Birmingham’s Bullring shopping centre was shut for a second day today as seven more people were taken to hospital following a chemical leak that police say may have been caused deliberately.

The seven people given medical treatment this morning fell ill after turning up to work at the centre.

Bosses at Bullring were given the all clear for shops to reopen today after the centre was evacuated yesterday.

However, it was closed again just after 7.30am after a number of staff started to feel ill.

Roads around the shopping centre including Edgbaston Street were closed off while investigations continued, with around 20 police on scene.

West Midlands Police investigating the claim the respiratory problems may have been caused by a petrochemical-based substance potentially contaminating either the ventilation system or air conditioning system. However, they have not yet confirmed what the chemical is.

Police spokesman Steve Garey said: “At this stage the emergency services do not know whether this would be the result of an accident or a malicious act.

“The investigation to try and determine the cause is now being led by the police working with specialists from the fire service and Birmingham City Council’s Environmental Health Department.”

Paramedics were first called out in the early hours of yesterday after staff complained of feeling dizzy and nauseous. In total 250 staff were evacuated with a total of 33 people treated by the 25 ambulance staff on scene.

West Midlands Ambulance Service spokesman Murray MacGregor said: “Of the 33, four patients were transferred to Heartlands Hospital by ambulance for further assessment and treatment. One of these patients was suffering from a cardiac related problem which was unrelated to the chemical incident.”