Authorities in Changzhi town in Shanxi in coal-producing northern China, where the spill occurred, apologized for the delay in reporting the spill affecting supplies of drinking water, China Daily reported Tuesday.
Changzhi Mayor Zhang Bao, who also apologized, said the local government had initially been told about 1.5 metric tons (1.65 tons) of the chemical aniline had leaked from a ruptured valve at a site run by the Tianji Coal Chemical Industry Group into the Zhuozhang River on Dec. 31, the report said.
Officials had underestimated the potential damage from that much spill, the mayor said. Later, when the spill was fully investigated, it was found the spill was closer to 9 metric tons (nearly 10 tons) with another 30 metric tons (33 tons) spilling into a disused reservoir, he said.
The report said Changzhi authorities reported the spill to the Shanxi government last Saturday, five days after the incident.
On Saturday, authorities in Handan city in neighboring Hebei province cut off water supply to more than 1 million people because of the contamination in the Zhuozhang River, the report said. Supply was restored the next day using groundwater.
Earlier, authorities in Hebei said dead fish were discovered in a reservoir.
Anyang city, another downstream town in Henan province, also has been informed about the spill.
China Daily said Chen Jianwen, general manager, and Ren Yongjie, deputy manager, and two more officials at the Tianji plant have been dismissed.
Health experts criticized Changzhi authorities for the delay in reporting the accident.
"Aniline is a toxic substance," Professor Xia Zhaolin at Fudan University's School of Public Health told China Daily. "A lethal dose for humans is 4 grams."
The aniline level in the river Sunday was 2.15 milligrams per liter, down from a peak of 72 mg per liter immediately after the leak, Liu Dashan, spokesman for Shanxi's environmental protection bureau, was quoted as saying. However, the report said the river water is still not safe to drink as the national standard allows less than 0.1 mg per liter of aniline.
"Dealing with the leak will be a great challenge," Professor Xia said.
Hu Sanhu, spokesman for Changzhi authorities, said no humans or livestock had been affected as much of the Zhuozhang River remains frozen.
However, China National Radio said Monday Jin Xiaohong, a shepherd from Nanzhuang village near the source of the leak, had reported several ewes suffered miscarriages after drinking river water not frozen over. But China Daily said tests did not confirm any link to the leak.
The Financial Times reported Changzhi officials Monday ordered the closure of 112 chemical plants until completion of emergency inspections.
The report said public anger over the delay in informing about the spill had not abated despite the mayor's apology. The spill is the latest incident as China continues to fight pollution threatening water supplies.
"The big problem is again the covering up," the Times quoted Ma Jun, author of the book China's Water Crisis, as saying.