Officials said the explosion occurred about 9:30 a.m. at a rig near Milford, about 40 miles south of Dallas. A Chevron crew punctured a 14-inch line, and company spokesman Justin Higgs said the accident involves a liquefied petroleum gas pipeline.
Milford, which has about 700 residents, was evacuated after Chevron requested a 1 1/2-mile evacuation zone. Deputies went door to door advising people to leave, said sheriff's spokesman Lt. James Saulter.
Those residents were expected to remain out of their homes until Friday, said sheriff's spokeswoman JoAnn Livingston. Residents with no place to stay were directed to the high school gymnasium six miles northeast on Interstate 35E in the town of Italy.
Saulter said no injuries were reported. He said Chevron has indicated it could take until Friday for the flare to burn itself out and allow the repairs to the rupture.
In a statement Thursday night, Chevron said it was depressurizing the pipeline through the day and overnight, reducing the size of the flare as residual gas in the pipeline burned off.
Flames could be seen shooting into the air Thursday afternoon as some vehicles at the worksite burned. A column of billowing black smoke could be seen from miles away.