PARIS (AP) — Firefighters are battling a blaze at a chemical plant in western France, and authorities have closed schools in 11 surrounding towns and asked residents to stay indoors.

The administration for the Seine-Maritime region urged people to avoid non-essential travel in the area after the fire alarm rang at the Lubrizol plant in Rouen early Thursday. The Interior Ministry tweeted that schools and nurseries in the area have been closed, and residents in nursing homes are being confined.

Images aired by BFM television show a mass of black smoke and bursts of orange flames above the plant. Sirens sounded over and over.

The cause of the fire is being investigated.

The plant produces additives for lubricants and paint, according to Lubrizol's website. The company didn't comment.