An abandoned natural gas line that had been cut but not capped caused an explosion last month that destroyed a home, killed two people and critically injured another in Colorado, investigators said Tuesday.

“It was an unusual and tragic set of circumstances,” said Ted Poszywak, chief of the Frederick-Firestone Fire Protection District, which led the investigation.

The one-inch pipeline, extending from a nearby gas well owned by Anadarko Petroleum Co., was buried 7 feet underground and 6 feet from the foundation of the house owned by Mark and Erin Martinez in Firestone, 25 miles north of Denver.

Poszywak said he didn’t “have all the facts” about how the line was cut or even who owned it. Though Anadarko owns the well, drilled in 1993, it is unclear whether it is also responsible for the abandoned line.


The pipe leaked unrefined natural gas that was undetectable because odorants — often added to gas to signal leaks — were not used. Propane and methane leached through the soil, entering the home through a French drain and sump pump before accumulating enough to become explosive, investigators said.

Sometime around 4:45 p.m. on April 17, Mark Martinez and his brother-in-law Joey Irwin, both 42, were working on a water heater in the basement when a huge explosion leveled the home, killing both men and badly burning Erin Martinez. The ignition source is still unknown. In response, Anadarko shut down 3,000 vertical gas wells across northern Colorado out of what the company called “an abundance of caution.”

“The origin of the explosion was non-odorized gas from a gas line,” Poszywak said. “The fugitive gas came from a severed, uncapped line. The pipeline, not the wellhead, caused the buildup of gas.”

Poszywak said neither Martinez nor Irwin, both experienced handymen, were responsible for the blast. When investigators found the leaking gas line, the valve was switched to the “on” position, he said. A second line had been cut but properly capped.


Colorado Gov. John Hickenlooper, a Democrat, responded to the findings by ordering oil and gas operators to inspect and pressure-test flow lines from all working and abandoned natural gas wells within 1,000 feet of occupied buildings. He said all lines not being used must be marked and capped. Abandoned lines were ordered to be cut below the surface and sealed.

Poszywak said that so far tests have not shown any additional gas in Firestone’s Oak Meadows subdivision, where the explosion occurred.

The gas well is 178 feet from the Martinez home. Anadarko left it dormant through 2016 before restarting the well Jan. 28, investigators said.

Al Walker, Anadarko chairman, president and chief executive, said in a statement that the company would continue to cooperate in the ongoing investigation “to ensure we fully understand the basis for the fire district’s conclusions and that no stone is left unturned prior to any final determinations.”


Anadarko is the largest oil and gas producer in Colorado.

Mark McDonald, of Boston-based NatGas, a consultant who is an expert in natural gas explosions, called it “reckless to abandon a line without capping it.”

“There are regulations requiring abandoned lines to be secure,” he said. “Transmission lines are not odorized because they are not usually up against someone’s home. But when you have gas lines within 30 or 40 feet of a home you have to odorize the gas. That’s the only way to protect yourself.”

Rep. Jared Polis (D-Colo.) called the accident “avoidable.”


“What occurred in Firestone, while devastating, was predictable, because Colorado sadly does not have adequate protections against dangerous oil and gas developments in our neighborhoods,” he said. “The days where oil and gas profits are valued more than Coloradans’ safety, property, and quality of life needs to end.”

Heather Sawlidi, 31, treasurer of the Oak Meadows Homeowners Assn., said Anadarko had requested a meeting with her group’s board Tuesday.

“We are looking for an open dialogue,” she said. She worried that the accident has permanently devalued homes in the neighborhood.

Kelly is a special correspondent.