[Federal Register Volume 64, Number 163 (Tuesday, August 24, 1999)]
[Proposed Rules]
[Pages 46166-46178]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-21941]


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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 261

[SW-FRL-6426-6]


Hazardous Waste Management System; Identification and Listing of 
Hazardous Waste; Proposed Exclusion

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule and request for comment.

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

SUMMARY: The EPA is proposing to grant a petition submitted by 
Chaparral Steel Midlothian, L.P. (Chaparral) to exclude (or delist) 
certain solid wastes generated by its Midlothian, Texas, facility from 
the lists of hazardous wastes.
    Any person may petition the Administrator to modify or revoke any 
provision of the solid waste regulations. Generators are specifically 
provided the opportunity to petition the Administrator to exclude a 
waste on a ``generator specific'' basis from the hazardous waste lists.
    The Agency bases its proposed decision to grant the petition on an 
evaluation of waste-specific information provided by the petitioner. 
This proposed decision, if finalized, would conditionally exclude the 
petitioned waste from the requirements of hazardous waste regulations 
under the Resource Conservation and Recovery Act (RCRA).
    If finalized, we would conclude that Chaparral's petitioned waste 
is nonhazardous with respect to the original listing criteria and that 
the waste process Chaparral uses will substantially reduce the 
likelihood of migration of hazardous constituents from this waste. We 
would also conclude that their process minimizes short-term and long-
term threats from the petitioned waste to human health and the 
environment.

DATES: We will accept comments until October 8, 1999. We will stamp 
comments postmarked after the close of the comment period as ``late.'' 
These ``late'' comments may not be considered in formulating a final 
decision.

ADDRESSES: Please send three copies of your comments. Two copies should 
be sent to William Gallagher, Delisting Section, Multimedia Planning 
and Permitting Division (6PD-O), Environmental Protection Agency, 1445 
Ross Avenue, Dallas, Texas 75202. A third copy should be sent to the 
Texas Natural Resources Conservation Commission (TNRCC), P.O. Box 
13087, Austin, Texas, 78711-3087. Identify your comments at the top 
with this regulatory docket number: ``F-99-TXDEL-CHAPARRAL.''
    You should address requests for a hearing to the Acting Director, 
Robert Hannesschlager, Multimedia Planning and Permitting Division 
(6PD), Environmental Protection Agency, 1445 Ross Avenue, Dallas, Texas 
75202.
    Your requests for a hearing must reach EPA by September 8, 1999. 
The request must contain the information prescribed in section 
260.20(d).

FOR FURTHER INFORMATION CONTACT: William Gallagher at (214) 665-6775.

SUPPLEMENTARY INFORMATION:
    The information in this section is organized as follows:
I. Overview Information
    A. What action is EPA proposing?
    B. Why is EPA proposing to approve this delisting?
    C. How will Chaparral manage the waste if it is delisted?
    D. When would the proposed exclusion be finalized?
    E. How would this action affect states?
II. Background
    A. What is the history of the delisting program?
    B. What is a delisting petition, and what does it require of a 
petitioner?
    C. What factors must EPA consider in deciding whether to grant a 
delisting petition?
III. EPA's Evaluation of the Waste Information and Data
    A. What wastes did Chaparral petition EPA to delist?
    B. What information and analysis did Chaparral submit to support 
this petition?
    C. Who is Chaparral and what process do they use to generate the 
petition waste?
    D. How did Chaparral sample and analyze the data in this 
petition?
    E. What were the results of Chaparral's analysis?
    F. How did EPA evaluate the risk of delisting this waste?
    G. What did EPA conclude about Chaparral's analysis?
    H. What other factors did EPA consider in its evaluation?
    I. What is EPA's final evaluation of this delisting petition?
IV. Next Steps
    A. With what conditions must the petitioner comply?
    B. What happens if Chaparral violates the terms and conditions?
V. Public Comments
    A. How may I as an interested party submit comments?
    B. How may I review the docket or obtain copies of the proposed 
exclusions?

