StacksVerified U.S. regulatory reference

40 CFR §63.11526

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)You must not discharge to the atmosphere visible emissions (VE) from the control device that exceed 5 percent of accumulated occurrences in a 60-minute observation period.
  2. (b)You must not discharge to the atmosphere fugitive PM emissions from the furnace building containing the electrometallurgical operations that exhibit opacity greater than 20 percent (6-minute average), except for one 6-minute average per hour that does not exceed 60 percent.