Anadarko's Colorado Operations Draw Criticism After Second Deadly Blast -- 2nd Update

A second deadly accident in Colorado involving Anadarko Petroleum Corp. is spurring criticism of the company's oil and gas operations in the state.

A fire at oil storage tanks owned by the Houston-based company killed a maintenance worker and injured three others Thursday afternoon. Authorities haven't identified the person killed.

At the time of the accident, "crews were finishing projects associated with a facility upgrade" and the tank facility wasn't in operation, Anadarko said in a brief statement Friday.

The blast follows a home explosion that killed two people in Firestone, Colo. last month, after natural gas leaked from an abandoned line that remained attached to a 24-year-old well operated by Anadarko less than 200 feet away from the residence. At some point the line was severed, allowing gas to seep into the soil and migrate into the house, which was built in 2015.

The National Transportation Safety Board is investigating the Firestone explosion.

Anadarko voluntarily closed more than 3,000 wells after the April 17 home blast, and Colorado Gov. John Hickenlooper called for a statewide review of existing oil and gas operations. The Colorado Oil and Gas Conservation Commission notified producers they would be required to reinspect any flow lines and pipelines within 1,000 feet of an occupied building by May 30.

The latest accident occurred as a crew performed maintenance on a collection of oil tanks near Highway 66 and Weld County Road 13 near the town of Mead, Colo., just a few miles from site of the Firestone explosion, according to the Weld County Sheriff's Office.

Tank batteries are used to hold oil and gas being pumped from wells, and are connected to those wells by flow lines like the abandoned one that was severed sometime before the Firestone explosion.

"When law enforcement personnel arrived on scene they found that an Anadarko oil tank battery was fully engulfed in flame," the sheriff's office said.

In the wake of the fire, the Sierra Club called on Anadarko to immediately shutter all its operations in Colorado pending a review by state and federal authorities.

"Anadarko, like so many fossil fuel companies across the country, [has] proven that it cannot be trusted to put its workers and the communities surrounding its operations first," said Lena Moffitt, director of the Sierra Club's Our Wild America campaign, which opposes mining and drilling in wilderness areas.

A representative for the Colorado Oil and Gas Conservation Commission couldn't immediately be reached for comment Friday.

Gov. Hickenlooper called Thursday's fatal fire a "terrible tragedy" and offered his condolences to the Mead community.

"We certainly recognize the safety concerns raised given the recent home explosion in Firestone, but at this time we have no reason to believe that there is any relationship between the circumstances that led to these two accidents," he said.

Write to Erin Ailworth at Erin.Ailworth@wsj.com