StacksVerified U.S. regulatory reference

40 CFR Part 63, Table 2

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov
For vents from these processes . . .You must meet the following emissions limits . . . a
Total hydrocarbon ppm by volume expressed as propane corrected to 4 percent carbon dioxideDioxin and furan (dioxins and furans) nanograms/dscmexpressed as TEQ corrected to7 percent O2
Collocated blast and reverberatory furnaces (new and existing)20 ppmv | 0.50 ng/dscm.
Collocated blast and reverberatory furnaces when the reverberatory furnace is not operating for units that comments construction or reconstruction before June 9, 1994360 ppmv | 170 ng/dscm.
Collocated blast and reverberatory furnaces when the reverberatory furnace is not operating for units that commence construction or reconstruction after June 9, 199470 ppmv | 170 ng/dscm.
Blast furnaces that commence construction or reconstruction before June 9, 1994360 ppmv | 170 ng/dscm.
Blast furnaces that commence construction or reconstruction after June 9, 199470 ppmv | 170 ng/dscm.
Blast furnaces that commence construction or reconstruction after May 19, 201170 ppmv | 10 ng/dscm.
Reverberatory and electric furnaces that commence construction or reconstruction before May 19, 201112 ppmv | 0.20 ng/dscm.
Reverberatory and electric furnaces that commence construction or reconstruction after May 19, 201112 ppmv | 0.10 ng/dscm.

a There are no standards for dioxins and furans during periods of startup and shutdown.