Officials monitoring controlled burn at Arkema

Federal and state environmental officials say they're continuing to monitor smoke and air quality at a controlled burn at a Houston-area chemical plant.

The U.S. Environmental Protection Agency and the Texas Commission on Environmental Quality said Sunday afternoon that they were outside the evacuation zone for the Arkema plant in Crosby, but could respond quickly if needed.

Three trailers containing the compounds had already caught fire at the plant after backup generators were engulfed by Harvey's floodwaters, which knocked out the refrigeration necessary to keep the organic peroxides from degrading and catching fire.

The agencies say that they've been monitoring the air after the initial fires and have not found toxic concentration levels in areas away from the evacuated facility.