N.Y.C. Admin. Code § 15-207: § 15-207 Fire lines.

During the actual prevalence of any fire or other emergency, the officers of the police and fire departments shall remove, or cause to be removed and kept away from the vicinity of such fire or other emergency, all idle and suspicious persons, and all persons unfit to be employed, or not actually and usefully employed, in aiding the extinguishment and termination of such fire or other emergency or in the preservation of property in the vicinity thereof.