Standards for the Management and Use of Slag Residues Derived From HTMR Treatment of K061, K062, and F006 Wastes

Federal RegisterDec 29, 1994

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 261, 266, and 268

[SW-FRL-5127-2]

RIN 2050-AE15

Standards for the Management and Use of Slag Residues Derived

From HTMR Treatment of K061, K062, and F006 Wastes

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule and request for comment.

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SUMMARY: The Environmental Protection Agency (EPA or the Agency) is

proposing to allow materials resulting from the treatment of certain

hazardous wastes to be used as a product in road construction and as an

anti-skid/deicing material on road surfaces. These materials are

residues (``slags'') generated from the treatment of pollution control

dusts resulting from scrap metal recycling (electric arc furnace dust).

The Agency evaluated the potential risks that might arise from the use

of these ``slags'', and determined that these uses do not present a

significant risk. This action would reclassify these treated materials

as nonhazardous and allow these uses, but only if the toxic metals in

the waste are reduced to safe levels by treatment.

The Agency is proposing this action to clarify two seemingly

inconsistent parts of the regulations governing residual materials

generated from the treatment of hazardous wastes. This rule clarifies

what uses of the treatment residues are allowed, and specifies what

conditions must be met for these materials to be used in this manner.

Furthermore, this action partially fulfills a settlement agreement

entered into by the Agency with the Natural Resources Defense Council

(NRDC) and the Hazardous Waste Treatment Council (HWTC) to resolve the

apparent inconsistency in the regulations.

The Agency believes these proposed actions will promote recycling

and resource recovery in two ways. This action will directly encourage

the recovery of metals from the hazardous electric arc furnace dust and

other metal wastes by allowing the ``slag'' residuals to be used in a

beneficial and environmentally sound way. Furthermore, this proposed

rule will encourage the recycling of scrap metal by helping to reduce

the costs that result from the treatment and disposal of the electric

arc furnace dust. The Agency believes that this rule would satisfy the

goals of resource recovery, while also ensuring protection of human

health and the environment.

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

February 13, 1995. Comments postmarked after this date will be marked

``late'' and may not be considered.

ADDRESSES: The public must send an original and two copies of their

comments to EPA RCRA Docket Number F-94-SRTP-FFFFF, room 2616 (Mail

Code 5305), 401 M Street S.W., Washington, DC 20460. The docket is open

from 9:00 a.m. to 4:00 p.m., Monday through Friday, except on Federal

holidays. The public must make an appointment to review docket

materials by calling (202) 260-9327. A maximum of 100 pages may be

copied at no cost. Additional copies cost $0.15 per page.

FOR FURTHER INFORMATION CONTACT: For general information contact the

RCRA Hotline, toll free at (800) 424-9346, or at (703) 412-9810. For

specific questions concerning this notice, contact Narendra Chaudhari,

Office of Solid Waste (Mail Code 5304), U.S. Environmental Protection

Agency, 401 M Street, S.W., Washington, DC 20460, (202) 260-4787.

SUPPLEMENTARY INFORMATION:

I. Background

A. Existing Regulations for Hazardous Wastes Used in a Manner

Constituting Disposal

Currently, hazardous wastes that are used in a manner constituting

disposal (applied to or placed on land), including waste-derived

products that are produced in whole or in part from hazardous wastes

and used in a manner constituting disposal, are not subject to

hazardous waste disposal regulations provided the products produced

meet two conditions. First, the hazardous wastes must undergo a

chemical reaction in the course of becoming products so as to be

inseparable by physical means (see Sec. 266.20(b)). A second condition

for exemption is that the waste-derived products must meet best

demonstrated available technology (BDAT) treatment standards under the

land disposal restrictions program for every prohibited hazardous waste

that they contain before they are placed on land (see Sec. 266.20(b)).

The exemption in Sec. 266.20 is used for slag residues (slags)

generated from the treatment of hazardous waste K061 (and, to a limited

extent, K062 and F006) using high temperature metal recovery (HTMR)

processes. Section 266.20 is applicable because the majority of this

slag is used in highway construction materials (e.g., as road subbase),

and a limited amount is also used by directly applying it to road

surfaces (i.e., top grade and as an anti-skid or deicing agent). (See

56 FR 15020, April 12, 1991.)

On August 19, 1991 and August 18, 1992 (see 56 FR 41164 and 57 FR

37194), EPA finalized ``generic exclusions'' for nonwastewater slag

residues generated from the HTMR treatment of several metal-bearing

hazardous wastes (K061, K062, and F006). These HTMR slag residues are

excluded from the hazardous waste regulations provided they meet

designated concentration levels (generic exclusion levels) for 13

metals, are disposed of in Subtitle D units, and exhibit no

characteristics of hazardous waste (see Sec. 261.3(c)(2)(ii)(C)). The

generic exclusion levels for the metals were based on the use of the

EPA Composite Model for Landfills (EPACML), which predicts the

potential for groundwater contamination from wastes that are placed in

a landfill. EPA limited the generic exclusion to residues disposed of

in a Subtitle D unit because, at that time, the Agency could not

properly evaluate concerns over potential releases to other media

resulting from uses of the HTMR slag as product, especially as an anti-

skid material on road surfaces (see 56 FR 41164, August 19,1991).

