Hong Kong held a major drill simulating a biochemical attack on Friday to test its preparedness at different levels to cope with potential incidents during the Olympic equestrian competitions in August.

The chemical, biological, radiological and nuclear (CBRN) field exercise, dubbed "Equinox VII," was launched at the Sha Tin Olympic equestrian venue and involved nine departments of the Hong Kong Special Administrative Region (HKSAR) government and a company specially established to run the equestrian events of Beijing Olympics.

During the exercise, a simulated CBRN device was "activated" shortly before an event, resulting in multiple fatalities and injuries and spectator contaminations.

Organizers of the Olympic events, Police and the Fire Services Department swung into immediate rescue and evacuation operations. The explosive ordnance disposal unit of the Police was dispatched to the scene and successfully made the CBRN device safe. The firemen conducted mass decontamination of the spectators at the nearby Sha Tin Fire Station. The injured were treated at the scene and transported to hospital.

The scene was later decontaminated to ensure that it was safe to enter.

Senior officials of the HKSAR government also took part in the drill, including the chief secretary for administration and the secretary for security. Representatives from other departments and related agencies were also present.

The drill was the last of a series of exercises ahead of the Games planned by the Security Bureau of the HKSAR government. The first of the drills began on March 7.

Chief Secretary Henry Tang said that the drills were important because they were aimed to test and fine-tune the contingent plans for emergencies and the overall coordination.

"I am confident that all parties involved in the Olympic equestrian events have geared up to ensure that the events will be held smoothly in a safe and secure environment," he said.