Raleigh, N.C. — A team from Fort Bragg detonated additional explosives found at a Raleigh recycling plant Tuesday night after an explosion sent two workers to the hospital.

Witnesses said they heard two explosions and saw some smoke at Raleigh Metals Recycling, at 2310 Garner Road, at about 11 a.m.

"I heard something like a big explosion and the shaking of the building," witness Glendora Alston said.

Plant owner Greg Brown said the force of the explosion knocked one worker over, and a second worker complained of ringing in his ears. Isai Bravo Santiago, 33, and Adrian Bravo, 27, were taken to WakeMed for treatment. Santiago was released a short time later and Bravo was listed in good condition Tuesday night.

Police said it was a military device that exploded in the recycling process and put a hole in the roof.

"A shell, projectile, something like that," said Jim Sughrue, spokesman for the Raleigh Police Department.

Fort Bragg investigators determined there was more than one explosive, and decided it was best to blow them up Tuesday night. A phone-tree notified people living within a 1 mile radius.

"Obviously that is something that is done with a great deal of care and preparation," Sughrue said.

As a precaution, police evacuated the Biltmore Court Apartments across the street from the scrap plant. One person was taken to a motel. The remaining residents who left the area went to stay with family or friends, Sughrue said.

Brown, who bought Raleigh Metals Recycling last August, said ammunition is not supposed to be accepted for recycling. He said he wasn't sure how the devices got into the mix.

Agents with the FBI and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives were contacted while State Department of Labor investigators were reviewing the incident.