;

(2) Assumptions regarding design and operation of land treatment

units, including methods used to prevent excess build-up of

constituents in land treatment units;

(3) Methods used to predict soil concentrations at receptor

locations, with particular emphasis on the contribution of soil run-

off from land treatment units in which residuals are disposed and

the maintenance of a mass balance of constituents at the receptor

location; and

(4) Overall maintenance of mass balance of constituents among

multiple exposure pathways.

Three academic experts on risk assessment issues such as these were

selected to review the risk assessment for non-ground water pathways.

Comments have been received from these peer reviewers and will be

addressed concurrently with public comments on this proposed rule.

G. Waste-specific Listing Determination Rationales

1. Crude Oil Storage Tank Sediment

a. Summary. EPA is proposing to not list as hazardous tank sediment

from the storage of crude oil at petroleum refineries. This wastestream

does not meet the criteria set out at 40 CFR 261.11(a)(3) for listing a

waste as hazardous, because it does not pose a substantial or potential

hazard to human health and the environment. The Agency identified

limited risks to consumers of groundwater associated with releases from

off-site Subtitle D landfilling due solely to a single constituent,

benzene, which is already regulated under the Toxicity Characteristic

(TC). Home gardeners and adult residents show low risks from

polynuclear aromatic hydrocarbons (PAHs) potentially released from land

treatment operations. The risk assessment results are summarized in

Table III-2.

Table III-2.--Waste Characterization and Risk Estimates--Crude Oil Storage Tank Sediment

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

On-site land treatment * Off-site land treatment * Waste characterization

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

Constituents of concern Central Central

tendency High end tendency High end Avg. conc. High conc. Low conc. # of pts. Notes

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

Home Gardener

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

Benzo (a) pyrene............. 2E-9 9E-7 2E-9 1E-7 12.3 26.0 6.6 3 of 6...... J(2), 1

Dibenz (a,h), anthracene..... 9E-10 3E-7 7E-10 3E-8 2.1 3.7 .......... 1 of 6...... J(1), 1

Benzo (a) anthracene......... 4E-10 7E-8 3E-10 9E-9 11.5 31.0 .......... 1 of 6...... 1

Indeno (1, 2, 3-cd) pyrene... 2E-10 7E-8 1E-10 8E-9 15.0 15.0 3.0 2 of 6...... J(1)

Benzo (b) fluoranthene....... 3E-10 1E-7 3E-10 1E-8 11.4 29.0 5.9 2 of 6...... J(1), 1, 2

Total Carcinogen Risk***..... 4E-9 1E-6 3E-9 2E-7 .......... .......... ..........

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

Adult Resident

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

Benzo (a) pyrene............. 4E-9 7E-7 3E-9 9E-8 12.3 26.0 6.6 3 of 6...... J(2), 1

Dibenz (a, h) anthracene..... 2E-9 5E-7 2E-9 6E-8 2.1 3.7 .......... 1 of 6...... J(1), 1

Total Carcinogen Risk***..... 8E-9 1E-6 6E-9 2E-7 .......... .......... ..........

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

Notes:

1. Detection limits greater than the highest detected concentration are excluded from the average concentration calculations.

2. Concentration for combined benzo(b)fluoranthene and benzo(k)fluoranthene. J(#) Samples were estimated concentrations below quantitation limits, ``#''

indicates number of samples that are ``J'' values.

[[Page 57763]]

Only the combination of high-end factors resulting in the greatest overall carcinogen risk are presented:

* Scenario: high-end factors of quantity, duration of exposure for all scenarios.

** Scenario: high-end factors of small area, duration of exposure for all scenarios.

*** Total carcinogen risk includes risks from other PAHs not tabulated. The risks for the PAHs not presented in this table are lower than those that are

presented.

All concentrations are in mg/kg.

Waste Characterization and Risk Estimates, Crude Oil Storage Tank Sediment

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

On-site land treatment Off-site land treatment Off-site landfill Waste characterization

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

Constituents of concern Central Central Central

tendency High end tendency High end tendency High end Avg. conc. High conc. Low conc. # of pts Notes

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

Groundwater

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

Benzene......................... -5) due to benzene for an adult consuming groundwater

contaminated from an off-site landfill. The high-end carcinogenic risks

from PAHs in the home gardener and adult resident pathways were 1E-6

for the on-site land treatment scenario. The central tendency estimates

did not show significant risk for any exposure scenario.