I. Overview Information

A. What Action is EPA Proposing?

    The EPA is proposing:
    (1) To grant Chaparral's petition to have their Landfill No. 3 
leachate, baghouse storm water, and other

[[Page 46167]]

wastewater that may have been in contact with the K061 waste excluded, 
or delisted, from the definition of a hazardous waste; and
    (2) To use a fate and transport model to evaluate the potential 
impact of the petitioned waste on human health and the environment. The 
Agency uses this model to predict the concentration of hazardous 
constituents released from the petitioned waste once it is disposed.

B. Why is EPA Proposing to Approve This Delisting?

    Chaparral petitioned the Agency to exclude, or delist, the landfill 
leachate, baghouse storm water, and other wastewaters that may have 
potentially come in contact with K061 waste because they do not believe 
that the petitioned waste meets the criteria for which EPA listed it. 
Chaparral also believes no additional constituents or factors could 
cause the wastes to be hazardous.
    Based on our review, described below, EPA has determined that the 
waste is nonhazardous with respect to the original listing criteria. 
(If our review had found that the waste remained hazardous based on the 
factors for which EPA listed the waste, we would have proposed to deny 
the petition.)
    In reviewing this petition, we considered the original listing 
criteria and the additional factors required by RCRA section 3001(f), 
42 U.S.C. 6921(f), and 40 CFR 260.22(d)(2)-(4). We evaluated the 
petitioned waste against the listing criteria and factors cited in 
Secs. 261.11(a)(2) and (a)(3).
    We also evaluated the waste for other factors or criteria to assess 
whether these additional factors could cause the waste to be hazardous. 
These factors included: (1) whether the waste is considered acutely 
toxic, (2) the toxicity of the constituents, (3) the concentration of 
the constituents in the waste, (4) the waste constituent's tendency to 
migrate and to bioaccumulate, (5) its persistence in the environment 
once released from the waste, (6) plausible and specific types of 
management of the petitioned waste, (7) the quantity of waste produced, 
and (8) waste variability.
    The EPA believes that the petitioned waste does not meet the 
criteria for which it listed the waste and does meet the criteria for 
delisting. The EPA's proposed decision to delist waste from Chaparral's 
facility is based on the description of the proposed treatment system 
and analytical data from the Midlothian facility submitted to support 
today's rule.

C. How Will Chaparral Manage the Waste if it is Delisted?

    The facility would like to manage the waste in their onsite cooling 
system of which cooling ponds are a part. The wastewater would be 
substituted for some of the well water presently used for cooling 
purposes which would help conserve that natural resource. In this case, 
the requested change in waste management is subject to delisting by EPA 
and subsequent waste management practices in accordance with TNRCC 
rules and regulations.

D. When Would the Proposed Delisting Exclusion be Finalized?

    The Hazardous and Solid Waste Act specifically requires EPA to 
provide notice and an opportunity for comment before granting or 
denying a final exclusion. Thus, EPA will not grant the exclusion until 
it addresses all timely public comments (including those at public 
hearings, if any) on today's proposal.
    This rule, if finalized, will become effective immediately upon 
final publication. Section 3010(b) at 42 United States Code Annotated 
6930(b) of RCRA allows rules to become effective in less than six 
months when the regulated community does not need the six-month period 
to come into compliance. That is the case here, because this rule, if 
finalized, would reduce the existing requirements for persons 
generating hazardous wastes.
    The EPA believes that this exclusion should be effective 
immediately upon final publication because a six-month deadline is not 
necessary to achieve the purpose of section 3010(b), and a later 
effective date would impose unnecessary hardship and expense on this 
petitioner. These reasons also provide good cause for making this rule 
effective immediately, upon final publication, under the Administrative 
Procedure Act, 5 U.S.C. 553(d).

