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Composts Disallowed in California and An Update on Pesticide Residues

(February 5, 2010)California growers should know that the California Department of Food and Agriculture (CDFA) prohibited three composts for use in organic production: Nortech Gold made by Nortech Waste LLC, Grover Wonder Grow Compost made by Grover Landscape Services, and Clean City Compost made by Feather River Organics.

If growers have concerns about the application of compost on their farms, they should contact their certifier.

Because the contamination is suspected to be coming from yard waste feedstocks, OMRI is investigating yard waste composts. Most yard waste composts will remain on the OMRI Products List until a full investigation is completed for each compost. This is based upon OMRI’s due process, which allows our clients to be informed of an investigation, provide further information to defend their product listing, and contest OMRI’s final decision.

OMRI is concerned about these recent findings that some composts contain residues of bifenthrin, a synthetic pesticide that is prohibited for use in organic production. OMRI is testing a number of products on the OMRI List to determine how widespread of a problem this is among composts.  We have also communicated with the NOP and other agencies to determine what levels of pesticide residues are prohibited in organic production. Unfortunately, it is not clear what levels are prohibited.



The issue of pesticide contaminated composts arose in August 2009 when the California Department of Food and Agriculture (CDFA) received complaints about three composts containing bifenthrin. CDFA made three separate announcements in August, September, and October confirming that the composts listed above are prohibited in organic production in California.

The National Organic Program (NOP) is aware of this issue and is working to develop thresholds for contamination in compost. The NOP Rule allows for the use of composts that contain conventional agricultural products and yard waste as feedstocks. However, the compost should be relatively free of contaminants when applied to an organic farm, so that the compost does not contribute to the contamination of crops, soil, or water (see section 205.203(c) of the NOP Rule).

The issue of contamination is complicated by the use of many different types of pesticides and the differing rates that they break down during the composting process. Due to this complication, it may be several months, or more, before a standard is developed.

While the NOP works to develop a threshold for pesticide residues in compost, OMRI will continue to investigate products and test for known contaminants. The testing results will be provided in a summary fashion to the NOP to help inform its standard-making process.

OMRI acknowledges that the possibility of contamination is a concern for everybody in the organic industry. Alternately, recycling green waste and encouraging composting is a positive step toward better resource management. OMRI looks forward to a clear, consistent standard that OMRI, certifiers, and growers can use when verifying compliance of input materials for organic growers.