The Huixian County Non-Ferrous Metal Smelting Plant in northwest China's Gansu Province has been confirmed as the source of pollution which has sickened 368 villagers, including 149 children, said an official with the State Environmental Protection Administration (SEPA).

An investigation by a team of inspectors, which included five experts from SEPA and the local government, shows the smelter failed to conduct an environmental assessment after its upgrade in 2004 and its waste disposal equipment does not meet national standards, said Wan Yue with the Science and Technology department of SEPA.

Workers are dismantling the plant, according to local sources.

Meanwhile, a four-member team has been dispatched by the State Health Ministry to Huixian County. Together with seven experts from the provincial health bureau, they will draft plans to speed the recovery of the victims.

Ten students from the Mingde Primary School remain hospitalized in the Xijing Hospital in Xi'an, capital city of Shaanxi, 300 kilometers away from Huixian County. Another ten students are receiving out-patient treatment at the county's hospital. The other children have been released from hospital and have returned to school.