N.J. Stat. § 34:2-31: Protection of openings in floor

The openings of all hoistways, hatchways, elevators and wellholes on every floor of any mercantile establishment shall be protected by good and sufficient trapdoors or self-closing hatches and safety catches, or strong guard rails at least three feet high, and shall be kept closed and protected at all times except when in actual use by the occupant of the building having the use and control of the same.