Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58015

PART 39—AIRWORTHINESS

DIRECTIVES

1. The authority citation for part 39

continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Airbus Industrie: Docket 2000–NM–79–AD.

Applicability: Model A330 and A340 series

airplanes, certificated in any category;

excluding those on which Airbus

Modification 43021 has been installed.

Note 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

otherwise modified, altered, or repaired in

the area subject to the requirements of this

AD. For airplanes that have been modified,

altered, or repaired so that the performance

of the requirements of this AD is affected, the

owner/operator must request approval for an

alternative method of compliance in

accordance with paragraph (b) of this AD.

The request should include an assessment of

the effect of the modification, alteration, or

repair on the unsafe condition addressed by

this AD; and, if the unsafe condition has not

been eliminated, the request should include

specific proposed actions to address it.

Compliance: Required as indicated, unless

accomplished previously.

To prevent fatigue cracking at the rib 1/

center spar angle and bottom corner fitting,

which could result in reduced structural

capability of the wing, accomplish the

following:

Modification

(a) Modify the rib 1/wing center spar

attachment, as specified by paragraph (a)(1)

or (a)(2), as applicable, of this AD.

(1) For Model A330 series airplanes:

Modify before the accumulation of 9,600 total

flight cycles or 29,900 total flight hours,

whichever occurs first. Do the modification

in accordance with Airbus Service Bulletin

A330–57–3017 including Appendix 01,

Revision 02, dated October 11, 1999.

(2) For Model A340 series airplanes:

Modify before the accumulation of 9,300 total

flight cycles or 37,200 total flight hours,

whichever occurs first. Do the modification

in accordance with Airbus Service Bulletin

A340–57–4022 including Appendixes 01 and

02, dated October 8, 1999.

Note 2: Modification prior to the effective

date of this AD in accordance with Airbus

Service Bulletin A330–57–3017, dated

October 14, 1998, or Revision 01, dated April

9, 1999, is acceptable for compliance with

the requirements of paragraph (a) of this AD.

Alternative Methods of Compliance

(b) An alternative method of compliance or

adjustment of the compliance time that

provides an acceptable level of safety may be

used if approved by the Manager,

International Branch, ANM–116, Transport

Airplane Directorate, FAA. Operators shall

submit their requests through an appropriate

FAA Principal Maintenance Inspector, who

may add comments and then send it to the

Manager, International Branch, ANM–116.

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the International Branch.

Special Flight Permits

(c) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Note 4: The subject of this AD is addressed

in French airworthiness directives 2000–

073–111(B) and 2000–074–136(B), both dated

February 23, 2000.

Issued in Renton, Washington, on

September 21, 2000.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–24753 Filed 9–26–00; 8:45 am]

BILLING CODE 4910–13–U

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 261

[SW–FRL–6878–3]

Hazardous Waste Management

System; Proposed Exclusion for

Identification and Listing Hazardous

Waste

AGENCY: Environmental Protection

Agency, (EPA).

ACTION: Proposed rule and request for

comment.

SUMMARY: The EPA (also, ‘‘the Agency’’

or ‘‘we’’ in this preamble) is proposing

to grant a petition submitted by USG

Corporation (USG), Chicago, Illinois, to

exclude (or ‘‘delist’’), on a one-time

basis, certain solid wastes that are

interred at an on-site landfill at its

American Metals Corporation (AMC)

facility in Westlake, Ohio from the lists

of hazardous wastes contained in

Subpart D of 40 Code of Federal

Regulations (CFR) Part 261. This landfill

was used exclusively by Donn

Corporation, the original site owner, for

disposal of its wastewater treatment

plant (WWTP) sludge from 1968 to

1978.

USG submitted the petition under 40

CFR 260.20 and 260.22(a). Section

260.20 allows any person to petition the

Administrator to modify or revoke any

provision of parts 260 through 266, 268

and 273. Section 260.22(a) specifically

provides a generator the opportunity to

petition the Administrator to exclude a

waste on a ‘‘generator specific’’ basis

from the hazardous waste lists.

The Agency has tentatively decided to

grant the petition based on an

evaluation of waste-specific information

provided by USG. This proposed

decision, if finalized, conditionally

excludes the petitioned waste from the

requirements of hazardous waste

regulations under the Resource

Conservation and Recovery Act (RCRA).

We conclude that USG’s petitioned

waste is nonhazardous with respect to

the original listing criteria or factors

which could cause the waste to be

hazardous.

DATES: Comments. We will accept

public comments on this proposed

decision until November 13, 2000. We

will stamp comments postmarked after

the close of the comment period as

‘‘late.’’ These ‘‘late’’ comments may not

be considered in formulating a final

decision.

Request for Public Hearing. Your

request for a hearing must reach EPA by

October 12, 2000. The request must

contain the information prescribed in

§ 260.20(d).

ADDRESSES: Comments. Please send two

copies of your comments to Todd

Ramaly, Waste Management Branch

(DW–8J), Environmental Protection

Agency, 77 W. Jackson Blvd., Chicago,

IL 60604.

Request for Public Hearing. Any

person may request a hearing on this

proposed decision by filing a request

with Robert Springer, Director, Waste,

Pesticides and Toxics Division,

Environmental Protection Agency, 77

W. Jackson Blvd., Chicago, IL 60604.

FOR FURTHER INFORMATION CONTACT: For

technical information concerning this

document, contact Todd Ramaly at the

address above or at 312–353–9317. The

RCRA regulatory docket for this

proposed rule is located at the EPA

Region 5, 77 W. Jackson Blvd., Chicago,

IL 60604, and is available for viewing

from 8:00 a.m. to 4:00 p.m., Monday

through Friday, excluding federal

holidays. Call Todd Ramaly at (312)

353–9317 for appointments. The public

may copy material from the regulatory

docket at $0.15 per page.

SUPPLEMENTARY INFORMATION:

I. Overview Information

A. What action is EPA proposing?

B. Why is EPA proposing to approve this

delisting?

C. How will USG manage the waste if it is

delisted?

D. When would EPA finalize the proposed

delisting exclusion?

E. How would this action affect the states?

II. Background

A. What is the history of the delisting

program?

58016 Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules

B. What is a delisting petition, and what

does it require of a petitioner?

C. What factors must EPA consider in

deciding whether to grant a delisting

petition?

III. EPA’s Evaluation of the Waste

Information and Data

A. What wastes did USG petition EPA to

delist?

B. What information and analyses did USG

submit to support this petition?

C. How did USG generate the petitioned

waste?

D. How did USG sample and analyze the

data in this petition?

E. What were the results of USG’s analysis?

IV. Methodology for Risk Assessments

A. How did EPA evaluate the risk of

delisting this waste?

B. What risk assessment methods has the

Agency used in previous delisting

determinations?

V. Evaluation of This Petition

A. What other factors did EPA consider in

its evaluation?

B. What did EPA conclude about USG’s

analysis?

C. What is EPA’s final evaluation of this

delisting petition?

VI. Conditions for Exclusion

A. What are the maximum allowable

concentrations of hazardous constituents

in the waste?

B. What are the conditions of the

exclusion?

C. What happens if USG fails to meet the

conditions of the exclusion?

VII. Regulatory Impact

VIII. Regulatory Flexibility Act

IX. Paperwork Reduction Act

X. Unfunded Mandates Reform Act

XI. Executive Order 12875

XII. Executive Order 13045

XIII. Executive Order 13084

XIV. National Technology Transfer and

Advancement Act

I. Overview Information

A. What Action Is EPA Proposing?

The EPA is proposing to grant USG’s

petition to have its wastewater

treatment sludge excluded, or delisted,

from the definition of a hazardous

waste. We evaluated the petition using

a fate and transport model to predict the

concentration of hazardous constituents

which could be released from the

petitioned waste after it is disposed.

B. Why Is EPA Proposing To Approve

This Delisting?

USG petitioned EPA to exclude, or

delist, the wastewater treatment sludge

because USG believes that the

petitioned waste does not meet the

criteria for which EPA listed it. USG

also believes there are no additional

constituents or factors which could

cause the wastes to be hazardous. Based

on our review described below, we

agree with the petitioner that the waste

is nonhazardous.

In reviewing this petition, we

considered the original listing criteria

and the additional factors as required by

the Hazardous and Solid Waste

Amendments of 1984 (HSWA). See 222

of HSWA, 42 U.S.C. 6921(f), and 40 CFR

260.22 (d)(2) through (4). We evaluated

the petitioned waste against the listing

criteria and factors cited in

§ 261.11(a)(2) and (3) and in the

background documents.

We also evaluated the waste for other

factors including (1) the toxicity of the

constituents; (2) the concentration of the

constituents in the waste; (3) the

tendency of the hazardous constituents

to migrate and to bioaccumulate; (4)

persistence in the environment of any

constituents released from the waste; (5)

plausible and specific types of

management of the petitioned waste; (6)

the quantity of waste produced; and (7)

waste variability.

We believe that the petitioned waste

does not meet the criteria for which the

waste was listed, and have tentatively

decided to delist waste from the AMC

Westlake landfill.

C. How Will USG Manage the Waste If

It Is Delisted?

If the petitioned waste is delisted,

USG must dispose of it in a Subtitle D

landfill which is permitted, licensed, or

registered by a state to manage

industrial waste. This exclusion does

not change the regulatory status of the

landfill in Westlake, Ohio where the

waste has been disposed.

D. When Would EPA Finalize the

Proposed Delisting Exclusion?

HSWA specifically requires the EPA

to provide notice and an opportunity for

comment before granting or denying a

final exclusion. Thus, EPA will not

make a final decision or grant an

exclusion until it has addressed all

timely public comments (including

those at public hearings, if any) on

today’s proposal.

Since this rule would reduce the

existing requirements for persons

generating hazardous wastes, the

regulated community does not need a

six-month period to come into

compliance in accordance with section

3010 of RCRA as amended by HSWA.

Therefore, the exclusion would become

effective upon finalization.

E. How Would This Action Affect the

States?

Because EPA is issuing today’s

exclusion under the federal RCRA

delisting program, only states subject to

federal RCRA delisting provisions

would be affected. This exclusion may

not be effective in states having a dual

system that includes federal RCRA

requirements and their own

requirements, or in states which have

received our authorization to make their

own delisting decisions.

Under section 3009 of RCRA, EPA

allows states to impose their own nonRCRA regulatory requirements that are

more stringent than EPA’s. These more

stringent requirements may include a

provision that prohibits a federally

issued exclusion from taking effect in

the state. Because a dual system (that is,

both federal (RCRA) and state (nonRCRA) programs) may regulate a

petitioner’s waste, we urge petitioners to

contact the state regulatory authority to

establish the status of their wastes under

the state law.

EPA has also authorized some states

to administer a delisting program in

place of the federal program, that is, to

make state delisting decisions.

Therefore, this exclusion does not apply

in those authorized states. If USG

transports the petitioned waste to or

manages the waste in any state with

delisting authorization, USG must

obtain a delisting from that state before

it can manage the waste as

nonhazardous in the state.

II. Background

A. What Is the History of the Delisting

Program?

The EPA published an amended list

of hazardous wastes from nonspecific

and specific sources on January 16,

1981, as part of its final and interim

final regulations implementing Section

3001 of RCRA. The EPA has amended

this list several times and published it

in 40 CFR 261.31 and 261.32.

We list wastes as hazardous because:

(1) they typically and frequently exhibit

one or more of the characteristics of

hazardous wastes identified in Subpart

C of Part 261 (that is, ignitability,

corrosivity, reactivity, and toxicity) or

(2) they meet the criteria for listing

contained in § 261.11(a)(2) or (3).

Individual waste streams may vary

depending on raw materials, industrial

processes, and other factors. Thus,

while a waste described in these

regulations generally is hazardous, a

specific waste from an individual

facility meeting the listing description

may not be.

For this reason, 40 CFR 260.20 and

260.22 provide an exclusion procedure,

called delisting, which allows a person

to demonstrate that EPA should not

regulate a specific waste from a

particular generating facility as a

hazardous waste.

Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58017

B. What Is a Delisting Petition, and

What Does It Require of a Petitioner?

A delisting petition is a request from

a facility to EPA or an authorized state

to exclude waste generated at a

particular facility from the list of

hazardous wastes.

In a delisting petition, the petitioner

must show that wastes generated does

not meet any of the criteria for listed

wastes and does not exhibit any of the

hazardous waste characteristics in 40

CFR Part 261, Subpart C. The criteria for

which EPA lists a waste are in 40 CFR

261.11 and in the background

documents. The petitioner must also

present sufficient information to

determine whether factors other than

those for which the waste was listed

warrant retaining it as a hazardous

waste. (See § 260.22, 42 U.S.C. 6921(f)

and the background documents for the

listed wastes.)

A generator remains obligated under

RCRA to confirm that its waste remains

nonhazardous based on the hazardous

waste characteristics even if EPA has

‘‘delisted’’ the wastes.

C. What Factors Must EPA Consider in

Deciding Whether To Grant a Delisting

Petition?

EPA must also consider as a

hazardous waste, a mixture containing

listed hazardous wastes and wastes

derived from treating, storing, or

disposing of a listed hazardous waste.

See 40 CFR 261.3(a)(2)(iv) and (c)(2)(i),

called the ‘‘mixture’’ and ‘‘derivedfrom’’ rules, respectively. These wastes

are also eligible for exclusion and

remain hazardous wastes until

excluded.

The ‘‘mixture’’ and ‘‘derived-from’’

rules are now final, after having been

vacated, remanded, and reinstated.

III. EPA’s Evaluation of the Waste

Information and Data

A. What Wastes Did USG Petition EPA

To Delist?

On May 22, 1997, USG petitioned

EPA to exclude the estimated total

landfill volume of the WWTP sludge

(estimated at 12,400 cubic yards) from

the list of hazardous wastes contained

in 40 CFR 261.31 in order to facilitate

ongoing corrective action at the AMC

site. The WWTP sludge is described in

USG’s petition as a mixture of (1) EPA

Hazardous Waste Number F019

wastewater treatment sludge that was

generated from the chemical coating of

aluminum, (2) other nonhazardous

wastewater treatment sludges derived

from the chemical coating of steel and

galvanized steel, and (3) various

nonhazardous solid wastes. F019 is

defined as ‘‘Wastewater treatment

sludges from the chemical conversion

coating of aluminum except from

zirconium phosphating in aluminum

can washing when such phosphating is

an exclusive conversion coating

process.’’ The constituents of concern

for which F019 is listed are hexavalent

chromium and complexed cyanide.

B. What Information and Analyses Did

USG Submit To Support This Petition?

To support its petition, USG

submitted (1) descriptions and

schematic diagrams of its manufacturing

and wastewater treatment processes,

including historical information on past

waste generation and management

practices; (2) detailed chemical and

physical analysis of the landfilled

sludge (see Section III.D.); and (3)

environmental monitoring data from

recent studies of the facility, including

groundwater data from wells located in

and around the on-site landfill.

C. How Did USG Generate the Petitioned

Waste?

AMC began generating wastewater

treatment sludge in 1965 with the start

of its metal coil coating line. After 1967,

AMC cleaned, chemically coated,

painted, and slit large coils of steel,

galvanized steel, and aluminum, into

metal strips that were fabricated into the

structural components for suspended

ceiling panels. Wastewater from the coil

coating line contained dissolved metals

and vegetable oils that were treated in

the AMC WWTP. As part of the

wastewater treatment process, oils were

removed in an oil/water separator and

metals were precipitated in a ‘‘lime’’

sludge. The AMC wastewater treatment

system received process water from the

coil coating process line from the initial

wash and rinse phase and from the

chemical processing phase. The pH was

adjusted and the solid materials were

precipitated. When steel or galvanized

coils were processed, wastewater

treatment sludges were generated which

were not listed RCRA hazardous waste.

The F019 listed wastes were generated

when aluminum coils were processed.

Both the listed and the non-listed

sludges were commingled and pumped

into several on-site surface

impoundments for settling and drying.

In 1965 and 1966, sludges were

transferred to surface impoundments for

settling and drying. From 1968 to 1978,

this sludge was transferred from the

surface impoundments to the landfill or

were disposed of off-site. Sludges that

were placed in the landfill were comingled with other waste debris. The

landfill was covered with a layer of clay

soils obtained from an off-site highway

construction project. In 1978, the use of

the landfill was discontinued and the

landfill was covered with approximately

1 to 5 feet of fill soils.

The AMC WWTP would batch treat

process wastewater from the coil coating

final hot rinse step in order to reduce

hexavalent chromium to trivalent

chromium. The wastewater was treated

with sodium metabisulfite and emptied

once a week into the chemical sump for

further treatment in the WWTP.

D. How Did USG Sample and Analyze

the Data in This Petition?

USG analyzed the landfilled sludge

and groundwater samples from the

monitoring well network for hazardous

constituents listed in 40 CFR Part 264,

Appendix IX and for other parameters.

USG’s sampling strategy consisted of

dividing the landfill surface area into

four equal quadrants. One boring was

drilled near the center of each quadrant.

One composite sample representing the

total depth of the landfill was collected

and submitted. The Agency evaluated

the petitioned waste using these four

samples in combination with data from

the RCRA Facility Investigation (up to

20 additional samples) and subsequent

waste designation studies (up to 13

additional samples).

To quantify the total constituent and

leachate concentrations, USG used the

following SW–846 Methods: 6010/7000

series for antimony, arsenic, barium,

beryllium, cadmium, chromium,

hexavalent chromium, cobalt, copper,

iron, lead, manganese, mercury, nickel,

selenium, silver, thallium, tin,

vanadium, and zinc; 8240 for Appendix

IX Volatile Organic Compounds (VOCs);

8270 for Appendix IX Semi-Volatile

Organic Compounds (SVOCs); 8080 for

organochlorine pesticides and

polychlorinated biphenyls (PCBs); 8140

for organochlorine pesticides; 8150 for

chlorinated herbicides. USG used these

methods along with the Toxicity

Characteristic Leaching Procedure

(TCLP, SW–846 Method 1311) to

determine leachate concentrations of

metals, herbicides, pesticides, PCBs,

VOCs, and SVOCs. Characteristic testing

of the filter cake samples also included

analysis of ignitability (SW–846 Method

1010) and corrosivity (SW–846 Method

9095). Historical analysis for dioxins

and furans was done using method

8280. More recent dioxins and furans

data was submitted using EPA Method

8290.

E. What Were the Results of USG’s

Analysis?

The maximum total and leachate

concentrations for 17 metals, total

cyanide and all detected organic

58018 Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules

constituents in USG’s waste samples are

summarized in the table found in

section VI.A. below. We believe it is

inappropriate to evaluate a constituent

in our modeling efforts if the constituent

was not detected using an appropriate

analytical method. EPA does not

generally verify submitted test data

before proposing delisting decisions.

The sworn affidavit submitted with the

petition binds the petitioner to present

truthful and accurate results. USG

submitted a signed Certification of

Accuracy and Responsibility statement

presented in 40 CFR 260.22(i)(12).

IV. Methodology for Risk Assessment

A. How Did EPA Evaluate the Risk of

Delisting This Waste?

For this delisting determination, we

used information gathered to identify

plausible exposure routes (i.e.,

groundwater, surface water, air) to

hazardous constituents present in the

petitioned waste. We estimated the risk

posed by the waste if disposed of in an

unlined Subtitle D landfill which, under

a plausible mismanagement scenario,

did not receive daily cover for 30 days

at a time. Constituents of concern are

assumed to migrate to a receptor

through groundwater, air, and surface

water routes. We used a Windows based

software tool, the Delisting Risk

Assessment Software Program (DRAS)

developed by Region 6, to estimate the

potential releases of waste constituents

and to predict the risk associated with

those releases. A detailed description of

DRAS and the fate, transport and risk

models it uses follows.

1. Introduction

During a delisting determination, the

Agency uses risk assessment

methodologies to predict the

concentration of hazardous constituents

released from the petitioned waste after

disposal to determine the potential

impact on human health and the

environment. The DRAS Program has

been used to estimate the potential

releases of waste constituents to waste

management units. The program also

predicts the risk associated with

exposure to those releases using fate and

transport mechanisms to predict

releases and risk assessment algorithms

to estimate adverse effects from

exposure to those chemical releases.

The DRAS computes chemical-specific

exit values or ‘‘delisting levels.’’ The

delisting levels are calculated using

modeled, medium-specific chemical

concentrations and standard EPA

exposure assessment and risk

characterization algorithms. We detailed

all chemical release, exposure, and risk

characterization methodologies in the

EPA Region 6 RCRA Delisting Technical

Support Document.

The Agency has used the maximum

estimated annual waste volume and the

maximum reported leachate and total

waste constituent concentrations as the

input data into the DRAS program to

generate compliance point

concentrations and estimate risk. The

compliance point is the location of an

individual exposed to potential releases

of delisted wastes for the purpose of

evaluating risk. Compliance point

concentrations are generated in a twopart process. First, the DRAS backcalculates a waste constituent

concentration that an individual

(receptor) may be exposed to without

unacceptable risk. Then, knowing the

maximum concentration permitted at

the compliance point, the fate and

transport models are used to backcalculate the maximum permissible

concentration at the waste management

unit that could be disposed of without

exceeding the compliance point

concentration.

The risk assessment performed by the

DRAS program which underlies the

proposed rule is based upon a

comprehensive approach to evaluating

the movement of waste constituents

from their waste management units,

through different routes of exposure or

pathways, to the points where human

and ecological receptors are potentially

exposed to these constituents. This risk

assessment is being used in today’s

proposed rule to determine whether the

petitioned RCRA listed waste can be

defined as ‘‘low-risk’’ waste, able to exit

the Subtitle C system and be managed

in Subtitle D units. Low risk wastes are

generally defined by Region 5 as wastes

with a cancer risk of no more than

1×10¥6 or a hazard quotient of no more

than 1.0. A cancer risk of 1×10¥6

indicates a one in 1,000,000 probability

of an individual developing cancer over

a lifetime. For noncarcinogenic

chemicals, a hazard quotient of one

represents potential exposure equal to

the safe toxicity threshold value. The

program back-calculates allowable

waste constituent concentrations at the

selected risk levels.

Although the pathway of ingestion of

contaminated groundwater may be

appropriate to propose exit levels for

some wastes and constituents, it may

not be protective for others, depending

on the physical and chemical properties

of each waste constituent. Some

constituents have a high potential to

bioaccumulate or bioconcentrate in

living organisms. Pathways in which

these constituents come in contact with

fish would be important to evaluate.

The DRAS program performs an

extensive risk assessment that examines

numerous exposure pathways, rather

than just the groundwater ingestion

pathway. The DRAS program evaluates

exposures associated with managing

wastes in Subtitle D landfills or surface

impoundments. Elements of the risk

assessment procedure performed by the

DRAS that support this proposal have

undergone review by the Science

Advisory Board and EPA’s Office of

Research and Development. The use of

CMTP as used in the DRAS was

favorably received by the SAB. ORD

reviewed all other aspects of the DRAS

program and responded favorably with

comments. All ORD comments were

addressed and incorporated into the

DRAS program.

2. What Conditions Does the Agency

Use in Determining Whether a Waste

May Be Delisted?

The EPA’s approach in RCRA

delisting risk analyses has typically

been to represent a reasonable worstcase waste disposal scenario for the

petitioned waste rather than use of sitespecific factors. The Agency believes

that a reasonable worst-case scenario

results in conservative values for the

compliance point concentrations and is

appropriate when determining whether

a waste should be relieved of the

management constraints of RCRA

Subtitle C. Site-specific factors (e.g., site

hydrogeology) are not considered

because a delisted waste is no longer

subject to hazardous waste control, and

therefore, the Agency is generally

unable to predict and does not control

where and how a waste will be managed

after delisting.

