Tumbling processes creating dangerous air contaminants shall be provided with means to remove or control such contaminants at the point of generation.
Exception:
The above does not apply to mills, drums, cages or barrels which are completely enclosed during rotation and which disseminate air contaminants only when being charged or discharged. Means shall be provided to control such contaminants.
N.Y. Comp. Codes R. & Regs. Tit. 12 §§ 12-2.5