N.J. Stat. § 2A:84A-18
Rule 24.
Within the meaning of this article, a matter will incriminate (a) if it constitutes an element of a crime against this State, or another State or the United States, or (b) is a circumstance which with other circumstances would be a basis for a reasonable inference of the commission of such a crime, or (c) is a clue to the discovery of a matter which is within clauses (a) or (b) above; provided, a matter will not be held to incriminate if it clearly appears that the witness has no reasonable cause to apprehend a criminal prosecution. In determining whether a matter is incriminating under clauses (a), (b) or (c) and whether a criminal prosecution is to be apprehended, other matters in evidence, or disclosed in argument, the implications of the question, the setting in which it is asked, the applicable statute of limitations and all other factors, shall be taken into consideration.
N.J.S. § 2A:84A-18