True Grit: Safer Sand and Play Sets

Among parents, sandboxes may trigger worries about sharp objects or about cats or rodents that might visit after dark. Wooden jungle gyms may inspire histories of scraped knees or bumped chins. But most parents don't consider that the sand or the wood itself might be a health hazard.

Twenty years ago, the Health Research Group, a division of Public Citizen, raised an alarm about sand safety after a geologist found play sand contained traces of the fibrous mineral tremolite, a form of the human carcinogen asbestos. But the stone industry insisted the sand was safe, and the Consumer Product Safety Commission declined to take action.

Of course, the risk of asbestos exposure is greatest to workers who handle the material every day—far more intense and prolonged than the exposure of a tot in the sandbox. Still, as Philip Landrigan, M.D., director of the Center for Children's Health and the Environment at Mt. Sinai School of Medicine, points out, children breathe proportionately more air than adults, and they play close to the ground, where airborne particles swirl about. Most importantly, he says, malignant mesothelioma—a lung cancer caused almost exclusively by asbestos—is extremely sensitive to limited exposure. "Even very small doses of asbestos exposure," Landrigan says, "can increase the risk of malignant mesothelioma for four or five or six decades."

Tremolite isn't the only potential hazard. A parent purchasing a bag of play sand may be startled to discover a warning label that the bag contains a substance "known to the State of California to cause cancer." California requires these labels because the primary ingredient in sand, crystalline silica, has been determined a human carcinogen by the International Agency for Research on Cancer. However, no reports exist of the disease in children exposed to silica-containing sand.

Finally, because the sandbox may indeed attract critters, infections are possible, especially from E. coli bacteria; keep cuts and scrapes well bandaged.

Or just follow Landrigan's advice: "I encourage my grandchildren to stay out of the sandbox," he says. He guides them instead toward the swings or the jungle gym.

That jungle gym warrants a second look, too. Many are made of wood preserved with chromated copper arsenate (CCA), the basis of which is arsenic, a carcinogenic chemical that can leach out of CCA-treated wood onto children's hands and into soil and groundwater. Although CCA has been banned in residential uses since 2004, millions of CCA-treated play sets still exist.