Authorities said 30 to 40 propane tanks were stolen from a business Monday night, prompting police to notify federal authorities.

The FBI is investigating the theft and warned that the tanks are highly flammable.

The Willingboro storeowner said the theft is the first in 27 years operating the business.

“They were filled the night before for deliveries the next morning,” said Steve Merksamer, owner of Energy Resources on Route 130. “Everything was locked up. They just came in with bolt cutters.”

Merksamer said when he arrived at work on Tuesday, he discovered the gate to the propane yard was open and the padlock was cut.

Dozens of propane tanks worth $143 each had disappeared.

When full, the tanks weigh up to 80 pounds.

Merksamer said the tanks would not work with grills. He said the tanks are used for large lifts on job sites and to heat warehouses.

The Department of Homeland Security was notified as a precaution, authorities said.