New York Consolidated Laws, Multiple Dwelling Law - MDW § 192. Cellar entrance

a. If there is a cellar, there shall be an independent entrance thereto from outside the dwelling by means of a metal fire ladder or fireproof stair leading to an opening in the outside cellar wall at least two feet six inches in width and six feet in height. Such entrance to the cellar may be through an areaway or through a fireproof passageway leading directly to the street. The entrance to the cellar may be closed off with a grating or doors which shall not be locked or bolted unless they can be readily unbolted or unlocked from the inside without a key and shall be arranged and constructed so as to be readily opened at all times.

b. In lieu of the requirements set forth in subdivision a hereof, buildings existing November first, nineteen hundred forty-nine in cities having a population between five hundred thousand and one million may comply with the following: