The ambulance service said at least a dozen people were treated for injuries. No one was believed to be seriously hurt. Many more people were expected to be treated for minor injuries by local doctors, or to make their own way to hospital.
Emergency housing staff said the blast damaged properties over a wider area than had ever been known, with homes and buildings affected in a radius of a mile and a half. More than 1,000 homes are thought to have been damaged, with a power cut in some areas as cables were brought down by the explosion.
The bomb went off outside the laboratory at Newtownbreda while Army bomb disposal experts were moving in to investigate a large, abandoned van. The alarm was raised when the IRA made a telephone warning saying that it had planted a 'massive van bomb'.
Debris was strewn over a wide area in the blast and shocked residents in nearby houses stumbled into the streets to inspect their damaged homes. Others sat, head in hands, on their doorsteps.
The blast was heard across Belfast and for miles into the surrounding countryside, where doors and windows in houses shook.
The blast came after a temporary lull in an IRA bombing campaign.
Damage to the forensic science laboratory had yet to be assessed late last night but there were fears that it could hamper the detailed scientific work used in the campaign against terrorism. The laboratory has been the target of attacks in the past.