What can you tell me about the use of treated lumber in organic operations?

Answer: The USDA National Organic Program (NOP) Regulations state that producers must not use lumber treated with arsenate or other prohibited materials for new installations or replacement purposes in contact with soil or livestock. The key words here are “in contact with.”Many certifiers realize that zoning regulations and federal conservation programs may prescribe treated wood for specific applications, and some certifiers will allow treated wood for some purposes, as long as the necessity of its use can be substantiated and documented on the farmer’s organic system plan. Also, the farmer must verify that effective barriers are in place to ensure that no contact is made between crops or livestock. An example of where some certifiers allow treated wood is in fence posts for pastures.It is important to understand that the NOP Regulations are quite clear about preventing contact between treated wood and crops or livestock. The certifier must be sure that organic integrity is maintained and is responsible to the NOP for ensuring that integrity. Therefore, there must be a seamless audit trail and justification of materials use in the farmer’s organic system plan to substantiate the use of any material, especially those that come into question like treated wood. The main thing to remember is that the organic certifier has the responsibility to review and approve or disapprove the use of materials under the authority of the NOP Regulations.For more information, see the ATTRA publication Pressure Treated Wood: Natural and Organic Alternatives at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=73. This publication includes a discussion of currently used materials, lumber treatments using less-toxic materials, decay-resistant lumber species, and an explanation of the National Organic Program Regulations.