On May 7, 2026, the Board proposed amendments to its “potentially infectious medical waste” (PIMW) rules for first-notice publication in the Illinois Register. BioSAFE Engineering initiated this rulemaking by filing a proposal to add an indicator microorganism, Bacillus Atrophaeus, to the Part 1422 PIMW rules for validation testing low-pressure treatment systems. Along with adding Bacillus Atrophaeus, the Board proposed clarifying amendments to Part 1422.

On May 7, 2026, the Board issued an opinion and order proposing second-notice amendments to update its Part 219 air pollution rules (35 Ill. Adm. Code 219). The proposed amendments concern volatile organic material (VOM) emissions from aerospace facilities in the Metro East counties of Madison, Monroe, and St. Clair. The Joint Committee on Administrative Rules has placed these Part 219 amendments on the agenda for its June 16, 2026 meeting

By an opinion and order of November 7, 2024, in RCRA Subtitle C (Hazardous Waste) Update, USEPA Amendments (July 1, 2023 through December 31, 2023), docket R24-12, the Board adopted amendments to the Illinois hazardous waste rules intended to be “identical in substance” (IIS) to amendments made by the United States Environmental Protection Agency to its corresponding hazardous waste regulations. The Board’s amendments became effective on November 7, 2024, including amendments to 35 Ill. Adm. Code 722.116 and 722.117. The heading of Section 722.116 is “Conditions for Exemption for a Small Quantity Generator That Accumulates Hazardous Waste.” And the heading of Section 722.117 is “Conditions for Exemption for a Large Quantity Generator That Accumulates Hazardous Waste.

On April 16, 2026, the Board adopted an opinion and order proposing non-substantive amendments to its air pollution rules for first-notice publication in the Illinois Register. The proposed amendments are part of a larger undertaking by the Board to update its rules across multiple media and subject areas. The proposal will remove unnecessary language, replace outdated text, update statutory references, and reorganize provisions for clarity. In all, the firstnotice proposal covers 26 Parts of the Board’s Subtitle B air pollution rules in Title 35 of the Illinois Administrative Code: Parts 201, 202, 205, 207, 211, 212, 214, 215, 216, 217, 218, 219, 220, 223, 225, 226, 228, 229, 232, 237, 240, 241, 243, 244, 245, and 249.

On April 16, 2026, for public comment, the Board proposed amendments to keep Illinois’ hazardous waste regulations “identical in substance” to the federal regulations. The proposal reflects actions taken by the United States Environmental Protection Agency (USEPA) during the second half of calendar year 2024. During this timeframe, among other things, USEPA (1) amended the hazardous waste manifest regulations to increase utility of the electronic manifest or “e-Manifest” system, (2) established alternative standards for specified ignitable spent refrigerants being recycled for reuse, and (3) adopted technical corrections to its 2016 Hazardous Waste Generator Improvements Rule and 2019 Hazardous Waste Pharmaceuticals Rule.

On April 2, 2026, the Board adopted amendments to keep Illinois’ ambient air quality standards (35 Ill. Adm. Code 243) identical in substance to the National Ambient Air Quality Standards (NAAQS). The amendments reflect three actions taken by the United States Environmental Protection Agency (USEPA) during the 18-month period of July 1, 2024 through December 31, 2025.

On January 22, 2026, the Board adopted amendments to keep Illinois’ primary drinking water standards (35 Ill. Adm. Code 611) “identical in substance” to the National Primary Drinking Water Regulations (NPDWRs). The amendments reflect actions taken under the NPDWRs by the United States Environmental Protection Agency (USEPA) during 2024. USEPA’s actions included adding new regulations for six per- and poly-fluoroalkyl substances (PFAS), updating the comprehensive Lead and Copper Rule, and approving 93 alternative testing methods (ATMs) for analyzing contaminants in drinking water.

On January 22, 2026, the Board proposed first-notice rules addressing the management of used electric vehicle (EV) batteries. The proposed rules are intended to minimize the risks of fire and explosion associated with storing used EV batteries, including lithium-chemistry batteries. By mitigating used EV battery fires, the proposed rules seek to prevent releases of harmful contaminants into the atmosphere, land, and groundwater.

On January 8, 2026, the Board proposed amendments to keep Illinois’ ambient air quality standards (35 Ill. Adm. Code 243) identical in substance to the National Ambient Air Quality Standards (NAAQS). The amendments reflect three actions taken by the United States Environmental Protection Agency (USEPA) during the 18-month period of July 1, 2024 through December 31, 2025.

On June 26, 2025, the Board issued a final opinion and order in sub-docket A of R20-19 (R20- 19(A)), adopting amendments to the Board’s Part 845 rules on coal combustion residual (CCR) surface impoundments (35 Ill. Adm. Code 845). The amendments, among other things, added obligations and restrictions on using CCR storage units during the closure of CCR surface impoundments. Relatedly, during the first-notice comment period in sub-docket A, the Illinois Environmental Protection Agency proposed that the Board amend Section 845.220 to require that construction permit applications include additional information concerning CCR storage units. However, because Section 845.220 was not included in sub-docket A’s proposed first-notice amendments, the Board opened a sub-docket B of R20-19 (R20-19(B)) to propose the corresponding changes to Section 845.220. In sub-docket B, the Board issued its first-notice opinion and order on May 15, 2025, and its second-notice opinion and order on August 7, 2025.

