StacksVerified U.S. regulatory reference

40 CFR §1039.401

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
We may perform in-use testing of any engine subject to the standards of this part. However, we will limit recall testing to the first 75 percent of each engine's useful life as specified in § 1039.101(g).