3. How Is the Risk Assessment in the

DRAS Program Structured?

The assessment estimated the risk

associated with constituent-specific

concentrations in the petitioned waste

at the management unit that could be

expected to result in an acceptable

exposure to human or ecological

receptors (determined through using the

toxicity benchmarks such as reference

doses—RfDs). The risk assessment took

into account the various pathways by

which waste constituents may move

through the environment from the waste

management unit to a receptor. The

DRAS uses the fate and transport

mechanisms to predict waste

constituent movement. The potential

exposure pathways considered in the

assessment are not all-inclusive but

were selected to reflect those that might

be commonly associated with the

management of wastes in Subtitle D

units. The management units could

Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58019

potentially be located in the range of

environments that exist across the

United States. Various environments

have differing characteristics (e.g.,

meteorological conditions, soil type)

with some environments more

conducive for the movement of certain

constituents in certain pathways.

Conditions resulting in a conservative

evaluation were used for each pathway,

regardless of whether or not these

conditions are likely to occur

simultaneously at any one location. The

assessment was structured using a

deterministic approach. A deterministic

approach uses a single, point estimate of

the value of each input or parameter and

calculates a single result based on those

point estimates. The assessment used

the best data available to select typical

(i.e., approximately 50th percentile) and

high-end (i.e., approximately 90th

percentile) values for each parameter or

parameter. The DRAS code which

performs the assessment is constructed

as a set of calculations that begin with

an acceptable exposure level for a

constituent to a receptor, and backcalculates to a waste constituent

concentration in the management unit

that corresponds to the acceptable risk

level.

The steps of the assessment which

provide estimates of acceptable

constituent-specific concentrations in

waste include the following:

Step 1—Specify acceptable risk levels

for each constituent and each receptor.

Step 2—Specify the exposure

medium. Using the toxicity benchmarks

as a starting point and the exposure

equations, the assessment back

calculates the concentration of

contaminant in the medium (e.g., air,

water, soil) that corresponds to

‘‘acceptable’’ exposure at the specified

risk level. The exposure equations

coded into the DRAS software include

a quantitative description of how a

receptor comes into contact with the

contaminant and how much the

receptor takes in through specific

mechanisms (e.g., ingestion, inhalation,

dermal adsorption) over some specified

period of time.

Step 3—Calculate the point of release

concentration from the exposure

concentration. Based on the backcalculated concentration in the

exposure medium (from Step 2), the

concentration in the medium to which

the contaminant is released to the

environment (i.e., air, soil, groundwater)

for each pathway/receptor was modeled.

The end result of this calculation is a

waste constituent concentration at the

point of release from the waste

management unit (where the exempted

waste is disposed) that will not result in

adverse effects to human health and the

environment.

4. When Assessing the Risk of the

Exempted Waste, Where Does the DRAS

Assume the Waste is Deposited?

The DRAS risk assessment evaluates

risks associated with petitioned RCRA

wastes deposited to two waste

management scenarios: landfills and

surface impoundments. A landfill waste

management scenario is used for the

evaluation of solid wastes, while a

surface impoundment waste

management scenario is used for the

evaluation of liquid wastes. The

determination of whether a waste is a

liquid waste is made using EPA

approved Test Method 9095, referred to

as the Paint Filter Test. Data to

characterize landfills were obtained

from a 1987 nationwide survey of

industrial Subtitle D landfills. For

releases to groundwater, EPA’s

Composite Model for leachate migration

with Transformation Products

(EPACMTP) fate and transport model

was used by DRAS. The model assumes

that solid wastes remain uncovered for

thirty days after disposal and that the

landfill will finally be covered with a 2-

foot-thick native soil layer. The Subtitle

D landfill is assumed to be unlined or

if lined, that any liner at the base of the

landfill will eventually completely fail.

The DRAS assumes that liquid

industrial wastes are disposed of in an

unlined surface impoundment with a

sludge or sediment layer at the base of

the impoundment and that releases of

contaminants originate from the surface

impoundment. The surface

impoundment is taken to have a 20-year

operational life. After this period, the

impoundment may be filled in, or

simply abandoned. In either case, the

remaining waste in the impoundment

will leach into the unsaturated zone

relatively quickly. Therefore, the

duration of the leaching period in the

modeling analysis is set equal to 20-

years.

5. What Types of Chemical Releases

From the Waste Management Units Does

the DRAS Evaluate?

The DRAS evaluates chemical

releases of waste constituents from the

waste management units to air, surface

runoff and ground water. Using the

EPACMTP fate and transport model,

DRAS evaluates the potential release of

waste contaminants to the ground water.

In this evaluation, the differences

between waste management units are

represented by different values or

frequency distributions of the sourcespecific parameters. Source-specific

parameters used by the EPACMTP

predict releases to the ground water

from landfills include:

• Capacity and dimensions of the

waste management unit;

• Leachate concentration;

• Infiltration and recharge rates;

• Pulse duration;

• Fraction of hazardous waste in the

waste management unit;

• Density of the waste and;

• Concentration of the chemical

constituent in the hazardous waste.

The source-specific parameters used

by the model for surface impoundments

include:

• The area;

• The ponding depth (such as the

depth of liquid in the impoundment)

and;

• The thickness and hydraulic

conductivity of the sludge or sediment

layer at the bottom of the impoundment.

Data on the areas, volumes, and

locations of waste management units

were obtained from the 1987 EPA

Survey of Industrial Subtitle D waste

facilities in the United States.

Derivation of the parameters for each

type of waste management unit is

described in the EPACMTP Background

Document and User’s Guide.

For finite-source scenarios,

simulations are performed for transient

conditions, and the source is assumed to

be a pulse of finite duration. In the case

of landfills, the pulse duration is based

on the initial amount of contaminant in

the landfill, infiltration rate, landfill

dimensions, waste and leachate

concentration, and waste density. For

surface impoundments, the duration of

the leaching period is determined by the

waste management unit’s lifetime (the

default value is 20 years). For a finitesource scenario, the model can calculate

either the peak receptor well

concentration for noncarcinogens or an

average concentration over a specified

period for carcinogens. The finite-source

methodology in the EPACMTP is

discussed in detail in the background

document.

The DRAS evaluates releases of waste

constituents from the waste

management to the air. Releases of

chemicals to the air may be in the form

of either particulates or volatile

concentrations. Inhalation of

particulates and their absorption into

the lungs at the point of exposure (POE)

and air deposition of particulates and

subsequent ingestion of the soil-waste

mixture at the POE are a function of

particulate releases. The DRAS

calculates particulate emissions

resulting from wind erosion of soilwaste surfaces, from vehicular traffic,

and from waste loading and unloading.

To estimate the respirable particulate

58020 Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules

emissions resulting from wind erosion

of surfaces with an infinite source of

erodible particles, DRAS uses the

methodology documented in Rapid

Assessment of Exposure to Particulate

Emissions from Surface Contamination

Sites (RAEPE). The methodologies

documented in Compilation of Air

Pollutant Emission Factors, Volume 1:

Stationary Point and Area Sources (AP–

42) were employed to calculate the dust

and particulate emissions resulting both

from vehicular traffic and from waste

loading and unloading operations at a

facility.

Particulate emission rates computed

using these methodologies were

summed and entered in the Ambient Air

Dispersion Model, a steady-state,

Gaussian plume dispersion model

developed by EPA to predict the

concentrations of constituents 1,000 feet

downwind of a hypothetical land

disposal facility. For a complete

description and discussion, refer to the

1985 Ambient Air Dispersion Model

(AADM). The model assumes that:

1—the emission rate is constant over

time;

2—the emissions arise from an

upwind virtual point source with

emissions occurring at ground level and;

3—no atmospheric destruction or

decay of the constituent occurs.

The DRAS assumes typical or

conservative values for all variables that

are likely to influence the potential for

soil erosion, including wind velocity

and vegetative cover. The AADM unit

dimension assumptions were modified

to more closely resemble a landfill’s.

The DRAS equations compute emissions

resulting from wind erosion, vehicular

traffic, and waste loading and

unloading. These equations are

thoroughly described in the Region 6

Delisting Technical Support Document.

For the landfill waste disposal scenario,

the DRAS assumed that no vegetative

cover is present, thereby assuming

enhanced erodability of soil or waste.

The mean annual wind speed is

assumed to be 4 meters per second. This

value represents the average of the wind

speeds registered at U.S. climatological

stations as documented in Table 4–1 of

RAEPE. The DRAS assumes a month’s

(30 days’) worth of waste would be

uncovered at any one time.

Although particulates greater than 10

micrometers (μm) in size generally are

not considered respirable, the DRAS

calculates the emission rate for particle

sizes up to 30 μm in order to assess the

potential impact of deposition and

ingestion of such particulates using the

distributions of wind-eroded

particulates presented in RAEPE.

Specifically, these distributions indicate

that the release rate for particulates up

to 30 μm in size should be

approximately twice the release rate

calculated for particulates 10 μm in size.

The DRAS calculates the total annual

average emissions of respirable

particulates by summing for wind

erosion, for vehicle travel, and for waste

loading and unloading operations. The

DRAS evaluates air deposition of the

annual total emissions of particulates

less than or equal to 30 μm in size to

soil 1,000 feet from the edge of a

disposal unit. DRAS calculates the

resulting soil concentration after one

year of accumulation, conservatively

assuming no constituent removal (no

leaching, volatilization, soil erosion, or

degradation).

The DRAS also evaluates the

atmospheric transport and inhalation of

volatile constituents which was

developed by EPA’s Office of Air

Quality Planning and Standards

(OAQPS) and has been recommended

for use in risk assessments conducted

under the Superfund program. The

DRAS program, is currently being

revised to incorporate Shen’s

modification of Farmer’s equation

which will result in a better estimate of

volatile emissions. Since the maximum

concentration of volatiles in USG’s

waste is low, this pathway will not be

reevaluated using the revised approach,

unless the revised version of DRAS

becomes available. Estimates of

emissions of VOCs from disposal of

wastewaters in surface impoundments

are computed with EPA’s Surface

Impoundment Modeling System (SIMS).

SIMS was developed by EPA’s OAQPS.

Further information can be found in the

Background Document for the Surface

Impoundment Modeling System Version

2.0. The volatile emission rates derived

from the respective waste management

scenario are used by the AADM steadystate Gaussian plume dispersion model

to predict the concentrations of

constituents 1,000 feet downwind of a

hypothetical disposal facility.

The DRAS evaluates potential releases

of waste constituents to accessible

surface waters. Exposure through the

surface water pathway results from

erosion of hazardous materials from the

surface of a solid waste landfill and

transport of these constituents to nearby

surface water bodies. The DRAS uses

the universal soil loss equation (USLE)

to compute long-term soil and waste

erosion from a landfill in which delisted

waste has been disposed of. The USLE

is used to calculate the amount of waste

that will be eroded from the landfill. In

addition, the size of the landfill is

computed using the waste volume

estimate provided by the petitioner. The

volume of surface water into which

runoff occurs is determined by

estimating the expected size of the

stream into which the soil is likely to

enter. The amount of soil delivered to

surface water is calculated using a

sediment delivery ratio. The sediment

delivery ratio determines the percentage

of eroded material that is delivered to

surface water based on the assumption

that some eroded material will be

redeposited between the landfill and the

surface water body. A distance of 100

meters (m) to the nearest surface water

body is assumed. The DRAS program as

used here is currently being revised to

account for partitioning between water

and suspended solids when the eroded

waste enters the stream. Due to the

significant impact of this pathway in the

evaluation of USG’s petition, the risk

posed through this pathway was

reevaluated manually using the same

partitioning approach which is being

incorporated into the next version of the

DRAS program (See the Docket Report

on Evaluation of Contaminant Releases

to Surface Water Resulting from

American Metals’ Petitioned Waste).

Conservative values are used in the

manual recalculation for variables likely

to influence the potential for soil

erosion and subsequent discharge to

surface water. Rainfall erosion factor

values range from 20 to 550 per year.

