Police were called to West End Lane, NW6, by London Ambulance Service shortly before 10.30am on Thursday, 2 September to a report of a man taken unwell after coming into contact with an unknown noxious substance.
It is understood that a substance had been placed on a vehicle parked near a property on West End Lane property and the owner’s claimed that he felt faint and his hands started to feel like they were burning.
Officers attended along with London Fire Brigade attended.
The man was treated at the scene. The substance has been tested and nothing suspicious was found.
The scene has been closed.