HUNDREDS of Bullring workers were screened by doctors today after a mystery chemical incident forced the busy shopping centre to close.

Around 250 members of staff were taken to a “clean safety zone” where they were tested and checked by doctors.

It is understood that around 20 have complained of nausea, together with two security guards who said they felt dizzy and sick.

The centre was closed at 9.30am – just 40 minutes after re-opening following an earlier chemical scare.

This afternoon it remained sealed off.

In the earlier incident the centre delayed opening for more than an hour after several security guards complained of feeling sick.

It had been evacuated at 5am following the alert and the guards were treated in hospital before being discharged.

The centre eventually opened at 8.50am, only to be forced to close for a second time following reports of two more people in a basement area being overcome by fumes.

They were taken to hospital and a check on their conditions was not immediately available.

A West Midlands Ambulance spokesman said: “The latest information we have is that there are believed to be around 20 patients complaining of nausea.

“It’s very busy on the scene.”

Tim Walley, general manager at Bullring, said: “Fumes were coming from the security office in the basement of the centre resulting in the immediate area being cordoned off.”