TOONE, Tenn. (AP) -- A fire was burning itself out Tuesday night after an explosion injured six workers at a manufacturing plant in southwestern Tennessee that makes flares for the military.
Hardeman County Sheriff John Doolen said firefighters at Kilgore Flares Co. in Toone were monitoring the blaze because of the danger there could be another explosion.
"There's a lot of material in that building," he said Tuesday. "I just think there's a possibility of another explosion."
Smoke continued to rise from the plant about 75 miles northeast of Memphis long after the explosion happened shortly before noon Tuesday. Authorities haven't said what caused it but they have ruled out terrorism.
Employee Gretchen Ellison said she saw sparks and heard a boom and then heard orders from fellow workers to start running.
"I just ran out and saw two people on fire," she said. "They were telling them to drop and roll."
Ellison said just minutes before the explosion she had been working with one of the employees who was injured.
Doolen said when firefighters arrived at the scene, "our main goal was getting everyone away from the explosion and getting the critical people airlifted."
Jackie Harris, a spokeswoman at the Regional Medical Center at Memphis, said two women and one man from the plant were in critical condition at the hospital. Kay Cranford, spokeswoman for West Tennessee Health Care, said a hospital in Bolivar reported three people there in good condition.
The company's Tennessee production site is a sprawling 264 acres, with another 242 acres for testing, according to the company's website. Kilgore was founded in 1920 and became a major military contractor during World War II. It is owned by Chemring Group PLC, a British company that bought it in 2001.
A statement from Chemring North America said the fire started in one of the assembly facilities and it appeared isolated to one building.
"Due to the nature of the materials involved, and its proximity to other materials, the emergency services consider it best to let the fire burn itself out," the company said in the statement.
The company said they would work in cooperation with local authorities to investigate the cause of the fire. Mike Rooney, a chief financial officer of Kilgore, said the incident was a flash fire, though he wouldn't specify how that was different from an explosion. He said 20 to 30 people were in the building when it caught fire.
County Mayor Willie Spencer, who was at the scene, said the fire could have been a lot worse.
"Any time you have an explosion ... you never know how many people are around," he said.
A flash fire and explosion at the same plant in April 2001 killed one worker and the company had to pay $200,000 in penalties for several workplace violations, according to reports from the Occupational Health and Safety Administration.
In another incident in 1999, an employee suffered burns over 80 percent of his body after material ignited and sparked multiple explosions, according to OSHA records. The employee later died at the hospital. Records indicated that the building had not been cleaned of residual material that posed a fire hazard. In 1993, two employees died after pellets of the material used in making the flares caught fire.
The company website says Kilgore supplies infrared decoy flares to counter the threat of guided missiles. The company announced earlier this year a $22.5 million Department of Defense order for flares for B-52 aircraft.
Tammy Pusser, who works at the Food Shack about 300 feet from the plant entrance, said she saw a plume of black smoke rising above the plant when she went out to make a food delivery.
"It was chilling because I knew that if they had to call 911 it was probably bad," she said.
Associated Press Writers Joe Edwards, Rose French and Kristin M. Hall in Nashville contributed to this report.