RALEIGH, N.C. (AP) — About two dozen factory workers are accusing more than a dozen design, manufacturing and installation firms of negligence in a deadly explosion that ripped through a Slim Jim production plant in North Carolina last year.

Their lawsuit also accuses inspectors for the town of Garner of failing to properly oversee the installation of a commercial water heater. The plant is located in Garner.

Garner Town Manager Hardin Watkins said Thursday afternoon that the town's attorney hasn't seen the lawsuit and advised officials not to make any comments on it. Watkins did say he thought the town shouldn't be accused.

"We believe that including the town is improper and there's no basis for that," Watkins said. "It's unfortunate that some have decided to include the town in this matter."

Neither this lawsuit, which was filed Tuesday, nor one filed last summer targets plant owner ConAgra Foods Inc.

Federal inspectors said contractors installing the water heater likely purged a gas line inside the building, allowing natural gas to collect before the explosion.

The blast killed four people and injured more than 70.