Nearly 100 children in Hunan province in Central China were found to have suffered from the second lead poisoning case in the country within a month, and local authorities said 600 children altogether are being tested.
An unlicensed manganese smelter unleashed the toxic substance, said environmental authorities in Wugang county in the west of Hunan.
Police have detained two owners of the Jinglian Manganese Smelting Factory, which was built last August and went into operation earlier this year.
It was the second lead poisoning case exposed this month, after another smelting plant in Northwest China's Shaanxi province was shut down on Monday amid public anger over heavy metal discharges that have left at least 851 children ill as of Tuesday.
Hundreds of villagers broke into a smelting plant in Shaanxi's Fengxiang county on Monday to protest against the plant unleashing the toxic substance and police were mobilized to retain order.
Jin Yinlong, director-general of the National Institute for Environment and Health under China's Center for Disease Control, said the public is now widely exposed to lead pollution after years of rushed industrialization nationwide.
"From chinaware, children's toys, even to food products, sources of lead poisoning widely exist in China. But the most important source is still industrial emissions, which the authorities must address as soon as they can," Jin told China Daily.
Jin urged authorities to hand out lists of lead-containing products to less developed regions in China for educational purposes.
"Greater awareness is necessary for less informed residents who live near smelters. At least they will know it when they need to report to the authorities."
Most lead problems are caused by metal processors, such as smelters and battery manufacturers, in the industrial boom China is experiencing, said Jacob de Boer, professor of environmental chemistry and toxicology at the Institute for Environmental Studies at VU University in Amsterdam.
In Wugang's Hengjiang village, about 1,000 villagers launched a protest on the night of Aug 8 by blocking a road near the lead-emitting plant and engaged in a standoff with about 200 officials and the local police, villagers told China Daily.
Villagers said they flipped a police car because they were irritated by the government's attitude.
Village officials and the police yesterday would not comment on the standoff.
Order had been restored yesterday, villagers said.
Liu Zhongqi, party chief of the Hengjiang village, where the smelter is located, said the plant was closed last week.
"Eighty-six kids have been taken to an occupational diseases center in the provincial capital Changsha for further tests. Twenty have been found to be poisoned and are now receiving treatment," Liu said yesterday.
Test results on the 600 children will be released in coming days, Liu said.
"Test results, so far, show that 80 percent have excessive lead in their blood and the authorities will cover medical expenses," the official said.
A villager surnamed Xiao, 31, said he took his two daughters for a medical test last month after he found his younger daughter, a 10-month-old, was losing hair and throwing up milk.
Xiao said the amount of lead was 232 micrograms and 362 micrograms per liter of blood, respectively, for the older and the younger daughters, both far exceeding China's safety standard, 100 micrograms.