WASHINGTON — The U.S. Department of Agriculture has initiated a public comment period concerning 232 materials on the National Organic Program’s National List of Allowed and Prohibited Substances (National List) that are due to sunset in 2012. The U.S.D.A.’s advanced notice of proposed rulemaking appeared March 26 in the Federal Register.

The National List identifies synthetic substances that are exempted (allowed) and non-synthetic (natural) substances that are prohibited from use in organic production and handling, as recommended by the National Organic Standards Board (NOSB). Substances may not remain on the National List for more than five years without being reviewed and recommended for renewal by the NOSB and adopted by the Secretary of Agriculture.

The comment period is scheduled to end May 25. For more information, visit www.regulations.gov and search for AMS-NOP-09-0074.