Local children have seen their growth stunted, and have had trouble concentrating at school and sleep at night. Tests show that children have been affected by unusually high level of lead in their blood, in many cases three times over the safe level, meaning they could suffer lifelong illness.

Residents complain that since the smelter began operations a strange smell in the air and the water tasted bitter. Farmers have also seen a huge drop in crop yields because of the pollution

No one has checked the health situation although residents within one kilometre of the smelter were supposed to have been relocated.

Last week, furious villagers besieged the industrial park and forced the smelter to shut for two days. But then it reopened.

A spokesman for the county government said health authorities did provide free blood tests to determine the amount of lead for all children in the two neighbouring villages but the results have yet not been released.

Before the extent of the lead poisoning emerged, factory and county authorities said the smelter's emissions met safety standards.

Now the authorities are saying it would take another four years to relocate all residents.

Lead poisoning in a child can lead to learning disabilities, behavioural problems, slowed growth, brain damage, coma and even death.

In the meantime the controversy surrounding a heavy metal poisoning case in Zenthou, Liuyang (Hunan) is not abating. Residents living near the Xianghe Chemical factory were found to have high concentrations of cadmium, a highly toxic heavy metal.

The same metal has contaminated the Xiang River, a tributary of the Yangtze, which runs through the provincial capital, Changsha, and provides drinking water to more than 40 million people.

Although authorities have spent tens of billions of dollars to clean up the river, pollution seems to have only gotten worse.

In China pollution is a daily emergency since its industrial miracle became a reality. For years factories have operate without real controls. Now local authorities are trying to nip scandals in the bud fearing the reaction of higher authorities even though the latter were the first to urge local officials to promote economic development.