The Agency conducted another level of analysis of its risk results

to further evaluate the PAH risks that were identified for land

treatment. One of the major assumptions in the Agency's run-off models

for releases from land treatment units (LTUs) is that the unit does not

have controls for run-on and run-off waters from precipitation. A

significant portion of the predicted risk for the PAHs is associated

with contaminated soils washing off of the LTU into residential areas.

PAH risks are reduced below listing levels of concern if no run-on/run-

off is assumed (i.e., the refinery diverts all run-on and collects all

run-off). EPA's data collection effort showed most LTUs reported run-

on/run-off controls to be in place. A survey of some state programs,

however, showed that non-hazardous waste LTUs run-on/run-off controls

were voluntary.\6\ Permits were not required, nor were management

standards (where developed) mandatory. The Agency believes that an

assumption of complete run-on/run-off control would overstate reality

in that existing controls for Subtitle D land treatment units may be

inadequate to control all releases, including dike failures during

severe storm events, and, more routinely, tracking wastes from the unit

on trucks and earthmoving equipment. While the Agency does not have

information on the actual effectiveness of land treatment units at

controlling releases associated with run-on/run-off, the Agency

believes the risks may lie somewhere between those posed by scenarios

with and without controls. For crude oil storage tank sediment, LTU

controls that reduced off-site run-off to nearby residential areas

(e.g., by about 50%) would reduce the high-end risk from land treatment

to below the 10-6 level.

\6\ See ``Communications with State Authorities on Requirements

for Land Treatment Units,'' U.S. EPA 1995.

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

The Agency believes the management practices of most concern (land

treatment and landfills) were assessed, and that the other management

practices would not serve as a basis for listing. The wastes being

disposed of in Subtitle C landfills are already handled as hazardous

and should not present significant risk. As described in Section II.F.2

(``Risk Analysis''), EPA believes that potential risks associated with

disposal of wastes to wastewater treatment plants are largely covered

by existing regulations. In addition to the existing NPDES or air

programs: (1) Refinery sludges generated by wastewater treatment

systems are already listed hazardous wastes (K048, K051, F037, F038);

(2) the volumes of the crude oil storage tank residuals are relatively

small compared to volumes in refinery wastewater treatment systems; and

(3) residual risk associated with treatment would be covered by the

proposed Phase IV Land Disposal Restrictions treatment requirements.

Concerning on-site recovery for this waste, nearly all of this material

is currently excluded from the definition of solid waste because it is

reinserted into the refining process prior to distillation and

catalytic cracking. See Sec. 262.4(a)(12). A proposed expansion of this

exclusion and its rationale are discussed in Section III.E. of this

notice.

Today's listing determination is limited in scope to crude oil

storage tank sediment that is generated from storage tanks associated

with petroleum refineries, either on-site or at affiliated tank farms

(e.g., tank storage areas owned or under contract to the refinery). The

Agency is not attempting to evaluate sediments generated from the

storage of crude oil at exploration

[[Page 57764]]

and production sites or associated with pipelines or other crude oil

transportation conveyances. The Agency has not collected data necessary

to support a risk characterization of these non-refinery sediments and

is not, at this time, making a determination whether to list these

materials. Furthermore, these non-refinery materials are governed by

special statutory provisions (i.e., the ``Bevill'' provisions), and are

currently exempt from regulation as hazardous waste.

Under today's proposal, hazardous oil-bearing wastes that are

inserted into the petroleum refining process (including the coker)

would be excluded from the definition of solid waste, and thus from

regulation, as a petroleum refining process feed under amended

Sec. 261.4(a)(12). This exemption allows refineries to continue a

practice currently in use where crude oil storage tank sediment or oil

recovered from crude oil storage tank sediment are returned to the

refinery operations, whether or not the Agency lists this waste as

hazardous. The Agency believes this is appropriate for many reasons

(see Section III.E for the Agency's detailed rationale for this

exemption), and also reasonable given the inherent similarity between

crude oil feedstock, crude oil storage tank sediment, and recovered oil

from crude oil storage tank sediments.

Based on an analysis of the risks associated with current

management practices, EPA is proposing not to list crude oil storage

tank sediment from petroleum refining operations as a hazardous waste.

The Agency found essentially no significant risks arising from land

treatment. The only risk of possible concern arises from management in

landfills. However, even the landfill risks are within EPA's

discretionary range for listing, and EPA believes that a number of

additional factors argue for not listing this residual.

