MORGANTOWN, W.Va. — A crew drilling a natural gas well through an abandoned coal mine in West Virginia’s Northern Panhandle hit a pocket of methane gas that ignited, triggering an explosion that burned seven workers, state and company officials said today.

The blast created a column of flame that was initially at least 70 feet high, but the rig operator said the site was secure and the fire was about 40 feet high by late morning.

A team from Texas-based Wild Well Control, a company that specializes in rig fires, will decide whether to let the methane burn or try to extinguish the flames, said Kristi Gittins of Dallas,Texas-based Chief Oil and Natural Gas.

The explosion occurred about 1:30 a.m. in a rural area outside Moundsville, about 55 miles southwest of Pittsburgh, and presents no danger to any structures or people, said Bill Hendershot, an inspector with the state Department of Environmental Protection’s Office of Oil and Gas.

The operation was less than a week old: DEP records show a permit was issued June 2 to AB Resources PA LLC of Brecksville, Ohio.

Gittins said AB Resources is the operator of the well, while Chief has a “participation interest.” It is Chief’s responsibility to drill and complete the well, she said.

Chief’s site contractor, Union Drilling of Buckhannon, had drilled the first 1,000 feet of a second well on the property and was preparing to install surface casing when crews apparently hit and ignited the methane, she said.

Crews had drilled through the abandoned Consol Energy mine before without incident, she said.

Methane is a known risk when working near old mines, and the company typically takes a variety of precautions, including venting systems. Gittins could not immediately say what precautions were in place at this site.

“Luckily, our response team got there quickly, secured the area and evacuated the workers,” she said. “From all appearances, there weren’t any life-threatening injuries, so that’s a good thing.”

The seven workers were taken the West Penn Burn Center in Pittsburgh and were in fair condition, a hospital spokeswoman said.

Five were employed by Union and two worked for BJ Services Co. of Houston, Texas, said Jeff Funke, area director of the Occupational Safety and Health Administration’s Charleston office.

A spokesman for Union in Fort Worth, Texas, did not immediately return a telephone message.

The BJ Services workers were among four that had just arrived on site to place the casing, said Gary Flaharty, a spokesman for the parent company, Baker Hughes Inc. of Houston. The crew runs a safety check at the start of each shift and was just preparing to do that when the blast occurred.

Flaharty could not provide any details about the injured employees but said they’re being treated for burns and are expected to survive.

Funke said OSHA learned of the accident shortly after 8 a.m., and two investigators were being dispatched. However, they cannot enter the site and begin work until the fire is out, he said.

OSHA created a program to deal with gas drilling in the vast Marcellus shale fields about five years ago and has been proactively inspecting sites to ensure compliance with safety regulations, he said. The gas reserve is about the size of Greece and lies more than a mile beneath New York, Pennsylvania, West Virginia and Ohio.

OSHA knew there would be a lot of drilling in West Virginia and Pennsylvania, “and we did our best to get out in front of that curve,” Funke said. “So we’re well-equipped to respond to this.”

About 98 percent of the region’s drilling now involves Marcellus shale, he said.

Gittins, the spokeswoman for Chief, confirmed the company was tapping into the Marcellus reserves. The company has drilled about 75 Marcellus wells in West Virginia and Pennsylvania so far, she said, with about 15 of them in West Virginia.

This was the company’s first major accident, she said.

However, it’s the latest in a string of accidents related to the rapidly growing pursuit of Marcellus gas.

In Pennsylvania, environmental regulators are investigating what caused another well to spew explosive gas and polluted water for about 16 hours last week until it was brought under control.

A crew of eight was evacuated from the Clearfield County site Thursday, but no one was injured. That accident involved EOG Resources Inc. of Houston.