Values greater than 300 occur in only a

small proportion of the southeastern

United States. A value of 300 was

chosen as a conservative estimate

ensuring that a reasonable worst-case

scenario is provided for most possible

landfill locations. Soil erodibility factors

range from 0.1 to 0.69 ton per acre. A

value of 0.3 was selected for the

analysis, which is estimated to exceed

66% of all values assuming a normal

distribution. One month’s worth of

waste is assumed to be left uncovered at

any one time and thus would be readily

transportable by surface water runoff.

Other variables used by the DRAS and

in the manual calculation to evaluate

releases to surface waters employed

conservative assumptions. Both the

DRAS and the manual recalculation

multiply the total annual mass of eroded

material by the sediment delivery ratio

to determine the mass of soil and waste

delivered to surface water.

The predicted erosion capacity is

gradually diluted as it mixes with

nearby surface waters. DRAS selects a

representative volume or flux rate of

surface water based on stream order,

which is a system of taxonomy for

streams and rivers. A stream that has no

other streams flowing into it is referred

to as a first-order stream. Where two

Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58021

first-order streams converge, a secondorder stream is created. Where two

second-order streams converge, a thirdorder stream is created. Data indicate

that second-order streams have an

estimated flow rate of 3.7 cubic feet per

second. The second-order stream was

selected for analysis as the smallest

stream capable of supporting

recreational fishing. Fifth-order streams

were also chosen for analysis as the

smallest streams capable of serving as

community water supplies. Fifth-order

stream flow is estimated to be 380 cubic

feet per second.

6. By What Means May an Individual Be

Exposed to the Proposed Exempted

Waste?

An exposure scenario is a

combination of exposure pathways

through which a single receptor may be

exposed to a waste constituent.

Receptors may be human or other

animal in an ecosystem. There are many

potential exposure scenarios. The DRAS

evaluated the risks of the proposed

waste associated with the exposure

scenarios most likely to occur as a result

of releases from the waste management

unit. Receptors may come into contact

with delisted waste constituent releases

from a waste management unit via two

primary exposure routes, either (1)

directly via inhalation or ingestion of

water or (2) indirectly via subsequent

ingestion of soil and foodstuffs (such as

fish) that become contaminated by

waste constituents through the food

chain. Receptors may also be exposed to

waste constituents released from a waste

management unit to surface media (via

volatilization to air or via windblown

particulate matter) or to groundwater

(via ingestion of groundwater). The

exposure scenarios assessed by DRAS

are generally conservative in nature and

are not intended to be entirely

representative of actual scenarios at all

sites. Rather, they are intended to allow

standardized and reproducible

evaluation of risks across most sites and

land use areas. Conservatism is

incorporated to ensure protection of

potential receptors not directly

evaluated, such as special

subpopulations. The recommended

exposure scenarios and associated

assumptions assessed by DRAS are

reasonable and conservative and they

represent a scientifically sound

approach that allows protection of

human health and the environment.

7. What Receptors Are Assessed for Risk

From Exposure to the Proposed

Exempted Waste?

Adult and child residents are the two

receptors evaluated in this analysis. The

adult resident exposure scenario is

evaluated to account for the

combination of exposure pathways to

which an adult receptor may be exposed

in an urban or rural (nonfarm) setting.

The adult resident is assumed to be

exposed to waste constituents from an

emission source through the following

exposure pathways:

1—Direct inhalation of vapors and

particles;

2—Ingestion of fish;

3—Ingestion of drinking water from

surface water sources;

4—Ingestion of drinking water from

groundwater sources;

5—Dermal absorption from

groundwater sources via bathing;

6—Inhalation from groundwater

sources via showering.

DRAS evaluates two exposure

pathways for children: (1) dermal

absorption while bathing with

potentially contaminated groundwater

and (2) the ingestion of soil containing

contaminated particulates which have

need emitted from the landfill and

deposited on the soil. Child residents (1

to 6 years old) were not selected as

receptors for the groundwater ingestion

and inhalation pathways, the surface

water pathways, or the direct air

inhalation pathways because the adult

resident receptor scenario has been

found to be protective of children with

regard to these pathways. There is no

indication that children consume more

drinking water or inhale more air per

unit of body weight, factoring in the

recognized exposure duration, than

adults. Therefore, average daily

exposure normalized to body weight

would be identical for adults and

children. Likewise, a child receptor was

not included for the freshwater fish

ingestion pathway because there is no

evidence that children consume more

fish relative to their body weight,

factoring in exposure duration, than do

adults. The dermal absorption while

bathing with groundwater exposure

pathway is evaluated differently for

child residents than it is for adult

residents because of the following

considerations: (1) The ratio of exposed

skin surface area to body weight is

slightly higher for children than for

adults, resulting in a slightly larger

average daily exposure for children than

for adults; and (2) the exposure duration

for such children is limited to 6 years,

thus lowering the lifetime average

exposure to carcinogens. Typically, the

adult scenario is more protective with

regard to carcinogens (because of the

longer exposure duration), and the child

scenario is more protective with regard

to noncarcinogens (because of the

greater skin surface area to body weight

ratio).

8. Where Does the DRAS Assume That

Receptors Are Located When

Performing the Risk Evaluation?

The EPACMTP, a probabilistic

groundwater fate and transport model,

was used to predict groundwater

constituent concentrations at a

hypothetical receptor well located

downgradient from a waste management

unit. This receptor well represents the

POE. That is, the predicted waste

constituent concentration at the POE is

used to assess the risk of the proposed

exempted waste. The distance to the

well is based on the results of the 1987

nationwide survey of landfills

conducted by EPA’s Office of Solid

Waste (OSW) which determined the

distance to the nearest drinking water

well downgradient from municipal

landfills. The survey data are entered in

the EPACMTP model as an empirical

distribution: minimum = 0 m, median =

427 m, and maximum = 1,610 m

(approximately 1 mile). In contrast to

the 1990 Toxicity Characteristic (TC)

Rule (55 FR 11798), there is no

requirement that the well lie within the

leachate plume.

For carcinogenic waste constituents,

the exposure concentration is defined as

the maximum 30 year average receptor

well concentration; for noncarcinogens,

the exposure concentration is taken to

be the highest receptor well

concentration during the modeled

10,000 year period. A 10,000 year limit

was imposed on the exposure period;

that is, the calculated exposure

concentration is the peak or highest 30

year average concentration occurring

within 10,000 years following the initial

release from the waste management

unit. The fate and transport simulation

within the CMTP provided a probability

distribution of receptor well

concentrations as a function of expected

leachate concentration. Using the

receptor well concentrations as a

function of the waste constituent

concentration, the EPACMTP derived

chemical-specific dilution attenuation

factors (DAFs) which convert a leachate

concentration in the landfill to a

groundwater concentration at the

receptor well.

Human exposure routes for surface

water include ingestion of surface water

used as drinking water and ingestion of

fish from nearby surface water bodies.

For the surface water ingestion exposure

route, the surface water POE modeled is

a fifth-order stream 100 m from the

waste management unit. Fifth-order

streams were chosen for analysis

because EPA assumes that a fifth-order

58022 Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules

stream is the smallest stream capable of

serving as a community water supply.

The assumption of a 100 m distance to

the nearest surface water body is a

conservative assumption based on

available data. An EPA survey of

municipal landfill facilities showed that

3.6 percent of the surveyed facilities are

located within 1 mile of a river or

stream and that the average distance

from these facilities to the closest river

or stream is 586 m. For the fish

ingestion exposure route, a second-order

stream was chosen for analysis. This

stream segment was determined to be

the smallest stream capable of

supporting fisheries. The POE in the

surface water body for collection of fish

is assumed to be 100 m downgradient

from the disposal facility. Human

exposure to emissions of windblown

particulates from landfills and to

emissions of volatiles from landfills and

surface impoundments is assessed by

the DRAS. For the air pathway, the

DRAS assumes the POE is 305 m (1,000

feet) downwind of the waste

management unit.

9. How Does DRAS Determine Rates of

Exposure?

The calculation of constituent-specific

exposure rates for each exposure

pathway evaluated were based on:

1—The estimated concentration in a

given medium as calculated in DRAS;

2—The contact rate;

3—Receptor body weight, and;

4—The frequency and duration of

exposure.

This calculation is repeated for each

constituent and for each exposure

pathway included in an exposure

scenario. Exposure to hazardous

constituents is assumed to occur over a

period of time. To calculate an average

exposure per unit of time, the DRAS

divides the total exposure by the time

period. Exposures are intended to

represent reasonable maximum

exposure (RME) estimates for each

applicable exposure route. The RME

approach is intended to combine upperbound and mid-range exposure factors

so that the result represents an exposure

scenario that is both protective and

reasonable, not the worst possible case.

10. What Rate of Contact With a

Contaminated Media Does the DRAS

Use?

The contact rate is the amount of

contaminated medium contacted per

unit of time or event. Contact rates for

subsistence food types (fish for the fish

ingestion pathway) are assumed to be

100 percent from the hypothetical

assessment area (surface water body).

The following sections describe

exposure pathway-specific contact rates.

11. What Are the Contact Rates at

Which Individuals Are Exposed to

Contaminated Media?

For groundwater and surface water

ingestion, the intake rate is assumed to

be 2.0 liters per day (l/day), the average

amount of water that an adult ingests.

This value, which is currently used to

set drinking water standards, is close to

the current 90th percentile value for

adult drinking water ingestion (2.3l/day)

reported in the EPA Exposure Factors

Handbook. This value approximates the

8 glasses of water per day historically

recommended by health authorities. The

contact for the dermal exposure

pathway is assumed to occur while

bathing with contaminated

groundwater. In this analysis, the DRAS

assumes that the average adult resident

is in contact with groundwater during

bathing for 0.25 hour per event and that

the average child resident is in contact

with groundwater during bathing for

0.33 hour per event, with one event per

day. For dermal bathing exposure to

contaminated groundwater, the selected

receptors are an adult and a young child

(1 to 6 years old). During bathing,

generally all of the skin surface is

exposed to water. The total adult body

surface area can vary from about 17,000

to 23,000 square centimeters (cm2). The

EPA Exposure Factors Handbook (EFH)

reports a value of 20,000 cm2 as the

median value for adult skin surface area.

A value of 6,900 cm2 has been

commonly used for a child receptor in

EPA risk assessments; this value is

approximately the average of the

median values for male children aged 2

to 6. The EFH presents a range of

recommended values for estimates of

the skin surface area of children by age.

The mean skin surface area at the

median for boys and girls 5 to 6 years

of age is 0.79 square meters (m2) or

7,900 cm2. Given that the age for

children is defined as 0 to 6 years (see

EFH Section 3.3.4), a skin surface area

value for ages 5 to 6 years would be a

conservative estimate of skin surface

area for children. For calculation of

dermal exposure to waste constituents,

the DRAS uses a value of 7,900 cm2 for

the skin surface area of children and a

value of 20,000 cm2 for the skin surface

area of adults.

For the groundwater pathway of

inhalation exposure during showering,

the contact with water is assumed to

occur principally in the shower and in

the bathroom. The DRAS analysis

assumes that the average adult resident

spends 11.4 minutes per day in the

shower and an additional 48.6 minutes

per day in the bathroom. Daily

inhalation rates vary depending on

activity, gender, age, and so on. Citing

a need for additional research, the EFH

does not recommend a reasonable

upper-bound inhalation rate value. The

EFH recommended value for the average

inhalation rate is 15.2 cubic meters per

day (m3/day) for males and 11.3 m3/day

for females. The EPA established an

upper-bound value for an individual’s

inhalation rate at 20 m3/day which has

been commonly used in past EPA risk

assessments. This value is used by the

DRAS for assessment of inhalation

exposure.