First, the only constituent of significant concern for this waste

is benzene, and this constituent is already regulated under the

Toxicity Characteristic (TC). Wastes which contain levels of mobile

benzene above 0.5 mg/L (as measured by the TCLP) are already subject to

regulation as D018. Therefore, the Agency believes that the TC captures

as hazardous the crude oil storage tank sediment that contains benzene

levels of concern.

For this waste, EPA is confident that constituents of most concern

were identified, and that the risks are unlikely to be significantly

higher. Several factors are compelling. First, the Agency compiled a

comprehensive database on constituents found in crude oil storage tank

sediments and concluded risks would be posed only by benzene.

Uncertainty in potential risk levels from other toxicants or from

unknown toxicants is low. Second, the Agency has employed a more

accurate, realistic risk assessment approach, which the Agency believes

accurately projects actual risks posed. Uncertainty in exposure

analysis for crude oil storage tank sediments is also low. Finally,

while the Agency did not factor biodegradation of benzene directly into

its risk assessment, model runs using preliminary data suggest that the

levels of benzene reaching a drinking water well will be reduced to

some extent due to biodegradation. See Section III.F.2.c for further

discussion of this point.

EPA considers the listing decision for this waste to be a case in

which the decision on whether or not to list crude oil storage tank

sediments was difficult to make. The risk levels projected for the

single constituent of concern, benzene, are above the Agency's initial

risk level of concern (10-5). However, other factors can and were

considered , which suggest the actual risk posed is not of concern. The

Agency requests comment on the decision not to list crude oil storage

tank sediments, and on other factors that may affect the final

decision. EPA seeks comment on whether the TC effectively captures

wastes of concern, whether the Agency adequately characterized the risk

for this waste, and whether any other factors should be considered.

If comments on this proposal provide sufficient information to show

that the TC is not effective in regulating the wastes of concern, or

that the risks from this waste have not be adequately characterized by

the Agency's analysis, EPA would consider making a final decision to

list this residual. If listed, this waste would be identified as EPA

Hazardous Waste Number K169--Crude oil storage tank sediment from

petroleum refining operations, and benzene would be added to Appendix

VII to Part 261--Basis for Listing for the K169 wastestream. In today's

notice, the Agency is also including treatment standards, the CERCLA

reportable quantity, and exemptions that would apply to this waste

stream if the waste were to be listed. Certain background documents in

the docket for this rule present elements involving costs and treatment

standards EPA would use were this waste to be listed. Thus, final

action may not be delayed by the need for additional proposals. If the

waste were to be listed, the Agency also seeks comments on whether the

listing description might be narrowed to exempt crude oil storage tank

sediments that are treated or disposed of in certain ways (e.g., if

deoiled). See Section III.H, ``Request for Comment on Options for

Conditional Exemptions,'' for a general discussion of possible

approaches.

2. Clarified Slurry Oil (CSO) Tank Sediment and/or In-line Filter/

Separation Solids

a. Summary. EPA is proposing to list as hazardous sediment from the

storage of clarified slurry oil and/or in-line filter/separation solids

from the filtration of clarified slurry oil. 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 mismanaged. The Agency

has identified risks of concern associated with two of four selected

management practices: on-site land treatment, and off-site land

treatment. The home gardener and adult resident receptors showed

potential risks of concerns, and the contaminants of concern are

polynuclear aromatic hydrocarbons (PAHs). The risk assessment results

are summarized in Table III-3.

[[Page 57765]]

Table III-3.--Waste Characterization and Risk Estimates: K170--Clarified Slurry Oil Tank Sediment and/or In-line Filter/Separation Solids

[Assumes no run-off controls]

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

On-site land treatment* Off-site land treatment** Waste characterization

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

Constituents of concern Central Central

tendency High end tendency High end Avg. conc. High conc. Low conc. # of pts. Notes

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

HOME GARDENER

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

Benzo(a) pyrene.............. 1E-7 1E-5 5E-7 7E-6 132.0 230.0 52.0 4 of 4...... J(1).

Dibenz(a,h)anthracene........ 8E-8 6E-6 3E-7 3E-6 37.0 49.0 .......... 1 of 4...... 1.

3-Methylcholanthrene......... 2E-7 1E-5 7E-7 6E-6 23.8 27.0 .......... 1 of 4...... J(1), 1.

Benzo(a)anthracene........... 3E-8 2E-6 1E-7 1E-6 203.0 390.0 360.0 2 of 4...... ............

7, 12-Dimethylbenz 3E-7 3E-5 1E-6 4E-5 331.0 1,200.0 .......... 1 of 4...... ............

(a)anthracene.

