At least four workers at a cement plant in Midlothian were burned Thursday while doing maintenance on a kiln, authorities said.
They were rushed to Parkland Hospital's burn unit.
Three of the men were in critical condition, a nursing supervisor said. The fourth was in serious condition.
The accident happened at about 5 p.m. at the Texas Industries cement plant at Highway 67 and Ward Road.
It wasn't immediately clear exactly how it happened, but there was no fire or explosion, TXI spokesman Maurice Osborn said.
He also said the extent of the injuries isn't known.
"We do have company personnel there with the employees right now," he said. "We want to make sure they're well taken care of and certainly our hopes and prayers are with them and their families right now."
The Midlothian Fire Department said it was investigating the incident but referred questions to the company.