"It might be dangerous to hose water at the scene as some explosives might detonate when hit by water," said Sun Huashan, the deputy director of the State Administration of Work Safety who arrived in Yichun late Monday to lead the rescue work.

Sun urged other methods be used to prevent further explosions and fires.

Traffic near the scene has been restricted since Monday. No one apart from rescuers and fire fighters have been allowed near the scene since early Tuesday.

The fire spread to a chopstick factory Monday but it was brought under control.

More than 2,000 residents were evacuated after the explosion shattered windows within one kilometer radius of the factory.

Iron fences 100 meters from the factory were also damaged in the blast.

Witnesses said the shockwave of the explosion was felt up to five kilometers away.

More than 1,700 people and 62 fire trucks were dispatched to fight the blaze and search for survivors Monday.

Forty medical experts arrived in Yichun at around 10 p.m. Monday to help treat the injured.

The cause of the accident is under investigation.

Heilongjiang provincial work safety bureau said Tuesday they ordered an immediate carpet inspection over all businesses for producing and wholesaling of fireworks and for trading and using dangerous chemicals.

Any factories failing to meet safety standards will be suspended from operating for improvement or will face closure.

Production at six fireworks plants of the province has already been halted, said an official from Heilongjiang provincial work safety bureau.