StacksVerified U.S. regulatory reference

40 CFR §60.1925

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Use EPA Reference Method 9 in appendix A of this part to determine compliance with the opacity limit.
  2. (b)Conduct an initial test for opacity as specified in § 60.8.
  3. (c)After the initial test for opacity, conduct annual tests no more than 13 calendar months following the date of your previous test.