EPA Issues Final Tier 3 Emissions and Fuel Standards

By SEMA Washington, D.C., Staff

The U.S. Environmental Protection Agency (EPA) has issued tougher tailpipe and evaporative emissions standards known as “Tier 3.” Reduced tailpipe emissions standards for particulate matter, non-methane organic gases and nitrogen oxides will be phased-in between 2017 and 2025, and the useful life period will be raised from 120,000 miles to 150,000 miles. The evaporative emissions standards will also be reduced by nearly 50% from current standards and the useful life period raised to 150,000 miles. The EPA will also adopt California’s Onboard Diagnostic System (OBD) requirements.

Tier 3 will lower the sulfur content in gasoline by more than 60%. California has already adopted this approach as of 2017, and the automakers are relying on the fuel to run lean-burn gasoline direct-injection engines and allow the vehicle’s catalytic converter to work more efficiently. 

Under Tier 3, new vehicles will be tested and certified to gasoline with 10% ethanol (E10) rather than 15% (E15) as originally proposed. The rule will apply to new light-duty vehicles, medium-duty passenger cars and some heavy-duty vehicles.  

For more information, contact Stuart Gosswein at