Tests by the district revealed concentrations of lead as high as 18,000 parts per million. A second sample tested at 8,500 ppm. The allowable level is 250 ppm, said Curt Hart, an Ecology Department spokesman. The Ruston smelter is a Superfund cleanup site. Milltown Mall is a former bus barn.
Officials speculate the lead came from leaded gasoline or lead in batteries.
Dangers of lead Lead, a heavy metal, is toxic in high levels. Lead poisoning is not always accompanied by unique signs or symptoms. Lead is particularly harmful to children because they are still growing. In adults, lead can impair hearing, vision and muscle coordination. It can also damage blood, kidneys, and the heart and reproductive system.