As EPA noted in the final rule for the initial generic exclusion

for K061 residues (see 56 FR 41164, August 19, 1991), the use of HTMR

residues as anti-skid material was not prohibited, provided the residue

meets the exemption conditions given in Sec. 266.20. EPA also noted in

the same notice that it would further evaluate the uses of K061 HTMR

residues that constitute disposal, and would consider amendments to

Sec. 266.20 for HTMR slags that might require further controls on such

uses.

B. Summary of Petition and Settlement Agreement

The Natural Resources Defense Council (NRDC) and the Hazardous

Waste Treatment Council (HWTC) filed a petition for review challenging

EPA's decision not to apply ``generic exclusion levels''--levels at

which K061 slags are deemed nonhazardous--to K061 slags used as waste-

derived ``products'' and applied to or placed on land. The generic

exclusion levels established for some metals in the K061 HTMR slags are

lower than the BDAT standards that apply to K061. Therefore, while the

generic exclusion requires that the nonhazardous K061 slag that meets

exclusion levels be disposed of in a Subtitle D unit, K061 HTMR slag

that may exhibit metal levels above the exclusion levels (but below

BDAT) may be used as a product in a manner constituting disposal under

the exemption in Sec. 266.20(b). The petitioners pointed out the

seeming anomaly of the slag used in an uncontrolled manner being

effectively subject to lesser standards than slag disposed in a

controlled landfill.

On August 13, 1993, EPA entered into a settlement agreement with

these petitioners which would address their concerns through two

separate notice-and-comment rulemakings. EPA agreed to propose the

first rule within 6 months of the settlement date (and issue a final

rule within 12 months) to either establish generic exclusion levels for

``non-encapsulated'' uses of K061 slags, or effectively prohibit such

uses of K061 slags on the land. EPA also agreed to propose a second

rule within 16 months of the settlement date (and issue a final rule

within 28 months), to establish generic exclusion levels for

encapsulated uses of K061 slags on the land. The agreement specified

that the generic exclusion levels for K061 slags will be based on an

evaluation of the potential risks to human health and the environment

from the use of K061 slags as waste-derived products, taking into

account all relevant pathways of exposure.

C. Implementation of Settlement Agreement

This action represents the second proposed rule required under the

settlement agreement. EPA has promulgated the first rules required

under the settlement agreement. (See 59 FR 8583, February 23, 1994

(proposed) and 59 FR 43496, August 24, 1994 (final)). The final rule

will effectively prohibit, beginning on February 24, 1995, anti-skid/

deicing uses of HTMR slags derived from K061, K062, and F006, as waste-

derived products placed on land. Today's proposal contains EPA's risk-

based determinations for all major K061, K062, and F006 HTMR slag uses,

including anti-skid/deicing uses, and thus implements the remaining

portion of the agreement.

II. Overview of Production, Processing, and Uses

A. Production of HTMR Slags

According to information available to EPA, HTMR slags are by-

products of metal recovery operations (which involve recovery of metals

from metal-bearing hazardous wastes) produced primarily at two

facilities, Horsehead Resource Development Company, Inc. (HRD) and

International Metal Reclamation Company (Inmetco). HRD is currently the

major generator of HTMR slags which are at issue in this proposed rule.

In 1992, HRD processed 376,000 tons of electric arc furnace (EAF) dust,

which is reportedly 68 percent of the EAF dust generated domestically.

From this amount of EAF dust, HRD produced 120,000 tons of zinc

calcine, 19,000 tons of lead concentrate, and 237,000 tons of slag (see

EPA's Report to Congress on Metal Recovery, Environmental Regulation &

Hazardous Waste; EPA 530-R-93-018). Inmetco provided information that

it processed a total of 58,100 tons of wastes in 1993, recovering

22,196 tons of metals and producing 15,000 tons of slag (See docket for

information submitted by Inmetco at a meeting with EPA on March 10,

1994).

B. Process Description

There are a number of HTMR processes, all of which are multi-step

processes. The rotary kiln is the HTMR process primarily used to

recover metals from K061, K062, and F006 wastes. The process steps are

generally these: (1) wastes are mixed with coal or coke and fluxes to

prepare feed materials, (2) high temperature processing is used to

reduce metal oxides to their metallic form, 3) volatile metals

(primarily cadmium, zinc, and lead) are recovered by collection

systems, and 4) residual materials are discharged from the process and

cooled to form a slag (see BDAT Background Document for K061). It

should be noted that not all metal-bearing hazardous wastes are

amenable to recovery by HTMR processes, possibly because their metal

content is too low or because of significant quantities of impurities

or contaminants that cannot be removed due either to economic or

technical limitations. Therefore, metal reclaimers usually set

specifications for materials that they will accept for processing (see

EPA's Report to Congress on Metal Recovery, Environmental Regulation &

Hazardous Waste; EPA 530-R-93-018).

