Site Feedback

Title 40

Displaying title 40, up to date as of 8/17/2026. Title 40 was last amended 8/17/2026.
eCFR Content

The Code of Federal Regulations (CFR) is the official legal print publication containing the codification of the general and permanent rules published in the Federal Register by the departments and agencies of the Federal Government. The Electronic Code of Federal Regulations (eCFR) is a continuously updated online version of the CFR. It is not an official legal edition of the CFR.

Learn more about the eCFR, its status, and the editorial process.

Title 40Protection of EnvironmentPart / Section
Chapter IEnvironmental Protection Agency1 – 1099
Subchapter UAir Pollution Controls1000 – 1099
Part 1039Control of Emissions from New and In-Use Nonroad Compression-Ignition Engines1039.1 – 1039.825
Subpart GSpecial Compliance Provisions1039.601 – 1039.699
§ 1039.601What compliance provisions apply?
§ 1039.605What provisions apply to engines certified under the motor-vehicle program?
§ 1039.610What provisions apply to vehicles certified under the motor-vehicle program?
§ 1039.615What special provisions apply to engines using noncommercial fuels?
§ 1039.620What are the provisions for exempting engines used solely for competition?
§ 1039.625What requirements apply under the program for equipment-manufacturer flexibility?
§ 1039.626What special provisions apply to equipment imported under the equipment-manufacturer flexibility program?
§ 1039.627What are the incentives for equipment manufacturers to use cleaner engines?
§ 1039.630What are the economic hardship provisions for equipment manufacturers?
§ 1039.635What are the hardship provisions for engine manufacturers?
§ 1039.645What special provisions apply to engines used for transportation refrigeration units?
§ 1039.650 [Reserved]
§ 1039.655What special provisions apply to engines sold in American Samoa or the Commonwealth of the Northern Mariana Islands?
§ 1039.665Special provisions for use of engines in emergency situations.
§ 1039.670Approval of an emergency equipment field modification (EEFM).
§ 1039.699Emission standards and certification requirements for auxiliary power units for highway tractors.