1886 N.J. Laws 358, An Act to Regulate the Manufacture and Storage of Gun Powder, Dynamite and Other Explosives, § 1.

. . . nothing in this act shall be so construed as to prevent any person or persons from storing in any fire-proof magazines any quantity of gun powder or blasting powder not exceeding in quantity two thousand pounds, within the said distance of one thousand feet of a public road; and provided, further, that the prohibition in this act contained shall not apply to any establishment, storehouse or building heretofore erected and used for the manufacturing, storing or keeping of any of said explosives.