DES MOINES, Iowa (AP) – An explosion and fire Monday at a chemical distribution facility northeast of Des Moines sent plumes of thick smoke into the sky and burned out of control for several hours after it ignited.

Flames and clouds of black smoke soared above the Barton Solvents facility, and exploding barrels could be seen jetting into the sky. Fire departments from throughout the Des Moines area responded to the fire, and the smoke thinned out by early evening.

The explosion occurred about 1:15 p.m. when a substance in a warehouse was being moved into a portable storage tank, said Barton President David Casten. He said he didn’t know what substance was being moved or how it ignited.

One worker suffered slight burns.

and was treated at the scene, and a firefighter was taken to a hospital with heat exhaustion, officials said.

A.J. Mumm, coordinator for the Polk County Emergency Management Agency, said 55-gallon barrels and 300-gallon tanks exploded and there were concerns about loaded rail cars and truck tanks on the site.

Firefighters were battling a second blaze at a nearby recycling center that apparently started when a flaming barrel flew from the Barton plant and landed on a wood pile at the center, said Neil Shultz, a spokesman for the sheriff’s office. Officials were still assessing damage at the recycling center and were not sure whether the blaze had been extinguished.

Police closed Interstates 80 and 235 near the fire for more than two hours before opening them around 4 p.m., after tests showed the air quality was acceptable, officials said. The Federal Aviation Administration advised pilots to avoid the area because of poor visibility, said agency spokeswoman Elizabeth Isham Cory.

Barton Solvents Inc. is a wholesale distributor of industrial chemicals, oils and surfactants under the Barsol trade name. Casten said it wasn’t clear what was burning but that a variety of substances were stored at the site, including hydrocarbons and petroleum-based solvents.

Of particular concern was the rail car, which was filled with hexane, a flammable chemical.

An explosion at a Barton Solvents plant in Valley Center, Kan., in July prompted widespread evacuations in the community of about 6,000 people north of Wichita. Investigators have said it was caused by static electricity as workers filled a tank that contained a dry-cleaning product.

AP-ES-10-29-07 2057EDT