A study of commonly used pressure-treated lumber boards in the US suggests that the risk of arsenic exposure from these is higher than previously feared. Environmental Working Group, an environmental organisation, in conjunction with public interest groups and an US government-approved lab have made this claim. The group said it detected levels of arsenic high enough that one in 500 children who regularly play on these boards would be likely to develop lung or bladder cancer later in life. "The residue data certainly enhances our understanding of the degree to which arsenic leaches out of treated wood,' said Jim Jones, deputy director of the US Environmental Protection Agency's pesticide office.