Emergency crews on Wednesday afternoon were working to extinguish a fire that erupted at the ExxonMobil Baytown Olefins Plant on the Houston Ship Channel, which houses one of the largest ethylene plants in the world.

Six people, who reportedly were involved in trying to extinguish the blaze, were treated for injuries that were not considered to be life threatening, ExxonMobil said.

“The unit affected processes light hydrocarbons including propane and propylene,” the company said. The company’s Industrial Hygiene staff was monitoring air quality and reported no adverse impacts at midafternoon Wednesday.

Emergency responders from the City of Baytown responded, and the Texas Commission on Environmental Quality also was expected to be on the scene. The City of Baytown had issued a precautionary shelter-in-place order for residents living near the complex.

ExxonMobil, which said it is cooperating with regulatory authorities, recently completed building an ethane cracker at the olefins plant with 1.5 million tons/year of capacity. The complex provides ethylene feedstock for two polyethylene lines at ExxonMobil’s nearby Mont Belvieu Plastics Plant. The projects are part of the supermajor’s Growing the Gulf expansion program.

The Baytown complex employs about 7,000 people among at four manufacturing sites and covers 3,400 acres. The refinery at the complex began operations in 1920, while the chemical plant started operations in 1940.

“Our first priority is people in the community and in our facilities,” a spokesperson said. “We deeply regret any disruption or inconvenience that this incident may have caused the community.”