An official says a rocket motor exploded and caused a fire at a weapons factory in southern Arkansas, and that one worker was killed.

Calhoun County Sheriff Bob Dunn says the Aerojet employee apparently was working on the motor in a bay area when the explosion occurred about 3:15 p.m. at the company's plant in East Camden.

Dunn says the fire was contained by evening and the site is secured, although emergency workers had not recovered the body and planned to resume their search in the morning.

Company spokesman Glenn Mahone says the company did not know what caused the explosion.

Aerojet is based in Sacramento, Calif. The company, which contracts with the defense department, makes guided missiles and space propulsion systems.

Aerojet employs 500 people in the manufacture of weapons at its Highland Industrial park plant. About 450 people would have been working when the explosion occurred.