N.J. Stat. Ann. § 13:1E-124

The exemption provided for in this supplementary act shall apply only to solid waste collected pursuant to contracts signed prior to January 1, 1982. The solid waste collector, at his initial disposal of the exempt waste, shall submit to the owner or operator of the sanitary landfill facility a copy of his contract with an agency of the federal government indicating an effective date of the contract prior to January 1, 1982. The owner or operator of the sanitary landfill facility, at his initial request for the exemption provided for in this act, shall submit the contract with the monthly tax return filed pursuant to the acts cited in section 1 of this act.