Emergency services are lining the streets in Romford following a “chemical incident”.
Police were called at about 3.50pm to a commercial premises in Davidson Way, Romford, following reports.
Officers, the London Ambulance Service and London Fire Brigade are at the scene.
A passer-by said: “The whole area is blocked off because of what’s happened, there are blue lights everywhere.”
A 37-year-old man was treated at the scene for minor injuries.
He was then arrested on suspicion of possession of an offensive weapon and taken to an east London police station.
There were no other reported injuries.
This is not being treated as a terrorist incident.
Inquiries continue.
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