London Fire Brigade (LFB) sent 25 fire engines and 150 firefighters to the incident on Bridge Road, Southall, after declaring a major incident due to the suspected presence of fireworks and cylinders.
The cause of the fire, which was first reported at 8.55am, is not yet known.
In a statement, the fire service said that the blaze “is located in a two-storey structure consisting of a warehouse and retail space”.
“Around three-quarters of the structure is currently alight,” LFB added. “Three of the Brigade turntable ladders have been deployed to scene, allowing crews to fight the fire from height.”
Jonathan Smith, London’s fire commissioner, warned people to “keep away” from the 200-metre perimeter which has been set by the LFB.
“To everyone in the area, just keep yourself safe,” said Mr Smith. “Keep yourselves out of the perimeter. We’ve got a 200-metre perimeter around the scene. We’ll make sure that everyone keeps away.
“It’s going to be a very, very busy scene of operations for the foreseeable future, certainly overnight.
“So, we would ask members of the public to keep away, keep a safe distance and allow the fire brigade to do their job.”
Assistant Commissioner Pat Goulbourne, the Brigade’s incident commander, had earlier said that “a major incident has been declared” at the scene.
“This decision has been taken due to the suspected presence of fireworks and cylinders being stored within the structure,” the incident commander added.
“All firefighters have withdrawn to a safe distance and are now fighting the fire from a greater distance to ensure crew safety.”
The service said residents in the area were advised to keep doors and windows closed “due to the large amount of smoke being produced by the incident”.
Traffic in the area would “also be impacted,” the LFB added, also saying first reports of the fire were received at 8.55am.
The brigade’s control officers have taken some 60 calls regarding the fire.
“This will be a protracted incident with crews carrying out firefighting operations throughout the day,” the brigade said in a post on X.
