Monday, fire investigators in Statesville told Eyewitness News they can't get inside a plant that exploded Sunday because it's not safe.
The incident happened at Bartlett Milling Company. Officials said the mill distributes flour and animal feed. The company said the building that exploded was a cleaning house used for the early stages of the milling process.
The building exploded and caught fire. Four people were inside and one was seriously injured.
The fire marshal called it the worst explosion he's every seen in Statesville and damage has made it tough for investigators to determine the cause.
"It's not secure enough for us to get in there," said Statesville Fire Marshal Mike Billings.
OSHA regulators were also at the mill Monday working to make sure no safety or health rules were broken.
Eyewitness News checked records and found the company was given three $1,900 dollar fines in 2009.
Two of those violations were deleted from the OSHA database and the third is for "machine and equipment maintenance."
A spokesman for OSHA said inspectors would investigate whether a similar problem may have caused the explosion Monday.
Workers with the Department of Agriculture were also there making sure that flour and animal products distributed by the company weren't tainted by the explosion.
The fire marshal told Eyewitness News that flour from the company is distributed to several fast-food companies.
OSHA said if it finds a violation the company could face a fine up to $7,000. A spokesman also said the OSHA inspection could take anywhere from a couple of weeks to six months.
Bartlett Milling Company sent the following statement regarding the incident Monday night:
"There was an explosion at the Bartlett Milling Company facility in Statesville, North Carolina, on Sunday morning.
"A Bartlett employee was injured, and was driven to the hospital by a fellow employee. He is in the local hospital and is reported to be in stable condition. His well-being certainly is our first concern.
"The incident occurred in the "cleaning house," a building which houses the early stages of the milling process; the flour mill itself experienced little or no damage. We are working with our experts as well as local authorities to assess exactly what happened."