An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Regulations for Emissions from Vehicles and Engines

Direct Final Rule: Amendments to Emission Requirements Applicable to New Nonroad CI Engines at or Above 37 Kilowatts: Provisions for Replacement CI Engines and the Use of On-Highway CI Engines in Nonroad Vehicles

On this page:

Rule Summary

These amendments adopt the original replacement-engine exemption for nonroad engines. These amendments also allow nonroad vehicle manufacturers to use certified highway engines in nonroad vehicles in certain circumstances.

Regulations for Emissions from Vehicles and Engines Home