A massive inferno at a petrochemical plant outside of Houston, Texas, is still raging. The fire started Sunday morning at the Intercontinental Terminals Company facility in Deer Park and has destroyed eight of the company’s large chemical storage tanks. Although early estimates predicted the fire would be extinguished by Wednesday, issues with firefighting equipment have complicated the response.

“Fuel has burned off and we’ve said from the beginning that may be what has to happen,” said Laurie Christensen, the Harris County Fire Marshal while briefing the press, according to Bloomberg. “I’m not going to give you a time because, as we know, overnight it has changed.”

The tanks involved contain a chemical known as naphtha, which according to the chemical’s Safety Data Sheet, is highly flammable and poses a threat to health, especially if swallowed or inhaled. Naphtha is used in the manufacturing of gasoline to boost the liquid’s octane. The chemical can also cause damage to the environment, if released.

The fire has spewed smoke and fumes into the surrounding area, including downtown Houston. At this time, no regulatory agency has issued any type of health advisory due to the smoke, but that could change if the situation deteriorates. Many Houston residents have taken to social media and expressed their concern over the smoke and fumes which are still billowing from the fire.