The DRAS assesses the ingestion of

soil contaminated with air-deposited

particulates from a nearby landfill. The

potential for exposure to constituents

via soil ingestion is greater for children

because they are more likely to ingest

more soil than adults as a result of

behavioral patterns present during

childhood. Therefore, exposure to waste

constituents through ingestion of

contaminated soils is evaluated for the

child in a delisting risk assessment. The

mean soil ingestion values for children

range from 39 to 271 milligrams per day

(mg/day), with an average of 146 mg/

day for soil ingestion and 191 mg/day

for soil and dust ingestion (see EPA

EFH). Based on the EFH statement that

200 mg/day may be used as a

conservative estimate of the mean, the

DRAS uses 200 mg/day as the soil

ingestion rate for children.

Fish consumption rates vary greatly,

depending on geographic region and

social or cultural factors. The

recommended value for fish

consumption for all fish is 0.28 grams of

fish per kilogram body weight per day

for an average adult (see EPA EFH). This

value equates with a fish consumption

rate of 20.1 grams per day (g/day) for all

fish. The DRAS estimated that an

exposed individual eats 20 g of fish per

day, representing one 8-ounce serving of

fish approximately once every 11 days.

A consumption rate of 57.9 g/day was

used in the manual reevaluation of risk

posed through fish ingestion. This

higher consumption rate, corresponding

to a high-risk subpopulation present in

Region 5 (low income minority sport

fisherman) was added to the evaluation

for USG’s waste at the request of

Regional risk assessors.

12. At What Frequency Does the DRAS

Assume That Receptors Are Exposed to

Contaminated Media?

An exposure frequency of 350 days

per year is applied to all exposure

scenarios (see EPA EFH). Until better

data become available, the common

assumption that residents take 2 weeks

Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58023

of vacation per year is used to support

a value of 15 days per year spent away

from home, leaving 350 days per year

spent at home and susceptible to

exposure.

13. For What Duration Does the DRAS

Assume Receptors Are Exposed to

Contaminated Media?

The exposure duration reflects the

length of time that an exposed

individual may be expected to reside

near the constituent source. For the

adult resident, this value is taken to be

30 years, and for the child resident, this

value is taken to be 6 years (see EPA

EFH). The adult resident is assumed to

live in one house for 30 years, the

approximate average of the 90th

percentile residence times from two key

population mobility studies. For the

child resident, the exposure duration is

assumed to be 6 years, the maximum

age of the young child receptor. For

carcinogens, exposures are combined for

children (6 years) and adults (24 years).

For noncarcinogenic constituents, the

averaging time (AT) equals the exposure

duration in years multiplied by 365

days per year. For an adult receptor, the

exposure duration is 30 years, and for a

child receptor, the exposure duration is

6 years. For carcinogenic constituents,

the AT has typically been 25,550 days,

based on a lifetime exposure of 70 years

at 365 days per year. The life

expectancy value in the EFH is 75 years.

Given this life expectancy value, the AT

for a delisting risk assessment is 27,375

days, based on a lifetime exposure of 75

years at 365 days per year.

14. What Body Weights Are Assumed

for Receptors in the DRAS Evaluation?

Risk Assessment Guidance for

Superfund defines the body weight of

the receptor as either adult weight (70

kilograms (kg)) or child weight (1 to 6

years, 15 kg). The EFH recommended

value of 71.8 kg for an adult differs from

the 70-kg value commonly used in EPA

risk assessments. In keeping with the

latest EFH recommendation, the DRAS

used a 72-kg adult weight and a 15-kg

child weight for the proposed delisting

determination.

B. What Risk Assessment Methods Has

the Agency Used in Previous Delisting

Determinations That Are Being Revised

in This Proposal?

1. Introduction

The fate and transport of constituents

in leachate from the bottom of the waste

unit through the unsaturated zone and

to a drinking water well in the saturated

zone was previously estimated using the

EPA Composite Model for Landfill

(EPACML) (See 55 FR 11798). The

EPACML accounts for:

• One-dimensional steady and

uniform advective flow;

• Contaminant dispersion in the

longitudinal, lateral, and vertical

directions;

• Sorption.

However, advances in groundwater

fate and transport have been made in

recent years and the Agency proposes

the use of a more advanced groundwater

fate and transport model for RCRA

exclusions.

2. What Fate and Transport Model Does

the Agency Use in the DRAS for

Evaluating the Risks to Groundwater

From the Proposed Exempted Waste?

The Agency proposes to use the

EPACMTP in this delisting

determination. The EPACMTP considers

the subsurface fate and transport of

chemical constituents. The EPACMTP is

capable of simulating the fate and

transport of dissolved contaminants

from a point of release at the base of a

waste management unit, through the

unsaturated zone and underlying

groundwater, to a receptor well at an

arbitrary downstream location in the

aquifer. The model accounts for the

following mechanisms affecting

contaminant migration: transport by

advection and dispersion, retardation

resulting from reversible linear or

nonlinear equilibrium adsorption onto

the soil and aquifer solid phase, and

biochemical degradation processes.

3. Why Is the EPACMTP Fate and

Transport Model an Improvement Over

the EPACML?

The modeling approach used for this

proposed rulemaking includes three

major categories of enhancements over

the EPACML. The enhancements

include:

1—Incorporation of additional fate

and transport processes (e.g.,

degradation of chemical constituents);

2—Use of enhanced flow and

transport solution algorithms and

techniques (e.g., three-dimensional

transport) and;

3—Revision of the probabilistic

methodology (e.g., site-based

implementation of available input data)

A discussion of the key enhancements

which have been implemented in the

EPACMTP is presented here and the

details are provided in the proposed

1995 Hazardous Waste Identification

Rule (HWIR) background documents (60

FR 66344–December 21, 1995).

The EPACML was limited to

conditions of uniform groundwater

flow. It could not handle accurately the

conditions of significant groundwater

mounding and non-uniform

groundwater flow due to a high rate of

infiltration from the waste units. These

conditions increase the transverse

horizontal as well as the vertical

spreading of a contaminant plume. The

EPACMTP accounts for these effects

directly by simulating groundwater flow

in the vertical as well as horizontal

directions.

The EPACMTP can simulate fate and

transport of metals, taking into account

geochemical influences on the mobility

of metals. The EPA’s MINTEQA2 metals

speciation model is used to generate

effective sorption isotherms for

individual metals, corresponding to a

range of geochemical conditions. The

transport modules in EPACMTP have

been enhanced to incorporate the

nonlinear MINTEQ sorption isotherms.

This enhancement provides the model

with capability to simulate, in the

unsaturated and in the saturated zones,

the impact of pH, leachate organic

matter, natural organic matter, iron

hydroxide and the presence of other

ions in the groundwater on the mobility

of metals. The saturated zone module

implemented in the EPACML was based

on a Gaussian distribution of

concentration of a chemical constituent

in the saturated zone. The module also

used an approximation to account for

the initial mixing of the contaminant

entering at the water table underneath

the waste unit. The approximate nature

of this mixing factor could sometimes

lead to unrealistic values of

contaminant concentration in the

groundwater close to the waste unit,

especially in cases of a high infiltration

rate from the waste unit. The enhanced

model incorporates a direct linkage

between the unsaturated zone and

saturated zone modules which

overcomes these limitations of the

EPACML.

To enable a greater flexibility and

range of conditions that can be modeled,

the analytical saturated zone transport

module has been replaced with a

numerical module, based on the highly

efficient state-of-the-art Laplace

Transform Galerkin (LTG) technique.

The enhanced module can simulate the

anisotropic, non-uniform groundwater

flow, and transient, finite source,

conditions. The latter requires the

model to calculate a maximum receptor

well concentration over a finite time

horizon, rather than just the steady state

concentration which was calculated by

the EPACML. The saturated zone

modules have been implemented to

provide either a fully three-dimensional

solution, or a highly efficient quasi-3D

solution. The latter has been

implemented for probabilistic

58024 Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules

applications and provides nearly the

same accuracy as the fully three

dimensional option, but is more

computationally efficient. Both the

unsaturated zone and the saturated zone

transport modules can accommodate the

formation and the transport of parent as

well as of the transformation products.

A highly efficient semi-analytical

unsaturated zone transport module has

been incorporated to handle the

transport of metals in the unsaturated

zone and can use MINTEQA2 derived

linear or nonlinear sorption isotherms.

Conventional numerical solution

techniques are inadequate to handle

extremely nonlinear isotherms. An

enhanced method-of-characteristic

based solution has been implemented

which overcomes these problems and

thereby enables the simulation of metals

transport in the probabilistic framework.

Non-linearity in the metals sorption

isotherms is primarily of concern at

higher concentration values; for low

concentrations, the isotherms are linear

or close to linear. Because of the

attenuation in the unsaturated zone, and

the subsequent dilution in the saturated

zone, concentrations in the saturated

zone are usually low enough so that

properly linearized isotherms are used

by the model in the saturated zone

without significant errors.

The internal routines in the model

which determine placement of the

receptor well relative to the areal extent

of the contaminant plume have been

revised and enhanced to eliminate bias

which was present in the

implementation in the EPACML. The

calculation of the areal extent of the

plume has been revised to take into

consideration the dimensions of the

waste unit. The logic for placing a

receptor well inside the plume limits

has been improved to eliminate a bias

towards larger waste unit areas and to

ensure that the placement of the well

inside these limits, for a given radial

distance from the unit, is truly

randomly uniform. However, for this

proposal, the closest drinking water

well is located anywhere on the

downgradient side of the waste unit.

The data sources from which

parameter distributions for nationwide

probabilistic assessments are obtained

have been evaluated, and where

appropriate, have been revised to make

use of the latest data available for

modeling. Leachate rates for Subtitle D

waste units have been revised using the

latest version of the Hydrologic

Evaluation of Landfill Performance

(HELP) model with the revised data

inputs. Source specific input parameters

(e.g., waste unit area and volume) have

been developed for various different

types of industrial waste units besides

landfills. Input values for the

groundwater related parameters have

been revised to utilize information from

a nationwide industry survey of actual

contaminated sites. The original version

of the model was implemented for

probabilistic assessments assuming

continuous source (infinite source)

conditions only. This methodology did

not take into account the finite volume

and/or operational life of waste units.

The EPACMTP model has been

implemented for probabilistic

assessments of either continuous source

or finite source scenarios. In the latter

scenario, predicted groundwater impact

is not only based on the concentrations

of contaminants in the leachate, but also

on the amount of constituent in the

waste unit and/or the operational life of

the unit.

The landfill is taken to be filled to

capacity and covered when leaching

begins. The time period during which

the landfill is filled-up, usually assumed

to be 20 years, is considered to be small

relative to the time required to leach all

of the constituent mass out of the

landfill. The model simulation results

indicate that this assumption is not

unreasonable; the model calculated

leaching duration is typically several

hundred years. The leachate flux, or

infiltration rate, is determined using the

HELP model. The net infiltration rate is

calculated using a water balance

approach, which considers

precipitation, evapo-transpiration, and

surface run-off. The HELP model was

used to calculate landfill infiltration

rates for a representative Subtitle D

landfill with 2-foot earthen cover, and

no liner or leachate collection system,

using climatic data from 97 climatic

stations located throughout the US.

These correspond to the reasonable

worst case assumptions as explained in

the HWIR Risk Assessment Background

Document for the HWIR proposed

notice (60 FR 66344–December 21,

1995). Additional details on the

methodologies used by the EPACMTP to

derive DAFs for waste constituents

modeled for the landfill scenario are

presented in the Background Documents

for the proposed HWIR docket (60 FR

66344–December 21, 1995). The fraction

of waste in the landfill is assigned a

uniform distribution with lower and

upper limits of 0.036 and 1.0,

respectively, based on analysis of waste

composition in Subtitle D landfills. The

lower bound assures that the waste unit

will always contains a minimum

amount of the waste of concern. The

waste density is assigned a value based

on reported densities of hazardous

waste, and varies between 0.7 and 2.1

grams per cubic centimeter (g/cm3.