C. Properties and Uses of HTMR Slags

According to information provided by the generators on the

physical/chemical properties of HTMR slags (see RCRA docket), these

slags are highly dense, chemically stable (inert), and highly durable

(resistant to breakdown). These are all properties which the generators

claim make HTMR slags desirable construction materials.

HTMR slags are primarily used as subbase materials (e.g., in

construction of roads, parking lots, and driveways) and as additive

ingredients in cement or concrete/asphalt mixtures. Because the subbase

is covered by a relatively hard/impermeable material and cement or

concrete/asphalt mixtures lock in any additive ingredients, EPA

considers these uses of HTMR slags to be ``encapsulated'' uses. A

smaller portion of HTMR slags (believed to be less than 25 percent) are

used as anti-skid/deicing materials, as top grade or surfacing

materials (e.g., in construction of roads), and for other similar uses.

Because anti-skid/deicing materials are dispersed freely on roads

(during icy or snowy conditions to provide traction for vehicles) and

top grade materials result in uncovered (unpaved) roads, parking lots,

driveways, and the like, EPA considers these uses of HTMR slags to be

``non-encapsulated'' uses.

III. Proposed Standards for the Management and Use of HTMR Slags

EPA is proposing that risk-based generic exclusion levels in

Sec. 261.3(c)(2)(ii)(C), in addition to being exclusion standards for

disposing HTMR slags derived from hazardous wastes K061, K062, and F006

in a Subtitle D unit, also become exclusion standards for managing

these slags and for using these slags as follows: 1) covered subbase

materials (e.g., in construction of paved roads, parking lots, and

driveways), 2) additive ingredients in cement or concrete/asphalt

mixtures, 3) top grade or surfacing materials (e.g., in construction of

roads, parking lots, and driveways), and 4) anti-skid/deicing

materials.

The Agency is proposing this action for the following reasons.

Based on the results of a very conservative risk assessment completed

by EPA for the relevant management practices and end-uses of HTMR slags

(see Section IV. for details), EPA has tentatively determined that the

wastepile, transport, road subbase, and landfill waste management

scenarios for HTMR-derived slags do not require regulation in order to

protect human health and the environment, if these slags meet the

generic exclusion levels. In addition, EPA is proposing that use of

HTMR slags as additive ingredients in cement or concrete/asphalt

mixtures would also not require regulation, if these slags meet the

generic exclusion levels. This is primarily because the cement or

concrete/asphalt mixtures would mix with and chemically bind or

encapsulate the portion of HTMR slags that are added, and any

significant releases of slag constituents into the environment are

unlikely. Finally, the risk assessment results, which are based on very

conservative release and exposure assumptions, indicated little

potential risk for the top grade and anti- skid/deicing end-uses of

HTMR slags that meet the generic exclusion levels. Therefore, EPA is

also proposing that uses of HTMR slags as top grade and anti-skid/

deicing materials would also not require regulation, if these slags

meet the generic exclusion levels.

As a consequence of the above proposed changes, EPA is also

proposing to amend the existing regulations under Sec. 266.20 that

conditionally exempt hazardous waste-derived products used in a manner

constituting disposal from RCRA Subtitle C regulation. Specifically,

the language of Sec. 266.20 would be revised to prohibit the uses of

products containing HTMR slags derived from hazardous wastes K061,

K062, and F006 when these slags are still hazardous wastes, i.e.,

contain hazardous constituents at concentrations exceeding the

exclusion levels. This prohibition implements RCRA section 3004(g)(5)

and 3004(m), which require EPA to prohibit land disposal of hazardous

wastes that have not been pre-treated so as to minimize the short-term

and long-term threats posed by their land disposal. In addition, EPA is

including a cross-reference in the table ``Treatment Standards for

Hazardous Wastes'' in Sec. 268.40 (the Land Disposal Restriction

treatment standards) which notes the changes concerning utilization of

HTMR slags in Secs. 261.3 and 266.20.

As described in section IV.C, the Agency is also taking this

opportunity to update the generic exclusion levels to reflect the

changes in the drinking water Maximum Contaminant Levels (MCLs) for

some of the metals of concern. Therefore, the Agency is proposing to

amend the generic exclusion levels for antimony, beryllium, and nickel.

EPA requests comments on the proposed changes. EPA also requests

comments on the data used in the risk assessment, the methodology and

assumptions used in the risk assessment, and other analysis supporting

the proposed rule. Further, EPA requests comments on whether the uses

of HTMR slags identified in this proposal are the only uses in practice

or whether there are other uses practiced or planned. If EPA is alerted

to other significant uses, the Agency could use the information to

determine whether or not further analysis of those uses would be

required.