E. How would this action affect states?

    Because EPA is issuing today's exclusion under the Federal RCRA 
delisting program, only States subject to Federal RCRA delisting 
provisions would be affected. This would exclude two categories of 
States: States having a dual system that includes Federal RCRA 
requirements and their own requirements, and States who have received 
authorization from EPA to make their own delisting decisions.
    Here are the details: We allow states to impose their own non-RCRA 
regulatory requirements that are more stringent than EPA's, under 
section 3009 of RCRA. These more stringent requirements may include a 
provision that prohibits a federally issued exclusion from taking 
effect in the State. Because a dual system (that is, both Federal 
(RCRA) and State (non-RCRA) programs) may regulate a petitioner's 
waste, we urge petitioners to contact the State regulatory authority to 
establish the status of their wastes under the State law.
    The EPA has also authorized some States (for example, Louisiana, 
Georgia, Illinois) to administer a RCRA delisting program in place of 
the Federal program, that is, to make State delisting decisions. 
Therefore, this exclusion does not apply in those authorized States. If 
Chaparral transports the petitioned waste to or manages the waste in 
any State with delisting authorization, Chaparral must obtain delisting 
authorization from that State before they can manage the waste as 
nonhazardous in the State.

II. Background

A. What is the history of the delisting program?

    The EPA published an amended list of hazardous wastes from 
nonspecific and specific sources on January 16, 1981, as part of its 
final and interim final regulations implementing section 3001 of RCRA. 
The EPA has amended this list several times and published it in 
Secs. 261.31 and 261.32.
    We list these wastes as hazardous because: (1) they typically and 
frequently exhibit one or more of the characteristics of hazardous 
wastes identified in subpart C of part 261 (that is, ignitability, 
corrosivity, reactivity, and toxicity) or (2) they meet the criteria 
for listing contained in Secs. 261.11(a)(2) or (a)(3).
    Individual waste streams may vary, however, depending on raw 
materials, industrial processes, and other factors. Thus, while a waste 
described in these regulations generally is hazardous, a specific waste 
from an individual facility meeting the listing description may not be 
hazardous.
    For this reason, sections 260.20 and 260.22 provide an exclusion 
procedure, called delisting, which allows persons to prove that EPA 
should not regulate a specific waste from a particular generating 
facility as a hazardous waste.

B. What is a delisting petition, and what does it require of a 
petitioner?

    A delisting petition is a request from a facility to EPA or an 
authorized State to exclude wastes from the list of hazardous wastes. 
The facility petitions the Agency because they do not consider the 
wastes hazardous under RCRA regulations.

[[Page 46168]]

    In a delisting petition, the petitioner must show that wastes 
generated at a particular facility do not meet any of the criteria for 
the listed wastes. The criteria for which EPA lists a waste are in part 
261 and in the background documents for the listed wastes.
    In addition, under section 260.22, a petitioner must prove that the 
waste does not exhibit any of the hazardous waste characteristics (that 
is, ignitability, reactivity, corrosivity, and toxicity) and present 
sufficient information for EPA to decide whether factors other than 
those for which the waste was listed warrant retaining it as a 
hazardous waste. See part 261 and the background documents for the 
listed wastes.
    Generators remain obligated under RCRA to confirm whether their 
waste remains nonhazardous based on the hazardous waste characteristics 
even if EPA has ``delisted'' the wastes.

C. What factors must EPA consider in deciding whether to grant a 
delisting petition?

    Besides considering the criteria in section 260.22(a), in 42 U.S.C. 
6921(f), and in the background documents for the listed wastes, EPA 
must consider any factors (including additional constituents) other 
than those for which we listed the waste if a reasonable basis exists 
that these additional factors could cause the waste to be hazardous. 
See 3010(b) of the Solid Waste Disposal Act.
    The EPA must also consider as hazardous wastes mixtures containing 
listed hazardous wastes and wastes derived from treating, storing, or 
disposing of listed hazardous waste. See Secs. 261.3(a)(2)(iii and iv) 
and (c)(2)(i), called the ``mixture'' and ``derived-from'' rules, 
respectively. These wastes are also eligible for exclusion and remain 
hazardous wastes until excluded.
    The ``mixture'' and ``derived-from'' rules are now final, after 
having been vacated, remanded, and reinstated. On December 6, 1991, the 
U.S. Court of Appeals for the District of Columbia vacated the 
``mixture/derived from'' rules and remanded them to EPA on procedural 
grounds. See Shell Oil Co. v. EPA., 950 F.2d 741 (D.C. Cir. 1991). On 
March 3, 1992, EPA reinstated the mixture and derived-from rules, and 
solicited comments on other ways to regulate waste mixtures and 
residues. See (57 FR 7628) These rules became final on October 30, 
1992. See (57 FR 49278) Consult these references for more information 
about mixtures derived from wastes.

