A fire at a chemical factory in the northern French city of Rouen threatens to pollute the River Seine, local officials have warned.
Schools in the area were closed and residents advised to remain inside as 200 firefighters, with 60 fire vehicles, tried to put out the blaze.
Thick clouds of black smoke billowed from the fire, though officials said tests showed the smoke was not toxic.
No-one was injured, and the cause of the blaze was not immediately clear.
The fire broke out at a storage facility owned by Lubrizol, a US specialty chemical manufacturer owned by the billionaire investor Warren Buffett.
“We’re still fighting the blaze, with the risk that pollution could spill into the Seine,” Pierre-André Durand, the prefect of Normandy, told reporters.
Officials said firefighters were attempting to prevent the fire from spreading to other parts of the factory.
The Seine is one of France’s biggest rivers. The river flows from Dijon in the east through Paris and Rouen before extending to the Channel at Le Havre.
The factory made the headlines in 2013 when a gas leak at the site spread a foul-smelling gas as far as Paris and parts of southern England.
And in 2015, the site leaked 2,000 litres (440 gallons) of mineral oil into the sewer system of Rouen – a city of about 100,000 people.