SHIJIAZHUANG, May 13 (Xinhua) -- The blast occurred on Friday at a chemical workshop in Cangzhou, north China's Hebei Province, has polluted water, but not caused toxic gas leak, according to the environmental watchdogs.

    Environmental departments at state and provincial levels have designated three sites at a village near the workshop to monitor water quality. The local environmental bureau announces every 10 minutes the contents of sulfur dioxide, nitrogen dioxide, chlorine and phosgene in the air.

    Thus far, all barometers of air quality are normal.

    However, about 2,000 cubic meters of water used for putting out the fire and cleaning the scene of blast have been contaminated.

    The polluted water has been stored in the sewage pipes and a pool at the pump station in the chemical plant, and is banned from discharging by the city's environmental authorities.

    Five workers have been confirmed dead and 14 others were seriously injured after a workshop in Cangzhou Dahua TDI Co. Ltd. exploded at 1:40 p.m. on Friday. More than 40 people with slight injuries are still receiving treatment in local hospitals, according to a spokesperson for the Cangzhou city government.

    Investigations into the cause of the explosion are underway.