Criteria for the Safe and Environmentally Protective Use of Granular Mine Tailings Known as “Chat”, 16729-16749 [06-3104]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 71, Number 64 (Tuesday, April 4, 2006)]
[Proposed Rules]
[Pages 16729-16749]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-3104]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 278

[EPA-HQ-RCRA-2006-0097; FRL-8050-8]
RIN 2050-AG27


Criteria for the Safe and Environmentally Protective Use of 
Granular Mine Tailings Known as ``Chat''

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA or Agency) is 
proposing mandatory criteria for the environmentally protective use of 
chat for transportation construction projects carried out in whole or 
in part with Federal funds, and a certification requirement. Chat used 
in transportation projects must be encapsulated in hot mix asphalt 
concrete or Portland cement concrete unless the use of chat is 
otherwise authorized by a State or Federal response action undertaken 
pursuant to applicable Federal or State environmental laws. Such 
response actions are undertaken with consideration of risk assessments 
developed in accordance with State and Federal laws, regulations, and 
guidance. EPA is also proposing to establish recommended criteria as 
guidance on the environmentally protective use of chat for non-
transportation cement and concrete projects. The chat covered by this 
proposal is from the lead and zinc mining area of Oklahoma, Kansas and 
Missouri, known as the Tri-State Mining District.

DATES: Submit comments on or before May 4, 2006.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
RCRA-2006-0097, by one of the following methods:
     https://www.regulations.gov: Follow the online instructions 
for submitting comments.
     E-mail: Comments may be sent by electronic mail (e-mail) 
to rcra-docket@epa.gov, Attention Docket ID No. EPA-HQ-RCRA-2006-0097. 
In contrast to EPA's electronic public docket, EPA's e-mail system is 
not an ``anonymous access'' system. If you send an e-mail comment 
directly to the Docket without going through EPA's electronic public 
docket, EPA's e-mail system automatically captures your e-mail address. 
E-mail addresses that are automatically captured by EPA's e-mail system 
are included as part of the

[[Page 16730]]

comment that is placed in the official public docket, and made 
available in EPA's electronic public docket.
     Fax: Comments may be faxed to 202-566-0272.
     Mail: Send two copies of your comments to Criteria for the 
Safe and Environmentally Protective Use of Granular Mine Tailings Known 
as Chat, Environmental Protection Agency, Mailcode: 5305T, 1200 
Pennsylvania Ave., NW., Washington, DC 20460.
     Hand Delivery: Deliver two copies of your comments to the 
Criteria for the Safe and Environmentally Protective Use of Granular 
Mine Tailings Known as Chat Docket, EPA/DC, EPA West, Room B102, 1301 
Constitution Ave., NW., Washington, DC 20460. Such deliveries are only 
accepted during the Docket's normal hours of operation, and special 
arrangements should be made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-RCRA-
2006-0097. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
https://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through https://
www.regulations.gov or e-mail. The https://www.regulations.gov Web site 
is an ``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an e-mail comment directly to EPA without 
going through https://www.regulations.gov, your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses. For additional information about EPA's public 
docket visit the EPA Docket Center homepage at https://www.epa.gov/
epahome/dockets.htm. For additional instructions on submitting 
comments, go to the SUPPLEMENTARY INFORMATION section of this document.
    Docket: All documents in the docket are listed in the https://
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in https://www.regulations.gov or in hard copy at the Criteria for the 
Safe and Environmentally Protective Use of Granular Mine Tailings Known 
as Chat Docket, EPA/DC, EPA West, Room B102, 1301 Constitution Ave., 
NW., Washington, DC. This Docket Facility is open from 8:30 a.m. to 
4:30 p.m., Monday through Friday, excluding legal holidays. The Docket 
telephone number is (202) 566-0270. The Public Reading Room is open 
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal 
holidays. The telephone number for the Public Reading Room is (202) 
566-1744, and the telephone number for the Criteria for the Safe and 
Environmentally Protective Use of Granular Mine Tailings Known as Chat 
Docket is (202) 566-0270.

FOR FURTHER INFORMATION CONTACT: Stephen Hoffman, Office of Solid Waste 
(5306W), U.S. Environmental Protection Agency, Ariel Rios Building, 
1200 Pennsylvania Avenue, NW., Washington, DC 20460-0002, telephone 
(703) 308-8413, e-mail address hoffman.stephen@epa.gov. For more 
information on this rulemaking, please visit https://www.epa.gov/
epaoswer/other/mining/chat/.

SUPPLEMENTARY INFORMATION:

I. Does This Action Apply To Me?

    These proposed criteria may affect the following entities: 
Aggregate, asphalt, cement, and concrete facilities, likely limited to 
the tri-state mining area. Other types of entities not listed could 
also be affected. To determine whether your facility, company, 
business, organization, etc., is affected by this action, you should 
examine the applicability criteria in Section I.B.6 of this preamble. 
If you have any questions regarding the applicability of this action to 
a particular entity, consult the person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section.

II. What Should I Consider as I Prepare My Comments for EPA?

    1. Tips for Preparing Your Comments. When submitting comments, 
remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Follow directions--The agency may ask you to respond to 
specific questions or organize comments by referencing a Code of 
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree; suggest alternatives 
and substitute language for your requested changes.
     Describe any assumptions and provide any technical 
information and/or data that you used.
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns, and 
suggest alternatives.
     Explain your views as clearly as possible.
     Make sure to submit your comments by the comment period 
deadline identified.
    2. Docket Copying Costs. The first 100 copies are free. Thereafter, 
the charge for making copies of Docket materials is 15 cents per page.

III. How Should I Submit CBI to the Agency?

    Do not submit information that you consider to be CBI 
electronically through https://www.regulations.gov or by e-mail. Send or 
deliver information identified as CBI only to the following address: 
RCRA CBI Document Control Officer, Office of Solid Waste (5305W), U.S. 
EPA, 1200 Pennsylvania Avenue, NW., Washington, DC 20460, Attention 
Docket ID No. EPA-HQ-RCRA-2006-0097. You may claim information that you 
submit to EPA as CBI by marking any part or all of that information as 
CBI (if you submit CBI on disk or CD ROM, mark the outside of the disk 
or CD ROM as CBI and then identify electronically within the disk or CD 
ROM the specific information that is CBI). Information so marked will 
not be disclosed, except in accordance with procedures set forth in 40 
CFR Part 2.
    In addition to one complete version of the comment that includes 
any information claimed as CBI, a copy of the comment that does not 
contain the information claimed as CBI must be submitted for inclusion 
in the public docket and EPA's electronic public docket. If you submit 
the copy that does not contain CBI on disk or CD ROM, mark the outside 
of the disk or CD ROM clearly that it does not contain CBI. Information 
not marked as CBI will be included in the public docket and EPA's 
electronic public docket without prior

