N.Y.C. Admin. Code § 17-337: § 17-337 Air quality standards for compressed air in underwater breathing tanks.

Compressed air to be used in tanks for underwater breathing that are offered for sale, sold, or distributed in the city of New York, shall, at a minimum, meet the air quality standards for grade e air of the compressed gas association publication "G-7.1-2004, commodity specification for air," or a more stringent standard as may be determined by the department.