N.J. Stat. § 52:27D-199
A building, which is subject to this act but the use of which shall have commenced in good faith on or before the effective date of any retroactive regulations, shall comply with the provisions of this act on or before the first anniversary of the effective date of the regulations and, in the case of any building subject to local rent control, any improvement required to be made pursuant to this act, or any other law, ordinance, or regulation concerning fire safety shall, for the purposes of the rent control ordinance, be deemed to be a capital improvement, the cost of which may be passed on to the tenants. In a case of imminent hazard to life, a building shall comply within the period of time designated by the enforcing agency.
N.J.S. § 52:27D-199