The area of the surface impoundment

and the impoundment depth used by

the EPACMTP are obtained from the

OSW Subtitle D Industrial Survey and

were entered into the probabilistic

analyses as distributions. The sediment

layer at the base of the impoundment is

taken to be 2 feet thick, and have an

effective equivalent saturated

conductivity of 10¥7 centimeters per

second (cm/s). These values were

selected in recognition of the fact that

most non-hazardous waste surface

impoundments do have some kind of

liners in place. Additional details on the

methodologies used by the EPACMTP to

derive DAFs for waste constituents

modeled for the surface impoundment

waste management scenario are

presented in the Background Documents

for the 1995 proposed HWIR docket (60

FR 66344–December 21, 1995).

4. Has the EPACMTP Methodology Been

Formally Reviewed?

The Science Advisory Board (SAB), a

public advisory group that provides

information and advice to the EPA,

reviewed the EPACMTP model as part

of a continuing effort to provide

improvements in the development and

external peer review of environmental

regulatory models. Overall, the SAB

commended the Agency for making

significant enhancements to the

EPACMTP’s predecessor (EPACML) and

for responding to previous SAB

suggestions. The SAB also concluded

that the mathematical formulation

incorporating transformation or

degradation products into the model

appeared to be correct and that the sitebased approach using hydrogeologic

regions is superior to the previous

approach used in EPACML. The model

underwent public comment during the

1995 proposed HWIR (60 FR 66344–

December 21, 1995).

5. Has the Agency Modified the

EPACMTP as Utilized in the HWIR

Proposal?

The EPACMTP, as developed for

HWIR, determined the DAF using a

probabilistic approach that selected, at

random, a waste volume from a range of

waste volumes identified in EPA’s 1987

Subtitle D landfill survey. In delisting

determinations, the waste volume of the

petitioner is known. Therefore,

application of EPACMTP to the

delisting program has been modified to

evaluate the specific waste volume. The

Agency modified the DAFs determined

under the HWIR proposal to account for

a known waste volume. To generate

waste volume-specific DAFs, EPA

Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58025

developed ‘‘scaling factors’’ to modify

DAFs developed for HWIR (based on the

entire range of disposal unit areas) to

DAFs for delisting waste volumes. This

was accomplished by computing a 90th

percentile DAF for a conservative

chemical for 10 specific waste volumes

(ranging from 1,000 cu. yds. to 300,000

cu. yds.) for each waste management

scenario (landfill and surface

impoundment). The Agency assumed

that DAFs for a specific waste volume

are linearly related to DAFs developed

by EPACMTP for the HWIR. DAF

scaling factors were computed for the

ten increment waste volumes. Using

these ten scaling factor DAFs, regression

equations were developed for each

waste management scenario to provide

a continuum of DAF scaling factors as

a function of waste volume.

The regression equations are coded

into the DRAS program which then

automatically adjusts the DAF for the

waste volume of the petitioner. The

method used to verify the scaling factor

approach is presented in Application of

EPACMTP to Region 6 Delisting

Program: Development of Volumeadjusted Dilution Attenuation Factors.

For the landfill waste management

scenario, the DAF scaling factors ranged

from 9.5 for 10,000 cu. yard to

approximately 1.0 for waste volumes

greater than 200,000 cu. yards.

Therefore, for solid waste volumes

greater than 200,000 cu. yds., the waste

volume-specific DAF is the same as the

DAF computed for the proposed HWIR.

The regression equation that can be

used to determine the DAF scaling

factor (DSF) as a function of waste

volume (in cubic yards) for the landfill

waste management unit is: DSF = 6152.7

* (waste volume)—0.7135. The

correlation coefficient of this regression

equation is 0.99, indicating a good fit of

this line to the data points. DAF scaling

factors for surface impoundment waste

volumes ranged from 2.4 for 2,000 cu.

yards to approximately 1.0 for 100,000

cu. yds. For liquid waste volumes

greater than 200,000 cu. yds., the waste

volume-specific DAF is the same as the

DAF computed for the proposed HWIR.

The regression equation for DSF as a

function of waste volume for surface

impoundment wastes is: DSF = 14.2 *

(waste volume)—0.2288. The correlation

coefficient of this regression equation is

also 0.99, indicating an extremely good

fit of this line to the data points.

V. Evaluation of This Petition

A. What Other Factors Did EPA

Consider in Its Evaluation?

We also consider the applicability of

ground-water monitoring data during

the evaluation of delisting petitions

where the waste in question is or has

ever been placed on land. In this case,

a substantial record of groundwater

analysis from monitoring wells in and

around the existing landfill which

contains the waste was available and

submitted as part of the petition.

Historical data showed elevated levels

of hazardous constituents in the

groundwater and indicated that the

landfilled waste was a possible source.

Additional groundwater analysis

became available utilizing a more

sophisticated EPA recommended

sampling technique. The new data

could not establish that hazardous

substances were currently leaching from

the landfill sludge at levels exceeding

those predicted by the EPACMTP model

in the DRAS program. The evaluation

was based on a statistical analysis

conducted in accordance with

Statistical Analysis of Ground-Water

Monitoring Data at RCRA Facilities—

Interim Final Guidance, EPA, April

1989 and Statistical Analysis of GroundWater Monitoring Data at RCRA

Facilities—Addendum to Interim Final

Guidance, EPA, July 1992. Leachate

analysis of sludge samples generally

supported the conclusion that the

landfilled sludge was not currently a

source of groundwater contamination

above health-based levels.

Specifically, the landfilled sludge did

not appear to be leaching arsenic,

cadmium, lead, or nickel to

groundwater at this time. Cadmium and

nickel in groundwater appear to be a

concern at the facility, but the cadmium

and nickel contamination could not be

attributed to the landfilled sludge based

only on the recent data. The landfilled

sludge could be contributing chromium,

zinc and/or thallium to the

groundwater, but currently at levels

below concern. The elevated thallium

was detected in upgradient wells and all

detections were very close to the

detection levels. Based on most recent

data, the landfilled sludge does not

appear to currently leach hazardous

constituents to groundwater at

significantly different levels than

predicted by leachate analysis and

subsequent modeling (See Docket

Report for Statistical Analysis of Recent

Groundwater Analysis).

B. What Did EPA Conclude About USG’s

Analysis?

The total cumulative risk posed by the

waste, including the revised dioxin risk

through fish ingestion is approximately

9.69 × 10¥6. EPA believes that this risk

is acceptable because the value is within

a generally acceptable range of 1 × 10¥4

to 1 × 10 ¥6 and a large portion of the

estimated risk is associated with a single

contaminant/pathway which may be

evaluated in more than one way.

Specifically, ingestion of carcinogenic

arsenic in groundwater contributes 8.39

× 10¥6, or 86.5% of the total risk. Total

arsenic levels in the landfilled waste

were not statistically different than

arsenic levels in soils not associated

with the landfill and recent groundwater monitoring at the facility did not

detect arsenic at a detection level of

0.005 milligrams per liter (mg/L).

Furthermore, if the POE target

concentration was set at the Safe

Drinking Water Act (SWDA) Maximum

Contaminant Level (MCL), the

maximum allowable waste leachate

concentration would be 7.09 mg/L TCLP

arsenic, over 100 times higher than the

maximum observed leachate

concentration in the waste. EPA’s July

1996 Soil Screening Guidance: User’s

Guide, EPA/540/R–96/018, states that

acceptable levels of contaminants in

soils for the ground-water pathway

should be derived from SWDA

Maximum Contaminant Level Goals

(MCLG) or MCLs. Health-based limits as

used in the DRAS program can be used

if MCLs are not available. Given that the

difference between the MCL for arsenic

and the health-based POE concentration

is three orders of magnitude, we believe

that some allowance can be exercised in

setting the allowable level for arsenic in

the leachate. EPA proposes to set the

allowable arsenic leachate level at a

concentration which corresponds to a

total waste cancer risk of 1 × 10¥4

which is still within the generally

acceptable range of 1 × 10¥4 to 1 × 10¥6.

Delisting levels for constituents other

than arsenic will still be set at

concentrations corresponding to the

original Region 5 target of 1 × 10¥6. By

this method, the delisting level for

leachable arsenic in this proposed

exclusion will be set at a value which

corresponds to a POE concentration of

approximately one tenth of the existing

MCL. The EPA has recently proposed to

lower the arsenic MCL to one tenth its

current value and thus, if finalized,

would correspond well with the

delisting level we are setting.

After reviewing USG’s processes, the

EPA concludes that (1) hazardous

constituents of concern are present in

USG’s waste, but not at levels which are

likely to pose a threat to human health

and the environment when placed in a

solid waste landfill; and (2) the

petitioned waste does not exhibit any of

the characteristics of ignitability,

corrosivity, or reactivity. See 40 CFR

261.21, 261.22, and 261.23, respectively.

58026 Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules

C. What is EPA’s Final Evaluation of

This Delisting Petition?

The descriptions of the USG

hazardous waste process and analytical

characterization, with the proposed

verification testing requirements (as

discussed later in this document,

provide a reasonable basis for EPA to

grant the exclusion.

We have reviewed the sampling

procedures used by USG and have

determined they satisfy EPA criteria for

collecting representative samples of

constituent concentrations in the

wastewater treatment sludge.

We believe the data submitted in

support of the petition show that USG’s

waste will not pose a threat when

disposed of in a Subtitle D landfill

regulated by a state. We therefore,

propose to grant USG an exclusion for

its WWTP sludge.

If we finalize the proposed rule, the

Agency will no longer regulate the

petitioned waste under 40 CFR Parts

262 through 268 and the permitting

standards of Part 270.

VI. Conditions for Exclusion

A. What Are the Maximum Allowable

Concentrations of Hazardous

Constituents in the Waste?

The following table summarizes

maximum observed total and TCLP

concentrations in USG’s waste,

maximum allowable leachate levels for

USG’s waste, and the level of regulatory

concern at the point of exposure for

groundwater. The EPA calculated

delisting levels for most constituents

detected.

Maximum allowable leachate

concentrations (expressed as a result of

the TCLP test) were calculated for all

constituents for which leachate was

analyzed. Most of the allowable leachate

concentrations were derived from the

health-based calculation within the

DRAS program. The remaining

maximum allowable leachate levels

were derived from MCLs, SDWA

Treatment Technique (TT) action levels,

or toxicity characteristic levels from 40

CFR 261.24 if they resulted in a more

conservative delisting level. The

singular exception is arsenic which was

discussed in section V.B. The maximum

allowable point of exposure

groundwater concentrations correspond

to the lesser of the health-based values

calculated within the DRAS program or

the MCLs or TT action levels. MCLs

were used for maximum point of

exposure groundwater concentrations

for constituents which were not

analyzed for in leachate extracts.

A statistical review of some of the

data indicates that the maximum values

used in the modeling and risk

estimation correspond to a very high

confidence interval (See Docket Report

on Degree of Characterization of

Existing Landfilled Sludge at the

American Metals Corporation Facility,

Westlake, Ohio). Assuming that the

distribution of the data is adequately

defined, future samples are likely to

exhibit concentrations which are less

than the maximum values used in this

evaluation. All of the maximum waste

concentrations observed are less than

the corresponding delisting levels

assigned. The maximum observed

concentration of PCBs was close to the

delisting level. However, PCBs were not

detected in most samples.