IV. Overview of Risk Assessment Supporting This Proposal

EPA performed a very conservative assessment of the potential risks

to human health and the environment from the relevant management

practices and uses of K061, K062, and F006 HTMR slags. This section

summarizes the methods and results of EPA's risk assessment. A more

detailed presentation of the risk assessment and uncertainties involved

is provided in a technical background document entitled ``Assessment of

Potential Risks to Human Health and the Environment from Management and

Uses of HTMR Slags,'' which is included in the docket for this proposed

rulemaking.

A. Methodology of Risk Assessment

EPA's methodology consisted of four primary steps. First, a

lifecycle analysis for the HTMR slags was performed, starting from the

point of manufacture and ending at the point of disposal, to identify

potential contaminant release scenarios (air, ground water, surface

water, and soil) associated with slag management, use, and disposal

practices. Second, based on the release scenarios, exposure pathways

and receptor locations relevant to contaminants in HTMR slags were

identified. Third, appropriate release, fate, and transport models were

used to compute contaminant concentrations at receptor points for each

release and exposure pathway. Finally, the media-specific

concentrations for air, ground water, surface water, and soil were

compared to the appropriate human health and ecological effects

reference concentrations to determine the quantitative risks from

exposures to contaminants in HTMR slags.

EPA focused on selecting high-end values for use in the models to

estimate the individual risk for those persons at the upper end (>90th

percentile of the population distribution) of the risk distribution.

The Agency chose this very conservative approach in order to identify

any pathways or chemicals which would warrant a more in depth risk

assessment and characterization. A summary of the data sources and risk

assessment methodology for HTMR slags is provided below.

1. Sources of Constituents Data for HTMR Slags

The constituents of concern in HTMR slags were identified in the

Land Disposal Restrictions for Electric Arc Furnace Dust (K061) - Final

Rule (56 FR No. 160, p 41164) and supported by the Best Demonstrated

Available Technology (BDAT) Background Document for K061 (US EPA,

1988). Specifically, the K061 Final Rule identified fourteen metals

requiring BDAT treatment standards for K061, including: antimony,

arsenic, barium, beryllium, cadmium, chromium, lead, mercury, nickel,

selenium, silver, thallium, vanadium, and zinc. However, for various

reasons discussed in the K061 Final Rule, EPA promulgated the standard

for vanadium as ``reserved.''

For the purposes of the risk assessment, total concentrations of

constituents of concern in HTMR residuals were based on the EPA-

collected data base presented in the BDAT Background Document for K061

(US EPA, 1988). For each constituent of concern, the 95th percentile

upper confidence limit of the mean (95th UCLM) was calculated for the

total metal concentration (in ppm or, equivalently, mg constituent per

kg HTMR residual). EPA selected this value to represent a reasonable

high-end measure of constituent concentrations in HTMR residuals. Table

1 presents the total concentrations and summary statistics for that

data set, including maximum concentration, mean, and the range of

concentrations.

For exposure scenarios involving HTMR leachate (e.g., landfilling

of HTMR-derived slag), the leachate concentration was assumed to be

equal to the maximum levels allowed under the generic exclusion

established in the K061 final rule. Table 1 also presents the generic

exclusion levels (in mg/L).

Table 1.--Summary Statistics for Constituent Concentrations for HTMR Residuals

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Total constituent concentrations in HTMR residuals

fromrotary kiln incinerator Generic exclusion

Constituent --------------------------------------------------------- levels for

Range (ppm) Mean (ppm) 95% UCLM (ppm) leachate (mg/L)

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Antimony............................ 111-405 195 266 0.10

Arsenic............................. 75-113 86 98 0.50

Barium.............................. 331-467 374 408 7.6

Beryllium........................... 1.7-4 2 3 0.01

Cadmium............................. air pathway: emission and dispersion of respirable

particulates ( groundwater pathway: release of contaminants to

subsurface soils and subsequent leaching into groundwater;

surface water pathway: overland transport (via runoff and

soil erosion) of contaminants to surface water; and

soil pathway: overland transport of contaminants via soil

erosion to offsite residential soils.

In addition to these direct exposure pathways, EPA identified one

indirect exposure pathway with respect to potential release scenarios,

i.e., release of nonrespirable particulates (30 microns in size)

followed by deposition to soil.

EPA did not model each of these four pathways for every source of

HTMR slags. The exposure pathways evaluated by EPA for each exposure

source/scenario are summarized in matrix form in Table 2. Only those

pathways relevant to a given source scenario were modeled for that

scenario. For example, as noted previously, direct air pathways for the

road subbase scenario were not evaluated because the subbase is

essentially a covered source that is not subject to wind erosion,

overland transport, or air dispersion. Similarly, EPA did not

explicitly include HTMR slags contained in cement or concrete/asphalt

mixtures for any of the exposure scenarios of concern.

