Authorities in northern China closed a smelter that left more than 300 children ill with lead poisoning, state media reported on Wednesday in Beijing.

Families who lived near the Dongling Lead and Zinc Smelting Co. in Shaanxi province began bringing sick children to hospitals and clinics in July and blamed the factory, according to the official news agency Xinhua.

An investigation found that lead from the factory had leaked into the soil, air and water source for 425 families residing near it in the town of Changqing, the report said.

Local officials plan to relocate all 581 households living within 500 metres of the factory over the next two years, the report said.

Lead poisoning typically occurs in children and can damage the nervous and reproductive system, cause high blood pressure, anemia, memory loss, and in extreme cases, cause victims to fall into comas and die.

With files from The Associated Press