N.Y.C. Admin. Code § 24-711: § 24-711 Labeling requirements.

Within thirty days after a facility inventory form is first required to be filed for a facility, all hazardous substances present at such facility shall be clearly marked with a label showing the chemical name and CAS identification number of the hazardous substance. The information set forth on the label shall be in accordance with a recognized hazardous substances labeling system, accepted by the commissioner. In the case of a substance protected under the "trade secrets" provision contained in section 24-709 of this chapter, the label should bear the specific code assigned by the commissioner for such substance.