Table 2.--Exposure Pathways Evaluated for Sources/Scenarios Associated With the Use or Disposal of HTMR Slag

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Exposure source/scenario

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Exposure pathway Top grade

Wastepile andanti-skid Slaglandfill Subbase Transportation

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Ground Water Ingestion.............. X X X1 X

Surface Water....................... X X X

Soil Ingestion...................... X X X

Air Deposition to Soil and Ingestion X X X

Particulate Inhalation.............. X X X ............. X

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1Evaluated previously (see 57 FR 37194; August 18, 1992)

5. Evaluation Criteria

EPA used human health and ecological (aquatic) effects criteria to

evaluate levels of hazardous constituents in various media.

a. Human Health--The human health reference values for the

constituents of concern includes carcinogenic slope factors (CSFs),

reference doses (RfDs), and reference concentrations (RfCs). The CSFs,

a measure of carcinogenic potency, were used for both the inhalation

and ingestion routes of exposure. The RfD is an estimate of the daily

intake of a substance, within an order of magnitude, to which the adult

human population (including sensitive subgroups) may be exposed without

any adverse noncarcinogenic effects. The RfC is the analog to the RfD

for inhalation exposure, although the RfC units are typically converted

to concentration (mg/m3), using default exposure assumptions for

breathing rate and body weight. Virtually all the reference values

(i.e., CSFs, RfDs, and RfCs) were obtained from the Integrated Risk

Information System (IRIS), EPA's primary source for verified human

health reference values. Reference values were also identified in the

Health Effects Assessment Summary Tables (HEAST). When no verified RfC

values were available, the RfC values were extrapolated from RfDs,

assuming that a 70 kg adult inhales 20 m3 of air per day. Based on

the human health reference values, the Agency calculated the reference

concentrations in Table 3 for soil, drinking water, and air. The table

includes Maximum Contaminant Levels (MCLs) for drinking water, when

available. The human health reference values, and the methods used to

calculate the reference concentrations, are summarized in the docket

for today's rule. Two constituents of concern, thallium and lead, did

not have reference values for ingestion or inhalation in either IRIS or

HEAST. The reference value (i.e., RfD) for thallium was estimated from

the lowest reference value of the thallium salts (e.g., thallium

sulfate, thallium nitrate). A reference value for lead is not available

at this time since Agency consensus has not been reached on how an RfD

or RfC should be calculated for lead. However, EPA has established

regulatory and recommended levels for lead in the various media, and

these are included in Table 3.

b. Ecological (Aquatic) Receptors--A comparison of chemical

concentrations in surface water to their aquatic benchmarks was used to

determine if any given constituent would pose a threat to aquatic

organisms. Those chemicals whose surface water concentrations exceeded

their aquatic water quality criteria would be identified as

constituents of concern. The National Ambient Water Quality Criteria

(NAWQC) were selected as the ecological reference concentrations for

the protection of aquatic organisms (e.g., fish and daphnids). Since

NAWQC were not available for all constituents, alternate criteria or

advisory values were identified in the open literature. A complete

description of the methods used to estimate the advisory NAWQC may be

found in Toxicological Benchmarks for Screening of Potential

Contaminants of Concern for Effects on Aquatic Biota on the Oak Ridge

Reservation, Oak Ridge, Tennessee (Suter et al., 1992). Table 3

provides the NAWQC and advisory NAWQC for aquatic organisms for each of

the constituents of concern.

6. Characterization of Risk

The modeling results for the ground-water, surface water, soil, and

air pathways were compared to the reference concentrations for the

different media to assess the potential risk to human health and

aquatic receptors. The resulting risk ratios (i.e., media concentration

divided by reference concentration) were then evaluated to determine

whether any of the metals of concern in HTMR slag would pose

significant risks to humans or aquatic receptors for any of the

exposure scenarios evaluated.

Table 3.--Reference Concentrations for Soil, Water, and Air for the HTMR Constituents of Concern

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

Reference Reference Surface

Reference Soil Drinking Water Reference Air Water

Constituent Concentration\1\ Concentrations\2\ Concentrations3 Concentrations\4\

(mg/kg) (mg/L) (ug/m\3\) (mg/

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

Antimony............................... 3.2E+01 0.006 1.4E+00 0.018

Arsenic................................ 9.7E-01 0.05 5.7E-04 0.190

Barium................................. 5.6E+03 2 5.0E-01 0.109

Beryllium.............................. 4.0E+02 0.004 1.0E-03 0.00061

Cadmium................................ 8.0E+01 0.005 1.4E-03 0.0011

Chromium III........................... 8.0E+04 0.1 3.5E+03 0.210

Chromium VI............................ 4.0E+02 0.1 2.0E-04 0.011

Lead................................... 4.0E+02 0.015 1.5E-01 0.0032

Mercury................................ 2.4E+01 0.002 3.0E-01 0.000012

Nickel................................. 1.6E+03 0.1 7.0E+01 0.160

Selenium............................... 4.0E+02 0.05 1.8E+01 0.035

Silver................................. 4.0E+02 0.18 1.8E+01 0.00039

Thallium............................... 6.4E+00 0.002 2.8E-01 0.0025

Zinc................................... 2.4E+04 10 1.1E+03 0.110

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

\1\RfDs and CSFs were used to calculate reference soil values, except for lead; the value for lead is a

recommended screening level for lead in soil for residential land use which is contained in the Agency's

interim soil lead guidance (this guidance suggests use of this screening level to identify sites that do not

require further study, and not as a clean up goal).

