SUPPLEMENTARY INFORMATION:

Table of Contents

I. Public Participation

A. Does this action apply to me?

B. Written comments

II. General Information

A. List of Abbreviations and Acronyms

B. What action is the EPA taking?

C. What is the EPA's authority for taking this action?

D. What are the incremental costs and benefits of this action?

III. Background

A. RCRA Rulemaking Petitions

B. Regulatory Background on Phosphogypsum and Process Wastewater

IV. Reasons for the EPA's Proposed Denial of the Petition

Petition Does Not Adequately Support a Decision by the EPA To Reconsider the Bevill Status of Phosphogypsum or Process Wastewater Under RCRA

V. References

I. Public Participation

A. Does this action apply to me?

The EPA is not proposing any regulatory changes at this time. Entities that may be interested in this proposed denial of the rulemaking petition include any facility that generates, stores, or uses phosphogypsum or associated process wastewater generated as a byproduct of phosphoric acid production. If you have questions regarding the applicability of this action to a particular entity, consult the person listed in the FOR FURTHER INFORMATION CONTACT section.

B. Written Comments

Submit your comments, identified by Docket ID No. EPA-HQ-OLEM-2026-0232, at https://www.regulations.gov (our preferred method), or the other methods identified in the ADDRESSES section. Once submitted, comments cannot be edited or removed from the docket. The EPA may publish any comment received to its public docket. Do not submit to the EPA's docket at https://www.regulations.gov any information you consider to be Confidential Business Information (CBI), Proprietary Business Information (PBI), or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( i.e., on the web, cloud, or other file sharing system). Please visit https://www.epa.gov/​dockets/​commenting-epa-dockets for additional submission methods; the full EPA public comment policy; information about CBI, PBI, or multimedia submissions; and general guidance on making effective comments.

II. General Information

A. List of Abbreviations and Acronyms

CBD—Center for Biological Diversity

CFR—Code of Federal Regulations

EPA—Environmental Protection Agency

FACA—Federal Advisory Committee Act

FR—Federal Register

NESHAP—National Emissions Standards for Hazardous Air Pollutants

RCRA—Resource Conservation and Recovery Act

TSCA—Toxic Substances Control Act

B. What action is the EPA taking?

The EPA is providing notice of and requesting comment on its proposed denial of CBD's 2021 petition requesting a rulemaking to: (1) reverse the EPA 1991 Bevill regulatory determination excluding phosphogypsum and phosphoric acid production process wastewater (“process wastewater”) from RCRA Subtitle C hazardous waste regulations; and (2) govern the safe treatment, storage and disposal of phosphogypsum and process wastewater as hazardous wastes under RCRA Subtitle C. With this action, the EPA is publishing its evaluation of the rulemaking petition and supporting materials and requesting public comment on the proposed denial.

C. What is the EPA's authority for taking this action?

On February 8, 2021, the Center for Biological Diversity (CBD) on behalf of People for Protecting Peace River, Atchafalaya Basinkeeper, Bayou City Waterkeeper, Calusa Waterkeeper, Center for Biological Diversity, Cherokee Concerned Citizens, Healthy Gulf, Manasota-88, Our Santa Fe River, Rise St. James, Sierra Club Delta Chapter, Sierra Club Florida Chapter, Suncoast Waterkeeper, Suwannee Riverkeeper, Tampa Bay Waterkeeper, Waterkeeper Alliance, Waterkeepers Florida, and WWALS Watershed Coalition petitioned the EPA to: (1) reverse the EPA 1991 Bevill regulatory determination excluding phosphogypsum and process wastewater from RCRA Subtitle C hazardous waste regulations; and (2) govern the safe treatment, storage and disposal of phosphogypsum and process wastewater as hazardous wastes under RCRA Subtitle C (“Petition”). The EPA is responding to this Petition for rulemaking pursuant to 42 U.S.C. 6912(a), 6921(a) and 6974, and the EPA's regulations at 40 CFR 260.20. The EPA identifies hazardous wastes subject to the RCRA Subtitle C regulations pursuant to 42 U.S.C. 6921(a), with implementing regulations 40 CFR parts 261 and 262.11.

D. What are the incremental costs and benefits of this action?

This action consists entirely of the rationale for denying the Petition and proposes no regulatory changes. This action has neither incremental costs nor benefits.

