Important laws recently passed by New York City Council include Local Law 152 (Intro 1088) and Local Law 150 (Intro 738).
LL 152 requires that, commencing January 1, 2019, owners of buildings with gas piping systems have such systems periodically inspected for damage, illegal hookups, etc.
LL 150 bars individuals from performing work on gas piping systems after January 1, 2020, unless such individuals are (1) licensed master plumbers, (2) hold a gas qualification or (3) hold a limited gas qualification and perform work under the personal and immediate supervision of a gas qualification holder.
See below links for the full text of these important laws.