Allowable TLV of coke gases at the breathing levels of the employees.

This is an OSHA interpretation letter responding to a question about ANSI A10.9-1970 Paragraph 5.6.4(1) as adopted in 29 CFR 1926.700(a). It states that covers must guide effluent gases through an exhaust stack outdoors, that 29 CFR 1926.55(a) and 29 CFR 1926.154 apply, and that grating-type covers are not permitted where enclosed areas use flammable materials.