Spontaneous combustion of oily rags cited as cause of Poplar Bluff restaurant fire

POPLAR BLUFF, Mo. -- Fire officials believe spontaneous combustion caused the recent fire at Dairy Queen after employees put hot rags with oily residue into a plastic container after laundering them, causing the rags to build up heat and eventually ignite.

With Dairy Queen, "we know two restaurants have had this issue," according to Poplar Bluff Fire Chief Ralph Stucker.

An early morning fire on Oct. 17 damaged the interior of Dairy Queen, located at 2730 N. Westwood Blvd., while a September 2002 fire destroyed Western Sizzlin'.

In both instances, Stucker said, employees had washed towels and/or rags, which had "gone through the washing system" at the restaurants and were hot when placed "wadded up" in containers after coming out of the dryers.

That procedure, Stucker said, is not uncommon.

Even after the oil-soaked rags are washed, there is still "enough oily residue because they weren't washed properly to remove all the oil," said Capt. David Dudley.

If the rags are then "packed in a container with no air flow, the oil can still oxidize, causing heat and a sufficient amount creates an ignition," Dudley said.

A study by the Consumer Product Safety Commission, Stucker said, indicates towels containing as low as 3 percent residue of vegetable oil after normal laundering could still generate spontaneous combustion.

At Dairy Queen, Stucker said, there was a container of oily rags, which was located next to a plastic laundry basket of "clean" rags.

Between 11 p.m. and midnight, Dudley said, employees put clean rags in the basket. A heat sensor in the kitchen notified the fire department at 1:32 a.m.

The "average" time for spontaneous combustion to cause an ignition of solvent-soaked rags is five to six hours, Dudley said.

"The reason why the time frame was so short (at Dairy Queen) … is because (the rags) were warm when they came out of the dryer," Dudley said. "They had initial heat to begin with."

The heat then built up and began to smolder, until it reached a sufficient temperature to result in ignition, Dudley said.

"Once it ignited, it burned the plastic container and the fire spread from there," Dudley said.

An investigator with the State Fire Marshal's Office initially did not make a determination, but subsequently met with representatives of the restaurant's insurance company, Stucker said.

They were in agreement as to the fire's cause, Stucker said.

The container of rags, Dudley said, was the only thing in the area of ignition.

Battalion Chief Stacy Harmon recalled when Western Sizzlin' burned, there was speculation as to the cause of the fire.

Within the next week, Stucker said, firefighters will be visiting local businesses to see how employees are handling solvent-soaked rags and what types of containers are being used.

Firefighters, he said, also will be offering tips if employees continue washing the towels/rags in order to "make it a little safer."

Those tips will include washing towels multiple times or sending them out to be cleaned, laying warm towels out flat to dry and storing them in approved containers, Stucker said.

Approved containers, Dudley said, include metal or polyurethane cans, with lips on top and air vents on bottom so air can circulate.

Fire officials caution restaurants aren't the only ones potentially at risk of spontaneous combustion involving oily rags.

Any place, including homes or woodworking shops, using animal- or vegetable-based oil could be at risk, said Dudley, who described a residential setting in which towels were used to soak up oil in the kitchen and then placed in a laundry hamper, where they caught fire.

"Spontaneous combustion is real; we know we've had two for sure, we don't want to have any others," Stucker said.

Pertinent address:

2730 N. Westwood Blvd., Poplar Bluff, MO