III. Background

A. RCRA Rulemaking Petitions

Under RCRA, “[a]ny person” may “petition the [EPA] for the promulgation, amendment, or repeal of any regulation under” the statute (42 U.S.C. 6974(a)). The EPA's regulations require that every petition must include, among other components, “a statement of the need and justification for the proposed action, including any supporting tests, studies, or other information” (40 CFR 260.20(b)(4)). Therefore, when a petition fails to provide sufficient information, the EPA is not required to grant the petition and may deny it as a matter of its discretion. The EPA has refrained prescribing more specific content requirements for petitions such as this, because information needs associated with a petition request vary in accordance with the regulatory provisions that the petition may seek to amend or add.

Following receipt of a petition, the EPA's regulations provide that the EPA “will make a tentative decision to grant or deny a petition and will publish notice of such tentative decision, either in the form of an advanced notice of proposed rulemaking, a proposed rule, or a tentative determination to deny the petition, in the Federal Register for written public comment” (40 CFR 260.20(c)). Following evaluation of “all public comments the [EPA] will make a final decision by publishing in the Federal Register a regulatory ( printed page 22151) amendment or denial of the petition” (40 CFR 260.20(e)).

With this action, the EPA is issuing a proposed determination to deny the Center for Biological Diversity's 2021 rulemaking petition asking that the EPA: (1) reverse the EPA 1991 Bevill regulatory determination excluding phosphogypsum and process wastewater from RCRA Subtitle C hazardous waste regulations; and (2) [issue regulations that] govern the safe treatment, storage and disposal of phosphogypsum and process wastewater as hazardous wastes under RCRA Subtitle C.

In evaluating the Petition, the EPA considered whether the reopening of the EPA's 1991 Bevill regulatory determination is warranted, based on the post-regulatory determination information submitted by Petitioners. The EPA's review of the Petition is not a reopening of the Bevill regulatory determination itself. For the reasons identified in section IV, the Petition fails to support the reconsideration of the Bevill exclusion for phosphogypsum and process wastewater, and as such, reevaluation is unwarranted. Since the EPA is not reopening the Bevill determination, phosphogypsum and process wastewater remain excluded from regulation under RCRA Subtitle C. As a result, further response to the latter part of the Petition requesting the EPA list phosphogypsum and process wastewater as hazardous waste under Subtitle C is unwarranted.

B. Regulatory Background on Phosphogypsum and Process Wastewater

Phosphogypsum and process wastewater are large-volume waste products of wet process phosphoric acid production, as described in the 1998 EPA Technical Background Document (USEPA, 1998a). Phosphoric acid facilities largely produce phosphoric acid for use in fertilizer and animal feed products. Phosphate rock is typically received at facilities from mines by truck or rail car, and sulfuric acid is piped from storage tanks to phosphoric acid reactors. In the reactors, sulfuric acid is mixed with phosphate rock to produce weak phosphoric acid. A byproduct of the reaction is calcium sulfate dihydrate, referred to as phosphogypsum. Phosphogypsum is separated from the weak phosphoric acid by filtration. To recover additional weak phosphoric acid, the filtered phosphogypsum is rinsed with process wastewater pumped from ponds and ditches associated with phosphogypsum stacks ( i.e., large waste piles of phosphogypsum). The rinsed phosphogypsum is then mixed with water (slurried) and pumped to the phosphogypsum stacks for disposal. Approximately five tons of phosphogypsum are produced for every one ton of phosphoric acid manufactured. Approximately 90 percent of the water used at these facilities is recycled for reuse as process wastewater (USEPA, 1998a).

In 40 CFR 261.4(b)(7), phosphogypsum and process wastewater from phosphoric acid production are among the solid wastes from the processing of ores and minerals that are excluded from regulation as a hazardous waste under RCRA Subtitle C (42 U.S.C. 6921). As part of the Solid Waste Disposal Act Amendments of 1980 to RCRA, the Bevill Amendment (section 3001(b)(3)(A)(ii)) exempted “solid waste from the extraction, beneficiation, and processing of ores and minerals” from regulation as hazardous wastes under Subtitle C of RCRA, until the EPA performed a study and submitted a Report to Congress, as required by RCRA sections 8002(f) and 8002(p), to determine if these exempt wastes should be regulated under Subtitle C or that such regulations were unwarranted ( i.e., the exclusion should continue), as required by section 3001(b)(3)(C). The EPA modified its hazardous waste regulations in November 1980 to reflect this “Mining Waste Exclusion,” and issued a preliminary, broad interpretation of the scope of its coverage to encompass “solid waste from the exploration, mining, milling, smelting and refining of ores and minerals” (45 FR 76618; USEPA, 1990a). The Simpson Amendment in 1984 created regulatory flexibility for the EPA to modify some of the requirements of Subtitle C for special wastes that the EPA determined to be hazardous under RCRA Subtitle C (“Subtitle C-Minus”), including mineral processing wastes (42 U.S.C. 6924(x)).

