"SAN FRANCISCO -- Some children's face paints contain lead, a neurotoxin that can harm the brain at low doses, according to new product tests documented in a report from the Campaign for Safe Cosmetics, a national coalition of nonprofit health and environmental groups.
In some of the paints tested, the lab identified the heavy metals nickel, cobalt and chromium, which are skin allergens, even in products labeled "non-toxic" and "hypoallergenic."
Because these metals are not listed on product labels, parents shopping for Halloween makeup have no way of knowing which products are safe. The only way to know if a cosmetic product contains lead or other heavy metals is to test the product at a laboratory, which the Campaign for Safe Cosmetics did for this report at a cost of $270.00 per sample."
Environment News Service had the story October 28, 2009. 
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