O2 now open after chemical leak

Ammonia leaked through an air vent

The O2 entertainment complex in London has reopened as investigations continue into a chemical leak which left staff needing hospital treatment.

London Ambulance Service said 29 workers at the former Millennium Dome in Greenwich were treated for the effects of ammonia on Monday night.

Staff were dismantling stage equipment inside the arena when ammonia leaked from the ice rink plant room.

The venue was evacuated and later declared safe by the fire brigade.

Area monitored

Those affected by the leak were taken to four hospitals and all were discharged by Tuesday morning.

Emergency services was called to The O2 - the former Millennium Dome - at 2045 GMT.

London Ambulance Service sent 10 ambulances, a duty station officer and their hazardous response team to the venue.

Fire crews isolated the gas supply and declared the area safe after monitoring the affected area with specialist equipment.

A spokeswoman for The O2 said: "There was a minor ammonia leak last night at The O2. The building was immediately evacuated."

An internal investigation is being carried out.