Benzo(b)fluoranthene / 1E-8 1E-6 5E-8 5E-7 76.8 110.0 27.0 4 of 4...... J(3),2.

Benzo(k)fluoranthene (total).

Total Carcinogen Risk***..... 7E-7 6E-5 3E-6 5E-5 .......... .......... .......... ............

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

ADULT RESIDENT

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

Benzo(a)pyrene............... 2E-7 1E-5 9E-7 6E-6 132.0 230.0 52.0 4 of 4...... J(1).

Dibenz(a,h)anthracene........ 2E-7 1E-5 7E-7 5E-6 37.0 49.0 .......... 1 of 4...... 1.

3-Methylcholanthrene......... 3E-7 1E-5 1E-5 6E-6 23.8 27.0 .......... 1 of 4...... J(1),1.

7, 12-Dimethylbenz 7E-7 5E-5 3E-6 6E-5 331.0 1,200.0 .......... 1 of 4...... ............

(a)anthracene.

Benzo(b)fluoranthene......... 2E-8 1E-6 6E-8 4E-7 76.8 110.0 27.0 4 of 4...... J(3)2.

Total Carcinogen Risk***..... 2E-6 9E-5 6E-6 8E-5 .......... .......... .......... ............

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

Notes:

1. Detection limits greater than the highest detected concentration are excluded from the average concentration calculations.

2. Concentration for combined benzo(b)fluoranthene and benzo(k)fluoranthene.

J(#) Samples were estimated concentrations below quantitation limits, ``#'' indicates number of samples that are ``J'' values.

Only the combination of high-end factors resulting in the greatest overall carcinogen risk are presented:

* Scenario: high-end factors of quantity, duration of exposure.

** Scenario: high-end factors of distance to receptor, duration of exposure.

*** Total carcinogen risk includes risks from other PAHs not tabulated. The risks for the PAHs not presented in this table are lower than those that are

presented.

All concentrations are in mg/kg.

b. Discussion. Clarified slurry oil wastes are generated from

process unit residuals, and the storage or filtration of clarified

slurry oil, which is the bottom distillation fraction from the

Fluidized Catalytic Cracker (FCC) fractionator. CSO tank sediment is

generated every 5 to 10 years during storage tank cleanout. Some

refineries use in-line filters or separators to remove solids from CSO

prior to storage. For example, cartridge filters can be used to remove

catalyst fines entrained in the product CSO. Filter/separation solids

may be generated once or twice a year depending on product volume.

The results of the 1992 Sec. 3007 petroleum refining survey showed

that approximately 24,010 metric tons of clarified slurry oil tank

sediment and filter/separation solids were generated. The management

scenarios selected for risk assessment focussed on known Subtitle D

land disposal activities, which included on-site land treatment (12.1

percent of the CSO tank sediment and filter/separation solid volume),

off-site land treatment (9.9 percent), on-site Subtitle D landfilling

(2.8 percent), and off-site Subtitle D landfilling (47.2 percent).

Other major management practices included Subtitle C landfilling (14.8

percent), on-site recovery or reuse (2.3 percent), discharge to the

wastewater treatment plant (1.04 percent), transfer for use as fuel

(7.7 percent), and on-site road material (1.7 percent).

For this infrequently generated waste, the Agency was able to

collect four samples, including 3 tank sediment samples and 1 CSO

filter solid. These randomly selected samples are believed to be

representative of typical residuals generated throughout the industry.

The risks described in Table III-3 are significant for a variety of

exposure routes and management scenarios. The high-end cancer risk

arising from the home gardener exposure for on-site was 6E-5, and the

central tendency risk was 7E-7. For off-site land treatment, the high-

end risk for the home gardener was 5E-5, with a central tendency risks

of 3E-6. The adult resident scenario also showed a significant high-end

risk of 9E-5 for on-site land treatment, and a central tendency risk of

2E-6. For off-site land treatment, the high-end risk for the adult

resident was 8E-5, and the central tendency risk was 6E-6.

Similar to the analysis conducted for crude oil storage tank

sediment, the Agency conducted another level of analysis of the CSO

tank sediment and filter/separation solids risk results to further

evaluate the impacts of run-on/run-off controls. While the Agency does

not have information on the actual effectiveness of land treatment

units at controlling releases associated with run-on/run-off, the

Agency believes the risks lie somewhere between those posed by

scenarios with and without controls. EPA believes that these results

continue to warrant listing of the CSO wastes. In order for the high-

end risks to be reduced to a 10-6 level, the Agency estimates that for

both on-site and off-site LTUs, controls would need to be more than 90

percent effective in controlling releases to nearby fields.

