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.”

On March 20, 2025, the Board proposed first-notice rules concerning “paint and paint-related waste” (PPRW) that are hazardous waste. The rules would regulate hazardous waste PPRW as a universal waste. This rulemaking was initiated by the Illinois Environmental Protection Agency (IEPA) to comply with Public Act 103-887, which took effect on January 1, 2025.

On March 20, 2025, the Board issued an opinion and order proposing second-notice amendments to update its Part 217 air pollution rules (35 Ill. Adm. Code 217). The Board then submitted these amendments to the Joint Committee on Administrative Rules (JCAR) for its review. The amendments appear on JCAR’s April 8, 2025 meeting agenda

On March 10, 2025, the Illinois Environmental Protection Agency (IEPA) filed a proposal to amend numerous Parts of the Board’s rules. The proposed amendments update the address of IEPA’s Springfield office, which recently moved to a new location.

On March 20, 2025, the Board issued an opinion and order adopting final amendments to its groundwater quality rules at 35 Ill. Adm. Code 620. Before final adoption, the Board held three public hearings, admitted 33 hearing exhibits, received 81 public comments, and issued opinions and orders at first notice, proposed second notice, and second notice.

On November 21, 2024, the Board adopted amendments to Illinois’ wastewater pretreatment regulations. The changes are “identical in substance” to rule amendments adopted by the United States Environmental Protection Agency (USEPA) during the first half of 2024. Specifically, on May 9, 2024, USEPA updated the effluent limitations guidelines and standards (ELGs) for the steam electric power generating point source category.

On November 21, 2024, the Board adopted amendments to keep Illinois’ ambient air quality standards “identical in substance” to the National Ambient Air Quality Standards (NAAQS). The amendments reflect two actions taken by the United States Environmental Protection Agency (USEPA) during the first half of 2024. First, USEPA revised the primary annual NAAQS for fine particulate matter (PM2.5) from 12.0 micrograms per cubic meter of air (12.0 µg/m3 ) to 9.0 µg/m3 . USEPA set the more stringent standard due to human health effects associated with long- and short-term exposures to PM2.5 in ambient air. Second, USEPA updated its List of Designated Reference and Equivalent Methods. This update modified existing method designations and designated a new Federal Equivalent Method (FEM) for measuring concentrations of ozone (O3) in ambient air.

On November 7, 2024, the Board adopted amendments to keep Illinois’ hazardous waste regulations “identical in substance” to the federal regulations. The amendments reflect actions taken by the United States Environmental Protection Agency (USEPA) during the second half of calendar year 2023. During this timeframe, USEPA made technical revisions to correct or clarify provisions in the Generator Improvements, Pharmaceuticals, and Definition of Solid Waste rules under Subtitle C of the Resource Conservation and Recovery Act (RCRA). USEPA also made other minor corrections, clarifications, and updates to its hazardous waste regulations.

On July 8, 2024, the Illinois Environmental Protection Agency (IEPA) filed a proposal to amend the Board’s Part 217 air pollution rules (35 Ill. Adm. Code 217). The proposed amendments concern major stationary sources of nitrogen oxides (NOx) emissions in areas designated as nonattainment for the 2015 eight-hour ozone National Ambient Air Quality Standard (NAAQS).

On August 22, 2024, the Board amended its air pollution rules by adopting alternative emission limits for periods of startup, shutdown, breakdown, and malfunction. These amendments to 35 Ill. Adm. Code 212, 215, 216, and 217 are generally based on four rulemaking proposals separately filed by (1) Rain CII Carbon LLC; (2) Dynegy Midwest Generation LLC, Illinois Power Generating Company, Kincaid Generation, LLC, and Midwest Generation LLC; (3) American Petroleum Institute; and (4) East Dubuque Nitrogen Fertilizers LLC.

On September 5, 2024, the Board adopted amendments to its administrative rules at Part 2175 of Title 2 of the Illinois Administrative Code. The Board amended the rules to reflect, among other things, a recent change to the Open Meetings Act (5 ILCS 120/7(a) (2022)). The Open Meetings Act was amended so that a member of a public body could attend a meeting of that body by video or audio conference when the member is unable to physically attend the meeting because of “unexpected childcare obligations.” The Board added corresponding language to its rule that specifies the circumstances under which a Board Member may telephonically attend an open meeting of the Board.

On September 5, 2024, the Board proposed amendments to keep Illinois’ ambient air quality standards “identical in substance” to the National Ambient Air Quality Standards (NAAQS). The amendments reflect two actions taken by the United States Environmental Protection Agency (USEPA) during the first half of 2024. First, USEPA revised the primary annual NAAQS for fine particulate matter (PM2.5) from 12.0 micrograms per cubic meter of air (12.0 µg/m3) to 9.0 µg/m3. USEPA set the more stringent standard due to human health effects associated with long- and short-term exposures to PM2.5 in ambient air. Second, USEPA updated its List of Designated Reference and Equivalent Methods. This update modified existing method designations and designated a new Federal Equivalent Method (FEM) for measuring concentrations of ozone (O3) in ambient air.

On September 5, 2024, for public comment, the Board proposed amendments to Illinois’ wastewater pretreatment regulations. The proposed amendments are “identical in substance” to rule amendments adopted by the United States Environmental Protection Agency (USEPA) during the first half of 2024. Specifically, on May 9, 2024, USEPA updated the effluent limitations guidelines and standards (ELGs) for the steam electric power generating point source category.

On August 22, 2024, the Board issued an order proposing amendments to 35 Ill. Adm. Code 845 for first notice. The Board had opened this sub-docket when it adopted new Part 845, Illinois’ first Statewide standards for the disposal of coal combustion residuals (CCR) in surface impoundments. The sub-docket was established to further explore four issues: (1) historic, unconsolidated coal ash fill in the State; (2) the use of temporary storage piles of coal ash, including time and volume limits; (3) fugitive dust monitoring plans for areas surrounding CCR surface impoundments; and (4) the use of environmental justice screening tools.

On July 11, 2024, for review by the Joint Committee on Administrative Rules (JCAR), the Board proposed second-notice amendments to establish alternative emission limits for periods of startup, shutdown, breakdown, and malfunction. The proposal would amend four Parts of the Board’s air pollution rules, i.e., Parts 212, 215, 216, and 217 (35 Ill. Adm. Code 212, 215, 216, 217).

On July 11, 2024, for public comment, the Board proposed amendments to keep Illinois’ hazardous waste regulations “identical in substance” to the federal regulations. The proposed amendments reflect actions taken by the United States Environmental Protection Agency (USEPA) in the second half of calendar year 2023. During this timeframe, USEPA made technical revisions to correct or clarify regulations adopted as part of the Hazardous Waste Generator Improvements rule, the Hazardous Waste Pharmaceuticals rule, and the Definition of Solid Waste rule. USEPA also made other minor corrections, clarifications, and updates to its hazardous waste regulations.

On June 20, 2024, the Board adopted amendments to Illinois’ wastewater pretreatment regulations. The amendments to 35 Ill. Adm. Code 307 are “identical in substance” to rule amendments adopted by the United States Environmental Protection Agency (USEPA) during the second half of 2023. Specifically, on August 9, 2023, USEPA updated the reporting and recordkeeping requirements for dental offices as a point source category (40 C.F.R. § 441.50).