In 1984, the EPA was sued for failing to complete the section 8002 studies and associated Bevill Amendment regulatory determination by the statutorily imposed deadline ( Concerned Citizens of Adamstown vs. EPA, No. 84-3041, D.D.C, August 21, 1985). The District Court for the District of Columbia ordered the EPA to complete the section 8002 studies and regulatory determination in accordance with the regulatory agenda submitted to the court. In responding to this lawsuit, the EPA detailed its plans for proposing a narrower interpretation of the scope of the Mining Waste Exclusion, a schedule for completing the section 8002 studies of mineral extraction and beneficiation wastes and submitting the associated Report to Congress, and a schedule for proposing and promulgating a reinterpretation for mineral processing wastes. The EPA's approach, which the Court agreed to, split the wastes that might be eligible for exclusion from regulation into two groups: mining (mineral extraction and beneficiation) wastes and mineral processing wastes. The Petition and this proposed denial focus on mineral processing wastes, which include phosphogypsum and process wastewater.

As described in section IV of this proposed denial, the EPA was required to study the disposal and utilization of wastes excluded from regulation under section 8002(p) using the following eight Bevill study factors:

1. The source and volume of such materials generated per year;

2. Present disposal and utilization practices;

3. Potential danger to human health and the environment from the disposal and reuse of such materials;

4. Documented cases in which danger to human health or the environment has been proven;

5. Alternatives to current disposal methods;

6. The costs of such alternatives;

7. The impacts of these alternatives on the use of phosphate rock, uranium ore, and other natural resources; and

8. The current and potential utilization of such materials.

In 1985, the EPA proposed narrowing the scope of the Mining Waste Exclusion for mineral processing wastes to only include a few specific waste streams, including phosphogypsum (50 FR 40292). However, the EPA withdrew this proposal in October 1986 (51 FR 36233), given the difficulty in articulating criteria for distinguishing exempt from non-exempt wastes and the approaching court-ordered deadline for final action. In July 1988, the court in Environmental Defense Fund v. EPA, 852 F.2d 1316 (D.C. Cir. 1988), cert. denied 109 S. Ct. 1120 (1989), ordered the EPA to define the specific mineral processing wastes that were eligible for the Mining Waste Exclusion and directed the EPA to restrict the scope of the Mining Waste Exclusion to include only “large volume, low hazard” wastes.

In the three years that followed this decision, the EPA proposed and promulgated several rules that redefined the boundaries of the exclusion for mineral processing wastes (54 FR 36592; 55 FR 2322). These rulemaking documents included explicit criteria for defining mineral beneficiation and processing, large volume and low hazard, as well as evaluations of which specific mineral industry wastes were in ( printed page 22152) conformance with these criteria, and thus, eligible for special wastes status. The rulemaking process was completed with the publication of final rules in 1989 (54 FR 36592) and 1990 (55 FR 2322). Only 20 specific mineral processing wastes (“Special 20”), which included phosphogypsum and process wastewater from phosphoric acid production, fulfilled the special wastes criteria; all other mineral processing wastes were removed from the Mining Waste Exclusion.

In 1989, the EPA also promulgated a National Emissions Standards for Hazardous Air Pollutants (NESHAP) under the Clean Air Act, which required all phosphogypsum to be disposed of in stacks or mines and limited their radon emissions (54 FR 38044). The NESHAP was later amended in 1992 to allow for agricultural, and research and development uses, of certain phosphogypsum meeting a maximum radium threshold (57 FR 23305).

