Investigators confirmed Wednesday that they’re looking at a 24-year-old well operated by Anadarko Petroleum Corporation as part of their probe into the house explosion that killed two men in Firestone last week.

That revelation followed an announcement by Anadarko that it has shut down more than 3,000 similar vertical wells across northeast Colorado, including the well that sits about 170 feet from the home at 6312 Twilight Ave. that exploded April 17.

Investigators have not announced the origin or cause of the explosion.

Frederick-Firestone Fire Chief Theodore Poszywak said in a news release that officials have determined there is no threat to other homes in that Firestone neighborhood, and have communicated that with residents.

“We are fully engaged in this investigation to a final determination unimpeded by speculation to bring honor and any closure possible to the family and our community,” Poszywak said. “…Our priorities are to ensure the safety of the neighborhood, and to complete a systematic, thorough and timely investigation to determine a conclusive cause.”

Anadarko — the largest Weld County oil and gas producer in 2014, according to state data obtained by Natural Gas Intel — did not directly link its well to the explosion, and said in a news release that “there is still much that is not yet known regarding the potential contributing factors.”

The bodies of brothers-in-law Mark Martinez and Joey Irwin, both 42, were discovered in the basement one day after the explosion. Martinez’s wife, Erin, was seriously injured and continues to heal in the hospital. A child, believed to be her 11-year-old son, was also injured.

Family and friends said Irwin had been called to help the Martinez family with the hot-water heater in their two-story home that they had lived in since 2015. Both Martinez and Irwin were experienced handymen, working as a public works foreman and as a plumber, respectively.

Construction crews building new apartments have continued working behind the neighborhood since the explosion. A chain-link fence that once surrounded the leveled home and its mildly-burned western neighbor now extends around a field east of the home, where the Anadarko well is located, south-central from the field behind its own tan fence.

In its statement, Anadarko characterized the well as “an older vertical well that was drilled by a previous operator in 1993.” The company said it has shut down all of its vertical wells “of the same vintage” across northeastern Colorado, and will keep them off until the company’s field personnel conduct inspections and testing of wellheads and associated underground lines.

Traditional vertical drilling accesses oil and natural gas reserves directly underground, meaning it is limited from reaching a wider section below, according to Anadarko diagrams. Horizontal wells start with a vertical well, but then diverge horizontally through layers of rock to tap into more than one point.

“As such, the company has been working cooperatively with fire officials and state regulatory agencies in their investigations since the time of the accident,” Anadarko said in its news release.

The company — with other operations in Wyoming, Texas, Utah, the Gulf of Mexico, South America, Africa and New Zealand, according to its website — operates more than 3,000 producing vertical wells of the same approximate age as the one located near the site of the Firestone house explosion. The company said the wells account for a total production of about 13,000 net barrels of oil equivalent per day.

According to the release, inspections will focus on areas where housing and commercial developments are in close proximity to existing infrastructure. The company also said wells will not be reactivated for two to four weeks.

“Our teams will remain actively engaged with residents in the Firestone community,” said Brad Holly, an Anadarko official. “Colorado residents must feel safe in their own homes, and I want to be clear that we are committed to understanding all that we can about this tragedy as we work with each investigating agency until causes can be determined.”

The Colorado Oil and Gas Conservation Commission also released a statement to say that crews are taking environmental samples and inspecting oil and gas wells in the area of the explosion, which includes Anadarko’s oil and gas operation southeast of the house.

The commission said it has been assisting the Frederick-Firestone Fire Protection District and the Firestone Police Department with the ongoing investigation.

As of Wednesday, Anadarko shares, which trade on the New York Stock Exchange, were down 12 cents at the end of the day and closed at $59.96.

Amelia Arvesen: 303-684-5212, arvesena@times-call.com or twitter.com/ameliaarvesen