MEMPHIS, Tenn. — Several people were hurt today in an explosion and flash fire at a southwest Tennessee plant that makes flares for the military, authorities said.

The explosion at Kilgore Flares was reported just before noon, said Cris Hill, a dispatcher at the Hardeman County sheriff's office.

The number of injured wasn't immediately known. Medical helicopters had arrived to airlift them.

Tennessee Emergency Management Agency spokesman Jeremy Heidt in Nashville said there was a flash fire at the plant but local officials had not asked for state help responding to it.

An operator who answered the phone at the plant's facility about 75 miles northeast of Memphis said the company couldn't release any information.

The cause of the explosion wasn't immediately known.

The company website says Kilgore supplies infrared decoy flares for the military. Such flares can be used as counter measures to heat-seeking missiles.