BUTLER TWP — No one was injured Tuesday evening when a storage tank caught fire at a natural gas well site on Meridian Road.

The cause of the fire at the Rex Energy Corp. gas well pad was not immediately determined, authorities said.

But company officials revealed that preliminary information indicated a valve on one of the tanks malfunctioned.

No natural gas condensate was released from the holding tank. The liquid condensate, which contains hydrocarbons, is a byproduct of natural gas extraction.

“At about 6:45 p.m. (Tuesday), a small fire occurred on a production tank at our Lynn well pad in Butler Township,” Mike Endler, Rex Energy’s senior director of civil and environmental engineering, said in a statement.

He said two wells at the operation were immediately shut down.

The fire burned for less than an hour before Butler Township Fire District 3 firefighters got there and quickly put out the blaze with a chemical extinguisher.

“We blanketed the fire with a dry chemical agent,” said District 3 Chief Toby Wehr. “In 30 or 40 seconds, it was out.”

A drilling crew for Mark West Energy Partners spotted the fire about 6:35 p.m. and called 911. The crew was about 1,000 feet away working on a hillside above the gas well pad in the 600 block of Meridian Road near Powder Mill Road.

“It was going pretty good,” said one worker who requested anonymity. “It’s something I never expected to see.”

The storage tank on fire was one of six at the well head. Each tank stores about 200 barrels of either water or condensate removed during the gas extraction process authorities said.

One barrel equals about 42 gallons of water or condensate.