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.
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Scotland Yard said two murder investigations have been launched following the separate incidents, which both happened in the past week.
Photos show the extraordinary surgical procedures to remove the growth.
The Met Police says 143 firearms have been handed in at stations across the capital in just seven days, including two antique machine guns.