[[Page 16731]]

notice. If you have any questions about CBI or the procedures for 
claiming CBI, please contact: LaShan Haynes, Office of Solid Waste 
(5305W), U.S. Environmental Protection Agency, Ariel Rios Building, 
1200 Pennsylvania Avenue, NW., Washington, DC 20460-0002, telephone 
(703) 605-0516, e-mail address haynes.lashan@epa.gov.
    The contents of the SUPPLEMENTARY INFORMATION are listed in the 
following outline:

I. Background Information
    A. What Is the Statutory Authority for This Action?
    B. What Action Is EPA Taking?
    1. What Is Chat?
    2. What Is the Areal Scope for This Action?
    3. Are There Any Current Regulations or Criteria for the 
Management or Use of Chat?
    4. Physical and Chemical Characteristics of Chat.
    5. What Are the Environmental and Health Effects Associated with 
Pollutants Released From Raw Chat?
    6. Who Is Affected by This Action?
    C. What Was the Process EPA Used in Developing This Action?
II. Summary of the Proposed Rule
    A. What Criteria Are EPA Establishing for the Use of Chat?
    1. Transportation Construction Uses
    a. What is our proposed action?
    b. What is the rationale for the Proposed Rule?
    c. Is the EPA soliciting comments on specific issues?
    2. Non-Transportation Uses--Cement and Concrete Projects
    a. What is our proposed approach?
    b. What is the rationale for the Proposed Rule?
    c. Is the EPA soliciting comments on specific issues?
    B. Relationship of Proposed Criteria to Other State and Federal 
Regulations and Guidance
    C. How Does This Proposal Affect Chat Sales From Lands 
Administered by the U.S. Bureau of Indian Affairs or Directly from 
Tribal Lands?
    D. How Does This Proposal Affect CERCLA Liability, Records of 
Decision, and Removal Decisions?
III. Impacts of the Proposed Rule
    A. What Are the Potential Environmental and Public Health 
Impacts From the Use of Chat?
    B. What Are the Economic Impacts?
IV. Executive Orders and Laws Addressed in This Action
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act of 1995
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

    For the purposes of this action, the Agency defines the following 
terms as follows:
     Encapsulated--incorporated into hot mix asphalt concrete 
or Portland cement concrete (PCC).
     Hot mix asphalt--a hot mixture of asphalt binder and size-
graded aggregate, which can be compacted into a uniform dense mass.
     Pozzolanic--a silica and lime containing material which, 
in the presence of moisture, forms a strong cement.
     State or Federal remediation action--State or federal 
response action undertaken pursuant to applicable federal or state 
environmental laws. Such response actions are undertaken with 
consideration of risk assessments developed in accordance with state 
and or federal laws, regulations, and guidance.
     Raw chat--unmodified lead-zinc ore milling waste.
     Washed chat--lead-zinc ore milling waste that has been 
wet-screened to remove the fine-grained fraction and which is sized so 
as not to pass through a number 40 sieve (0.425 mm opening size) or 
smaller.
     Sized chat--lead-zinc ore milling waste that has been wet-
screened (washed) or dry sieved to remove the fine-grained fraction 
smaller than a number 40 sieve (0.425 mm opening size).
     Non-transportation cement and concrete projects are:

--Construction uses of cement and concrete for non-residential 
structural uses limited to weight bearing purposes such as foundations, 
slabs, and concrete wall panels. Other uses include commercial/
industrial parking and sidewalk areas. Uses do not include the 
residential use of cement or concrete (e.g., concrete counter tops).
     Transportation construction uses \1\ are:
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    \1\ User Guidelines for Waste and By-Product Materials in 
Pavement Construction Publication No. FHWA-RD-97-148 April 1998, 
U.S. Department of Transportation, Federal Highway Administration.

--Asphalt concrete--pavement consists of a combination of layers, which 
include an asphalt surface constructed over an asphalt base and an 
asphalt subbase. The entire pavement structure is constructed over the 
subgrade. Pavements, bases, and subbases must be constructed using hot 
mix asphalt.
--Portland cement concrete--(PCC) pavements consisting of a PCC slab 
that is usually supported by a granular (made of compacted aggregate) 
or stabilized base and a subbase. In some cases, the PCC slab may be 
overlaid with a layer of asphalt concrete. Uses include bridge 
supports, bridge decking, abutments, highway sound barriers, jersey 
walls, and non-residential side walks adjacent to highways.
--Flowable fill--refers to a cementitious slurry consisting of a 
mixture of fine aggregate or filler, water, and cementitious materials 
which is used primarily as a backfill in lieu of compacted earth. This 
mixture is capable of filling all voids in irregular excavations, is 
self leveling, and hardens in a matter of a few hours without the need 
of compaction in layers. Most applications for flowable fill involve 
unconfined compressive strengths of 2.1 MPa (300 lb/in\2\) or less.
--Stabilized base--refers to a class of paving materials that are 
mixtures of one or more sources of aggregate and cementitious materials 
blended with a sufficient amount of water that result in the mixture 
having a moist nonplastic consistency that can be compacted to form a 
dense mass and gain strength. The class of base and subbase materials 
is not meant to include stabilization of soils or aggregates using 
asphalt cement or emulsified asphalt.
--Granular bases--are typically constructed by spreading aggregates in 
thin layers of 150 mm (6 inches) to 200 mm (8 inches) and compacting 
each layer by rolling over it with heavy compaction equipment. The 
aggregate base layers serve a variety of purposes, including reducing 
the stress applied to the subgrade layer and providing drainage for the 
pavement structure. The granular subbase forms the lowest (bottom) 
layer of the pavement structure and acts as the principal foundation 
for the subsequent road profile.
--Embankment--refers to a volume of earthen material that is placed and 
compacted for the purpose of raising the grade of a roadway above the 
level of the existing surrounding ground surface.
     Unencapsulated--material that is not incorporated into hot 
mix asphalt concrete or Portland cement concrete.

[[Page 16732]]

Abbreviations and Acronyms Used in This Document

CAA--Clean Air Act (42 USCA 7401).
CERCLA--Comprehensive Environmental Response Compensation and Liability 
Act (42 USCA 9601).
CFR--Code of Federal Regulations.
CWA--Clean Water Act (33 USCA 1251).
EPA--Environmental Protection Agency.
FHWA--Federal Highway Administration.
FR--Federal Register.
ICR--Information Collection Request.
MCL--Maximum Contaminant Level (Safe Drinking Water Act).
NPL--National Priorities List.
ppmv--parts per million by volume.
ppmw--parts per million by weight.
Pub. L.--Public Law.
RCRA--Resource Conservation and Recovery Act (42 USCA 6901).
SMCL--Secondary Maximum Contaminant Level (Safe Drinking Water Act).
SPLP--Synthetic Precipitation Leaching Procedure (SW 846 Method 1312).
TCLP--Toxicity Characteristic Leaching Procedure (SW 846 Method 1311).
U.S.C.--United States Code.
DOT--United States Department of Transportation.

