Controlled burn at chemical plant, power off in west Houston

Authorities started a controlled burn Sunday of highly unstable compounds at a Houston-area chemical plant that flooded because of Harvey. Utility crews went door-to-door to shut off power and warn those still at homes in the western reaches of the metro area that more flooding was possible.

The Harris County Fire Marshal's Office said in a statement Sunday the decision was made to take "proactive measures" to ignite the remaining trailers at the Arkema plant in Crosby. The office said that it doesn't pose any additional risk to the public. The 1.5-mile evacuation zone around the plant is still in place.

Six of the trailers had remained after three others ignited in recent days and sent thick black smoke and tall flames into the air. Arkema had said Harvey's floodwaters engulfed its backup generators at the plant, knocking out the refrigeration necessary to keep the organic peroxides, used in such products as plastics and paints, from degrading and catching fire.