\2\Reference values for drinking water are MCLs, when available; the values for thallium and zinc are based on

RfDs, and the value for lead is the action level.

\3\Air reference values are based on CSFs or RfCs, when available; other values extrapolated from oral RfDs,

except for lead, which is based on 10% of the existing National Ambient Air Quality Standard.

\4\Reference values are National Ambient water Quality Criteria (NAWQC) for aquatic toxicity, except for

antimony, barium, beryllium, silver, and thallium, which are based on advisory NAWQC (see Section IV.A.5.b.)

B. Results of Risk Assessment

The results from EPA's very conservative risk assessment for the

relevant management practices and uses of HTMR slags indicate that

constituents of concern in HTMR slags pose little or no risk to human

health or the environment. Based on this assessment, no significant

risks were found for storage, transport, disposal, and encapsulated

uses of HTMR slags (use as subbase, as an ingredient in cement or

concrete/asphalt) that meet the generic exclusion levels. The non-

encapsulated uses of HTMR slags (top grade and anti-skid uses) that

meet the generic exclusion levels showed the potential for some excess

risk (i.e., risk above 1x10-6). The risk analysis indicates that

direct inhalation exposure to arsenic from non-encapsulated uses may

present an excess risk of cancer of 2.9x10-6. In other words, a

maximum of approximately 3 additional cases of cancer would be

predicted per million people exposed to the arsenic in the slag used in

this manner. The results also suggest that areal deposition of arsenic

from these non-encapsulated uses and subsequent ingestion of

contaminated soil may also present a comparable excess risk of cancer

(2.7x10-6). None of the other metals evaluated posed any

significant increase in risk for these uses.

These risks (from non-encapsulated uses) are at the low end of

EPA's risk range of 1x10-4 to 1x10-6. Furthermore, for this

assessment, EPA selected very conservative values for use in fate and

transport models and for exposure scenarios. If the risk assessment had

used a central tendency value (instead of a high-end value) for one of

the high-end exposure assumptions, then the calculated risks from these

uses would drop below the 1x10-6 level. For example, had the

Agency used a 9 year exposure period for an individual exposed instead

of the 30 year exposure period used in this risk calculation, the risk

from non-encapsulated uses would have dropped to 8.7x10-7 cancer

risk. This risk level is below the typical level of concern used by the

Agency.

C. Changes to the Generic Exclusion Levels

The generic exclusion levels promulgated for HTMR slags derived

from K061, K062, and F006 were based on the health-based levels and

MCLs in effect when the rule was put into place. Since then, the

drinking water standards (i.e., MCLs) for some constituents have

changed somewhat (see July 17, 1992, 57 FR 231776). Therefore, the

Agency is taking this opportunity to propose to update the exclusion

levels to reflect these changes. The original exclusion levels were

calculated by multiplying the MCLs by a dilution-attenuation factor of

10 (see August 18, 1992, 57 FR 37194). This factor is based on the

EPACML model (see July 18, 1991, 56 FR 32993 for a description of the

model used). Using this same factor, the new MCLs for antimony (0.006

mg/L) and beryllium (0.004 mg/L) would result in new generic exclusion

levels of 0.06 mg/L and 0.04 mg/L for antimony and beryllium,

respectively. Therefore, the Agency is proposing to replace the

existing exclusion levels in Sec. 261.3(c)(2)(ii)(C) for antimony and

beryllium with these values as part of today's rule. The Agency

promulgated an MCL for nickel in 1992. That regulatory standard was

challenged by a coalition of industry groups in a lawsuit filed in

September, 1992. See Nickel Development Institute et al. v. EPA, No.

92-1407, 1410, 1416 (D.C. Cir.). For the past two years, the Agency has

been involved in discussions with these industry parties in an effort

to resolve this litigation. Because of the uncertainties that currently

surround the outcome of this litigation over the nickel MCL, EPA

believes it is appropriate to consider alternative criteria to

establish the generic exclusion level for nickel. EPA considered using

the health-based level for nickel (0.7 mg/L) which is derived from the

existing RFD for nickel of 0.02 mg/kg/day (see IRIS). Based on the

calculations described in the above paragraph, this would result in a

generic exclusion level of 7 mg/L for nickel. The existing BDAT

treatment standard for nickel contained in the slags derived from HTMR

processing of K061, K062, and F006 wastes is 5 mg/L. Between these two

alternative criteria, EPA believes that it is appropriate to use the

lower (more conservative) BDAT standard at this time. Therefore, EPA is

proposing to replace the existing exclusion level in

Sec. 261.3(c)(2)(ii)(C) for nickel with the nickel BDAT treatment

standard of 5 mg/L.

V. Conclusions

Based on the results of the risk assessment, EPA is proposing that

HTMR slags that meet the generic exclusion levels in

Sec. 261.3(c)(2)(ii)(C) will be classified as nonhazardous waste, and

also allowed to be managed or used as described in this proposal.

