HARRISTOWN - A 30,000-gallon ethanol storage tank west of Harristown exploded about 3 a.m. Friday, apparently because of a lightning strike that ignited vapors trapped in the vessel after a vent on the top had frozen shut, preventing their escape.

That scenario is a supposition based on evidence at the scene, said Fire Chief Randy Hiser of the Niantic Fire Protection District. The Niantic department was called out about 3:15 a.m. and worked on the situation until 11:30 a.m., he said.

"It had to be a beautiful show," a tired Hiser said Friday afternoon. "It blew the top of the tank upwind 357 feet."

Dozens of firefighters and emergency response personnel were called to the scene, but there were no injuries. Damage was confined to the ethanol storage tank.

Illinois Environmental Protection Agency personnel were on the scene and inspected the tank, but no leaks were found, Hiser said.

The initial alarm involved firefighters from Niantic, Harristown, Latham and Blue Mound, while a second alarm brought firefighters from the Warrensburg, South Wheatland, Mount Zion, Hickory Point and Chestnut departments, Hiser said. A third alarm summoned the Decatur Fire Department's Hazardous Materials Team, he said.

Also on the scene were personnel from the Illinois and Macon County emergency management agencies, Bodine Environmental Services, the Salvation Army and the Norfolk Southern Corp., which has a track nearby.

Three snow plows from the Illinois Department of Transportation were used to clear snow and allow fire apparatus to get to a point where the fire could be fought efficiently, Hiser said.

"We had to use alcohol resistant foam, and we only have 400 gallons of it, so we didn't want to waste it," Hiser said. "Mount Zion brought some additional foam.

"We're pretty confident it was a lightning strike. The tank was about two-thirds full, or holding about 22,000 gallons of ethanol."

The ethanol storage tank and a neighboring 30,000-gallon tank holding biodiesel fuel are owned by Superior Fuels Inc. of Newton. The vessels were constructed last year just south of a gasoline storage terminal operated by Buckeye Partners LP of Hartford.

Buckeye Partners spokesman John Teriet said his company is very concerned with public safety and dispatched employees to the scene shortly after 4 a.m., when a call was received from the Macon County Emergency Management Agency.

"We wanted to make sure our facility was not a risk to the public in this situation," Teriet said. "Once that was determined, our employees joined the first responders to give them any aid we could."

Buckeye supported the firefighters' order to shut down the gasoline terminal until the situation with the ethanol tank was resolved, Teriet said. Normally, the terminal operates around the clock, he said.

Ron Ingram can be reached at ringram@herald-review.com or 421-7973.