A smelting plant in Changqing, Shaanxi province was closed after testing revealed more than 300 children living nearby had contracted lead poisoning, AFP reported. The children were diagnosed at the local hospital, revealing extremely high levels of lead in their blood, ranging from 100 milligrams to 400 milligrams per liter. Concentrations above 200 milligrams per liter are considered hazardous. State media said residents living within 500 meters of the plant should have been relocated already, but so far only 156 out of 581 families have moved. Deputy county head He Hongnian promised, "We will ensure that all the remaining 425 families are relocated within two years." Authorities are testing groundwater, soil, air and sewage for contamination.