(CNN) -- An underground natural gas pipeline exploded into flames Monday in Johnson County, Texas, injuring several people, a fire official said.
Several people were burned, and "we've got an unknown number of people still unaccounted for," said Cleburne Fire Chief Clint Ishmael. Crews could get no closer than 600 yards to the source of the fire, he said. "There's no way we can try to put this fire out."
The pipeline erupted around 2:40 p.m. (3:40 p.m. ET), and the shaking lasted for about 10 minutes, said Laura Harlin, who lives about a mile away. "Our house shook, glass shook," she said. "We watched this huge plume of smoke or steam rising above our neighborhood."
A rumble was continuing more than an hour later, she said.