I. Background Information

A. What Is the Statutory Authority for This Action?

    Through Title VI, Section 6018 of the Safe, Accountable, Flexible, 
and Efficient Transportation Equity Act of 2005 (H.R. 3 or ``the 
Act''), Congress amended Subtitle F of the Solid Waste Disposal Act (42 
U.S.C. 6961 et seq.) by adding Sec. 6006. This provision requires the 
Agency to develop environmentally protective criteria (including an 
evaluation of whether to establish a numerical standard for 
concentration of lead and other hazardous substances) for the safe use 
of granular mine tailings from the Tar Creek, Oklahoma Mining District, 
known as `chat,' in cement and concrete projects and in transportation 
construction projects that are carried out, in whole or in part, using 
Federal funds. Section 6006(a)(4) requires that any use of the granular 
mine tailings in a transportation project that is carried out, in whole 
or in part, using Federal funds, meet EPA's established criteria.
    In establishing these criteria, Congress directed EPA to consider 
the current and previous uses of granular mine tailings as an aggregate 
for asphalt and any environmental and public health risks from the 
removal, transportation, and use in transportation projects of granular 
mine tailings; i.e., chat. The Act also directs EPA to solicit and 
consider comments from the public, and to consult with the Secretary of 
Transportation and the heads of other Federal agencies in establishing 
the criteria.

B. What Action Is EPA Taking?

    In today's action, we are proposing, and requesting comment on, 
criteria requiring encapsulation in hot mix asphalt concrete or 
Portland cement concrete, for granular mine tailings, known as `chat,' 
from the Tri-State lead and zinc mining area of Oklahoma, Kansas and 
Missouri, used in transportation construction projects that are carried 
out, in whole or in part, using Federal funds. EPA is also proposing 
that the requirement of encapsulation in asphalt concrete or Portland 
cement concrete would not apply if the use of chat is otherwise 
authorized by a State or federal response action undertaken pursuant to 
applicable federal or state environmental laws. Such response actions 
are undertaken with consideration of risk assessments developed in 
accordance with state and federal laws, regulations, and guidance. For 
example, unencapsulated uses of chat may be authorized in a State or 
federal remediation action. EPA is proposing that these criteria would 
apply to the use of chat derived from the Tri-State area, wherever the 
use occurs, including outside of the Tri-state area. Section 6006(a)(4) 
mandates that transportation construction projects, carried out in 
whole or in part, using Federal funds, must comply with these criteria.
    The Agency is also proposing recommended criteria as guidance on 
the encapsulation of chat in non-transportation uses, to identify those 
uses that EPA believes are environmentally protective. Such uses would 
be limited to those where the Agency has reasonable assurances that 
such uses inherently limit direct exposure. It should be pointed out 
that the Agency has reviewed the literature and conducted interviews 
with Oklahoma, Kansas, and Missouri regulatory officials and Tribes and 
has determined that there is no evidence that chat is currently being 
used in non-transportation construction projects.
1. What Is Chat?
    Chat is the waste material that was formed in the course of milling 
operations employed to recover lead and zinc from metal-bearing ore 
minerals in the Tri-State mining district of Southwest Missouri, 
Southeast Kansas and Northeast Oklahoma. Chat is primarily composed of 
chert, a very hard rock. The primary properties that make chat useful 
in asphalt and concrete are grain size distribution, durability, non-
polishing, and low absorption.
2. What Is the Areal Scope for This Action?
    The Act directed EPA to develop criteria for chat from the Tar 
Creek, Oklahoma Mining District. There is no definition of the term 
``Tar Creek Oklahoma Mining District.'' Available literature references 
the ``Tar Creek Superfund site,'' which is in Oklahoma, but the term 
``mining district'' is only used in reference to the ``Tri-State Mining 
District.'' For purposes of today's action, the Agency is proposing the 
areal scope to include chat originating from the Tri-State mining 
district of Ottawa County, Oklahoma, Cherokee County of southeast 
Kansas and Jasper and Newton Counties of southwest Missouri, regardless 
of where it is used.
    In 1979, the U.S. Bureau of Mines completed a study to identify all 
mined areas and mine-related hazards which confirmed that lead-zinc 
mining covers a portion of each of the States of Kansas, Missouri, and 
Oklahoma. This area is the same area known as the Tri-State mining 
district.
    Chat located in the Tri-State historical mining district is a 
product of similar mineralization processes that sets it aside from 
related lead-zinc mineralization districts elsewhere in the United 
States. The Tri-State mineralization is specifically associated with 
wall rock alteration into dolomite and microcrystalline silica (chert). 
The term chat is derived from the word `chert,' which is from the 
cherty wallrock found in this mining district. The lead/zinc ore and 
its related waste, chat, in this district also have a well defined lead 
to zinc ratio.
    During close to one hundred years of activity ending in 1970, the 
Tri-State mining district has been the source of a major share of all 
the lead and zinc mined in the United States. Surface piles of chat, as 
well as underground mining areas, extend uninterrupted across the 
Oklahoma-Kansas state line. In communications with Kansas, Missouri, 
and Oklahoma environmental regulatory agencies and the departments of 
transportation and Tribes, government experts confirmed that there is 
no real factual distinction between chat derived from these three 
areas, and agreed that it would be reasonable to apply today's proposal 
to

[[Page 16733]]