The Agency believes the management practices of most concern (land

treatment and landfills) were assessed for this residual, and that the

other management practices would not serve as a basis for listing. EPA

did not

[[Page 57766]]

attempt to model wastes discharged to the wastewater treatment system,

disposed of in Subtitle C units, or recovered for use on-site, because

wastewater treatment sludges are already listed as hazardous wastes

(K048, K051, F037, and F037), and Subtitle C management and reuse

activities are viewed as protective. The on-site road use scenario for

this residual was not assessed because of the small volume and the

small number of facilities using this practice. Additionally, the

potential risks posed by the road use management scenario are likely to

be less than those calculated for the land treatment scenario (using a

much larger volume of >2,000 MT), which considered similar

environmental pathways.

Today's listing is limited in scope to clarified slurry oil tank

sediment and filter/separation solids that are generated from CSO

filtration/separation and storage tanks associated with petroleum

refineries, either on-site or at affiliated tank farms. The Agency is

not attempting to include sludges generated from the storage of

clarified slurry oil at carbon black manufacturing facilities using

clarified slurry oil as raw materials, or associated with

transportation conveyances or other off-site storage of clarified

slurry oil. The Agency has not collected data necessary to support a

risk characterization of these non-refinery sludges and is not, at this

time, making a determination regarding whether to list these materials.

Under today's proposal, hazardous oil-bearing clarified slurry oil

tank sediment or filter/separation solids that is inserted into the

petroleum refining process (including the coker) would be excluded from

regulation as a petroleum refining process feed under amended

Sec. 261.4(a)(12). This exemption allows refineries to continue a

practice currently in use where clarified slurry oil laded wastes or

oil recovered from clarified slurry oil tank sediment or filter/

separation solids are returned to the refinery operations. The Agency

believes this is appropriate for the reasons described in Section

III.E. of this preamble, and also reasonable given the inherent

similarity between refinery feedstocks, clarified slurry oil tank

sediment or filter/separation solids, and recovered oils from clarified

slurry oil sediment or filter/separation solids.

Based on an analysis of the risks associated with current

management practices, i.e., land treatment, EPA is proposing to list

clarified slurry oil storage tank sediment and filter/separation solids

from petroleum refining operations as a hazardous waste, designated as

EPA Hazardous Waste Number K170. However, the disposal of CSO storage

tank sediment and in-line filter/separation solids in landfills was not

associated with significant risks. Therefore, EPA is also proposing two

alternative listing descriptions that either limit the listing to CSO

residuals managed in land treatment units, or specifically exclude from

the listing waste managed in a landfill. These proposals and other

options are discussed in Section III.H, ``Request for Comment on

Options for Conditional Exemptions.''

Due to the risks described above, the Agency is proposing to add

the following constituents to Appendix VII to Part 261--Basis for

Listing: benzo(a)pyrene, dibenz(a,h)anthracene, 3-methylcholanthrene,

benzo(a)anthracene, 7,12-dimethylbenz(a)anthracene,

benzo(b)fluoranthene, and benzo(k)fluoranthene.

3. Catalyst from Hydrotreating

a. Summary. EPA is proposing to list as hazardous spent catalysts

from hydrotreating operations. 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 mismanaged. The Agency has identified

risks of concern associated with: off-site and on-site Subtitle D

landfilling. Health risks are associated with benzene and arsenic

releases to groundwater. The risk assessment results are summarized in

Table III-4. In addition, this material presents a hazard because it

has pyrophoric and self-heating properties, and is sometimes

characteristically hazardous due to its ignitability, or benzene and/or

arsenic leachability.

Table III-4.--Waste Characterization and Risk Estimates--K171--Spent Catalyst From Hydrotreating

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

On-site landfill Off-site landfill Waste characterization

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

Constituents of concern Central Central

tendency High end tendency High end Avg. conc. High conc. Low conc. # of pts Notes

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

GROUNDWATER

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

Benzene...................... 9E-7 9E-6 2E-7 1E-5 7.9 39.0 0.05 6 of 6...... J(1).

Arsenic...................... 8E-7 8E-6 2E-7 1E-5 1.1 4.9 1.5 2 of 6 .....

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

Notes:

J(#) Samples were estimated concentrations below quantitation limits, ``#'' indicates number of samples that are ``J'' values.

