The commissioner may authorize variances or exemptions from the regulations issued pursuant to section 4. of this act under conditions and in such manner as he deems necessary and desirable; provided, however, that such variances or exemptions shall be granted only under conditions and in a manner which are no less stringent than the conditions under, and the manner in which, variances and exemptions may be granted under the Federal act. Notwithstanding the foregoing variances may be granted for no longer than 5 years, subject to one or more renewals of no longer than 5 years each.
N.J.S. § 58:12A-5