The Environmental Protection Agency (EPA) ruled on January 6, 2004 on what certain treated wood residues will be considered a hazardous waste under Resource Conservation and Recovery Act (RCRA). Since 1980 there has been an exemption for special situations of treated wood residues. The EPA is further clarifying this exemption.

This exemption applies to CCA-treated lumber where "...the waste is generated by persons who utilize the arsenical-treated wood and wood product for these materials’ intended end use," therefore wood mulch produced from CCA-treated wood is not exempt from regulation as hazardous waste under 40CFR 261.4(b)(9). This is because the intended end uses of the CCA-treated wood products are as building materials, not for manufacturing mulch. For example, CCA-treated wood waste generated during construction using CCA-treated wood, is generated by persons using the wood for its intended end use, and therefore would not be regulated as hazardous waste under this exemption (unless of course this wood waste is then used to produce much). In contrast, persons who shred or chip waste CCA-treated lumber into wood much for uses such as in landscaping applications, are not using the treated wood for its intended end use. Therefore, the exemption does not exempt wood mulch produced from discarded CCA-treated wood.

This clarification is consistent with the Consumer Awareness Program (CAP) for consumers and users of CCA-treated lumber, which instructs consumers that they "...should never burn CCA-treated wood or use it as compost or mulch."

This directive is issued to ensure clarity and a consistent approach throughout the country and to clear up some erroneous information that may have been issued from the EPA.