A massive blaze caused when a natural gas pipeline burst released thousands of pounds of gas vapor.
Officials are still investigating what caused the pipeline to rupture and explode Sunday near Cuero.
No one was injured when the more than 3-foot-wide pipe burst, but the fire melted power lines and a section of roadway and triggered an air emission that is also being investigated.
Energy Transfer Partners reported to the Texas Commission on Environmental Quality that as much as 165,732 pounds of volatile organic compounds may have burned before the company was able to isolate the line.
Volatile organic compounds can cause irritation of the eyes, nose and throat; headaches; loss of coordination; nausea; and damage to the liver, kidney and central nervous system, according to the Environmental Protection Agency. Many organic compounds are suspected of causing or known to cause cancer in humans.
Energy Transfer Partners blocked in the affected pipeline segment and collaborated with local officials to secure the area and ensure the safety of the public, according to the company's initial report to the state environmental agency.
Seven homes were initially evacuated near the site of the rupture, at U.S. Highway 87 and Farm-to-Market 953.
Once the fire was extinguished, and there was no smoke, vapors did not pose a health threat, said Texas Commission on Environmental Quality spokeswoman Andrea Morrow.
Energy Transfer Partners and the Railroad Commission of Texas said the investigation into the cause of the rupture was ongoing Wednesday. The age of the pipeline was not available from either entity.
There are no federal or state pipeline regulations governing inspections of these gathering pipelines, said Railroad Commission of Texas spokeswoman Ramona Nye.
Energy Transfer Partners, based in Dallas, did not have a timeframe for when the investigation would conclude, said spokeswoman Vicki Granado.
"As you can appreciate, these are done very thoroughly," she said.