Cu-HDO is an outdoor wood preservative composed of copper (Cu) and N-cyclohexyl-diazeniumdioxide (HDO). Cu-HDO is used for pressure-treatment of lumber, poles, millwork, and piles. Cu-HDO is not likely to move through soils and contaminate groundwater. Cu-HDO is highly toxic to aquatic organisms, so it is not allowed in aquatic areas. Cu-HDO is also not intended for use in the packaging of food or feed or in the construction of beehives.
For help selecting the proper type of treated wood for any setting, consider consulting the primary standard-setting body for treated wood, the American Wood-Preservers' Association (AWPA).
If you have questions about this, or any pesticide-related topic, please call NPIC at 1-800-858-7378 (8:00am - 12:00pm PST), or email us at firstname.lastname@example.org.