The fire is now out at the factory in Greenwich which burst into flames in the early hours of the morning.
The area still smells strongly of the swimming pool chemicals which were stored here.
The fire brigade say those chemicals pose little health risk to anyone and are no worse than a strong bleach.
More top news
Europe's biggest street festival kicks off in Notting Hill for what promises to be another fun-filled weekend in west London
A woman from north London has been found guilty of causing death by careless driving after hitting two-year-old girl in a car park.
A 23-year-old man who was beaten up inside a cab in Farringdon is fighting for his life in hospital in a critical condition.