All concentrations are TCLP leachate values in mg/L.

b. Discussion. Spent catalysts from hydrotreating are generated

every 2 to 7 years during hydrotreater turnarounds and topping

activities. Hydrotreating is used to remove sulfur and nitrogen

compounds and to saturate olefins in naphthas, lube oils, and some

middle distillates. The catalyst is typically nickel and molybdenum or

cobalt and molybdenum on an alumina base. The catalyst is removed from

the unit because its activity has been reduced below acceptable levels

due to coking, metals poisoning, and/or particle degradation. As

described further in the listing background document in the docket to

this proposal, the Agency is defining hydrotreating to be

hydroprocessing applied to lighter boiling stocks and to not include

those catalysts with precious metals as their active catalytic metals.

Note that in this notice the Agency is also proposing to list

hydrorefining catalysts, which is one of two other major types of

hydroprocessing catalysts used by the industry. Today's listing

determinations, however, do not address catalysts from hydrocracking

operations which the Agency is studying separately under the consent

decree and which will not be addressed in this notice.7

\7\ The Agency recognizes that the terms hydrotreating and

hydroprocessing are used somewhat loosely within the industry and

that various definitions have been posed by different sources of

authority. One widely used set of definitions is used in the Oil and

Gas Journal's annual report on worldwide refining, which establishes

that hydrotreating includes processes where essentially no reduction

in the molecular size of the feed occurs, that hydrorefining

includes processes where 10 percent of the feed or less is reduced

in molecular size, and that hydrocracking includes processes where

50 percent of the feed or more is reduced in molecular size. The

Listing Background Document for this proposal discusses these

definitions further.

[[Page 57767]]

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

In 1992, the petroleum refining industry reported generating 5,640

metric tons of spent hydrotreating catalyst. Of this total 2,236 metric

tons were identified as hazardous, because the wastes were in most

cases D018-benzene, D001-ignitable, or D004-arsenic. The management

scenarios selected for risk assessment focussed on known Subtitle D

landfilling activities, which included off-site Subtitle D landfilling

(11.3 percent), and on-site landfilling (0.2 percent). Other major

spent hydrotreating catalyst management practices included transfer for

metals reclamation or regeneration (75.8 percent), or Subtitle C

landfilling (11.3 percent).

The Agency collected six samples of spent hydrotreating catalysts.

These samples are believed to be representative of the various types of

applications and active metals used by the industry. The Agency

observed that many refineries take great care to remove this residual

from the process units under an inert atmosphere due to the potential

for this residual to ignite spontaneously. On two occasions during

sampling, the refineries determined that the risk associated with

collecting catalyst samples from inert gas blanketed catalyst storage

bins was too great to allow EPA to collect the samples directly.

Specially trained refinery personnel collected these samples while

being observed by EPA representatives. A third refinery also requested

that EPA not collect a sample of their residual due to the risks

presented by the spent catalyst.

When sufficient quantities of spent hydrotreating catalysts are

stockpiled and exposed to air to allow self heating and self ignition

to occur, harmful quantities of toxic sulfur dioxide, carbon monoxide,

and other toxic constituents such as nickel carbonyl may be formed. The

Agency has received reports of fires, building evacuations, and metals

reclamation process disturbances attributed to the ignition of these

spent catalysts.8

\8\ Ibid.

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Due to the self-heating or self-ignition characteristics of spent

hydrotreating catalysts, the spent catalysts frequently meet the

Department of Transportation's (DOT) 49 CFR 173.124(b) definition of

spontaneously combustible material, and must be shipped accordingly. A

self-heating material is a material that once in contact with air and

without an energy supply, is liable to self-heat. A material of this

type may be classified as spontaneously combustible if the temperature

of a test sample exceeds 200 deg.C (392 deg.F) during the 24-hour test

period when tested in accordance with the DOT test in 49 CFR 173

Appendix E--Guidelines for the Classification and Packing Group

Assignment of Class 4 Materials. Test data obtained by the Agency

indicate that up to 60 percent of these spent hydrotreating catalysts

reclaimed at one site are self-heating solids.9 Furthermore, from

the data collected by EPA in the Sec. 3007 questionnaire, about 40

percent of this wastestream is characteristically hazardous, and a

significant portion is classified as ignitable under RCRA.

\9\ See May 19, 1995 letter from John N. Glover (CRI-MET) to

William F. Brandes (EPA).

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The risk assessment results showed that the primary toxicants of

concern for spent hydrotreating catalysts are benzene and arsenic. On-

site landfilling results in a high-end cancer risk of 9E-6, and a

central tendency risk of 9E-7 for benzene, and arsenic risks of 8E-6

and 8E-7 for high-end risk and central tendency risk, respectively.

