Firefighters believe it struck an LPG pipeline.
A massive fire broke out on Wednesday night at the oil refinery serving Iran’s capital, sending thick plumes of black smoke over Tehran.
It wasn’t immediately clear if there were injuries.
The fire struck the state-owned Tondgooyan Petrochemical Co. to the south of Tehran, said Mansour Darajati, the director-general of the capital’s crisis management team.
Firefighters believe it struck a pipeline for liquefied petroleum gas at the facility, Mr. Darajati told Iranian state television. He did not elaborate.
Mojtaba Khaledi, the spokesman for Iran’s emergency department, told the semiofficial ISNA news agency that 10 ambulances and other equipment had been deployed at the scene of the fire. Hospitals in the area are on standby as well, he said.
It wasn’t immediately clear what started the blaze. Temperatures in Tehran reached nearly 40 degrees Celsius on Wednesday.
Hot summer weather in Iran has caused fires in the past.