Pennsylvania's Sulfur Dioxide Zone Gets Clean Bill of Air Health

2026-18317, Updated Definition of “Waters of the United States”

The purpose of this supplemental notice of proposed rulemaking is for the U.S. Environmental Protection Agency (EPA) and the Department of the Army ("the agencies") to supplement and seek additional comment on certain aspects of an earlier proposal, published on November 20, 2025, to revise the regulations defining the scope of waters federally covered under the Clean Water Act in light of the U.S. Supreme Court's 2023 decision in Sackett v. Environmental Protection Agency. As stated in the agencies' November 20, 2025 Notice of Proposed Rulemaking (NPRM), the agencies intend for this rulemaking to provide greater regulatory certainty and increase Clean Water Act program predictability and consistency by clarifying the definition of "waters of the United States." After consideration of the public comments received on the NPRM, the agencies are issuing this notice to supplement the NPRM with additional regulatory options on certain aspects of the proposed rule.

2026-14112, Amendments and Nonconformance Penalties for Model Year 2027 and Later Heavy-Duty Highway Engines and Amendments to Inducement Provisions for SCR-Equipped Diesel Engines

Starting with model year 2027, the EPA is updating rules for big truck engines to make sure they last longer and pollute less. They’re also letting engine makers pay penalties if their engines don’t meet standards, and tightening rules for special pollution-control systems on diesel engines. These changes affect truck and engine makers and kick in soon, with public feedback due by August 29, 2026.

2026-13667, Minor New Source Review Program Air Permitting Public Participation Requirements for State Implementation Plans

The EPA wants to give states more freedom to decide how much public input is needed when approving small air pollution sources or changes. This means local air agencies can tailor public participation to fit their community’s needs while still protecting air quality. If you’re involved in air permits, watch for comment deadlines and possible virtual hearings this summer!

2026-13263, Revisions To Establish the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) for Public Water Systems

The EPA is rolling out the sixth Unregulated Contaminant Monitoring Rule (UCMR 6) to check for new, sneaky chemicals in public drinking water. Big water systems serving 3,300+ people and some smaller ones will test for 30 different contaminants, including certain PFAS and pesticides, to keep our water safe. Comments and feedback are open until late August 2026, and the EPA will host fun online meetings to chat about the plan!

2026-12927, U.S. Ecology Nevada, Inc. High Mercury Subcategory Wastes Land Disposal Restrictions Variance

The EPA is giving U.S. Ecology Nevada a special green light to handle and dispose of high-mercury waste a bit differently than usual. This means mercury waste treated in Pennsylvania can now be safely sent to U.S. Ecology’s Nevada site for disposal under new rules starting July 27, 2026. This change helps protect people and the environment while keeping mercury waste management efficient and cost-effective.

2026-11047, National Emission Standards for Hazardous Air Pollutants From Hazardous Waste Combustors: Residual Risk and Technology Review

The EPA just updated rules for places that burn hazardous waste, like incinerators and boilers, to keep the air safe and clean. They confirmed current standards work well but added new limits on harmful gases like hydrogen fluoride and hydrogen cyanide. These changes start June 3, 2026, and include easier electronic reporting and some new rules for startup and shutdown times—helping protect health without big costs.

Previous: 2026-15371, Air Plan Approval; Missouri; Construction Permit Exemptions

The Environmental Protection Agency (EPA) is proposing to approve revisions to the Missouri State Implementation Plan (SIP) received on February 10, 2026. The submission revises Missouri's regulation on construction permit exemptions in their Minor New Source Review (NSR) program. These revisions refine exemptions for emergency generators, update references to other rules, and update recordkeeping requirements. The EPA is proposing to approve this rule revision pursuant to the Clean Air Act (CAA).

Next: 2026-15374, Airworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters

The FAA proposes to supersede Airworthiness Directive (AD) 2024-04-10, which applies to all Airbus Helicopters Deutschland GmbH (AHD) Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC135T3, and EC635T2+ helicopters. AD 2024-04-10 requires repetitively inspecting certain part-numbered tail rotor (T/R) blades for a crack and, depending on the results, removing any cracked T/R blade from service. AD 2024-04-10 also prohibits installing certain T/R blades on any helicopter unless certain requirements are met. Since AD 2024-04-10 was issued, it was determined that inspection Method A should be discontinued and that additional limitations shall be provided. This proposed AD would retain the actions of AD 2024-04-10 and would require repetitively inspecting a certain tail rotor blade (TRB) assembly for cracks and, depending on the results, removing any cracked TRB assembly from service and replacing an affected part as terminating action for the repetitive inspections. This proposed AD would also prohibit installing an affected TRB assembly on any helicopter unless certain requirements are met. The FAA is proposing this AD to address the unsafe condition on these products.