III. EPA's Evaluation of the Waste Information and Data

A. What wastes did Chaparral petition EPA to delist?

    On February 23, 1999, Chaparral Steel petitioned EPA for a 
conditional exclusion for 500,000 gallons (about 2,500 cubic yards) per 
year of leachate from its Landfill No. 3 single RCRA landfill unit 
containing electric arc furnace dust. The furnace dust is captured in 
the baghouse during the steelmaking process and is a listed hazardous 
waste classified as K061. The petitioned wastes are largely leachate 
generated in the landfill's leachate collection system and minor 
amounts of K061 wastewater from various plant operations including 
storm water from the baghouse floor areas and the pelletizer sump. 
These liquid wastes are presently pumped to an onsite storage tank. The 
resulting waste is also listed under Sec. 261.3(c)(2)(i) (the ``derived 
from'' rule), as EPA Hazardous Waste No. K061. The listed constituents 
of concern for this waste code are hexavalent chromium, lead, and 
cadmium.

B. What information and analysis did Chaparral submit to support this 
petition?

    To support its petition, Chaparral submitted:
    (1) historical analytical data for the Electric Arc Furnace Dust 
(K061), and leachate analytical data from their Landfill No. 3 
containing the Electric Arc Furnace Dust, and analytical data for the 
liquid from the K061 waste water storage tank;
    (2) analytical results of the total constituent list for 40 CFR 
part 264, appendix IX volatiles, semivolatiles, metals (including 
hexavalent chromium), pesticides, herbicides, polychlorinated 
biphenyls, furans, and dioxins;
    (3) analytical results of the constituent list derived from 
appendix IX for identified constituents;
    (4) analytical results for reactive sulfide;
    (5) analytical results for reactive cyanide;
    (6) test results for corrosivity by pH;
    (7) analytical results of samples from bench tests of treated 
leachate/K061 wastewater; and
    (8) test results for oil and grease.

C. Who is Chaparral and what process do they use to generate the 
petitioned waste?

    Chaparral Steel operates a steel plant which manufactures primary 
steel from scrap steel utilizing an electric arc furnace process with 
continuous casting of billets, and then rolling to finished goods. 
Electric arc furnace dust, which is captured in the baghouse during the 
steelmaking process, is a listed hazardous waste (K061). In the past, 
K061 was landfilled on-site. The on-site landfills have been closed. 
The baghouse K061 wastes are currently shipped off-site for metals 
recovery or are reused on site by reintroduction to the electric arc 
furnace.
    Leachate from Landfill No. 3 which also bears the K061 waste 
classification, is collected from the landfill's leachate collection 
system and stored in an on-site tank. Small amounts of water from 
various locations within the facility including storm water from the 
palletizer sump and storm water from the baghouse floor (which is 
potentially mixed with electric arc furnace dust and therefore would 
also be designated as K061) is also placed in the tank occasionally. 
Also minor amounts of water that has potentially contacted K061 is 
occasionally added to the tank. However, the amounts of storm water and 
other potentially contaminated wastewaters are very minor as compared 
to the leachate. The contents of the leachate tank are presently 
transported to an offsite injection facility for disposal.

D. How did Chaparral sample and analyze the data in this petition?

    Chaparral developed a list of constituents of concern from prior 
analytical data and by analyzing the first sample for the entire 
appendix IX list of hazardous constituents found in 40 CFR part 264. 
More specifically, Chaparral analyzed one treated and one raw leachate 
composite sample for the total concentrations (i.e., mass of a 
particular constituent per mass of waste) of the volatiles and 
semivolatiles, metals, herbicides, pesticides, PCBs, and furans from 
appendix IX. These two samples were analyzed for the comprehensive list 
in order to confirm that there were no other constituents of concern in 
the petitioned waste.
    Chaparral collected four composite samples from the storage tank 
over a twenty-five week period. They collected these samples in this 
manner to ensure that the samples represented the potential time and 
space variability of the petitioned waste. All samples were analyzed 
for constituents of concern and were also analyzed to determine whether 
the waste exhibited ignitable, corrosive, or reactive properties as 
defined under 40 CFR 261.21, 261.22, and 261.23, including analysis for 
reactive constituent concentrations of cyanide and sulfide. These 
samples were not analyzed for TCLP

[[Page 46169]]

concentrations (i.e., mass of a particular constituent per unit volume 
of extract) since the leachate is a liquid and the total analysis 
concentration is considered to be the TCLP concentration.

