The thunderous explosion at Pueblo’s historic Branch Inn that killed one person and seriously injured several others last week was caused by natural gas that migrated into the restaurant’s basement from a leaking gas line, local and federal officials said Thursday.
Woody Percival, spokesman for the Pueblo Fire Department, said the leak occurred in a feeder line under Pueblo’s C Street.
The entrance and front of the Branch Inn were on Union Avenue, but the longest part of the building — about 120 feet — was on C Street.
The gas migrated through the soil to the basement of the Branch Inn, Percival said.
There it accumulated and was ignited by one of numerous possible sources, said Craig Roegner, spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives. Those included a compressor for a freezer, other electrical appliances or candles.
Percival said the leak occurred where the feeder line to the Seabels Building — located across C Street from the Branch Inn — connected with the main gas line under C Street.
Percival said a plastic sleeve had been inserted into the older iron pipe of the feeder line. Where the plastic pipe in the feeder line connected with the main gas line under the street may have been where the problem or leak occurred, he said.
Natural gas can normally be detected because of the “rotten egg” smell that is added to it to alert people to a leak. But officials said the pungent odor was filtered out by the soil.
“During our investigation, people reported what they thought was the smell of sewage. But there were no cracks in the sewage pipe,” Roegner said. “There was no methane.”
Just how long there had been a leak is still under investigation.
Both Percival and Roegner said the cause of the blast has been officially classified as “accidental.”
They stressed that asbestos was not found in the air after the initial explosion or in the days following.
A minimal amount of asbestos was found in the floor tiles of the Branch Inn and in the adhesive used to put the tiles in the floor, Percival said.
The explosion occurred at 2:20 p.m. Nov. 13, demolishing the Branch Inn and A Classic Boutique, immediately to the west.
Ashley R. Johnson, 22, who worked in the boutique, died at Parkview Medical Center.
Howard Pankratz: 303-954-1939 or hpankratz@denverpost.com