Furthermore, the Agency is also proposing to amend Sec. 266.20 so

that all uses constituting disposal of hazardous HTMR slag (i.e., HTMR

slag that does not meet the generic exclusion levels) are no longer

exempt from RCRA Subtitle C regulation. Because it is highly unlikely

that users of hazardous HTMR slag will choose to meet the stringent

requirements of Subtitle C, this change would effectively prohibit all

uses of slags that do not meet the generic exclusion levels. As a

consequence of the proposed changes to the generic exclusion in

Sec. 261.3(c)(2)(ii)(C), HTMR slags that are used as described in this

proposal would not be affected by the changes in Sec. 266.20, because

the HTMR slags used in these ways would not be hazardous waste

(provided the slags meet the generic exclusion levels and all of the

other requirements specified in Sec. 261.3(c)(2)(ii)(C)).

Finally, as described in section IV.C above, the Agency is also

proposing to update the generic exclusion levels for changes in MCLs

for antimony, beryllium, and nickel.

VI. Effective Date

The Agency is proposing that this rule be effective six months

after the date of publication of the final rule. (See RCRA section

3010(a)). The Agency believes that this would provide sufficient time

for affected parties to comply with the proposed changes.

VII. State Authority

A. Applicability of Rule in Authorized States

Under section 3006 of RCRA, EPA may authorize qualified States to

administer and enforce the RCRA program within the State. Following

authorization, EPA retains enforcement authority under sections 3008,

3013, and 7003 of RCRA, although authorized States have primary

enforcement responsibility. The standards and requirements for

authorization are found in 40 CFR part 271.

Prior to the Hazardous and Solid Waste Amendments (HSWA) of 1984, a

State with final authorization administered its hazardous waste program

in lieu of EPA administering the Federal program in that State. The

Federal requirements no longer applied in the authorized State, and EPA

could not issue permits for any facilities that the State was

authorized to permit. When new, more stringent Federal requirements

were promulgated or enacted, the State was obliged to enact equivalent

authority within specified time frames. New Federal requirements did

not take effect in an authorized State until the State adopted the

requirements as State law.

In contrast, under RCRA section 3006(g), new requirements and

prohibitions imposed by HSWA take effect in authorized States at the

same time that they take effect in nonauthorized States. EPA is

directed to carry out these requirements and prohibitions in authorized

States, including the issuance of permits, until the State is granted

authorization to do so. While States must still adopt HSWA-related

provisions as State law to retain final authorization, HSWA applies in

authorized States in the interim.

B. Effect on State Authorization

EPA views today's proposed rule as a HSWA regulation. The proposed

rule can be viewed as part of the process of establishing land disposal

prohibitions and treatment standards for K061, K062, and F006 hazardous

wastes. (See 56 FR 41175). The ultimate goal of the land disposal

prohibition provisions is to establish standards which minimize short-

term and long-term threats to human health and the environment posed by

hazardous waste land disposal. (See RCRA section 3004(m)(l)). In

addition, EPA must ensure that land disposal of hazardous wastes K061,

K062, and F006 are ultimately protective. (See RCRA Sec. 3004(g)(5)).

The proposed exclusion levels would implement these provisions by

assuring that these types of land disposal are ultimately protective

and establish levels at which pretreatment minimizes the threats to

human health and the environment posed by these types of land disposal.

Today's proposed rule will result in more stringent Federal

standards under Sec. 266.20, since it prohibits uses of hazardous HTMR

slags. Section 271.21(e)(2) requires that States that have final

authorization must modify their programs to reflect Federal program

changes and must subsequently submit the modifications to EPA for

approval.

Authorized States are only required to modify their programs when

EPA promulgates Federal regulations that are more stringent or broader

in scope than the existing Federal regulations. For those Federal

program changes that are less stringent or reduce the scope of the

Federal program, States are not required to modify their programs. This

is a result of section 3009 of RCRA, which allows States to impose

regulations in addition to those in the Federal program. EPA has

determined that the proposed changes to the generic exclusion are less

stringent or reduce the scope of the Federal program. Therefore,

authorized States are not required to modify their programs to adopt

regulations that are equivalent or substantially equivalent.

States with authorized RCRA programs may already have requirements

similar to those in today's proposed rule. These State regulations have

not been assessed against the Federal regulations being proposed today

to determine whether they meet the tests for authorization. Thus, a

State is not authorized to implement these requirements in lieu of EPA

until the State program modifications are approved. Of course, States

with existing standards could continue to administer and enforce their

standards as a matter of State law. In implementing the Federal

program, EPA will work with States under agreements to minimize

duplication of efforts. In many cases, EPA will be able to defer to the

States in their efforts to implement their programs rather than take

separate actions under Federal authority.