Constituent

Maximum 1 observed total concentration (mg/kg)

Maximum 1 observed leachate

concentration (mg/L

TCLP)

Maximum allowable

leachate concentration (mg/L TCLP)

Maximum allowable

point of exposure

concentration (mg/L

in groundwater)

Inorganic Constituents

Antimony .......................................................................... 1.2 <0.023 2 1.52 2 0.006

Arsenic ............................................................................. 19.0 0.058 0.691 0.005

Barium .............................................................................. 120 0.215 3 100 2 2.0

Beryllium .......................................................................... 0.86 0.003 2 3.07 2 0.004

Cadmium .......................................................................... 2.8 0.013 3 1.0 2 0.005

Chromium (total) .............................................................. 3660 0.277 3 5.0 2 0.1

Chromium (hexavalent) ................................................... 0.60 NR NA 2 0.1

Cobalt ............................................................................... 142 0.223 166 2.25

Copper ............................................................................. 31.9 0.010 2 67,300 2 1.3

Lead ................................................................................. 130 0.036 3 5 2 0.015

Mercury ............................................................................ 0.23 0.012 3 0.2 2 0.002

Nickel ............................................................................... 76.9 0.128 209 0.75

Selenium .......................................................................... 5.1 0.053 3 1 2 0.05

Silver ................................................................................ 0.5 <0.018 3 5 2 0.188

Thallium ........................................................................... 1.5 <0.002 2 0.65 2 0.002

Tin .................................................................................... 12.1 0.025 1,660 22.46

Vanadium ......................................................................... 75.5 0.014 156 0.263

Zinc .................................................................................. 104000 70.9 2,070 11.25

Cyanide (total) ................................................................. <1.0 NR NA 2 0.2

Cyanide (amenable) ........................................................ NA NR NA NA

Organic Constituents

Acetone ............................................................................ 0.16 NR NA NA

Benzene ........................................................................... 0.009 <0.025 0.089 0.00067

Bis(2-ethylhexyl) phthalate .............................................. 1.6 NR NA 2 0.006

Fluoranthene .................................................................... 0.2 NR NA NA

Methyl ethyl ketone .......................................................... 0.071 <0.250 3 200 22.57

Methylene chloride ........................................................... 0.019 NR NA 2 0.005

Phenanthrene .................................................................. 0.17 <0.010 NA NA

Polychlorinated biphenyls ................................................ 0.22 NR NA 2 0.0005

Pyrene .............................................................................. 0.29 <0.010 9.12 0.065

Tetrachlorethylene ........................................................... 0.034 <0.025 0.197 0.0014

Xylenes ............................................................................ 0.051 NR NA 2 10

Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58027

Constituent

Maximum 1 observed total concentration (mg/kg)

Maximum 1 observed leachate

concentration (mg/L

TCLP)

Maximum allowable

leachate concentration (mg/L TCLP)

Maximum allowable

point of exposure

concentration (mg/L

in groundwater)

Dioxins and furans

2,3,7,8-TCDD ................................................................... 0.000008 NR NA NA

1,2,3,7,8-PeCDD .............................................................. 0.0000026 NR NA NA

1,2,3,4,7,8-HxCDD ........................................................... 0.0000052 NR NA NA

1,2,3,6,7,8-HxCDD ........................................................... 0.0000074 NR NA NA

1,2,3,7,8,9-HxCDD ........................................................... 0.000011 NR NA NA

1,2,3,4,6,7,8-HpCDD ....................................................... 0.00109 NR NA NA

OCDD .............................................................................. 0.159 NR NA NA

2,3,7,8-TCDF ................................................................... 0.0000017 NR NA NA

1,2,3,7,8-PeCDF .............................................................. <0.0000082 NR NA NA

2,3,4,7,8-PeCDF .............................................................. <0.000088 NR NA NA

1,2,3,4,7,8-HxCDF ........................................................... <0.0000086 NR NA NA

1,2,3,6,7,8-HxCDF ........................................................... <0.0000074 NR NA NA

2,3,4,6,7,8-HxCDF ........................................................... <0.0000086 NR NA NA

1,2,3,7,8,9-HxCDF ........................................................... <0.0000097 NR NA NA

1,2,3,4,6,7,8-HpCDF ........................................................ 0.0000062 NR NA NA

1,2,3,4,7,8,9-HpCDF ........................................................ <0.000013 NR NA NA

OCDF ............................................................................... 0.000052 NR NA NA

2,3,7,8-TCDD TEQ4 ......................................................... 0.000182 NR NA NA

1These levels represent the highest constituent concentration found in any one sample, not necessarily the specific levels found in one sample.2The concentration is based on the MCL or TT action level.

3The concentration is based on the toxicity characteristic level in 40 CFR 261.24.

4 Concentrations of individual dioxin and furan congeners in a given sample were combined into a single concentration representing the equivalent concentration of 2,3,7,8-TCDD based on toxicity.

< The constituent was not detected at the stated concentration.

NA Not Applicable.

NR Analysis not run.

In addition to the delisting values in

the table, several delisting levels based

on total concentrations were also

established for USG’s waste. Total

arsenic is limited to 9,280 mg/kg. Total

mercury is limited to 94 mg/kg. Total

PCBs are limited to 0.265 mg/kg. Since

all of the dioxin and furan congeners

exhibit a toxicity which can be related

to 2,3,7,8-TCDD, delisting levels were

not calculated for each congener. Since

the dioxin and furan congeners also

bioaccumulate at different rates than

2,3,7,8-TCDD, the cumulative risk varies

among all dioxin and furan congeners.

The Docket Report on Evaluation of

Contaminant Releases to Surface Water

Resulting from American Metal’s

Petitioned Waste contains congener

specific factors which, when multiplied

by the congener concentration in the

waste, provides the individual risk

posed by each congener. These risks

were summed and compared to the

target risk level of 1×10¥6. None of the

samples analyzed for dioxins and furans

exceeded the target level. The congenerspecific factors for the combined 2,3,7,8-

TCDD delisting level are as follows:

2,3,7,8-TCDD—3.8×10¥2;

1,2,3,7,8-PeCDD—1.8×10¥2;

1,2,3,4,7,8-HxCDD—1.2×10¥3;

1,2,3,6,7,8-HxCDD—4.9×10¥4;

1,2,3,7,8,9-HxCDD—5.43×10¥4

1,2,3,4,6,7,8-HpCDD—2.09×10¥5;

OCDD—5×10¥7;

2,3,7,8-TCDF—2.72×10¥3;

1,2,3,7,8-PeCDF—4.17×10¥4;

2,3,4,7,8-PeCDF—3.04×10¥2;

1,2,3,4,7,8-HxCDF—2.99×10¥4;

1,2,3,6,7,8-HxCDF—7.33×10¥4;

2,3,4,6,7,8-HxCDF—2.46×10¥3;

1,2,3,7,8,9-HxCDF—2.66×10¥3;

1,2,3,4,6,7,8-HpCDF—4.38×10¥6;

1,2,3,4,7,8,9-HpCDF—1.55×10¥4; and

OCDF—6.7×10¥7.

The sum of the products of dioxin and

furan congener concentrations (mg/kg)

and these factors may not exceed

1×10¥6.

B. What Are the Conditions of the

Exclusion?

The proposed exclusion only applies

to the 12,400 cubic yards of landfilled

sludge described in the petition. Any

amount exceeding this volume cannot

be considered delisted under this

exclusion. Furthermore, USG must

dispose of this sludge in a Subtitle D

landfill which is permitted, licensed, or

registered by a state to manage

industrial waste.

USG must also complete additional

verification sampling in order to ensure

that the landfilled sludge meets

delisting requirements. The Docket

Report on Degree of Characterization of

Existing Landfilled Sludge at the

American Metals Corporation Facility,

Westlake, Ohio describes additional

characterization of the landfilled sludge

needed to provide a more adequate

delineation of the spatial distribution of

constituents of concern in the landfilled

sludge. The verification sampling was

evaluated based on the total number of

samples taken thus far, their location,

and the importance of the analytes

based on risk. Composite samples

comprising the vertical extent of the

landfilled sludge at each individual

boring location are to be collected from

six different boring locations within the

landfilled sludge areas. The samples are

to be analyzed for TCLP metals

including antimony, arsenic, barium,

beryllium, cadmium, chromium, lead,

mercury, nickel, selenium, silver,

thallium, tin, vanadium, and zinc. Five

of the borings are to be located within

the larger of the two landfilled sludge

deposits and placed in a manner that

compliments the existing seven samples

identified as WD–1 through WD–4 and

LB1 through LB3. The remaining

verification sample must be collected

from a single boring placed within the

smaller of the two landfilled sludge

deposits.

If, anytime after disposal of the

delisted waste, USG possesses or is

otherwise made aware of any

environmental or waste data (including

but not limited to leachate data or

groundwater monitoring data) or any

other data relevant to the delisted waste

indicating that any constituent

identified in Section VI.A. is at a level

58028 Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules

higher than the delisting level

established in Section VI.A. or is at a

level in groundwater that exceeds the

point of exposure concentration

established in Section VI.A., then USG

must report such data, in writing, to the

Regional Administrator within 10 days

of first possessing or being made aware

of that data.

Based on any information provided by

USG and any other information received

from any source, the Regional

Administrator will make a preliminary

determination as to whether the

reported information requires Agency

action to protect human health or the

environment. Further action may

include suspending, or revoking the

exclusion, or other appropriate response

necessary to protect human health and

the environment.

C. What Happens if USG Fails To Meet

the Conditions of the Exclusion?

If USG violates the terms and

conditions established in the exclusion,

the Agency may start procedures to

withdraw the exclusion.

The EPA has the authority under

RCRA and the Administrative

Procedures Act, 5 U.S.C. 551 (1978) et

seq. (APA), to reopen a delisting

decision if we receive new information

indicating that the conditions of this

exclusion have been violated.

If the Regional Administrator

determines that information reported by

USG as described in Section VI.B., or

information received from any other

source, does require Agency action, the

Regional Administrator will notify USG

in writing of the actions the Regional

Administrator believes are necessary to

protect human health and the

environment. The notice shall include a

statement of the proposed action and a

statement providing USG with an

opportunity to present information as to

why the proposed Agency action is not

necessary or to suggest an alternative

action. USG shall have 10 days from the

date of the Regional Administrator’s

notice to present the information.

If after 10 days, USG presents no

further information, the Regional

Administrator will issue a final written

determination describing the Agency

actions that are necessary to protect

human health or the environment. Any

required action described in the

Regional Administrator’s determination

shall become effective immediately,

unless the Regional Administrator

provides otherwise.

VII. Regulatory Impact

Under Executive Order 12866, EPA

must conduct an ‘‘assessment of the

potential costs and benefits’’ for all

‘‘significant’’ regulatory actions.

The proposal to grant an exclusion is

not significant, since its effect, if

promulgated, would be to reduce the

overall costs and economic impact of

EPA’s hazardous waste management

regulations. This reduction would be

achieved by excluding waste generated

at a specific facility from EPA’s lists of

hazardous wastes, thus enabling a

facility to manage its waste as

nonhazardous.

Because there is no additional impact

from today’s proposed rule, this

proposal would not be a significant

regulation, and no cost/benefit

assessment is required. The Office of

Management and Budget (OMB) has also

exempted this rule from the requirement

for OMB review under Section (6) of

Executive Order 12866.

VIII. Regulatory Flexibility Act

Under the Regulatory Flexibility Act,

5 U.S.C. 601–612, whenever an agency

is required to publish a general notice

of rulemaking for any proposed or final

rule, it must prepare and make available

for public comment a regulatory

flexibility analysis which describes the

impact of the rule on small entities (that

is, small businesses, small

organizations, and small governmental

jurisdictions). No regulatory flexibility

analysis is required, however, if the

Administrator or delegated

representative certifies that the rule will

not have any impact on small entities.

This rule, if promulgated, will not

have an adverse economic impact on

small entities since its effect would be

to reduce the overall costs of EPA’s

hazardous waste regulations and would

be limited to one facility. Accordingly,

the Agency certifies that this proposed

regulation, if promulgated, will not have

a significant economic impact on a

substantial number of small entities.

This regulation, therefore, does not

require a regulatory flexibility analysis.

IX. Paperwork Reduction Act

Information collection and recordkeeping requirements associated with

this proposed rule have been approved

by OMB under the provisions of the

Paperwork Reduction Act of 1980

(Public Law 96–511, 44 U.S.C. 3501 et

seq.) and have been assigned OMB

Control Number 2050–0053.

X. Unfunded Mandates Reform Act

Under section 202 of the Unfunded

Mandates Reform Act of 1995 (UMRA),

P.L. 104–4, which was signed into law

on March 22, 1995, EPA generally must

prepare a written statement for rules

with federal mandates that may result in

estimated costs to state, local, and tribal

governments in the aggregate, or to the

private sector, of $100 million or more

in any one year.

