FIRESTONE, Colo. (AP) " A red-orange fireball that killed two people and destroyed a Colorado home prompted the governor to order sweeping inspections of natural gas lines and is certain to worsen tensions in state already divided over how to regulate the industry.
Fire investigators said Tuesday the April 17 explosion was caused by a leak in an old gas line that was believed to be out of service but was connect to a producing gas well " for reasons they still do not know.
The line had been cut about 10 feet (3 meters) from the home of Mark and Erin Martinez in Firestone, about 30 miles (48 kilometers) north of Denver, officials said.
Mark Martinez was killed, and so was his brother-in-law, Joseph William Irwin III " Erin Martinez's brother. Erin Martinez was badly burned, and the Martinezes' young son was also hurt.
The pipeline that leaked was a 1-inch (2.5-cm) flow line. Flow lines carry gas from a well to a storage tank or other collection point.
After the Frederick-Firestone fire department announced the results of its investigation, Gov. John Hickenlooper, a Democrat and a geologist who once worked in the petroleum industry, quickly ordered inspections of all similar gas lines within 1,000 feet (300 meters) of occupied buildings.
Hickenlooper said the state will require energy companies to perform pressure tests, where the lines are sealed and pressurized so any leaks will register as a drop in pressure.
"Public safety is paramount," Hickenlooper said.
The Sierra Club and Conservation Colorado have already begun pushing for more, urging the Colorado Oil and Gas Conservation Commission " which regulates the industry " to impose tighter rules.
The commission "must take decisive action and not allow any oil and gas activity unless it is proven to be safe to human health and our air and water," said Pete Maysmith, executive director of Conservation Colorado
The proximity of fast-growing communities and big oil and gas fields in Colorado has long been contentious. Environmentalists and some local governments have pushed for tighter state rules, or for giving cities and counties the power to impose tougher restrictions than the state.
They have suffered a series of setbacks since 2015, when a state task force suggested giving cities and counties a consulting role but no regulatory power. Last year, the Colorado Supreme Court reinforced the state's supremacy, ruling that local governments have no power to regulate the industry. And this year, the Legislature killed a proposal that would have increased the minimum distance between schools and new oil and gas facilities.
But in March, Colorado's second-highest court ruled the oil and gas commission can put more weight on protecting public health and the environment when it draws up rules, giving environmentalists a new tool to argue for stricter regulations. The commission has not yet said whether it will appeal.
The industry appeared to be bracing for a long fight Tuesday. Dan Haley, president of the Colorado Oil and Gas Association, said that "in the weeks and months that follow," energy companies want to work with regulators, homebuilders and local governments to prevent a repeat of the explosion.
Anadarko Petroleum, which owns the well connected to the line that leaked, said it is cooperating with investigators.
Investigators said they do not know whether Anadarko or someone else was responsible for the pipeline. The well was drilled in 1993 and had other owners before Anadarko.
Investigators said they do not yet know when and how the line was cut.
Oil and Gas Conservation Commission Director Matt Lepore said the line was cleanly cut, which he said could mean it was severed by construction equipment while the neighborhood was being built.
The well was in place before the homes were constructed.
Lepore said a line taken out of service is supposed to be disconnected and sealed at both ends and all flammable gas is supposed to be removed.
He said regulators do not yet know whether this line had never been disconnected from the well, or if it had been disconnected but later reconnected for some reason.
The well was shut down for all of 2016 but resumed production in January, state records show.
Associated Press Writer Thomas Peipert in Denver contributed to this report.
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