Sealants can help reduce the cancer risk from arsenic-treated wood found primarily in playground equipment and backyard decks, government scientists report.

Using an oil- or water-based sealant or stain at least once a year can limit the amount of arsenic in pesticide-treated lumber that can escape and come into contact with people’s skin, according to the Environmental Protection Agency.

Results from the first year of a two-year study by the Consumer Product Safety Commission and the EPA show success in containing the pesticide, chromated copper arsenate.

The EPA said the sealants or stains are preferred because paints and other products “can chip or flake, requiring scraping or sanding for removal, which can increase exposure to arsenic.”

The lone Democrat on the three-member commission, Thomas Moore, criticized his agency for not making a more forceful statement “to motivate parents and municipalities” to act.

The agency staff “believes that hand-to-mouth behavior is the primary source of exposure. ... This is why parents of young children who routinely play on playgrounds, decks or other surfaces made of CCA pressure-treated wood should be concerned,” Moore said in a statement Wednesday.

The pesticide has been used mainly to protect lumber from decay and insect damage. Preliminary studies by the EPA have shown what officials describe as a marginally increased risk of cancer for children age 1 to 6 who are exposed to the pesticide.

The EPA has removed the pesticide from a list of approved chemicals. The lumber industry has stopped making new products with it.

The Wood Preservative Science Council, a trade group, said “coatings of any kind are not necessary” because CCA-treated wood products have been used safely for more than 70 years. It pointed out that arsenic is a naturally occurring element in nature.

The Environmental Working Group, which sought a ban on the treated wood, said the government is playing down the risks.