(CNN) Harris County, Texas, filed a lawsuit against ExxonMobil on Thursday, one day after an explosion and fire at the company's Baytown plant.
The lawsuit said Wednesday's fire "resulted in the emission of multiple air pollutants, including propylene, LPG, propane, and associated products of combustion." The county says the company violated the state's clean air act and asks for orders to prevent a recurrence.
The fire began late Wednesday morning at ExxonMobil's Baytown Olefins Plant at a unit that contains polypropylene material.
Residents were urged to shelter in place for hours because of concern about the air quality. The advisory was lifted after monitoring didn't detect any "levels of concern," Baytown officials said Wednesday afternoon.
Officials said 66 employees and contractors were examined at a health clinic Wednesday.
ExxonMobil is "currently reviewing" the lawsuit, spokeswoman Sarah Nordin told CNN in an email.
"We take public health and environmental protection seriously," Nordin said in an earlier email Thursday. "We will continue to work to identify ways to enhance our environmental performance.
Nordin said the fire has been extinguished, and all workers who had been treated are cleared to go back to work. Air monitoring in the area just outside the complex shows "levels are normal," she said.
Rock Owens, Harris County's lead environmental lawyer, told CNN the county is asking the State of Texas for temporary and permanent injunctions against the company to fix these alleged violations immediately, and to try to prevent potential violations from happening again in the future.
Harris County, along with the state of Texas, is also also suing Exxon because of a March 16 fire at the company's refinery in Baytown, CNN affiliates KPRC-TV and KTRK-TV reported.
ExxonMobil's website describes the Baytown Olefins Plant as "one of the largest ethylene plants in the world," and the Baytown complex of operations, including the refinery and chemical plant, as one of the largest refining and petrochemical complexes in the world.
The cause of Wednesday's fire is under investigation.