Exxon Mobil Corp said it was fighting a fire that erupted on Wednesday at its Baytown, Texas, refining and chemical plant complex injuring 37 people and sending nearby residents indoors.
As many as 37 people were being treated for non-life threatening injuries amid efforts to put out the fire, according to Exxon spokeswoman Sarah Nordin. Available air monitoring information showed "no adverse impact at this time," she said.
More than three dozen people were treated for minor burns, none requiring hospitalization, said plant manager Jason Duncan in an afternoon media briefing. The company was still working to shut down the olefins unit which processes propane and propylene - a plastics building block - and isolate the fuel keeping the fire burning, he said.
The fire, which was being fought by the company's employees, sent black smoke into the air over the complex in the Houston suburb. Firefighters and equipment from the city entered the plant at midday as smoke and flames continued to billow, a Reuters eyewitness at the scene said.
Baytown fire department referred questions to Exxon.
Residents around the plant were told to shelter in place, according to a Baytown emergency management official. Schools in several communities in the area kept summer students indoors. The city of 75,000 people is located about 30 miles (48 km) east of Houston.
The company said in a tweet it was in the process of accounting for employees at the site and was conducting air quality monitoring inside the facility.
The Baytown facility employs about 7,000 people among its four manufacturing sites and covers 3,400 acres (13.8 square kilometers). It sits along the Houston Ship Channel, the nation's largest energy port.
Aerial footage showed flames and heavy smoke emanating from a large column at the facility, which Exxon identified as part of its production of olefins, a component of plastic. Emergency vehicles and people were massing around the edge of the complex.
"The unit affected processes light hydrocarbons including propane and propylene," wrote Exxon spokeswoman Nordin. "We are cooperating with regulatory agencies. We deeply regret any disruption or inconvenience that this incident may have caused the community."
Exxon last year completed the construction of a multi-billion-dollar ethane cracker at the Baytown Olefins Plant. The cracker can produce 1.5 million tons per year, and provides feedstock to two other production lines at its Mont Belvieu, Texas, plastics plant.
Spot prices for U.S. Gulf Coast CBOB gasoline rose on Wednesday following news of the fire, traders said.
Reporting by Erwin Seba