In 1990, the EPA published a Report to Congress on special wastes from mineral processing (USEPA, 1990a; USEPA, 1990b). The EPA then promulgated the “Special Wastes from Mineral Processing Final Regulatory Determination and Final Rule” in June 1991 (56 FR 27300). In the regulatory determination (56 FR 27300), the EPA stated that although the management practices and state and federal regulations at the time did not adequately limit contaminant releases and associated risk from phosphogypsum and process wastewater, additional regulatory controls under RCRA Subtitle C or Subtitle D would result in unsustainable costs exceeding the operating margins of facilities. As a result, the EPA decided that additional controls may be warranted, but RCRA Subtitle C and Subtitle D were “too inflexible and costly for the industry to implement and remain viable” (56 FR 27300). For phosphogypsum and process wastewater specifically, the EPA decided at that time, to consider developing actions and initiatives under the Toxic Substances Control Act (TSCA) and to use existing authorities under RCRA section 7003 or CERCLA section 106 to respond to groundwater contamination at specific sites.

Under the TSCA regulatory program, the Phosphoric Acid Waste Dialogue FACA Committee was initiated in 1992, with members from interest groups, including industry, environmental organizations, and state and federal agencies. The Committee met six times between December 1992 and March 1994, with the charge to “provide a forum to address existing or potential risks to human health or the environment from phosphoric acid production wastes” (Phosphorus Acid Waste Dialogue FACA Committee, 1995). The Committee was tasked with evaluating current processes and identifying site-specific process changes that could potentially be applied to phosphoric acid production facilities on a case-by-case basis, to reduce the toxicity and/or volume of these wastes and achieve “environmental improvements from process changes that were technically and economically feasible” (Phosphorus Acid Waste Dialogue FACA Committee, 1995). While the Committee identified process changes and alternatives in their 1995 report, they did not find “any affordable, technologically feasible in-plant process changes that would significantly reduce volume and/or toxicity of phosphogypsum or phosphoric acid process wastewater,” and the EPA pursued no further regulatory action (Phosphorus Acid Waste Dialogue FACA Committee, 1995).

IV. Reasons for the EPA's Proposed Denial of the Petition

Petition Does Not Adequately Support a Decision by the EPA To Reconsider the Bevill Status of Phosphogypsum or Process Wastewater Under RCRA

When Congress originally excluded mining wastes from RCRA Subtitle C regulations (Bevill Amendment of 1980), it gave the EPA direction to study these wastes and determine which should remain exempt. In 1985, the EPA published the required Report to Congress on Solid Wastes from Mineral Extraction and Beneficiation (USEPA, 1985) and in 1991, the EPA promulgated the “Special Wastes from Mineral Processing Final Regulatory Determination and Final Rule” (56 FR 27300). The EPA studied all exempted mineral processing wastes and retained the exemption for only the Special 20 large volume wastes based on eight Bevill study factors (56 FR 27300). The EPA further studied phosphogypsum and process wastewater and found alternatives to current disposal methods where the toxicity of phosphogypsum wastes could be reduced. However, the costs involved were prohibitive to the industry (56 FR 27300; USEPA, 1998a).

Because an analysis of the Bevill study factors was the first step in determining whether the exemption should be retained, the EPA has analyzed this Petition by examining information submitted by the Petitioners relevant to the Bevill study factors in RCRA 8002. As described below, the Petition has not provided sufficient information to warrant the EPA's reconsideration of the 1991 Bevill determination that exempted phosphogypsum and process wastewater from RCRA Subtitle C.

The Petition states that the EPA is not precluded from revisiting the Bevill regulatory determination if more information becomes known. However, as described below, the Petition largely presents information that was already considered during the EPA's evaluation of phosphogypsum and process wastewater (USEPA, 1990a) and described in the cache of regulatory documents leading to the identification of the Special 20 (56 FR 27300) (USEPA, 1998a).

Bevill factor 1 pertains to the source and volume of materials generated per year. Petitioners cite sources (Petition section III and VII.A.2.b.) and quantities (Petition sections III and VII.A.2.h.) of phosphogypsum directly from the 1990 Report to Congress on Special Wastes from Mineral Processing (USEPA, 1990a). The information submitted by Petitioners does not differ from the sources and quantities previously studied by the EPA (USEPA, 1990a) and described in the cache of regulatory documents leading to the identification of the Special 20 (56 FR 27300).

