What: On July 14, 2026, the U.S. Environmental Protection Agency (EPA) proposed multiple revisions to heavy-duty engine regulations, including eliminating deratements (engine slowdowns) caused by diesel exhaust fluid (DEF) system failures.
Why: In January 2023, the EPA issued air pollution regulations for heavy-duty engines and vehicles, such as trucks, farm equipment, and construction vehicles. The EPA is now proposing to amend the 2023 rules relating to model year (2027) and later engines by:
- Changing to the regulatory useful life periods and the emission-related warranty periods.
- Adding clarity to certain regulatory compliance provisions and correct errors in the regulations to support the MYs 2027 and later program for heavy-duty highway engines and vehicles.
- Making nonconformance penalties available to engine manufacturers beginning in MY 2027.
- Amending the requirements for selective catalytic reduction system inducement provisions for newly manufactured diesel-fueled highway engines and vehicles, and nonroad engines and equipment.
- Considering new inducement guidance for in-use highway and nonroad diesel engines, vehicles, and equipment.
The EPA will hold virtual public hearings on July 29, 2026, at 9:00 AM ET, and July 30, 2026, at 10:00 AM ET. If there is sufficient interest, the agency may hold an additional day of hearings.
Action: Read the proposed rule and submit comments before the August 29, 2026, deadline.
PROPOSED RULE:
PUBLIC HEARING INFO:
Regulations for Emissions from Vehicles and Engines
To register to listen or testify, send an email to EPA-HD-MobileSource-Hearings@epa.gov.
CONTACT: Nick Goldstein
EMAIL: nick.goldstein@sba.gov
Regulatory Alerts
Is your small business or entity being impacted by a proposed rule? If yes, write a comment letter to the proposing agency.