Three people were killed and 28 injured on Thursday in an explosion on a Thai PTT PCL gas transmission line in Samut Prakan province, southeast of Bangkok, the company said.
"PTT joined local rescue teams to bring the wounded to the hospital," PTT said in a statement.
Video from the scene showed flames leaping dozens of metres into the air and a large cloud of smoke hanging high above the facility.
The charred remains of houses and cars can also be seen.
PTT said that the fire had been brought under control and that gas going into that pipeline had been stopped.
Gas supplies had been restored for industrial customers and power plants, company official Chokchai Thanamethee told reporters.