VIII. Regulatory Impact

A. Executive Order 12866

Under Executive Order 12866 (see 58 FR 51735, October 4, 1993), EPA

must determine whether the regulatory action is ``significant'' and

therefore subject to OMB review and the requirements of the Executive

Order. The order defines ``significant regulatory action'' as one that

is likely to result in a rule that may:

(1) have an annual effect on the economy of $100 million or more or

adversely affect in a material way the economy, a sector of the

economy, productivity, competition, jobs, the environment, public

health or safety, or State, local, or tribal governments or

communities;

(2) create a serious inconsistency or otherwise interfere with an

action taken or planned by another agency;

(3) materially alter the budgetary impact of entitlements, grants,

user fees, or loan programs or the rights and obligations of recipients

thereof; or

(4) raise novel legal or policy issues arising out of legal

mandates, the President's priorities, or the principles set forth in

the Executive Order.

Pursuant to the terms of Executive Order 12866, it has been

determined that this rule is a ``significant regulatory action''

because it raises novel policy issues in terms of defining when

products used in a manner constituting disposal should be regulated. As

such, this action was submitted to OMB for review. Changes made in

response to OMB suggestions or recommendations will be documented in

the public record.

B. Regulatory Flexibility Act

Under the Regulatory Flexibility Act, 5 U.S.C. 601 et seq.,

whenever an Agency is required to issue a general notice of rulemaking

for any proposed or final rule, it must prepare and make available for

public comment a regulatory flexibility analysis that describes the

impact of the rule on small entities (i.e., small businesses, small

organizations, and small governmental jurisdictions). No regulatory

flexibility analysis is required, however, if the head of the Agency

certifies that the rule will not have any impact on any small entities.

This proposed rule will not have any impact on any small entities,

since the regulated community will continue to have readily available

options for using and managing HTMR slags. Therefore, pursuant to

section 605(b) of the Regulatory Flexibility Act, the Administrator

certifies that this regulation will not have a significant economic

impact on a substantial number of small entities. This regulation,

therefore, does not require a regulatory flexibility analysis.

C. Paperwork Reduction Act

The Agency has determined that there are no additional reporting,

notification, or recordkeeping provisions associated with this proposed

rule. Such provisions, were they included, would be submitted for

approval to OMB under the Paperwork Reduction Act, 44 U.S.C. 3501 et

seq.

List of Subjects

40 CFR Part 261

Environmental protection, Hazardous waste, Recycling, Reporting and

recordkeeping requirements.

40 CFR Part 266

Energy, Hazardous waste, Recycling, Reporting and recordkeeping

requirements.

40 CFR Part 268

Hazardous waste, Reporting and recordkeeping requirements.

Dated: December 16, 1994.

Carol M. Browner,

Administrator.

For the reasons set forth in the preamble, 40 CFR Chapter I is

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. Section 261.3 paragraphs (c)(2)(ii)(C)(1) and (c)(2)(ii)(C)(2)

are revised as follows:

Sec. 261.3 Definition of hazardous waste.

(2) * * *

(ii) * * *

(C)(1) Nonwastewater residues, such as slag, resulting from high

temperature metals recovery (HTMR) processing of K061, K062, and F006

waste, in units identified as rotary kilns, flame reactors, electric

furnaces, plasma arc furnaces, slag reactors, rotary hearth furnace/

electric furnace combinations or industrial furnaces (as defined in

paragraphs (6), (7), and (13) of the definition for ``Industrial

furnace'' in 40 CFR 260.10)--provided that these residues meet the

generic exclusion levels identified in the tables in this paragraph for

all constituents, and exhibit no characteristics of hazardous waste and

are disposed in Subtitle D units, or used as covered subbase materials

(e.g., in construction of paved roads, parking lots, and driveways) or

as additive ingredients in cement or concrete/asphalt mixtures, or as

top-grade (e.g., surfacing material for roads, parking lots, and

driveways), or as anti-skid/deicing materials. Testing requirements

must be incorporated in a facility's waste analysis plan or a

generator's self-implementing waste analysis plan; at a minimum,

composite samples of residues must be collected and analyzed quarterly

and/or when the process or operation generating the waste changes.

Persons claiming this exclusion in an enforcement action will have the

burden of proving by clear and convincing evidence that the material

meets all of the exclusion requirements.

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

Maximum for

any single

Constituent composite

sample-TCLP

(mg/l)

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

Generic exclusion level for K061 and K062

nonwastewater HTMR residues

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

Antimony.................................................. 0.06

Arsenic................................................... 0.50

Barium.................................................... 7.6

Beryllium................................................. 0.04

Cadmium................................................... 0.05

Chromium (total).......................................... 0.33

Lead...................................................... 0.15

Mercury................................................... 0.009

Nickel.................................................... 5

Selenium.................................................. 0.16

Silver.................................................... 0.30

Thallium.................................................. 0.02

Zinc...................................................... 70

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

Generic exclusion level for F006

nonwastewater HTMR residues

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

Antimony.................................................. 0.06

Arsenic................................................... 0.50

Barium.................................................... 7.6

Beryllium................................................. 0.04

Cadmium................................................... 0.05

Chromium (total).......................................... 0.33

Cyanide (total) (mg/kg)................................... 1.8