------------------------------------------------------------------------
       Chaparral used these methods                  To quantify
------------------------------------------------------------------------
SW-846 Method 8260, and 8270..............  The total constituent
                                             concentrations of 40 CFR,
                                             part Sec.  264 Appendix IX
                                             Volatiles and Appendix IX
                                             Semivolatiles including
                                             PCBs, Pesticides, and
                                             Herbicides.
SW-846 Methods 6010, 7041, and 7740, and    Appendix IX Metals.
 7196.
SW-846 Methods 7470.......................  Mercury.
9071......................................  Total oil and grease.
9045......................................  pH
9030......................................  Reactive Sulfide.
9010......................................  Reactive Cyanide.
1010......................................  Ignitability.
------------------------------------------------------------------------

E. What were the results of Chaparral's analysis?

    Tables 1 and 2 present the maximum total constituent leachate 
concentrations for the raw waste and for the treated waste samples from 
bench test studies. The bench test study simulated a typical wastewater 
treatment process. If the raw (untreated) waste does not meet delisting 
criteria, then Chaparral intends to treat the waste in a wastewater 
treatment plant to meet the delisting criteria.
    The wastewater treatment process would add a coagulant such as 
ferric chloride to precipitate the metal constituents and then add a 
cationic polymer to flocculate the metal constituents. A filter unit 
would remove the precipitated metal constituents which would yield a 
wastewater with concentrations of constituents of concern well below 
the delisting criteria concentrations.
    Chaparral calculated, based on historical information and the worst 
case scenario, the maximum petitioned waste to be excluded on a yearly 
basis will be 500,000 gallons (or about 2500 cubic yards) of petitioned 
waste. The sworn affidavit submitted with this petition binds the 
petitioner to present truthful and accurate results. The EPA reviews a 
petitioner's estimates and, on occasion, has requested a petitioner to 
reevaluate the estimated waste volume. The EPA accepted Chaparrals' 
certified estimates. The EPA does not generally verify submitted test 
data before proposing delisting decisions. The EPA, however, has 
maintained a spot-check sampling and analysis program to verify the 
representative nature of the data for some percentage of the submitted 
petitions. A spot-check visit to a selected facility may be initiated 
before finalizing a delisting petition or after granting an exclusion.

  Table 1.--Maximum Organic Total Constituent Concentrations 1 For Raw
 Leachate/K061 Wastewater and Treated Leachate/K061 Wastewater from the
                              Storage Tank
------------------------------------------------------------------------
                                                              Total
                                             Total         Constituent
                                          Constituent      Analyses for
             Constituents                 Analyses for       Treated
                                         Raw Leachate 1  Leachate 1  (mg/
                                             (mg/l)             l)
------------------------------------------------------------------------
1,2-Dichloroethane....................            0.004           <0.005
2-Butanone............................            0.003            0.005
4-Methyl-2-pentanone..................            0.008            0.005
Acetone...............................            0.08             0.1
Carbon Disulfide......................            0.003            0.005
Chloromethane.........................           <0.01             0.001
Ethylbenzene..........................            0.004           <0.005
Methyl Iodide.........................           <0.01             0.002
Methylene Chloride....................            0.001           <0.005
Toluene...............................            0.001            0.004
Xylene................................            0.03             0.006 
------------------------------------------------------------------------
< Denotes that the constituent was not detected at the detection limit
  specified in the table.
\1\ These levels represent the highest concentration of each constituent
  found in any one sample. These levels do not necessarily represent the
  specific levels found in one sample.

