JACKSON TWP — State and local fire officials and police are investigating an overnight blaze that tore through a large warehouse containing two small businesses on Route 68.

The fire shortly after 11 p.m. at the old Bentley Industries site near Route 528 caused more than $1 million in damage and left nearly two dozen employees without jobs to go this morning, authorities said.

Investigators don't know what caused the blaze that sent more than 100 firefighters from 10 departments to the 40,000-square-foot steel structure.

Destroyed were Plant Growers Workshop, a garden supply distributor, and Zack Products, a records management company.