Enterprise Products Partners said it owned the 36-inch pipeline, which is part of its Texas Intrastate system. The explosion was 15 miles south of Godley, Texas.
WFAA-TV, a Dallas television station, quoted Chester Nolen, city manager of Cleburne, Texas, as saying 10 people were missing following the explosion. Cleburne is the largest city near the explosion.
The blast was originally thought to be an oil well explosion.
An electrical crew was digging a hole when it struck the gas pipeline, an emergency services spokesman in Hood County, Texas, said.
The first indication Enterprise had of a problem on the pipeline was a sudden drop in pressure seen at the company's operations center, said spokesman Rick Rainey.
"We have isolated that segment of line," Rainey said. "Our crews have been dispatched to the scene. Basically that line is equipped with line breaks that allows us to shut in that segment in case of a sudden drop in pressure."