F. How did EPA evaluate the risk of delisting this waste?

    Chaparral Steel's petition requests a conditional delisting for 
listed hazardous wastes. In making the initial delisting determination, 
EPA evaluated the petitioned wastes against the listing criteria and 
factors cited in Secs. 261.11(a)(1), 261.11(a)(2) and 261.11(a)(3). 
Based on this review, EPA has determined that the waste is nonhazardous 
with respect to the original listing criteria. (If EPA had found, based 
on this review, that the wastes remained hazardous based on the factors 
for which the wastes were originally listed, EPA would have proposed to 
deny the petition.) The EPA then evaluated the wastes with respect to 
other factors or criteria to assess whether there is a reasonable basis 
to believe that such additional factors could cause the wastes to be 
hazardous. The EPA considered whether the wastes are acutely toxic, the 
toxicity of the constituents, the concentration of the constituents in 
the wastes, their tendency to migrate and to bioaccumulate, their 
persistence in the environment once released from the wastes, plausible 
and specific types of management of the petitioned wastes, the 
quantities of wastes generated, and waste variability.
    For this delisting determination, EPA used such information 
gathered to identify plausible exposure routes (i.e., ground water, 
surface water and air) for hazardous constituents present in the 
petitioned wastes. The EPA determined that disposal in a surface 
impoundment is the most reasonable, worst-case disposal scenario for 
Chaparral's petitioned wastes, and that the major exposure route of 
concern would be ingestion of contaminated ground water. Therefore, EPA 
used a particular fate and transport model, EPA Composite Model for 
Landfills (EPACML), to predict the maximum allowable concentrations of 
hazardous

[[Page 46170]]