On October 2, 2025, the Board proposed amendments to keep Illinois’ primary drinking water standards (35 Ill. Adm. Code 611) “identical in substance” to the National Primary Drinking Water Regulations (NPDWRs). The proposed amendments reflect six actions taken under the NPDWRs by the United States Environmental Protection Agency (USEPA) during 2024. Specifically, USEPA expedited approval of 93 alternative testing methods (ATMs) for analyzing contaminants in drinking water, added new regulations for six per- and poly-fluoroalkyl substances (PFAS), and updated the comprehensive Lead and Copper Rule

On August 21, 2025, the Board adopted final rules prescribing procedures and standards for managing hazardous waste “paint and paint-related waste” (PPRW) as universal waste. In all, the Board amended seven Parts of its rules: Parts 703, 720, 721, 724, 725, 728, and 733 (35 Ill. Adm. Code 703, 720, 721, 724, 725, 728, 733).

On March 10, 2025, the Illinois Environmental Protection Agency (IEPA) filed a proposal that would update 15 Parts of the Board’s rules to reflect the new address of IEPA’s Springfield office. On March 20, 2025, the Board accepted for hearing IEPA’s proposal and sent it to first notice without comment.

On July 10, 2025, the Board proposed second-notice amendments to regulate hazardous waste “paint and paint-related waste” (PPRW) as a universal waste. In all, the Board proposes amendments to seven Parts of its rules: Parts 703, 720, 721, 724, 725, 728, and 733 (35 Ill. Adm. Code 703, 720, 721, 724, 725, 728, 733).

On March 10, 2025, the Illinois Environmental Protection Agency (IEPA) filed a proposal that would amend 15 Parts of the Board’s rules to update the address of IEPA’s Springfield office, which recently moved to a new location. On March 20, 2025, the Board accepted for hearing IEPA’s proposal and sent it to first-notice publication in the Illinois Register without comment

On August 22, 2024, the Board issued its first-notice opinion and order in this sub-docket A of R20-19 (R20-19(A)), proposing amendments to the Board’s rules on coal combustion residual (CCR) surface impoundments (35 Ill. Adm. Code 845). Specifically, the Board proposed adding obligations and restrictions on using CCR storage piles during the closure of CCR surface impoundments by CCR removal. In addition, the first-notice proposal included requirements for the Illinois Environmental Protection Agency (IEPA) to evaluate and act on public complaints over CCR fugitive dust. The proposal also added specifications for air quality monitoring at or near a facility’s property boundary, as well as provisions describing when the monitoring either may or must be imposed by IEPA on facility owners or operators.

The Board opened this sub-docket A in R20-19 (R20-19(A)) to further explore four issues: (1) historic, unconsolidated fill of coal combustion residual (CCR), also known as “coal ash”; (2) the use of temporary storage piles of coal ash, including time and volume limits; (3) CCR fugitive dust monitoring plans for areas neighboring CCR surface impoundments; and (4) the use of environmental justice screening tools.

On April 17, 2025, the Board issued an opinion and order adopting final amendments to update its Part 217 air pollution rules (35 Ill. Adm. Code 217). This rulemaking was initiated when the Illinois Environmental Protection Agency (IEPA) filed its proposal to amend Part 217, at which time the Board granted IEPA’s motion for expedited review. The Board did so to avoid mandatory Clean Air Act sanctions against the State of Illinois by giving IEPA enough time to submit the final Part 217 amendments to the United States Environmental Protection Agency (USEPA) in a complete State Implementation Plan or “SIP.” The Board therefore proceeded to first notice without commenting on the substantive merits of IEPA’s proposal.

On April 17, 2025, the Board issued an opinion and order adopting final amendments to its air pollution rules on permitting for the construction and modification of major stationary sources in non-attainment areas. The amendments update the Board’s Non-Attainment New Source Review (NA NSR) permitting rules consistent with the federal Clean Air Act and the United States Environmental Protection Agency’s underlying NA NSR permitting program. As adopted, the Project Emissions Accounting or “PEA” Rule is incorporated into the Board’s permitting rules on NA NSR and Prevention of Significant Deterioration or “PSD.”

On March 6, 2025, the Board issued an opinion and order proposing second-notice amendments to its air pollution rules on permitting for the construction and modification of major stationary sources in non-attainment areas. The amendments will update the Board’s Non-Attainment New Source Review (NA NSR) permitting rules consistent with the federal Clean Air Act and the United States Environmental Protection Agency’s underlying NA NSR permitting program. As proposed, the Project Emissions Accounting or “PEA” Rule will be incorporated into the Board’s permitting rules on NA NSR and Prevention of Significant Deterioration or “PSD.”