Off-site landfilling shows high-end modeled risks of 1E-5, and central

tendency risks of 2E-7 for each constituent. The on-site groundwater

risk is 18 times the MCL for benzene; the off-site risk is 30 times the

MCL for benzene.

The Agency believes the management practices of most concern (off-

site and on-site landfills) were assessed, and that the other

management practices would not serve as a basis for listing. The wastes

being disposed of in Subtitle C landfills are already handled as

hazardous and should not present significant risk. As described in

Section III.J. (``Third Party Regeneration/Reclamation of Spent

Petroleum Catalysts''), EPA believes that the regeneration and

reclamation of spent hydrotreating/hydrorefining catalysts is an

environmentally sound alternative to disposal, and is also proposing

that these units be excluded from regulation as Boilers and Industrial

Furnaces (BIFs). In summary, EPA does not believe that these off-site

recycling activities present significant risk because: (1) much of the

waste going to recycling is characteristically hazardous, and EPA has

found that recycling facilities typically handle nominally nonhazardous

waste in a protective manner due to its pyrophoric properties; and (2)

a preliminary survey of reclaimers/regenerators showed that these units

are already equipped with pollution control devices.10 Therefore,

EPA believes that any potential risks associated with regeneration and

reclamation are unlikely to be significant, and would be less than the

risks found to exist for the management practices modeled.

\10\ See ``Survey of Spent Petroleum Catalyst Regenerators and

Reclaimers,'' U.S. EPA 1995.

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Based on an analysis of the risks associated with current

management practices and the characteristically hazardous properties of

the waste, EPA is proposing to list spent catalysts from hydrotreating

from petroleum refining operations as a hazardous waste, designated as

EPA Hazardous Waste Number K171. Note that as described further in

Section III.J. of this preamble that this listing does not include

ceramic support media that is separated from the spent catalyst prior

to catalyst disposal or recycling.

For the reasons stated above, the Agency is proposing to add

benzene and arsenic to Appendix VII to Part 261--Basis for Listing.

4. Catalyst from Hydrorefining

a. Summary. EPA is proposing to list as hazardous spent catalysts

from hydrorefining operations. 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 mismanaged. The Agency has identified

risks of concern associated with: off-site and on-site Subtitle D

landfilling. Health risks are associated with benzene and arsenic

releases to groundwater. The risk assessment results are summarized in

Table III-5. In addition, this material presents a hazard because it

has pyrophoric and self-heating properties, and is sometimes

characteristically hazardous due to its ignitability, or benzene and/or

arsenic leachability.

[[Page 57768]]

Table III-5.--Waste Characterization and Risk Estimates--K172--Spent Catalyst From Hydrorefining

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

On-site landfill Off-site landfill Waste characterization

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Constituents of concern Central Central

tendency High end tendency High end Avg. conc. High conc. Low conc. No. of pts Notes

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

GROUNDWATER

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

Benzene...................... 1E-6 1E-5 2E-7 2E-5 1.5 4.2 0.1 3 of 3......

Arsenic...................... 4E-6 4E-5 8E-7 6E-5 13.7 34.0 0.2 3 of 3 .....

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

All concentrations are TCLP leachate values in mg/L.

b. Discussion. Spent catalysts from hydrorefining are generated

every 2 to 7 years during hydrorefiner turnarounds and topping

activities. Hydrorefining is used to remove sulfur and nitrogen

compounds and to saturate olefins in gas oil, residual oil, and some

middle distillates. The catalyst is typically nickel and molybdenum or

nickel and cobalt on an alumina base. The catalyst is removed from the

unit because its activity has been reduced below acceptable levels due

to coking, metals poisoning, and/or particle degradation. The Agency

observed that many refineries take great care to remove this residual

from the process units under an inert atmosphere due to the exposure

hazards associated with this residual. Similar to hydrotreating

catalysts, these hydrorefining catalysts also frequently exhibit the

properties of spontaneously combustible materials. Two of the three

refineries sampled insisted that refinery personnel collect the

Agency's record samples due to potential risks. Similar to spent

hydrotreating catalyst, the spent hydrorefining catalyst exhibits self-

heating and spontaneously combustible properties (see discussion in

Section III.G.3). Also like the hydrotreating residual, data collected

by EPA in the Sec. 3007 questionnaire showed that much of this

wastestream (nearly 30 percent) is characteristically hazardous, and

approximately 9 percent is classified as ignitable under RCRA.

