40 CFR § 426.120
Applicability; description of the incandescent lamp envelope manufacturing subcategory
June 9, 2020
The provisions of this subpart are applicable to discharges resulting from the processes by which (a) raw materials are melted in a furnace and mechanically processed into incandescent lamp envelopes or (b) incandescent lamp envelopes are etched with hydrofluoric acid to produce frosted envelopes.