ATF: ConAgra explosion caused by accidental natural gas leak

Members of the Bureau of Alcohol, Tobacco, Firearms and Explosives' National Response Team and other investigators went inside the plant for the first time Friday and finally were able to access the blast site Saturday.

"We've been able to make entry into the location of the explosion, which was in pump room No. 2," ATF agent Phil Durham said.

The natural gas leak was contained to that room, which houses vacuum pumps for sealing the snacks, and was ignited when one of the electrical components in the room started, Durham said.

ATF agents believe the spark could have come from a piece of equipment like a fan motor or thermostat, but ATF Agent Earl Woodham said another cause, like static electricity, couldn't be ruled out. Such electrical equipment would be capable of causing natural gas to erupt into flames even if it were operating normally, he said.

"It could have been anything that could have created a spark," Woodham said. "By the very nature of the fact that whatever caused it is no longer there due the destructive explosion, we're never going to be able to say, 'Yes this motor (was responsible)' or 'Yes, this thermostat' did that.'"

The cause was determined to be accidental and not criminal. The investigation will be turned over to the state Division of Occupational Safety and Health and the U.S. Chemical Safety Board, which will follow up on the cause of the leak and try to determine the ignition source.

Durham said the crews had been in the process of replacing their steam system with a hot water system. Employees who were interviewed said they did smell an odor on Tuesday.

“Some of the employees … thought they smelled something,” Durham said. It is unknown if they reported the smell to supervisors.

ATF agents returned the building to ConAgra managers Saturday night, allowing workers to go back inside the plant.

About 300 employees were in the plant at the time of the Tuesday morning explosion, which blew out a wall and punched holes in the roof, sparked small fires and ruptured the plant's ammonia lines.

Dozens of workers and contractors were injured, and three workers – Barbara McLean Spears, 43, of Dunn; Rachel Mae Poston Pulley, 67, of Clayton; and Louis Junior Watson, 33, of Clayton, – were killed.

Four employees remained in critical condition at the North Carolina Jaycee Burn Center at UNC Hospitals, officials said. One employee was listed in fair condition and two were in good condition Saturday afternoon.

After Saturday's press conference, Garner Mayor Ronnie Williams said the town will work with ConAgra to help rebuild the plant.

“I think the tax-based incentives are all on the table for discussion,” Williams said. “We are going to do everything we can to make sure they get back into operation and get the people back to work as soon as possible.”

Gwendolyn Sanders, an employee of ConAgra Foods for 10 years, is sure the plant will be back. She returned to the Garner facility on Saturday, saying she had to come back and take a look of the building she escaped on Tuesday.

“This is my first time actually standing here looking at this place that I love so much and it’s gone,” Sanders said.

Sanders’ hand and arm were severely cut during Tuesday’s explosion.

“I told everybody, ‘Run but stay low,’” Sanders said. “Stuff was falling.”

In a statement released Saturday, ConAgra Foods officials thanked the ATF and all agencies for their "support and quick response" to the accident.

"We appreciate ATF's swift determination to eliminate criminal activity. We continue to provide our full support to the authorities, including OSHA, the U.S. Chemical Safety Board and the Wake County Fire Department, as they investigate the cause of the accident and bring the investigation to conclusion."