Bevill factor 2 pertains to present disposal and utilization practices. The Petition discusses disposal of phosphogypsum in large stacks with basic engineered controls ( i.e., single liners, clay liners, vegetative and soil covers) and process wastewater in ponds and ditches for recirculation/utilization in the fertilizer plant (Petition sections III and VII.A.2.g.). The information submitted by Petitioners does not differ from the disposal and utilization practices previously studied by the EPA (USEPA, 1990a) and described in the cache of regulatory documents leading to the identification of the Special 20 (56 FR 27300).

Bevill factor 3 pertains to potential danger to human health and the environment from disposal and reuse. The Petition discusses impacts to ground and surface waters, aquatic life, and air quality (Petition section V) that were specifically identified in the 1990 Report to Congress on Special Wastes from Mineral Processing (USEPA, 1990a). This information was previously studied by the EPA (USEPA, 1990a) and described in the regulatory documents leading to the identification of the Special 20 (56 FR 27300).

Bevill factor 4 pertains to documented cases in which danger to human health or the environment has been proven. Petitioners identify recent damage cases ( printed page 22153) where levees/embankments were breached or sinkholes formed, releasing process wastewater and/or phosphogypsum (Petition section VII.A.2.g.). However, the 1985 Report to Congress (USEPA, 1985), “Damage Cases and Environmental Releases from Mines and Mineral Processing” document (USEPA, 1998b), and “Risks Posed by Bevill Wastes” document (USEPA, 1998c) considered similar levee/embankment breaches and sinkhole formation damage cases. Because the EPA has previously considered these types of damages in its prior studies, in effect, Petitioners have not presented information beyond what was considered in those documents and the original studies that retained phosphogypsum and process wastewater as mineral processing wastes exempted by Bevill.

Bevill factor 5 pertains to alternatives to current disposal methods. The Petition lists seven alternatives to current phosphogypsum and process wastewater management (Petition section XIV). However, Petitioners have not presented sufficient information on these alternatives and their feasibility (including costs, current use, potential use, and environmental impact) to convince the EPA that re-evaluation of Bevill is warranted. In addition, the EPA previously conducted an evaluation of alternatives, which did consider the costs, current use, potential use, and environmental impact of available alternatives at the time (USEPA, 1990a), and as described in the cache of regulatory documents leading to the identification of the Special 20 (56 FR 27300). The Phosphoric Acid Waste Dialogue FACA Committee also evaluated alternatives and concluded that none of the potential alternatives identified in their report, or any other known technology at the time, offered significant reductions in the volume and/or toxicity of the waste streams from the production of phosphoric acid using the sulfuric acid wet process (Phosphoric Acid Waste Dialogue FACA Committee, 1995).

Bevill factor 6 refers to the costs of such alternatives. The Petition does not present any information on this factor.

Bevill factor 7 pertains to the impact of those alternatives on the use of phosphate rock and uranium ore, and other natural resources. The Petition does not present any information on this factor.

Bevill factor 8 refers to current and potential utilization. The Petition mentions the 2020 approval of the use of phosphogypsum in road construction projects as part of its argument for a TSCA Significant New Use (Petition section XII). While this proposed denial does not address the TSCA elements of the Petition (previously addressed in 86 FR 27546), the EPA also does not think that the information presented by Petitioners regarding the use in road construction warrants reconsideration of Bevill, in terms of factor 8. In the 2020 rulemaking (85 FR 66550), the EPA concluded that the Fertilizer Institute's risk assessment was largely consistent with the EPA's 1992 amendment to NESHAP (57 FR 23305) and adequately demonstrated that the use of phosphogypsum in government road construction projects is at least as protective of human health, in the short- and long-term, as stacking. The EPA established specific terms and conditions including continued control, maintenance, and use of government roads constructed with phosphogypsum, which addressed concerns with potential exposures from abandoned roads (85 FR 66550).

Because Petitioners have failed to provide sufficient information to support the request to reverse the 1991 Bevill regulatory determination for phosphogypsum and process wastewater, the EPA is proposing to deny the Petition.

Furthermore, phosphogypsum and process wastewater are excluded from management as hazardous waste pursuant to the Bevill regulatory determination. Because the Petition does not adequately support a decision to reconsider the Bevill status of phosphogypsum and process wastewater under RCRA, further evaluation of Petitioner's secondary request to govern phosphogypsum and process wastewater as hazardous waste under RCRA Subtitle C is also not warranted. For the same reason, the EPA declines to further consider regulatory changes under the 1984 RCRA Simpson Amendment (Subtitle C-Minus), which provides flexibility for the EPA to modify some of the requirements of Subtitle C for special wastes that the EPA determines are hazardous.

