Thirty-eight people have been held accountable for a chemical leak that contaminated a river in North China's Shanxi province in December, a working group responsible for addressing the incident said Wednesday.

An investigation by the working group showed that Tianji Coal Chemical Industry Group caused the serious contamination and the Changzhi city government should also be blamed for failing to respond quickly to the emergency and not informing the downstream areas of the imminent health threats.

Changzhi Mayor Zhang Bao was removed from his post. The director of the work safety department in the city, Yang Fujin, was also sacked. Seven other officials were disciplined, including a deputy mayor and the environmental protection chief in the city. Twenty-four corporate executives received warnings, or demotion and removal from their posts.

Five people, including an environmental protection enforcer in the city, have been transferred to judicial authorities.

Some 8.8 metric tons of aniline leaked by Tianji Coal Chemical Industry Group entered the Zhuozhang River on Dec 31. The contamination affected drinking water supplies in downstream Handan, Hebei province, a city with a population of 1 million. Water in neighboring Henan province was also polluted.

A broken metal tube caused the leak. The working group's investigation found the tube's supplier was a company in Beijing unauthorized to produce such metal tubes.

Aniline, a derivative of benzene used in industries including rubber, dye and pigment processing, is a toxic chemical that is believed to cause liver and kidney damage.

Changzhi city did not file a report about the leak until Jan 5 to the Shanxi provincial environmental authority. The delay created a lot of panic in affected places, where residents emptied shop shelves of bottled water.

Zhang Bao, the mayor, apologized on Jan 8 for the five-day delay in reporting the chemical spill under intense public anger.

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