As of Monday, 698 people remain in hospital, of whom 57 are in a critical condition, 77 have been discharged.

On hearing of the accident, many off-duty health workers rushed to the to assist their colleagues.

"As soon as I saw the flames, I knew we were in big trouble, and left home at once," recalled Li Qing, director of the nephrology department of TEDA Hospital.

Du Huan headed straight for the hospital after fleeing her apartment, which was just a few hundred meters away from the blast site, along with her husband, daughter and mother-in-law.

Despite her husband suffering a leg injury and her 15-month-old baby sustaining shrapnel wounds, the chief nurse got straight to work.

Du said the firemen were the true heroes.

"Their will really impressed me. The seriously wounded firefighters could speak but there were no moans. They just lay there blinking, waiting quietly."