constituents that may be released from the petitioned wastes after 
disposal and to determine the potential impact of the disposal of 
Chaparral's petitioned wastes on human health and the environment. You 
can find a detailed description of the EPACML model, the disposal 
assumptions, and the modifications made for delisting in 56 FR 32993 
(July 18, 1991), 56 FR 67197 (December 30, 1991) and the RCRA public 
docket. This model includes both unsaturated and saturated zone 
transport modules. It uses the reasonable worse-case contaminant levels 
in ground water at a compliance point (that is, a receptor well serving 
as a drinking-water supply.)
    Specifically, EPA used the maximum estimated waste volumes and the 
maximum reported concentrations as inputs to estimate the constituent 
concentrations in the ground water at a hypothetical receptor well 
downgradient from a theoretical disposal site. The calculated receptor 
well concentrations (referred to as compliance-point concentrations) 
were then compared directly to the current Maximum Contaminant Levels 
(MCLs) promulgated under the Safe Drinking Water Act or health-based 
levels derived from verified Reference Doses. The values used for lead 
and copper are action levels for treatment of a water supply in lieu of 
an MCL (40 CFR 141.80).
    The EPA believes that this fate and transport model represents a 
reasonable worst-case scenario for disposal of the petitioned wastes in 
a surface impoundment, and that a reasonable worst-case scenario is 
appropriate when evaluating whether a waste should be relieved of the 
protective management constraints of RCRA subtitle C. The use of a 
reasonable worst-case scenario results in conservative values for the 
compliance-point concentrations and gives a high degree of confidence 
that the waste, once removed from hazardous waste regulation, will not 
pose a threat to human health or the environment. In most cases, 
because a delisted waste is no longer subject to hazardous waste 
control (unless conditionally delisted), EPA is generally unable to 
predict, and does not presently control, how a waste will be managed 
after delisting. Therefore, EPA normally believes that it is 
inappropriate to consider extensive site-specific factors when applying 
the fate and transport model. If however, conditions contained in a 
delisting indicate that it is necessary to consider site specific 
factors or otherwise indicate that the model is inappropriate, EPA may 
consider these factors in applying the model.
    The EPA also considers the applicability of ground water monitoring 
data during the evaluation of delisting petitions. The evaluation of 
the information submitted indicated that the waste is managed in a tank 
with secondary containment. Therefore ground water data is not 
applicable to this petition.
    From the evaluation of Chaparral's delisting petition, one of the 
constituents evaluated, lead, is being proposed as a verification 
testing condition. Proposed maximum allowable leachable concentrations 
for this constituent was derived by back-calculating from the delisting 
health-based levels through the proposed fate and transport model for a 
surface impoundment management scenario and by comparing results with 
the Land Disposal Restrictions (LDRs) maximum allowable concentration. 
The lowest of these two concentrations (i.e., delisting levels) are 
part of the verification testing conditions of the proposed exclusion. 
Therefore, delisting levels are less than LDR concentrations and thus 
the LDRs are met. Details of the evaluation of lead and other 
constituents of concern is explained in more detail later in this 
section.
    Chaparral's exclusion (if granted) would be contingent upon the 
facility conducting sampling and analysis of the waste to insure that 
the delisting conditions are met (i.e., wastes meet EPA's verification 
testing conditions).
    The EPA's proposed decision is based on the information submitted 
in support of today's rule, i.e., historical data from the Landfill No. 
3 leachate, analytical data from recent samples from the leachate 
storage tank containing leachate and K061 wastewaters, and analytical 
data from bench tests of the leachate/K061 wastewaters after treatment 
in a simulated wastewater treatment system.
    Finally, RCRA (7004(b)(1)) specifically requires EPA to provide 
notice and an opportunity for comment before granting or denying a 
final exclusion. Thus, a final decision will not be made until all 
timely public comments (including those at public hearings, if any) on 
today's proposal are addressed.
    The EPA's evaluation of the raw leachate using a Dilution 
Attenuation Factor of 68, a maximum waste volume annually of 2500 cubic 
yards (or 500,000 gallons per calender year), and the maximum reported 
constituent concentrations (see Tables 1 and 2), yielded compliance 
point concentrations (see Tables 3 and 4) that are below the current 
health-based levels except for the constituent lead which is discussed 
below.
    In Table 3, the calculated compliance point concentrations derived 
from the maximum reported leachate concentrations (see Table 1) of the 
organic constituents detected in the waste are compared with the levels 
of concern. The organic constituents are believed to be artifacts from 
sampling or analysis errors because: (1) the arc furnace process should 
have destroyed the organic chemicals, (2) the organic constituents are 
not detected consistently, (3) most detections are near the detection 
limits, and (4) several of the compounds are common laboratory 
contaminants. However, in spite of this reasoning, EPA completed the 
evaluation conservatively using the highest concentration found for 
each organic constituent in the petitioned waste. As shown in Table 3, 
the maximum reported leachate concentrations of 1,2-dichloroethane, 2-
butanone, 4-methyl-2-pentanone, acetone, carbon disulfide, 
ethylbenzene, methylene chloride, toluene, and xylene yielded 
compliance point concentrations below the health-based levels used in 
delisting decision-making. It should also be noted that the 
concentrations of the organic constituents found in the raw leachate 
are below LDR concentration values and therefore the LDRs are met. See 
Table 1.
    The EPA also evaluated the mobility of the two remaining organic 
constituents cloromethane and methyl iodide which were not detected in 
the leachate but were found in the treated leachate at concentrations 
of 0.001 and 0.002 mg/l yielding compliance concentrations of 0.00001 
and 0.00003 mg/l, in respective order. These concentrations are well 
below the levels of concern of 0.007 and 0.03 mg/l, respectively. The 
0.001 and 0.002 mg/l values are below the LDR concentration values and 
therefore the LDRs are met.
    In Table 4, the calculated compliance point concentrations derived 
from the maximum reported leachate/K061 wastewater concentrations of 
the inorganic constituents (see Table 2) detected in the petitioned raw 
waste are compared with the levels of regulatory concern. The maximum 
reported or calculated concentrations of arsenic, barium, cadmium, 
total chromium, copper, mercury, nickel, vanadium, and zinc yielded 
compliance point concentrations below Levels of Concern.
    The EPA did not evaluate the mobility of the constituents 
beryllium, hexavalent chromium, cobalt, selenium, silver, thallium and 
cyanide from Chaparral's petitioned waste because