the areal extent of the Tri-State mining district. Therefore, in 
today's action, the Agency is proposing criteria that extends to all 
chat generated and currently located in the following counties: Ottawa 
county, Oklahoma, Cherokee county, Kansas, and Newton and Jasper 
counties in Missouri.
    Given the ambiguity in the term ``Tar Creek Oklahoma Mining 
District,'' the Agency is soliciting comment on whether it should limit 
the scope of today's action to chat only located in Oklahoma. There is 
also some uncertainty regarding the exact boundary of the Tri-State 
mining district. The Agency is therefore soliciting comments on whether 
additional counties, such as Lawrence and Barry Counties in southwest 
Missouri, should be added to the scope.
3. Are There Any Current Regulations or Criteria for the Management or 
Use of Chat?
    During the preparation of this proposal, the Agency assessed 
existing regulations in Oklahoma, Kansas, and Missouri for hot mix 
asphalt plants, and cement plants to determine whether residual chat 
wastes from those operations are adequately managed. (See memorandum 
entitled: ``Evaluation of State Regulations'' in the docket.) Those 
regulations set standards for point and fugitive air emission sources 
and also set requirements for water discharges from point and non-point 
discharges. Each State also has fugitive dust and point source 
particulate emission permitting requirements for both hot mix asphalt 
plants and ready mix concrete plants.
     Kansas air quality regulations require a Class II point 
source particulate operating permit for hot mix asphalt and ready mix 
concrete plants (K.A.R. 28-19-500). Operators must comply with all 
applicable air quality regulations whether or not addressed in the 
permit. Missouri requires an operating permit for all facilities with 
the potential to emit any point source particulate matter of 25 tons 
per year or more, or particulate matter with a diameter less than or 
equal to 10 micrometers (PM10) in the amount of 10 tons per 
year or more (10 CSR 10-6.065). Missouri regulations require operators 
to comply with the State's air quality control requirements, including 
restrictions on point source particulate emissions beyond the premises 
of origin (10 CSR 10-6.170). Oklahoma requires a point source air 
pollution control operating permit for new minor facilities (OAC 
252:100-7) and all facilities with the potential to emit 100 tons per 
year, or more, of any criteria pollutant (which includes particulate 
matter), or 10 tons per year of any hazardous air pollutant or 25 tons 
per year of any combination of hazardous air pollutants (OAC 252:100-
8). Oklahoma regulations require that operators not exceed ambient air 
quality standards (OAC 252:100-29).
     In Oklahoma and Missouri, stormwater runoff is regulated 
through stormwater discharge permits (OAC 252:606-5-5, 10 CSR 20-
6.200). Oklahoma's Pollutant Discharge Elimination System Standards 
incorporate the National Pollutant Discharge Elimination System (NPDES) 
standards. Oklahoma also has a general permit for stationary and mobile 
concrete batch plants. In Kansas, stormwater discharges are regulated 
under the State's water quality regulations (K.A.R. 28-16). The 
regulations prohibit degradation of surface and groundwater and set 
effluent limitations for aquatic, livestock, and domestic uses. Kansas 
has not finalized its General Permit for Stormwater Discharges 
Associated from Industrial Activity; however, facility operators are 
required to file a Notice of Intent to discharge under the NPDES 
requesting coverage under the State's general water pollution control 
permit. Operators are also required to develop and implement a 
Stormwater Pollution Prevention plan. Permittees are obligated to 
comply with the general permit which sets effluent limitations and 
monitoring requirements.
     The Agency also assessed existing regulations in Oklahoma, 
Kansas, and Missouri for chat washing facilities to determine whether 
residual chat wastes from those operations are adequately managed. The 
Agency found that the States do not have regulations specific to chat 
washing facilities. However, these facilities are covered under the 
States' general fugitive air and general non-point source discharge 
regulations. These state general permits require that fugitive dusts 
and runoff be controlled in a fashion so that dusts do not leave the 
property line or the boundary of the construction activity. 
Additionally, the Bureau of Indian Affairs (BIA) is establishing air 
and water standards for chat washing facilities for chat originating on 
Tribal lands and lands administered by BIA. BIA's requirements include 
that the chat washing facility manage waste water discharges so that 
they do not exceed state standards, that fugitive dusts be controlled, 
and that fines are handled and disposed of so that they do not 
contaminate ground water.
     BIA is requiring all purchasers of chat from Tribal lands, 
or lands administered by BIA, to certify that the chat will be used in 
accordance with authorized uses set forth in EPA fact sheets and other 
guidance. (See report titled, Chat Sales Treatability Study Workplan 
for the Sale of Indian-owned Chat within the Tar Creek Superfund Site, 
Ottawa County, Oklahoma, June 23, 2005.) BIA also requires that trucks 
transporting chat from Tribal lands be covered to prevent blowing dust 
from the chat.
     The Oklahoma Department of Environmental Quality (ODEQ) 
has determined that the following transportation uses of chat are 
inappropriate: Use in residential driveways and use as gravel or 
unencapsulated surface material in parking lots, alleyways, or roadways 
(See A Laboratory Study to Optimize the Use of Raw Chat in Hot Mix 
Asphalt for Pavement Application: Final Report, August 2005 \2\). The 
ODEQ report also identified the following non-transportation uses of 
raw chat that are deemed inappropriate:
---------------------------------------------------------------------------

    \2\ The University of Oklahoma 2005 study entitled, A Laboratory 
Study to Optimize the Use of Raw Chat in Hot Mix Asphalt for 
Pavement Application, was reviewed internally by Drs. Tom Landers, 
Robert Knox, and Joakim Laguros and externally reviewed by various 
Oklahoma Department of Environmental Quality personnel. This report 
was designed to meet USEPA 1994 Data Quality Objectives which assure 
proper study design, sample collection and sample analyses. A 
separate Sampling and Analysis Plan was prepared for this effort 
which includes a QA/QC plan which was managed by a OU Quality 
Assurance Officer. Samples were collected and analyzed in accordance 
with EPA methods and lab results were verified by outside 
laboratories.

--Fill material in yards, playgrounds, parks, and ball fields.
--Playground sand or surface material in play areas.
--Vegetable gardening in locations with contaminated chat.
--Surface material for vehicular traffic (e.g., roadways, alleyways, 
driveways, or parking lots).
--Sanding of icy roads.
--Sandblasting with sand from tailings ponds or other chat sources.
--Bedding material under a slab in a building that has underfloor air 
conditioning or heating ducts.
--Development of land for residential use (e.g., for houses or for 
children's play areas, such as parks or playgrounds) where visible chat 
is present or where the Pb concentration in the soil is equal to or 
greater than 500 mg/kg unless the direct human contact health threat is 
eliminated by engineering controls (e.g., removing the contaminated 
soil or capping the contaminated soil with at least 18 inches of clean 
soil).


[[Page 16734]]


     EPA Region 6 issued a Tar Creek Mining Waste Fact Sheet on 
June 28, 2002 that identified the following as acceptable uses of chat: 
(1) Applications that bind (encapsulate) the chat into a durable 
product (e.g., concrete and asphalt), (2) applications that use the 
chat as a material for manufacturing a safe product where all waste 
byproducts are properly disposed, and (3) applications that use the 
chat as sub-grade or base material for highways (concrete and asphalt) 
designed and constructed to sustain heavy vehicular traffic. This fact 
sheet also incorporated the ODEQ list of unacceptable uses of chat. The 
Region 6 fact sheet is available at https://www.epa.gov/Arkansas/6sf/
pdffiles/tar_creek_june_2002_waste.pdf.
     EPA Region 7 issued a Mine Waste Fact Sheet in 2003 that 
identified uses of chat that are not likely to present a threat to 
human health or the environment. Those uses are: (1) Applications that 
bind material into a durable product; these would include its use as an 
aggregate in batch plants preparing asphalt and concrete, (2) 
applications below paving on asphalt or concrete roads and parking 
lots, (3) applications that cover the material with clean material, 
particularly in areas that are not likely to ever be used for 
residential or public area development, and (4) applications that use 
the material as a raw product for manufacturing a safe product. The 
fact sheet also lists mine waste (chat) uses that may present a threat 
to human health or the environment which are similar to those listed by 
ODEQ and the Region 6 fact sheet. However, the Region 7 fact sheet also 
lists use as an agricultural soil amendment to adjust soil alkalinity 
as a use that may present a threat to human health or the environment. 
The Region 7 fact sheet is available at https://www.epa.gov/Region7/
news_events/factsheets/fs_minewaste_moks_0203.pdf.
    A copy of these regulations/reports/fact sheets are available in 
the Docket to today's rulemaking.
    Based on the review of the States' regulations, EPA concludes that 
today's proposal does not need to establish additional criteria to 
address any environmental concerns arising from hot mix asphalt and 
batch concrete facilities or from chat washing facilities. The Agency 
believes that potential fugitive dust emissions and stormwater runoff 
from chat piles are adequately addressed by existing State regulations. 
Additionally, as stated previously, BIA requires covers on trucks 
transporting chat from Tribal lands to prevent blowing of chat dust. 
However, the Agency seeks information and comment on the adequacy of 
state and BIA requirements and solicits comment on requiring truck 
covers for transportation of chat. To address potential leaching to 
groundwater and runoff to surface streams, the Agency solicits comment 
on whether to require storage to be designed to control run-on and run-
off, leachate to ground water, fugitive dusts, and that chat be stored 
in a building, or on a concrete, clay, or synthetic lined pad, or 
covered, if storage exceeds 90 days.\3\
---------------------------------------------------------------------------

    \3\ While the Agency is not proposing that chat be sized before 
it is encapsulated, we are aware that chat is sized before it is 
beneficially used in certain instances. In these instances, we would 
expect that any residuals that are generated would be handled in 
connection with the remediation plans at the site.
---------------------------------------------------------------------------

    Furthermore, as discussed later in the preamble, the Agency expects 
that most chat used will be used within the Tri-state area because of 
transportation costs. Thus, the Agency has only evaluated the air and 
water rules in Oklahoma, Missouri and Kansas. However, there is nothing 
in this rule that would limit its use in these three states. Therefore, 
the Agency solicits comment on whether it should adopt general criteria 
for the management of chat in today's rule if the chat is managed in 
other states or whether other states would have similar types of 
controls that Oklahoma, Missouri and Kansas have in place.
    Today's action would require that chat used in Federally funded 
transportation projects be encapsulated in hot mix asphalt or concrete, 
unless the use is otherwise authorized by a State or federal response 
action. Such response actions are undertaken with consideration of risk 
assessments developed in accordance with state and federal laws, 
regulations, and guidance. This mandatory criteria is more restrictive 
than the guidances issued by Regions 6 and 7 since it is the Agency's 
current belief that the use of unencapsulated chat should be restricted 
to state or federal remediation actions, where a regulatory agency 
exerts oversight. This position was taken because the data generally 
lead EPA to believe that unencapsulated uses are not protective of 
human health and the environment. However, because state and federal 
remediation actions are based on site specific determinations that take 
into account a wide variety of factors at the site, EPA believes that 
such assessments provide sufficient safeguards that would ensure that 
any unencapsulated uses of chat authorized through this mechanism would 
be protective of human health and the environment.
4. Physical and Chemical Characteristics of Chat
    Some of the important physical properties of chat include hardness, 
soundness (durability), gradation, shape and surface texture. Bulk raw 
chat includes both large and small particle sizes.
Physical Characteristics
    In a University of Oklahoma (OU) study (A Laboratory Study to 
Optimize the Use of Raw Chat in Hot Mix Asphalt for Pavement 
Application: Final Report (August 2005)), the specific gravity of the 
raw chat was found to be 2.67, which is similar to some commonly used 
aggregates such as limestone and sandstone.
    According to an ODEQ study (``Summary of Washed and Unwashed Mining 
Tailings (Chat) from Two Piles at the Tar Creek Superfund Site, Ottawa 
County Oklahoma,'' Revised June 2003), chat consists of materials 
ranging in diameter from 15.875 mm (\5/8\ inch) to less than 0.075 mm 
(the size fraction that passes the No. 200 sieve).
    Since raw chat is a crushed material from mining operations, raw 
chat particles have fractured faces. Raw chat also has numerous voids 
in the loose aggregate form. The more angular the aggregate the higher 
the amount of voids. The uncompacted void content or the fine aggregate 
angularity of raw chat was found to be 46%. Raw chat has higher fine 
aggregate angularity than required by most state DOTs.
    Raw chat is harder than some other aggregates such as limestone. 
The L.A. abrasion value (determined by the Test for Resistance to 
Degradation of Aggregate by Abrasion and Impact in the Los Angeles 
Abrasion Machine) of raw chat was found to be 18% which is lower than 
that of limestone (23%) used in the OU study.
    Cubical shape is a desirable property of a good aggregate. The 
coarse aggregate in raw chat (particles retained on a 4.75 mm 
(4) sieve) has less than 5% flat or elongated particles. 
Therefore, chat is viewed as a desirable aggregate material.
    State DOTs specify minimum aggregate durability indices of 
approximately 40%. In the OU study, the aggregate durability index of 
raw chat was found to be 78%. The insoluble residue of raw chat was 
found to be 98%. The minimum requirement for insoluble residue is 40%.
    State DOTs also specify aggregate requirements for hot mix asphalt 
and Portland cement concrete. Most State DOTs, including Kansas, 
Oklahoma and Missouri, have adopted aggregate standards developed by 
the American

[[Page 16735]]

