United States
Environmental Protection
Pesticides And
Toxic Substances
September 1991
                        R.E.D.   FACTS
Sodium   Diacetate

     All pesticides sold or used in the United States must be registered by
EPA, based on scientific studies showing that they can be used without
posing unreasonable risks to people or the environment. Because of
advances in scientific knowledge, the law requires that pesticides which
were first registered years ago be reregistered to ensure that they meet
today's more stringent standards.
     In evaluating pesticides for reregistration, EPA obtains and reviews a
complete set of studies from pesticide producers,  showing  the human health
and environmental effects of each pesticide. The Agency imposes any
regulatory controls that are needed to effectively manage each pesticide's
risks.  EPA then reregisters pesticides that can be used without posing
undue hazards to human health or the environment.
     When a pesticide is eligible for reregistration, EPA announces this and
explains why in a Reregistration Eligibility Document, or RED.  This fact
sheet summarizes the information in the RED for sodium diacetate.
          Use Profile
     Sodium diacetate is a fungicide and bactericide registered to control
molds and bacteria, and thus prevent spoilage, in stored grains. The
pesticide is applied to hay as a dust or soluble concentrate (liquid spray)
during the baling process. It is applied to silage as an "aid" in fermentation,
to preserve the quality of field corn, alfalfa, sorghum, oats and grasses,
stored in silos.
     Sodium diacetate is composed of acetic acid and sodium acetate.  It
dissociates to acetate,  sodium and hydrogen ions, normal components of
plants and animals, and of human foods. Acetates are formed in living
organisms during the metabolism of food.  Acetates and acetic acid have
long been used in both human and animal foods, without significant adverse
     Sodium diacetate was first registered in 1968, for use as a food
preservative. Later products were registered to preserve the quality of
livestock feed crops. Currently, two such end-use pesticide products
are registered, each containing sodium diacetate as its sole active
ingredient.  Based on the chemical's Generally Recognized as Safe or GRAS
status, the post-harvest feed uses of sodium diacetate have been exempt from
tolerance, or legal residue limit, requirements since 1981.

 Human Health
     Based on acute toxicity studies, EPA places sodium diacetate in
Toxicity Category IV (the least toxic of four categories) for oral and dermal
toxicity and for primary dermal irritation.  However, sodium diacetate is an
eye irritant, and has been placed in Toxicity Category II for this effect.
     In some subchronic feeding studies, the highest dose test animals
experienced reduction in body weight gain, loss of appetite and reduction in
food consumption. Others had raised white blood cell counts.
     No maternal, fetal or teratogenic effects,  and no  signs of tumors, were
seen in chronic animal feeding studies.  Mutagenicity tests also have shown
negative results.
                     Dietary Exposure
                          People could be exposed to very low level residues of sodium
                     diacetate by eating meat, milk, poultry or eggs from animals fed hay or
                     silage treated with the pesticide.  However, since acetic acid is completely
                     utilized in metabolism, the residues of sodium diacetate in meat, milk or
                     poultry are considered to be negligible.  Sodium diacetate is exempt from
                     the requirement of a tolerance, or legal residue limit, when used post-
                     harvest on certain hays and grains, as listed in 40 CFR 180.1058.  It is
                     considered Generally Recognized as Safe, or GRAS,  for use in food (please
                     see 21 CFR 184.1754). Thus, EPA believes that any dietary exposure to
                     sodium diacetate is inconsequential.
                     Applicator Exposure
                          Workers mixing and loading the dust formulation of sodium  diacetate,
                     or the soluble powder for liquid  application, may experience significant
                     exposure via the dermal and (for the dust formulation) the inhalation routes.
                     If mixing and loading is performed using a closed system,  the potential for
                     exposure is minimized.  Without a closed system, protective clothing is
                     needed to protect the eyes from irritation. Product labels must be  amended
                     accordingly,  as specified in the RED.
                     Human Risk Assessment
                          EPA concludes that the general public's dietary exposure to sodium
                     diacetate resulting from proper use of the pesticide to protect livestock feed
                     is inconsequential.  However, workers mixing and loading the pesticide may
                     suffer eye irritation effects unless appropriate protective clothing (such as
                     goggles or a face shield)  is worn.  Therefore, EPA is requiring the use of
                     such protective equipment.
Environmental        EPA does not foresee the potential for significant environmental risks
   Assessment   associated with the registered uses of sodium diacetate. All environmental
                     fate and ecological effects data requirements are waived, as explained

    Additional Data
  Product Labeling
Changes Required
            For More
Environmental Fate
     Post-harvest applications of sodium diacetate to hay and silage are
made primarily within farm facilities, so limited environmental exposure
results.  There is sufficient knowledge about sodium diacetate to make the
assessment that the compound's impact on the environment will be
negligible.  EPA therefore is not requiring any environmental fate studies.
Ecological Effects
     The limited outdoor use of sodium diacetate is likely to have a
minimal impact on wildlife. Since this pesticide is of low toxicity, and is
normally present and functioning in the metabolic pathways of animals, its
use in treating hay and forage crops does not warrant the development of
ecological effects studies for reregistration.

     While the generic data base for sodium diacetate is complete, product-
specific acute toxicity and product chemistry data are required for

     The labels of the two end-use products containing sodium diacetate
must comply with EPA's current pesticide labeling requirements.  In
addition, since these products cause eye irritation, their labels must be
amended to include the following statement:  "Causes eye  irritation.  Do not
get in eyes. Wear goggles or a face shield during use."

        Registered pesticide products containing sodium diacetate  can
          be used without causing unreasonable adverse  effects in people
          or the environment.  Therefore, they are eligible for
        The two end-use products containing sodium diacetate as the sole
          active ingredient will be reregistered once product-specific data
          and amended labeling are received and accepted by  EPA.

     EPA is requesting public comments on the Reregistration  Eligibility
Document for sodium diacetate during a 60-day time period, as announced
in a Notice of Availability published in the Federal Register. To obtain a
copy of the RED or to submit written comments, please contact the Public
Response and Program Resources Branch, Field Operations Division
(7506C), Office of Pesticide Programs (OPP), US EPA, Washington, DC
20460, telephone 703-557-2805.
     In the future, the RED will be available from the National Technical
Information Service (NTIS), 5285 Port Royal Road, Springfield, VA
22161,  telephone 703-487-4650.
     For more information about sodium diacetate or about EPA's pesticide
reregistration program, please contact the Special Review  and Reregistration
Division (7508W), OPP, US EPA, Washington, DC 20460, telephone 703-
308-8000. For information about reregistration of individual sodium

diacetate products, please contact the Registration Division (7505C), OPP,
US EPA, Washington, DC 20460, telephone 703-557-5447.
     For information about the health effects of pesticides, or for assistance
in recognizing and managing pesticide poisoning symptoms, please contact
the National Pesticides Telecommunications Network (NPTN).  Call toll-
free 1-800-858-7378,  24 hours a  day,  seven days a week, or Fax your
inquiry to 806-743-3094.