[[Page 46171]]

these constituents were not detected in the leachate using the 
appropriate analytical test methods. See Table 2. The EPA believes that 
it is inappropriate to evaluate nondetectable concentrations of a 
constituent of concern in its delisting modeling efforts if the 
nondetectable value was obtained using the appropriate analytical 
method. If a constituent cannot be detected (when using the appropriate 
analytical method with an adequate detection limit), EPA, for delisting 
purposes, assumes that the constituent is not present and therefore 
does not present a threat to human health or the environment. In the 
delisting program EPA believes it is inappropriate to evaluate 
constituents undetected in the waste samples.
    The maximum reported raw leachate concentration for a single sample 
of lead (2.0 mg/l) yielded a calculated compliance point concentration 
(0.029 mg/l) slightly above the health-based level (0.015 mg/l) used in 
the delisting decision-making process.
    The lead value (0.029 mg/l) represents the calculated leachate 
concentrations of lead at a theoretical downgradient ground water 
monitoring well using the EPACML model and a concentration value of 2.0 
mg/l from one raw waste sample. This value was the highest 
concentration identified for the four analysis completed for lead. The 
four concentration values for lead as identified in the raw waste were 
2.0, 1.3, 0.5 and 0.55 mg/l and the values for the treated waste were 
0.081, 0.06, 0.026, and <0.0011 mg/l. Two of the raw waste lead values 
(0.5 and 0.55 mg/l) and all of the treated samples yield calculated 
compliance point concentrations below the concentration of concern. For 
this reason, verification testing for one waste constituent, lead, will 
be a condition of the delisting.
    Lead was the only constituent that did not consistently have 
calculated compliance point concentrations below the concentrations of 
concern. As shown in Tables 3 and 4, all other constituents were always 
below the concentrations of concern at the calculated compliance point. 
It should also be noted that the concentration values as measured in 
the raw waste for all other constituents of concern were below the LDR 
concentration values. Therefore, with the exception of the constituent 
lead, the petitioned waste meets LDR concentration values even before 
the compliance point concentrations are calculated. Seven years of 
historical leachate data also supported the decision that lead was the 
only Constituent of Concern which should require verification testing.

  Table 2.--Maximum Inorganic Total Constituent Concentrations For Raw
 Leachate/K061 Wastewater and Treated Leachate/K061 Wastewater From the
                            K061 Storage Tank
------------------------------------------------------------------------
                                                              Total
                                             Total         Constituent
                                          Constituent      Analyses for
             Constituents                 Analyses for       Treated
                                          Raw Leachate     Leachate \1\
                                           \1\ (mg/l)         (mg/l)
------------------------------------------------------------------------
Antimony..............................         <0.0066           0.008
Arsenic...............................          0.081            0.068
 Barium...............................          0.26             0.007
Beryllium.............................         <0.0017          <0.0017
Cadmium...............................          0.019            0.0020
Chromium (Total)......................          0.17             0.013
Chromium (Hexavalent).................         <0.1             <0.02
Cobalt................................         <0.0016          <0.0016
Copper................................          0.096            0.029
Lead..................................          2                0.081
Mercury...............................          0.00031          0.00016
Nickel................................          0.019            0.014
Selenium..............................         <0.01             0.044
Silver................................         <0.0012          <0.0012
Thallium..............................         <0.0096          <0.0096
Tin...................................          0.025            0.017
Vanadium..............................          0.042            0.038
Zinc..................................          5.6              0.08
Sulfide (Total).......................          1.3             <1.0
Cyanide (Total).......................         <0.0018          <0.0018
------------------------------------------------------------------------
< Denotes that the constituent was not detected at the noted detection
  limit.
\1\ These levels represent the highest concentration of each constituent
  found in any one sample. These levels do not necessarily represent the
  specific levels found in one sample.


Table 3.--EPACML: Calculated Compliance Point Organic Concentrations for
      Raw Leachate and K061 Wastewater From the K061 Storage Tank.
------------------------------------------------------------------------
                                       Compliance Point     Levels of
        Organic Constituents            Concentrations   Concern \2\ (mg/
                                          \1\ (mg/l)            l)
------------------------------------------------------------------------
1,2-Dichloroethane..................           0.00006           0.005
2-Butanone..........................           0.00004          20.
4-Methyl-2-pentanone................           0.0001            2.
Acetone.............................           0.001             4.
Carbon Disulfide....................           0.00004           4.
Ethylbenzene........................           0.00006          70.
Methylene Chloride..................           0.00001           0.005
Toluene.............................           0.00001           1.

[[Page 46172]]

 
Xylene..............................           0.0004           10.
------------------------------------------------------------------------