Association of State Highway and Transportation Officials (AASHTO). 
According to AASHTO, the 0.075 mm (200) sieve size is the 
dividing line between sand-size particles and the finer silts and 
clays. These finer particles often adhere to larger sand and gravel 
particles and can adversely affect the quality of hot mix asphalt 
cement and Portland cement concrete. The AASHTO standards for Fine 
Aggregate for Bituminous Paving Mixtures (M 29-03) and Fine Aggregate 
for Portland Cement Concrete (M 6-03) specify limits for the amount of 
aggregate, on a percent mass basis, in hot mix asphalt cement and 
Portland cement concrete according to aggregate size and gradation. The 
aggregate sizes included in the AASHTO standards range from .075 mm to 
9.5 mm which is within the range of particles found in raw chat. The 
AASHTO standards do not preclude the use of fine chat particles in hot 
mix asphalt or Portland cement concrete. Depending on the designated 
grading, AASHTO limits particles finer than sieve size 50 in 
the range of 7 to 60% for aggregate in asphalt. Fine aggregate for use 
in concrete is limited by the States of Oklahoma and Missouri to 5 to 
30% for particles less than sieve size 50, while the values 
are 7 to 30% in Kansas.
Chemical Characteristics
    Two studies [Dames and Moore, 1993 and 1995; ``Sampling and Metal 
Analysis of Chat Piles in the Tar Creek Superfund sites for the 
Oklahoma Department of Environmental Quality,'' 2002; Datin and Cates; 
``Summary of Washed and Unwashed Mining Tailings (Chat) from Two Piles 
at the Tar Creek Superfund Site, Ottawa County Oklahoma, Revised June 
2003,'' ODEQ] provide data on metals concentrations in washed and 
unwashed (or raw) chat. The Dames and Moore study indicated total lead 
concentrations in the raw chat ranged from 100 mg/kg to 1,660 mg/kg, 
while the Datin and Cates study noted that lead concentrations from 
piles located throughout the Tri-State area had mean total lead 
concentrations of 476 to 971 mg/kg. The Site Characterization report 
[AATA International, Inc. December 2005; Draft: Remedial Investigation 
Report for Tar Creek OU4 RI/FS Program] notes, however, that the 
concentration of lead in the raw chat ranged from 210 mg/kg to 4,980 
mg/kg with an average of 1,461 mg/kg; cadmium ranged from 43.1 mg/kg to 
199.0 mg/kg with an average of 94.0 mg/kg; and zinc ranged from 10,200 
mg/kg to 40,300 mg/kg with an average of 23,790 mg/kg.
    These studies also showed that as chat sizes become smaller, the 
metals content increases. The Datin and Cates report, ``Summary of 
Washed and Unwashed Mining Tailings (Chat) from Two Piles at the Tar 
Creek Superfund Site, Ottawa County Oklahoma, Revised June 2003,'' 
noted TCLP testing of all dry sieve sizes greater than 40 do not exceed 
5mg/l and could be classified as non-hazardous under RCRA.\4\ This same 
study also shows that total metals testing of wet screened material 
(larger fractions) resulting from chat washing have lead concentrations 
which range from 116 to 642 mg/kg, while TCLP testing of the same 
materials have lead concentrations of 1.028 to 3.938 mg/l (also well 
below 5mg/l). Therefore, the data show that either dry physical sieving 
of raw chat or chat washing generate chat aggregate (greater than sieve 
size 40) with considerably lower metals concentrations than raw chat.
---------------------------------------------------------------------------

    \4\ Since chat is a mining waste covered by the Bevill Amendment 
to the Solid Waste Disposal Act, it is not subject to the hazardous 
waste regulations under RCRA Subtitle C. However, we are using the 
TCLP leachate value for lead simply as a comparative measure.
---------------------------------------------------------------------------

5. What Are the Environmental and Health Effects Associated With 
Pollutants Released From Raw Chat?
    The Tri-State mining district includes four National Priority List 
(NPL) Superfund sites that became contaminated from the mining, 
milling, and transportation of ore and the management practices for 
chat. These sites are located in Tar Creek in Ottawa County, Oklahoma, 
Cherokee County in southeast Kansas, and Jasper and Newton Counties in 
southwest Missouri. Cleanup activities related to the millions of tons 
of mining waste that were deposited on the surface of the ground at 
these sites have been designated as Operable Units (OUs). OUs are 
groupings of individual waste units at NPL sites based primarily on 
geographic areas and common waste sources.
    Raw chat has caused threats to human health and the environment as 
a result of the concentrations of lead present in the chat. Evaluation 
of raw chat, noted above, also indicates that this waste in 
unencapsulated uses has the potential to leach lead into the 
environment at levels which may cause threats to humans (elevated blood 
lead concentrations in area children). Such threats have been fully 
documented in Records of Decision (RODs) for the OUs at these NPL sites 
(See Tri-State Mining District RODs in the docket to this action). 
Copies of Site Profiles and RODs can be searched at https://www.epa.gov/
superfund/sites/rods/index.htm.
    Lead toxicity targets the nervous system, both in adults and 
children. Long-term exposure of adults can result in decreased 
performance of the nervous system. It may also cause weakness in the 
fingers, wrists, or ankles. Lead exposure also causes small increases 
in blood pressure, particularly in middle-aged and older people and can 
cause anemia. Exposure to high lead levels can severely damage the 
brain and kidneys in adults or children and ultimately cause death. 
(Agency for Toxic Substances and Disease Registry (ATSDR) Fact Sheet 
for Lead, September 2005.)
    Recent risk assessments conducted at the Tar Creek NPL site 
indicate that cadmium and zinc may not pose a human health risk. 
Nevertheless, breathing high levels of cadmium may severely damage the 
lungs and can cause death. Eating food or drinking water with high 
levels of cadmium may severely irritate the stomach, leading to 
vomiting and diarrhea. Long-term exposure to lower levels of cadmium in 
air, food, or water may lead to a buildup of cadmium in the kidneys and 
possible kidney disease. Other long-term effects are lung damage and 
fragile bones. (ATSDR Fact Sheet for Cadmium, June 1999.)
    Zinc in the aquatic environment is of particular importance because 
the gills of fish are physically damaged by high concentrations of zinc 
(NAS1979). Harmful human health effects from zinc generally begin at 
levels from 10-15 times the recommended daily allowance (in the 100 to 
250 mg/day range). Long-term exposure may cause anemia, pancreas 
damage, and reduced levels of high density lipoprotein cholesterol (the 
good form of cholesterol). Breathing large amounts of zinc (as dust or 
fumes) may cause a specific short-term disease called metal fume fever. 
(ATSDR Fact Sheet for Zinc, September 1995.)
6. Who Is Affected by This Action?
    When promulgated, the proposed criteria will affect users of chat 
used in transportation construction projects that are carried out, in 
whole or in part, using federal funds. In addition, unencapsulated chat 
can be used provided it is part of and otherwise authorized by a State 
or federal response action undertaken pursuant to applicable federal or 
state environmental laws. Such response actions are undertaken with 
consideration of risk assessments developed in accordance with state 
and federal laws, regulations, and guidance. The Agency is also 
proposing

[[Page 16736]]

recommended criteria as guidance that will be applicable to the use of 
chat in non-residential non-transportation uses.