In 1992, the petroleum refining industry reported generating 18,630

metric tons of spent hydrorefining catalyst. Approximately 5,028 metric

tons (27 percent) were identified as hazardous because the waste

exhibited a hazardous characteristic, primarily D018-benzene, D001-

ignitable, or D004-arsenic. The management scenarios selected for risk

assessment focussed on known Subtitle D landfilling activities, which

included off-site Subtitle D landfilling (12.6 percent), and on-site

land filling (3.8 percent). Other major spent hydrorefining catalyst

management practices included transfer for metals reclamation or

regeneration (82.4 percent), or Subtitle C landfilling (1.1 percent).

Due to sample availability, the Agency was only able to obtain

three samples of spent hydrorefining catalysts during its data

collection effort. These samples are believed to be representative of

the various types of applications and active metals used by the

industry.

In this notice, the Agency is also proposing to list hydrotreating

catalysts, which is one of two other major types of hydroprocessing

catalysts used by the industry. Today's listing determinations,

however, do not address catalysts from hydrocracking operations which

the Agency is studying separately under the consent decree and which

will not be addressed in this notice. Note that as described further in

Section III.J of this preamble, this listing also does not include

ceramic support median that is separated from the spent catalyst prior

to catalyst disposal or recycling.

The risk assessment results showed that the primary toxicants of

concern for spent hydrorefining catalysts are arsenic and benzene. On-

site landfilling results in a high-end cancer risk of 4E-5, and a

central tendency risk of 4E-6. Off-site landfilling shows a modeled

high-end risk of 6E-5 and central tendency risk of 8E-7.

The Agency believes the management practices of most concern (off-

site and on-site landfills) were assessed, and that the other

management practices would not serve as a basis for listing. See

Section III.G.3. for a discussion explaining why EPA did not attempt to

model disposal in Subtitle C units or regeneration and reclamation

processes.

Based on an analysis of the risks associated with current

management practices and the characteristically hazardous properties of

the waste, EPA is proposing to list spent catalysts from hydrorefining

from petroleum refining operations as a hazardous waste, designated as

EPA Hazardous Waste Number K172.

For the reasons stated above, the Agency is proposing to add

benzene and arsenic to Appendix VII to Part 261--Basis for Listing.

5. Catalyst From Sulfuric Acid Alkylation

a. Summary. The Agency is proposing not to list spent catalysts

from sulfuric acid alkylation. This residual is currently managed

almost entirely under an existing exemption from the definition of

solid waste. In addition, this residual consistently exhibits the

characteristic of corrosivity and already is subject to regulatory

control if not returned to the production of virgin sulfuric acid.

b. Discussion. The sulfuric acid alkylation process contacts olefin

and isobutane gases over concentrated sulfuric acid catalyst to

synthesize alkylates for octane boosting. A portion of the acid

catalyst is continuously bled from the reactor and replaced with fresh

acid to maintain the reactor acid concentration at around 90 percent.

The acid bleed stream is the spent catalyst of concern for this

category. The industry reported the generation of almost 1,760,100

metric tons of spent catalyst in 1992. This residual consistently

exhibits the characteristic of corrosivity.

The Agency previously has exempted from the definition of solid

wastes (40 CFR 261.4(a)(7)) spent sulfuric acid used to produce virgin

sulfuric acid, unless it is accumulated speculatively (50 FR 614,

January 4, 1985). In 1992, more than 99 percent of spent sulfuric acid

generated was used to produce virgin sulfuric acid or reused on-site,

and less than 1 percent was used to neutralize wastewaters prior to

biological treatment. The Agency has reexamined the contaminants found

in such spent acids and has found no materials which would likely be

carried through production to the virgin acid. As noted in the preamble

to the January 4, 1985, final rule on the definition of solid waste,

the spent sulfuric acid recycling process more closely resembles a

manufacturing operation than a reclamation process. (50 FR 642, January

4, 1985). Spent sulfuric acid is a hazardous waste if disposed

(assuming it is corrosive or exhibits other hazardous waste

characteristics), and could be a hazardous waste if recycled

[[Page 57769]]

in some other manner (such as burning for energy recovery). The Agency

finds no reason to change the existing regulatory structure for spent

sulfuric acid used to produce virgin sulfuric acid and is taking no

action in this area.

Waste survey data indicate that 155 metric tons of spent acid from

spills were discharged to wastewater treatment units in 1992. The

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