Environment protection inspectors were stationed in the three big plants: Yuguang Gold and Lead Group, Wanyang Smeltery Group and Jinli Smelting.

All children living within 1,000 meters of the smelters had been moved away, with allowances and assistance in education provided by the government.

Some children under the age of 6 were living in a local hotel, and the government had opened a kindergarten for them.

Yang Anguo, board chairman of Yuguang Gold and Lead Group, the largest lead producer in the country, said, "We do bear responsibility for the pollution. Some pollution has accumulated over the past 20 years or more and the plant is too near homes."

Li Yuanxiang, chief engineer of Wanyang Smelter Group, said the company used the sintering pot technics for production from 2000 to 2004, which produced most of the plant's pollution.

The excessive blood lead levels are a result of longterm accumulation of pollution, and Jiyuan had a 52-year history of lead production, said Jiyuan Mayor Zhao Suping.

Zhao said more than 200 government officials had been sent to explain the situation in villages.

The government also organized a trip by representatives of villagers to Fengxiang, Shaanxi Province, where 851 children had excessive lead levels in their blood and 174 were considered serious enough to need hospital treatment, in a move to ease the villagers' anxieties.

The mass lead poisoning in Fengxiang was exposed in August, and sparked public outrage after wide media coverage.