C. What Was the Process EPA Used To Develop This Action?

    The Agency initially reviewed information concerning the 
environmental effects of the improper placement and disposal of chat 
found in the Records of Decision cited above for the four NPL sites 
located in the Tri-State mining district (Tar Creek, Jasper County, 
Cherokee County, Newton County). The Agency then reviewed reports which 
identified current or past uses of chat, primarily studies prepared to 
support Governor Keating's Taskforce (Governor Frank Keating's Tar 
Creek Superfund Task Force, Chat Usage Subcommittee Final Report, 
September 2000) and research on chat uses conducted by the University 
of Oklahoma (A Laboratory Study to Optimize the Use of Raw Chat in Hot 
Mix Asphalt for Pavement Application: Final Report August 2005). The 
Agency interviewed the principal authors of the University of Oklahoma 
studies to further evaluate their findings and representatives of the 
Departments of Transportation in Oklahoma, Kansas, and Missouri. The 
Agency met with the U.S. Department of Transportation, Federal Highway 
Administration to discuss the use of aggregate substitutes in road 
surfaces and relied on the joint EPA/FHWA document of the use of wastes 
in highway construction [User Guidelines for Waste and Byproduct 
Material in Pavement Construction, FHWA, 1997 (https://www.rmrc.unh.edu/
Partners/UserGuide/begin.htm)]. Additionally, EPA met with the BIA to 
discuss BIA requirements for the sale of chat on Tribal lands. The 
Agency also conducted a series of interviews with the environmental 
regulatory agencies in the three states to further identify acceptable 
versus unacceptable uses of chat. Moreover, the Agency conducted 
interviews with companies currently washing and selling chat and with 
asphalt and cement companies which either were currently using or had 
used chat. EPA visited the Tri-State area to observe the condition of 
chat piles and confirm the location of chat washing and asphalt 
companies in the area. The Agency has communicated with the tribal 
members in the Tri-State area to inform them about this action and seek 
information about current uses and has met the requirements of 
Executive Order 13175. In the spirit of Executive Order 13175, and 
consistent with EPA policy to promote communications between EPA and 
tribal governments, EPA specifically solicits any additional comment on 
this proposed rule from tribal officials.

II. Summary of the Proposed Rule

A. What Criteria Are EPA Establishing for the Use of Chat?

    EPA views chat uses in two basic categories: Unencapsulated and 
encapsulated. Unencapsulated uses of chat have contributed to human 
health and environmental risks resulting in EPA placing four sites on 
the NPL. Additionally, the use of unencapsulated chat in driveways and 
as fill material has contributed to lead contamination of soils in 
residential property that has resulted in elevated blood lead 
concentrations in area children. Therefore, EPA cannot establish 
specific criteria for individual unencapsulated uses of chat that are 
safe and environmentally protective. However, EPA has established a 
criterion that such uses will be safe and environmentally protective if 
they are part of, and otherwise authorized by a State or federal 
response action undertaken pursuant to applicable federal or state 
environmental laws. Such response actions are undertaken with 
consideration of risk assessments developed in accordance with state 
and federal laws, regulations, and guidance. By contrast, uses that 
encapsulate chat limit the release of the constituents of concern. 
Therefore, encapsulation of chat forms the basic criterion in today's 
proposal.
1. Transportation Construction Uses
    Transportation construction uses of chat are transportation 
construction projects funded, wholly or in part, with federal funds. 
The Agency has evaluated all the transportation construction uses 
defined previously and has concluded that the only transportation 
construction uses that are safe and environmentally protective are uses 
which encapsulate chat in hot mix asphalt concrete or in Portland 
cement concrete.
a. What is our proposed action?
    Today's action, if finalized as proposed, would require that chat 
used in transportation construction projects funded, wholly or in part, 
with Federal funds be encapsulated in asphalt concrete or Portland 
cement concrete, unless the use is authorized by a State or Federal 
response action undertaken pursuant to applicable Federal or State 
environmental laws.
    In addition, for all chat used in transportation construction 
projects funded in whole or in part using Federal funds that is not 
subject to the U.S. Department of Interior, Bureau of Indian Affairs 
Chat Use Certification requirements described in Section I.B.3. above, 
the Agency is proposing a certification requirement similar to that 
required by BIA. Specifically, EPA proposes that the acquirer of the 
chat would submit a signed, written certification that the chat will be 
used in accordance with EPA's criteria. The certification will also 
include the location of origin of the chat and the amount of chat 
acquired.
    EPA proposes that the certification be provided to the 
environmental regulatory agency in the State where the chat is 
acquired, except for chat acquired on lands administered by the BIA 
which is subject to the BIA certification requirements. The Agency also 
proposes that if the acquirer sells or otherwise transfers the chat, 
the new owner of the chat must also submit a signed, written 
certification as described in this section. Finally, the Agency 
proposes that the acquirer, or any other person that receives a copy of 
the certification, maintain a copy of the certification in its files 
for three years following transmittal to the State environmental 
regulatory agency.
    Today's action does not, in itself, modify or limit any existing 
state or Federal policies (including EPA Regions 6 and 7 guidances on 
chat use), positions, or decisions, nor any existing agreements or 
contracts among private or governmental entities. Because this action 
is a proposed rulemaking, provisions of the proposal, as well as EPA's 
assumptions and rationale leading to them, are subject to public notice 
and comment. Therefore, until a final rule governing these materials is 
issued, EPA's policies, positions or decisions regarding the use of 
chat remain unchanged.
b. What is the rationale for the Proposed Rule?
    The Agency is basing this action on our review of various studies 
and data that show that certain encapsulated uses of chat are 
reasonably expected to be environmentally safe.
i. Asphalt
    There are a number of factors which lead us to conclude that the 
encapsulation of chat into hot mix asphalt is safe and environmentally 
protective:
     Several studies have been conducted on the use of chat in 
hot mix asphalt. The most comprehensive study was conducted by the 
University of Oklahoma (OU) School of Civil Engineering and 
Environmental Science. OU published their findings in

[[Page 16737]]

a report titled, A Laboratory Study to Optimize the Use of Raw Chat in 
Hot Mix Asphalt for Pavement Application: Final Report (August 2005). 
OU tested the durability and leaching potential of a variety of 
mixtures of hot mix asphalt with raw chat for road surfaces and for 
road bases. In addition, OU milled (sawed) samples to simulate 
weathering. The Agency relied on these findings as one of the principal 
sources of data supporting the use of chat in hot mix asphalt. This 
study confirms an earlier study conducted by the U.S. Army Corps of 
Engineers (Tar Creek Superfund Site, Ottawa County, Oklahoma, Final 
Summary Report: Chat-Asphalt Paved Road Study U.S. Army Corps of 
Engineers--Tulsa District, February 2000).
     Comparison of the Synthetic Precipitation Leaching 
Procedure (SPLP) results of milled (weathered) chat asphalt samples in 
the OU study with the National Primary and Secondary Drinking Water 
Standards (https://www.epa.gov/safewater/mcl.html), without dilution and 
attenuation, show that milled surface and road base mixtures did not 
exceed the primary drinking water standard for lead (0.015 mg/l) or 
cadmium (0.005 mg/l). The OU results also show that milled asphalt road 
bases and surfaces did not exceed the secondary drinking water standard 
for zinc (5 mg/l).\5\
---------------------------------------------------------------------------

