# 64 FR 46166: Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Proposed Exclusion > Federal · Regulations · In force URL: https://www.frixlaw.com/law-library/statutes/FR_PRORULE_99-21941 ## Section - **Citation:** 64 FR 46166 - **Heading:** Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Proposed Exclusion - **Jurisdiction:** Federal - **Kind:** Regulations - **Status:** In force - **Text as of:** August 14, 2026 - **Source:** Compiled text - **Location:** Federal Register / Vol. 64 / 64 FR 46166 ## Text 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. nstituents 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 ion 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 wastewater that may have been in contact with the K061 waste excluded, or delisted, from the definition of a hazardous waste; and 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 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 d 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? e 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? blication 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? te 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. 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. 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 itional 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 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 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 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. 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 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 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. . 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? -------------------------------------------------------------- < 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 tence 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 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 ent 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 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 ions). 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 ould 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 he 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 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 ed 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. er 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 ................................... 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. Xylene.............................. 0.0004 10. ------------------------------------------------------------------------