SUPPLEMENTARY INFORMATION:

RIES submitted a request for reissuance of its existing exemption from the land disposal restrictions of hazardous waste on November 20, 2023, as amended on June 16, 2025, June 30, 2025, July 21, 2025, August 25, 2025, and November 5, 2025. EPA reviewed all data pertaining to the petition, including, but not limited to, well construction, well operations, regional and local geology, seismic activity, penetrations of the confining zone, and computational models of the injection zone. EPA has determined that the hydrogeological and geochemical conditions at the site and the nature of the waste streams are such that reliable predictions can be made that fluid movement conditions are such that injected fluids will not migrate out of the injection zone within 10,000 years, as set forth at 40 CFR 148.20(a)(1)(i). The injection zone includes the injection interval into which fluid is directly emplaced and the overlying arrestment interval into which it may diffuse. The injection interval for the RIES facility is composed of the Precambrian wash sediments, Mount Simon Sandstone, Eau Claire Formation, and Franconia-Galesville Formation between 3,937 and 4,537 feet below ground level (bgl). The arrestment interval for the RIES facility is composed of the Trempealeau Formation, Prairie du Chien Group, Glenwood Shale, and lower Black River Formation between 3,356 and 3,924 feet bgl. The confining zone at the RIES facility is composed of the upper Black River Formation, Trenton Limestone, and Utica Shale between 2,351 and 3,356 feet bgl. The confining zone is separated from the lowermost underground source of drinking water (at a depth of 342 feet bgl) by a sequence of permeable and less permeable sedimentary rocks. This sequence provides additional protection from fluid migration into drinking water sources.

EPA issued a draft decision, which described the reasons for granting this exemption in more detail, a fact sheet, which summarized these reasons, and a public notice on October 1, 2025, pursuant to 40 CFR 124.10. The public comment period ended on December 17, 2025. EPA received six comments during the comment period. EPA has prepared a response to the comments, which can be viewed at the following URL: www.epa.gov/​node/​88753#public-notices. This document is part of the Administrative Record for this decision.

Conditions

This exemption is subject to the following conditions. Non-compliance with any of these conditions is grounds for termination of the exemption:

(1) The exemption applies to the two existing hazardous waste injection wells, #1-12 and #2-12, located at the RIES facility at 28470 Citrin Drive, Romulus, Michigan;

(2) The injection zone for wells #1-12 and #2-12 is at depths of 3,369 to 4,537 ft below ground level (3,937 to 4,550 ft relative to kelly bushing; true vertical depths) and is composed of the Precambrian wash sediments, Mount Simon Sandstone, Eau Claire Formation, Franconia-Galesville Formation, Trempealeau Formation, Prairie du ( printed page 2130) Chien Group, Glenwood Shale, and lower Black River Formation;

(3) Injection shall only occur into the injection interval composed of the Precambrian wash sediments, Mount Simon Sandstone, Eau Claire Formation, and Franconia-Galesville Formation from 3,924 to 4,537 ft below ground level (3,937 to 4,550 ft relative to kelly bushing; true vertical depths);

(4) The only hazardous waste that can be injected are the hazardous wastes designated by the RCRA waste codes found in Table 1;

(5) The specific gravity of the injected waste must be within the range of 0.9 to 1.1 measured at a temperature of 68 °F;

(6) The combined total injection rate of both wells shall not exceed a monthly average of 130 gpm and a maximum instantaneous rate of 225 gpm;

(7) The total injection volume shall not exceed 68,374,800 gallons annually into wells #1-12 and #2-12;

(8) The injection pressure at the well head of wells #1-12 and #2-12 shall not exceed 968 psig;

(9) Maximum concentrations of chemical contaminants which are hazardous at less than one part in a trillion (1:1,000,000,000,000) shall meet any limits for maximum concentration at the wellhead set in the permits;

(10) RIES must submit copies of the reports on the annual bottom-hole pressure surveys conducted in wells #1-12, and #2-12 to EPA. The annual reports must include a comparison of reservoir parameters determined from the fall-off test, such as permeability, transmissibility, and long-term shut-in pressure, with parameters used in the approved no migration petition;

(11) RIES must annually submit copies of a waste sample report and the reports on the annual radioactive tracer surveys and annulus pressure tests for wells #1-12 and #2-12 to EPA;

(12) RIES shall notify EPA in writing if any injection well loses mechanical integrity and prior to any workover or plugging and shall provide workover or plugging to procedures to EPA prior to commencing the work;

(13) RIES must fully comply with all requirements set forth in Underground Injection Control Permits MI-163-1W-C010 and MI-163-1W-C011 issued by EPA;

(14) Upon the expiration, termination, revocation and reissuance, or modification of the permits referenced above, this exemption is subject to review;

(15) This exemption is granted only while the underlying assumptions presented in the no migration petition submitted by RIES are valid;

(16) Whenever EPA determines under 40 CFR 148.23 or 148.24 that the basis for approval of a petition may no longer be valid, EPA may terminate this exemption. There are also other causes for terminating an exemption at 40 CFR 148.24. Whenever EPA determines that the basis for approval of a petition may no longer be valid, EPA will require a new demonstration in accordance with 40 CFR 148.20 and 148.23(b);

(17) This exemption is only approved for the 20-year modeled injection period, which ends on January 31, 2043. RIES may petition EPA for a reissuance of the exemption beyond that date, provided that a new and complete petition and no-migration demonstration is received at EPA, Region 5, by July 31, 2041.

In addition to the above conditions, this approval of a petition for reissuance of an exemption is contingent on the validity of the information submitted in the RIES petition reissuance request for an exemption to the land disposal restrictions. This final reissuance decision is subject to termination when any of the conditions occur which are listed in 40 CFR 148.24, including noncompliance, misrepresentation of relevant facts, or a determination that new information shows that the basis for approval is no longer valid.

Electronic Access. You may access this Federal Register document electronically from the Government Printing Office under the “ Federal Register ” listings at www.govinfo.gov/​app/​collection/​FR/​.

91 FR 2129