    \5\ Several hot mix asphalt samples were also tested in the OU 
study using the toxicity characteristic leaching procedure (TCLP). 
For surface samples, TCLP average concentrations for lead ranged 
from <0.005 to a high of 0.46 mg/l. TCLP average concentrations for 
cadmium ranged from <0.010 to 0.223 mg/l and zinc concentration 
averages ranged from 11.3 to 28.53 mg/l. Road base samples usually 
have higher metals concentrations than do surface samples. For road 
base samples, average TCLP lead concentrations ranged from 0.069 to 
2.008 mg/l, while average TCLP cadmium concentrations ranged from 
0.011 to 0.087 mg/l and average TCLP zinc concentrations ranged from 
19.9 to 41.33 mg/l.
---------------------------------------------------------------------------

     The TCLP test was designed as a screening test to simulate 
leaching of materials in a municipal solid waste landfill. The SPLP 
test is also a screening test, and was designed to simulate leaching of 
materials when exposed to acid rain. It is highly unlikely that road 
surfaces would be exposed to leaching conditions found in municipal 
solid waste landfills. Therefore, the Agency believes that of these two 
tests, the SPLP tests on raw chat asphalt samples is likely to better 
mimic the leaching potential of such mixtures when they are to be used 
in road construction.
     The OU study tested unweathered and milled samples. The 
Agency believes milled samples represent worst case scenarios because 
milling exposes more surface area to leaching.
     In a dissertation submitted to the University of New 
Hampshire titled ``Contributions to Predicting Contaminant Leaching 
from Secondary Material Used in Roads,'' Defne S. Apul, September 2004, 
the author noted that if pavement is built on highly adsorbing soils, 
the concentrations of contaminants reaching groundwater are more than 
several orders of magnitude lower than the MCLs. Moreover, the Agency 
considered in its Report on Potential Risks that it is highly unlikely 
that leachate would be ingested directly by humans.
    The report entitled ``Summary of Washed and Unwashed Mining 
Tailings (Chat) from Two Piles at the Tar Creek Superfund Site, Ottawa 
County Oklahoma, Revised June 2003,'' ODEQ, also evaluated leachate 
from asphalt containing chat removed from the Will Rogers Turnpike 
located near Quapaw, Oklahoma. This evaluation was conducted to 
determine if asphalt that used chat as an aggregate removed at the end 
of its useful life posed threats from metals leaching into the 
environment. TCLP results for lead ranged from less than 0.050 mg/l to 
0.221 mg/l. There are no SPLP test data in this report. Based on best 
professional judgement and review of TCLP versus SPLP results, EPA 
believes that there would be a reduction in lead concentrations of 
approximately one order of magnitude. Therefore, we believe that SPLP 
results would not exceed the MCL for lead. Based on these results, EPA 
does not believe the disposal of chat asphalt should present risks to 
the environment.
    The Agency therefore concludes that the use of chat in hot mix 
asphalt for pavement (which accounts for about 95% of the current chat 
usage), base, and sub base is an environmentally protective use. EPA 
does not believe that it is necessary to establish specifications of 
what constitutes ``hot mix asphalt'' because transportation 
construction uses are required to comply with federal and state 
Department of Transportation material specifications. These 
specifications delineate requirements which ensure that when chat is 
used in hot mix asphalt, the resulting product will be structurally 
stable.
ii. Concrete
    The Agency also believes that the encapsulation of chat into 
Portland cement concrete is safe and environmentally protective:
     An undated University of Oklahoma Surbec-Art Environmental 
study \6\ and a 2000 University of Oklahoma Study \7\ conducted the 
only known assessments of the total metals and TCLP on concrete 
matrices mixed with raw chat. The 2000 OU results are also presented in 
the 2005 OU study. Following are the results from those studies.
---------------------------------------------------------------------------

    \6\ ``Preliminary Report on the Findings of Environmental and 
Engineering Tests Performed on Mine Residual Materials from Ottawa 
County, Oklahoma.''
    \7\ ``Development of Holistic Remediation Alternatives for the 
Catholic 40 and Beaver Creek.''

----------------------------------------------------------------------------------------------------------------
                                                    S1                      S2                      C40
                                         -----------------------------------------------------------------------
                                          Total (mg/   TCLP (mg/  Total (mg/   TCLP (mg/  Total (mg/   TCLP (mg/
                                              kg)         l)          kg)         l)          kg)         l)
----------------------------------------------------------------------------------------------------------------
Lead....................................         178        0.92         379        0.17         150           1
Cadmium.................................      30 (R)        0.09      35 (R)        0.12          35         0.1
Zinc....................................        4200        0.23        4400        0.16        4100  ..........
----------------------------------------------------------------------------------------------------------------
(R) = rounded to nearest whole number.

     While not a direct measure of the leaching potential of 
Portland cement concrete, waste stabilization technologies and their 
effectiveness are well defined in the Agency's Final Best Demonstrated 
Available Technology (BDAT) Background Document for Universal 
Standards, Volume A, July 1994 and Proposed Best Demonstrated Available 
Technology (BDAT) Background Document for Toxicity Characteristic Metal 
Wastes D004-D011, July 1995. One of those technologies is 
stabilization, such as encapsulation in a cement matrix, to reduce the 
mobility of the metal in the waste. The metals are chemically bound 
into a solid matrix that resists leaching when water or a

[[Page 16738]]

mild acid comes into contact with the waste. The Agency evaluated 
contaminant levels in unstabilized versus stabilized wastes to 
determine the reduction in mobility of metals, including lead and 
cadmium, when those wastes were stabilized in a cement matrix. These 
results indicate that stabilization with cement generally reduced lead 
and cadmium mobility by two to three orders of magnitude (See Table A4 
of the July 1994 document cited above).
     Although chat was not specifically discussed in the BDAT 
Background Documents, the data and information contained in the 
technical background documents cited in the previous bullet leads us to 
believe that chat added to concrete will bind a significant amount of 
metals and therefore limit the leaching potential of chat concrete. 
While limited leaching of metals from concrete may still occur, we 
believe metals in chat can be encapsulated in an environmentally 
protective manner for the following reasons:

--As shown in the table above, TCLP levels from raw chat contained in 
concrete, as measured in the undated and 2000 OU studies, for lead 
(0.17 to 1.0 mg/l) and cadmium (0.01 to 0.12 mg/l) are within the TCLP 
levels from the 2005 OU study for weathered (milled) hot mix asphalt 
(<0.005 to 2.008 mg/l for lead and <0.010 to 0.223 mg/l for cadmium).
--The Agency does not have SPLP data for concrete. In hot mix asphalt, 
the SPLP concentrations for both lead and cadmium were <0.01 mg/l, 
significantly below the TCLP levels for the same constituents. Should 
additional environmental release studies of chat used in concrete be 
performed, use of SPLP would be preferred over TCLP, since SPLP would 
better replicate the environmental conditions of the chat reuse.
--Because the Agency believes that it is highly unlikely that the 
leachate would be directly ingested by humans, applying a dilution and 
attenuation factor would lead to even lower metals concentrations.

     In a dissertation submitted to the University of New 
Hampshire titled ``Contributions to Pr