For the reasons set forth above, the EPA finds that the Petition has not provided sufficient information, beyond what was already considered during the EPA's evaluation of phosphogypsum and process wastewater (56 FR 27300; USEPA, 1990a; USEPA, 1998a), to consider additional modifications authorized by 42 U.S.C. 6924(x).

V. References

The following is a listing of the documents that are specifically referenced in this document. The docket includes these documents considered by the EPA. For assistance in locating these documents, please consult the person listed under FOR FURTHER INFORMATION CONTACT .

1. CBD. Notice of Intent to Sue for Failure to Perform a Nondiscretionary Duty under the Resource Conservation and Recovery Act. February 13, 2024.

2. CBD. Notice of Petition for Rulemaking Pursuant to section 7004(A) of the Resource Conservation and Recovery Act, 42 U.S.C. 6974(A); section 21 of the Toxic Substances Control Act, 15 U.S.C. 2620; and section 553(E) of the Administrative Procedure Act, 5 U.S.C 553(E), Concerning the Regulation of Phosphogypsum and Process Wastewater from Phosphoric Acid Production. February 8, 2021.

3. USEPA. Identification and Description of Mineral Processing Sectors; Technical Background Document; Final. EPA 530-R-99-022. April 1998a.

4. USEPA. Report to Congress on Special Wastes from Mineral Processing: Summary and Findings. EPA 530-SW-90-070B. July 1990a.

5. USEPA. Environmental Fact Sheet: Agency Releases Report to Congress on Special Wastes from Mineral Processing. EPA 530-SW-90-070A. July 1990b.

6. USEPA. Identification and Listing of Hazardous Waste. 45 FR 76618. November 19, 1980.

7. Concerned Citizens of Adamstown vs. EPA, No. 84-3041, D.D.C, August 21, 1985.

8. USEPA. Report to Congress on Wastes from the Extraction and Beneficiation of Metallic Ores, Phosphate Rock, Asbestos, Overburden from Uranium Mining, and Oil Shale. EPA 530-SW-85-033. December 1985.

9. USEPA. Regulatory Determination for Wastes from the Extraction and Beneficiation of Ores and Minerals. 51 FR 24496. July 3, 1986.

10. USEPA. Mining Waste Exclusion. 50 FR 40292. October 2, 1985.

11. USEPA. Mining Waste Exclusion; Withdrawal of Proposed Provision. 51 FR 36233. October 9, 1986.

12. Environmental Defense Fund v. EPA, 852 F.2d 1316 (DC Cir 1988), cert. denied, 109 S. Ct. 1120 (1989).

13. USEPA. Mining Waste Exclusion I. 54 FR 36592. September 1, 1989.

14. USEPA. Mining Waste Exclusion; Section 3010 Notification for Mineral Processing Facilities; Designated Facility Definition; Standards Applicable to Generators of Hazardous Waste. 55 FR 2322. January 23, 1990.

15. USEPA. National Emission Standards for Hazardous Air Pollutants. 54 FR 38044. September 14, 1989.

16. USEPA. National Emission Standards for Hazardous Air Pollutants; National Emissions Standards for Radon Emissions from Phosphogypsum Stacks. 57 FR 23305. June 3, 1992.

17. USEPA. Final Regulatory Determination for Special Wastes from Mineral Processing (Mining Waste Exclusion). Bevill Determination. 56 FR 27300. June 13, 1991. ( printed page 22154)

18. Phosphoric Acid Waste Dialogue FACA Committee. Report on the Activities and Recommendations of the Phosphoric Acid Waste Dialogue FACA Committee. September 1995.

19. USEPA. Damage Cases and Environmental Releases from Mines and Mineral Processing Wastes. EPA 530-R-99-023. April 1998b.

20. USEPA. Risks Posed by Bevill Wastes. RCRA Docket No. F-98-2P4F-FFFFF. April 1998c.

21. USEPA. Petition for Rulemaking under TSCA; Reasons for Agency Response; Denial of Requested Rulemaking. 86 FR 27546. May 21, 2021.

22. USEPA. Approval of the Request for Other Use of Phosphogypsum by the Fertilizer Institute. 85 FR 66550. October 20, 2020.

91 FR 22149