When such a statement is required for

EPA rules, under section 205 of the

UMRA, EPA must identify and consider

alternatives, including the least costly,

most cost-effective, or least burdensome

alternative that achieves the objectives

of the rule. EPA must select that

alternative, unless the Administrator

explains in the final rule why it was not

selected or it is inconsistent with law.

Before EPA establishes regulatory

requirements that may significantly or

uniquely affect small governments,

including tribal governments, EPA must

develop under section 203 of the UMRA

a small government agency plan. The

plan must provide for notifying

potentially affected small governments,

giving them meaningful and timely

input in the development of EPA

regulatory proposals with significant

federal intergovernmental mandates,

and informing, educating, and advising

them on compliance with the regulatory

requirements.

The UMRA generally defines a federal

mandate for regulatory purposes as one

that imposes an enforceable duty upon

state, local, or tribal governments or the

private sector.

The EPA finds that today’s delisting

decision is deregulatory in nature and

does not impose any enforceable duty

on any state, local, or tribal governments

or the private sector. In addition, the

proposed delisting decision does not

establish any regulatory requirements

for small governments and so does not

require a small government agency plan

under UMRA section 203.

XI. Executive Order 12875

Under Executive Order 12875, EPA

may not issue a regulation that is not

required by statute and that creates a

mandate upon a state, local, or tribal

government, unless the federal

government provides the funds

necessary to pay the direct compliance

costs incurred by those governments. If

the mandate is unfunded, EPA must

provide to OMB a description of the

extent of EPA’s prior consultation with

representatives of affected state, local,

and tribal governments; the nature of

their concerns; copies of written

communications from the governments;

and a statement supporting the need to

issue the regulation. In addition,

Executive Order 12875 requires EPA to

develop an effective process permitting

elected officials and other

representatives of state, local, and tribal

governments ‘‘to provide meaningful

and timely input in the development of

Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58029

regulatory proposals containing

significant unfunded mandates.’’

Today’s rule does not create a mandate

on state, local or tribal governments.

The rule does not impose any

enforceable duties on these entities.

Accordingly, the requirements of

section 1(a) of Executive Order 12875 do

not apply to this rule.

XII. Executive Order 13045

Executive Order 13045 is entitled

‘‘Protection of Children from

Environmental Health Risks and Safety

Risks’’ (62 FR 19885, April 23, 1997).

This order applies to any rule that EPA

determines (1) is economically

significant as defined under Executive

Order 12866, and (2) the environmental

health or safety risk addressed by the

rule has a disproportionate effect on

children. If the regulatory action meets

both criteria, the Agency must evaluate

the environmental health or safety

effects of the planned rule on children,

and explain why the planned regulation

is preferable to other potentially

effective and reasonably feasible

alternatives considered by the Agency.

This proposed rule is not subject to

Executive Order 13045 because this is

not an economically significant

regulatory action as defined by

Executive Order 12866.

XIII. Executive Order 13084

Under Executive Order 13084, EPA

may not issue a regulation that is not

required by statute, that significantly

affects or uniquely affects that

communities of Indian tribal

governments, and that imposes

substantial direct compliance costs on

those communities, unless the federal

government provides the funds

necessary to pay the direct compliance

costs incurred by the tribal

governments.

If the mandate is unfunded, EPA must

provide to OMB, in a separately

identified section of the preamble to the

rule, a description of the extent of EPA’s

prior consultation with representatives

of affected tribal governments, a

summary of the nature of their concerns,

and a statement supporting the need to

issue the regulation.

In addition, Executive Order 13084

requires EPA to develop an effective

process permitting elected and other

representatives of Indian tribal

governments ‘‘to meaningful and timely

input’’ in the development of regulatory

policies on matters that significantly or

uniquely affect their communities of

Indian tribal governments. This action

does not involve or impose any

requirements that affect Indian Tribes.

Accordingly, the requirements of

section 3(b) of Executive Order 13084

do not apply to this rule.

XIV. National Technology Transfer and

Advancement Act

Under Section 12(d) of the National

Technology Transfer and Advancement

Act, the Agency is directed to use

voluntary consensus standards in its

regulatory activities unless doing so

would be inconsistent with applicable

law or otherwise impractical.

Voluntary consensus standards are

technical standards (for example,

materials specifications, test methods,

sampling procedures, business

practices, etc.) that are developed or

adopted by voluntary consensus

standard bodies. Where EPA does not

use available and potentially applicable

voluntary consensus standards, the Act

requires that Agency to provide

Congress, through the OMB, an

explanation of the reasons for not using

such standards.

This rule does not establish any new

technical standards, and thus the

Agency has no need to consider the use

of voluntary consensus standards in

developing this proposed rule.

List of Subjects in 40 CFR Part 261

Environmental protection, Hazardous

waste, Recycling, and Reporting and

recordkeeping requirements.

Authority: Sec. 3001(f) RCRA, 42 U.S.C.

6921(f).

Dated: September 19, 2000.

Joseph M. Boyle,

Acting Director, Waste, Pesticides and Toxics

Division.

For the reasons set out in the

preamble, 40 CFR Part 261 is proposed

to be amended as follows:

PART 261—IDENTIFICATION AND

LISTING OF HAZARDOUS WASTE

1. The authority citation for part 261

continues to read as follows:

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

6922, and 6938.

2. In Table 1 of Appendix IX of Part

261 it is proposed to add the following

waste stream in alphabetical order by

facility to read as follows:

58030 Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules

Appendix IX to Part 261—Wastes Excluded Under §§ 260.20 and 260.22

TABLE 1—WASTES EXCLUDED FROM NON-SPECIFIC SOURCES

Facility Address Waste description

*******

American Metals Corporation ........ Westlake, Ohio .............................. Wastewater treatment plant (WWTP) sludges from the chemical conversion coating (phosphating) of aluminum (EPA Hazardous Waste

No. F019) and other solid wastes previously disposed in an on-site

landfill. This is a one-time exclusion for 12,400 cubic yards of

landfilled WWTP sludge. This exclusion was published on (insert

publication date of the final rule).

1. Delisting Levels:

(A) The constituent concentrations measured in the TCLP extract may

not exceed the following levels (mg/L): antimony—1.52; arsenic—

0.691; barium—100; beryllium—3.07; cadmium—1; chromium—5.0;

cobalt—166; copper—67,300; lead—5; mercury—0.2; nickel—209;

selenium—1; silver—5; thallium—0.65; tin—1,660; vanadium—156;

and zinc—2,070.

(B) The total constituent concentrations in any sample may not exceed the following levels (mg/kg): arsenic—9,280; mercury—94;

and polychlorinated biphenyls—0.265.

(C) The sum of the products of dioxin and furan congener concentrations (mg/kg) and the factors defined in Section VI. A. of the preamble may not exceed 1×10¥6.

2. Verification Sampling—Composite samples comprising the vertical

extent of the landfilled sludge at individual boring locations are to

be collected from six different boring locations within the landfilled

sludge areas. The samples are to be analyzed for TCLP metals including antimony, arsenic, barium, beryllium, cadmium, chromium,

lead, mercury, nickel, selenium, silver, thallium, tin, vanadium, and

zinc. Five of the borings are to be located within the larger of the

two landfilled sludge deposits and placed in a manner that compliments the existing seven samples identified as WD–1 through

WD–4 and LB1 through LB3. The remaining verification sample

must be collected from a single boring placed within the smaller of

the two landfilled sludge deposits. The results are to be compared

to the delisting levels in Condition (1)(a). Sludge from which samples collected exceed delisting levels are not delisted. Additional

sampling can be conducted with the approval of U.S. EPA Region 5

in order to isolate the sludge which exceeds the delisting levels

from sludge that meets the delisting levels.

Federal Register / Vol. 65, No. 188 / Wednesday, September 27, 2000 / Proposed Rules 58031

TABLE 1—WASTES EXCLUDED FROM NON-SPECIFIC SOURCES—Continued

Facility Address Waste description

3. Reopener Language—

(a) If, anytime after disposal of the delisted waste, USG possesses or

is otherwise made aware of any data (including but not limited to

leachate data or groundwater monitoring data) or any other data

relevant to the delisted waste indicating that any constituent identified in Condition (1) is at a level higher than the delisting level established in Condition (1), or is at a level in the groundwater at a

level exceeding the point of exposure groundwater levels established in Section VI.A. of the preamble, then USG must report such

data, in writing, to the Regional Administrator within 10 days of first

possessing or being made aware of that data.

(b) Based on the information described in paragraph (a) and any

other information received from any source, the Regional Administrator will make a preliminary determination as to whether the reported information requires Agency action to protect human health

or the environment. Further action may include suspending, or revoking the exclusion, or other appropriate response necessary to

protect human health and the environment.

(c) If the Regional Administrator determines that the reported information does require Agency action, the Regional Administrator will notify USG in writing of the actions the Regional Administrator believes are necessary to protect human health and the environment.

The notice shall include a statement of the proposed action and a

statement providing USG with an opportunity to present information

as to why the proposed Agency action is not necessary or to suggest an alternative action. USG shall have 10 days from the date of

the Regional Administrator’s notice to present the information.

(d) If after 10 days USG presents no further information, the Regional

Administrator will issue a final written determination describing the

Agency actions that are necessary to protect human health or the

environment. Any required action described in the Regional Administrator’s determination shall become effective immediately, unless

the Regional Administrator provides otherwise.

3. Notifications—USG must provide a one-time written notification to

any State Regulatory Agency to which or through which the waste

described above will be transported for disposal at least 60 days

prior to the commencement of such activities. Failure to provide

such a notification will result in a violation of the delisting petition

and a possible revocation of the decision.

*******

* * * * *

[FR Doc. 00–24790 Filed 9–26–00; 8:45 am]

BILLING CODE 6560–50–U

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety

Administration

49 CFR Part 571

[Docket No. 00–7794]

Federal Motor Vehicle Safety

Standards (FMVSS); Small Business

Impacts of School Bus Safety

AGENCY: National Highway Traffic

Safety Administration (NHTSA), DOT.

ACTION: Notice of regulatory review;

extension of comment period.

SUMMARY: This document grants a

request to extend the comment period

on an agency request for comments on

the economic impact of its regulations

on small entities. As required by Section

610 of the Regulatory Flexibility Act, we

are attempting to identify rules that may

have a significant economic impact on

a substantial number of small entities.

We also request comments on ways to

make these regulations easier to read

and understand. The focus of this notice

is rules that specifically relate to school

bus safety.

DATES: Extended comment closing date:

Comments on the September 13, 2000

notice, 65 FR 55212, Docket No. 00–

7794, must be received by the agency on

or before close of business on November

13, 2000.

ADDRESSES: You should mention the

docket number of this document in your

comments and submit your comments

in writing to: Docket Management,

Room PL–401, 400 Seventh Street, SW.,

Washington, DC, 20590. Alternatively,

you may submit your comments

electronically by e-mail at http://

dms.dot.gov.

You may call the Docket at 202–366–

9324, and visit it from 10 a.m. to 5 p.m.,

Monday through Friday.

FOR FURTHER INFORMATION CONTACT: Nita

Kavalauskas, Office of Regulatory

Analysis and Evaluation, Office of Plans

and Policy, National Highway Traffic

Safety Administration, U.S. Department

of Transportation, 400 Seventh Street,

SW., Washington, DC, 20590.

Telephone: (202) 366–2584. Facsimile

(fax): (202) 366–2559.

SUPPLEMENTARY INFORMATION: On

September 13, 2000, NHTSA published

a notice announcing a review of Federal

Motor Vehicle Safety Standards

(FMVSS) relating to school bus safety.

Section 610 of the Regulatory Flexibility

Act of 1980 (Pub. L. 96–354), as

amended by the Small Business

Regulatory Enforcement Fairness Act of

1966 (Pub. L. 104–121), requires

agencies to conduct periodic reviews of