WASHINGTON (AP) - Federal regulators Tuesday denied a request to ban arsenic-treated lumber used in playground equipment, which environmentalists say poses a health hazard. The Consumer Product Safety Commission voted unanimously to adopt its staff's finding and recommendation that a ban was not needed because most manufacturers already have stopped using the treated wood and other makers soon will follow suit. The lumber in question is treated with a pesticide, chromated copper arsenate, that protects it from decay and insect damage. Almost all wooden playground equipment has been treated with the pesticide. The concern is that children can get cancer-causing...