"This is probably why almost all the workers were gone and the ones who were there survived," Stephen Selk, lead investigator for the U.S. Chemical Safety and Hazard Investigation Board (CSB), told OccupationalHazards.com.
Two of the injured workers are in serious condition, according to officials.
CSB deployed an investigative team to assess the damage of the explosion and fire at the Synthron Inc. plant in Morganton, N.C.
The CSB team has yet to enter the plant's premises because of the massive destruction, agency officials said. Even nearby buildings, such as the plant's office building and a church, were completely destroyed. The force of the blast moved the house across the street from the facility off its foundation and blew out windows in nearby homes.
Fortunately, no one was in the church at the time of the blast, said CSB public affairs specialist Lindsey Heyl.
"The blast tore the ceiling and the heavy debris came down all over the pews," she said.
Because of the extent of the damage, investigators predict that even though the plant is small, the investigation can take up to 1 year.
"Site access is going to be very slow," Selk admitted.
"This was a serious event, injuring workers and affecting neighbors and causing considerable damage to the facility, said CSB board member John Bresland. "Our team will conduct interviews, review documents and examine the site in the next few days in order to determine whether a further investigation is warranted."
Cause of the Blast Unknown
Both Selk and Lee Peacock, OSHA's onsite lead investigator, told OccupationalHazards.com that the cause of the blast remains unknown.
"OSHA and other groups have assembled teams of experts to try to determine the cause of the explosion," Peacock said. "Nothing definitive has yet been identified."
Synthron is a subsidiary of Paris-based Protex International, which produces specialty chemicals in the United States, Europe, Asia and North Africa. The Morganton plant produces several chemicals, including toluene, a petroleum-based solvent that can be explosive.
Because of the nature of the chemicals produced by the plant, inspectors were wary that the air in Morganton could have been contaminated with dangerous toxins.
Toluene, used in making paints, thinners, adhesives and other products, is a liquid that can affect the nervous system. Inhaling high levels in a short time can make victims light-headed, dizzy or sleepy. In severe cases, it can cause unconsciousness or death.
Selk said that although precautionary measures should be taken, there is not much to fear.
"The Environmental Protection Agency has reported to emergency response teams that their samples did not show any findings of toxic substances in the air," he said.
Officials allowed residents who had voluntarily evacuated because of the smoke to return to their homes. They were advised to keep their windows closed and ventilation systems turned off, until firefighters could determine whether toxic chemicals were present, according to a statement released by CSB.
Inspectors last found problems at the plant in 1996, when the company was fined $602 for 10 violations, five of which were classified as serious, according to the North Carolina Department of Labor.