N.J. Stat. Ann. § 18A:6-7.1b

2. An individual employed by a board of education in any substitute capacity or position, who is rehired annually by that board, shall only be required to undergo a criminal history record check as required pursuant to P.L.1986, c.116 (C.18A:6-7.1 et seq.) upon initial employment, provided the substitute continues in the employ of at least one of the districts at which the substitute was employed within one year of the approval of the criminal history record check.