The Handan Winter Swimming Association took legal action on Wednesday against the company responsible for a toxic chemical spill that threatens drinking water supplies to thousands of homes in North China.

The public interest lawsuit was submitted to Handan Intermediate People's Court in Hebei province.

If accepted, Tianji Coal Chemical Industry Group in Changzhi, Shanxi province, could be forced to pay compensation to the affected Handan residents, plus 10 million yuan ($1.6 million) to the city government to cover the costs of dealing with the fallout of the spill.

"The court will decide whether to take the lawsuit by next Friday," said Sun Guanglin, a Handan lawyer representing the association, adding that the action is the first public interest litigation filed since the amended Civil Procedure Law took effect on Jan 1.

"We are confident in the case — the facts are clear," Sun said.

Calls to the court and Tianji Coal Chemical went unanswered.

The spill from a loose drainage valve led to at least 9 metric tons of aniline flowing into the Zhuozhang River and another 30 tons seeping into a nearby disused reservoir, according to an initial investigation by Shanxi provincial authorities.

Water samples showed aniline levels in the river reached 72 milligrams per liter after the accident. Aniline is a clear or slightly yellow liquid and can cause liver and kidney damage in humans.

Shanxi authorities have said no casualties — human or animal — were reported, but a senior Handan official who did not want to be named said dead fish had been found on Friday near the Yuecheng Reservoir.

"As (the government) did not give any warning (about the spill) for five days, the aniline has threatened the lives of Handan residents," Sun said. "We're just looking for justice."

The spill was detected on Dec 31 but was only revealed to the public five days later when Handan authorities cut off water supplies because of safety concerns, prompting panic buying of bottled water in the city.

The water supply was sourced from groundwater from Sunday to Tuesday.

"With the water quality in Yuecheng Reservoir testing safe, the water supply shifted back to the reservoir on Tuesday night," Liu Donghua, a spokeswoman for Handan Water Supply Co, said on Wednesday.

She said workers have tested the water quality hourly since Tuesday.

Hou Risheng, chief engineer of the Handan environmental protection bureau, said at a news conference on Tuesday that testing showed the water in Yuecheng Reservoir is safe, but the five monitoring spots upstream of the Zhuozhang River had excessive aniline levels.

On Sunday, Chen Jianwen, general manager of Tianji Coal Chemical, deputy manager Ren Yongjie and two other employees were sacked.

Changzhi authorities say they will suspend operations at 112 chemical companies along the Zhuozhang River to eliminate potential hazards.

China's coal-rich Shanxi province has been the scene of a series of accidents over the past week.

On Jan 3, the Work Safety Committee of the State Council condemned a subsidiary of the China Railway Tunnel Group for covering up a deadly explosion at a railway tunnel project in Shanxi for five days. The accident killed eight people and injured five.

On Monday, a gas explosion also killed seven people in a Yangquan Coal Industry mine in Jinzhong.

Li Xiaopeng, acting governor of Shanxi, said at an emergency conference on safety on Tuesday that Tianji Coal Chemical and Yangquan Coal Industry had suspended their operations. He urged authorities to make work safety a top priority.

"We have zero tolerance for coverups," Li said.

Zhang Bao, mayor of Changzhi in Shanxi, where the aniline spill occurred, apologized for a five-day delay in reporting the accident to the provincial authorities on Monday.

Sun Ruisheng in Taiyuan and Xiang Mingchao in Hefei contributed to this story.

Contact the writer at wangqian@chinadaily.com.cn