Because pressure-treated wood resists rot and insect infestation, it is commonly used for decks. Historically, most wood was pressure treated with chromate copper arsenate (CCA), which has an arsenic component. The industry has voluntarily stopped using CCA for residential applications. The EPA suggests that existing CCA-treated decks should be properly maintained and sealed. More information on CCA is available from the EPA at www.epa.gov or from the U.S. Consumer Product Safety Commission Consumer Hotline at 800-638-2772.