Guo's manager, Wang Changhong, admitted he knew when the factory would be checked, but refused to say where he got the information.

A Dafeng environmental protection bureau was unavailable to comment when contacted by China Daily yesterday.

However, Xia Xueluan, a sociology professor at Peking University, said local governments who put economic growth ahead of the environment are often reluctant to properly check polluting factories.

"The enforcement of environmental laws should be tightened and procedures for environmental checks must be improved to be more cautious. Officials should not be warning factories ahead of planned inspections," he said.

Authorities should work more on prevention, not simply look to act quickly once a disaster occurs, said Xia.

Local officials in nearby Dafeng said the battery plant's owner, Cheng Qihua, is being questioned. The factory has also been closed and ordered to relocate by March 31.

Guo, who also lives close to the plant, provided an early warning of the coming scandal last August when she was discovered to have a blood-lead level of 590 mcg/l.

"I felt a great pain, like a stone in my stomach. I had no idea I was suffering lead poisoning. At first, I thought it was menstrual pain but two days later I couldn't bear the pain and went to a doctor with my husband," said Guo, who earned 2,400 yuan (US$350) a month polishing lead ingots up to 11 hours a day.

Her health improved after taking medication offered by the factory and was soon back in the workshop.

For professions such as hers, factories are required to give workers regular health checks. But Guo said the factory only gave workers tests if they fell ill and were unable to work. Like her fellow workers, she stayed silent about her illness because she feared her wages would be docked.

Had they spoken up, however, the recent lead poisoning scandal that has resulted in at least six children being hospitalized may have been avoided, she said.

Guo's 4-year-old son, Shu Fanglin, was one of the children most seriously affected. Tests on Dec 14 showed his blood-lead level was almost 430 mcg/l. He fell into a coma two days later at Xinhua Hospital in Shanghai's Chongming Island, where he was taken for treatment along with three other children on Dec 5.

"I thought he would die. He just suddenly lost consciousness," said Guo's husband, Shu Changfu.

Fanglin is now back with his family in Hekou and, following advice from doctors, all his toys and clothes were thrown away. The family has also moved out of their home into a rented house 4 km away.

"It is financially tough, but money doesn't matter as much as my son's health. He lost 2.5 kg during treatment and we're now concerned it may have affected his mental development," said Guo.

Her husband added: "He used to be a happy little boy and played with other kids. Now he's shy and scared of strangers."

Health experts say lead poisoning poses more of a risk to children than adults because their bodies easily absorb and retain lead. Levels above 100 mcg/l can harm the nervous and reproductive systems, as well as cause high blood pressure and anemia.

In severe cases, lead poisoning can lead to convulsions, coma and even death.

Yan Chonghuai, a professor at Xinhua Hospital, also explained that the process of lowering a baby's blood-lead level causes them to lose nutrients and calcium, meaning their immune system would not function well and they would be more susceptible to colds and other illnesses.

Health campaigners have called for authorities to provide regular check-ups for children living near industrial zones to help spot potential problems as early as possible.

Youngsters are usually examined when they start kindergarten and elementary schools, although a teacher who asked to remain anonymous at Dafeng No 7 Elementary School said tests do not include checks for poisoning by heavy metals.

There is also a lack of awareness among doctors, experts warned. Hekou residents backed up this claim by telling China Daily that medics at Dafeng People's Hospital insisted the accepted blood-lead level was 400 mcg/l for adults and 300 mcg/l for children.

More than 100 families moved into the newly built Hekou neighborhood in 2004. The local government signed a contract in 2006 allowing Dafeng Shengxiang Power Supply to move its plant to the village from Jiangyin, a city about 200 km to the south.

Villagers said that the company owner, Cheng, warned the factory would cause pollution and should not be so close to a residential area. But in the agreement with the local authority, officials said they would "take care of villagers in the event of an incident".

The project passed all environmental impact assessments carried out by the Jiangsu environmental protection bureau.

Wang Kouzhu, 55, whose 9-month-old grandson registered a blood-lead level of 313 mcg/l in October, blasted factory bosses and local officials for the outbreak of illness caused by pollution.

"They both have to take responsibility," she said, crying as she held her grandson Zhang Fangjian, who was initially rushed to Xinhua Hospital suffering a cold and diarrhea. "The factory should never have been allowed to move there. It is too close to people's homes."

After the scandal was exposed in the local media, Cheng offered 500,000 yuan towards treatment costs and compensation, villagers said. The Dafeng government will make up any shortfall.

The public is now widely exposed to lead pollution after years of rushed industrialization, said Jin Yinlong, director-general of the National Institute for Environment and Health under China's Center for Disease Control.

"From chinaware, children's toys to even food products, sources of lead poisoning exist everywhere in China. But the most important source is still industrial emissions, which the authorities must address," Jin told China Daily.

Villagers and local officials are not conscious of the consequences of emissions, which in turn damages healthcare awareness in less developed areas, he said. Residents in under-developed regions should be given a list of products that contain lead by local authorities to help educate them.

"Greater awareness is necessary for less informed residents who live near smelters and battery factories," said Jin. "At least it will enlighten them on when they need to report poisonings to the authorities, instead of waiting for the pollution to worsen."

Meanwhile, authorities are in a dilemma, explained Sun Ping, spokesman of the Dafeng government. He said that because the north of the province is less developed than the south, officials seize any opportunity to push economic growth and enrich people's lives.

"Economic growth depends on industries, so it will certainly give rise to pollution," he warned.