United States
                Environmental Protection
                    Pesticides And
                    Toxic Substances
September 1991
                R.E.D.   FACTS
   Use Profile
Inorganic Nitrate/Nitrite

(Sodium  and  Potassium


    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 inorganic  nitrate/nitrite,
or sodium and potassium nitrates.

    Sodium and potassium nitrates are pyrotechnic fumigants used as
rodenticides, predacides  and insecticides. Each compound is combined with
other pesticide active ingredients (sulfur and carbon) and loaded into
fumigant gas cartridges,  which are designed to be ignited and placed in pest
burrows. The ignited cartridge bombs produce toxic gases which are lethal
to target rodents, skunks, coyotes and ground-nesting wasps.
    Both sodium and potassium nitrates are naturally occurring, common
chemical compounds. While they have limited pesticidal uses, both have
other industrial uses. Potassium nitrate is used in the production of
fireworks, blasting powders and gunpowder. Sodium nitrate is used in
producing other chemicals, glass, fertilizer and fireworks.

Human Health
     The first of the six currently registered sodium and potassium nitrate
pyrotechnic cartridge products was registered in 1948.  A high rate of
accidents, attributed to poor labeling and improper manufacture, prompted
EPA to issue a Notice of Intent to Cancel these products, in 1982.  In
response, the registrants improved product labeling and provided adequate
data on fuse and cartridge burn times.

     Few studies were needed by EPA to assess the potential health
hazards, exposures and risks of sodium and potassium nitrates.  Both are
common chemical compounds with very limited uses as pesticides, and both
are marketed in cartridges which prevent accidental exposure to the
chemicals themselves.
     Both sodium and potassium nitrates control target pests through an
unconventional mode of action. Rather than directly poisoning rodents, they
support the combustion of charcoal in gas cartridges, thus aiding in the
production of toxic gases, which,  when released, overtake the target pest.
Therefore,  EPA is concerned less about the risk of direct human exposure to
sodium or potassium nitrates, than about accidents associated with use of the
gas cartridge bombs—typically involving skin burns or inhalation of toxic
gases.  (Please see the Applicator Exposure section below.)
     EPA has sufficient information on the toxicology of sodium and
potassium nitrates to support their eligibility for reregistration.
     Available acute toxicity studies indicate that  sodium nitrate may cause
eye irritation (Toxicity  Category II effect level, with Category I indicating
the greatest toxicity and Category IV the least).  However, both sodium and
potassium nitrates pose a relatively low acute oral toxicity hazard (Toxicity
Category III).  Sodium nitrate also produces some low level acute  dermal
effects (Toxicity  Category III), and slight dermal irritation (Toxicity
Category IV).
     Available chronic toxicity studies indicate some effects on the blood,
as well as equivocal evidence of carcinogenicity.  However, these studies
are not considered relevant because people are not chronically exposed to
these chemicals used as pesticides.
Dietary Exposure
     Although pesticide products containing potassium nitrate  are registered
for use in agricultural areas, they  are used in a manner that does not bring
them into contact with crops.  Therefore, residues are not expected to
remain in or on food or feed crops,  and tolerances (legal residue limits)
need not be established.
                    Applicator Exposure
                          The only people potentially exposed to sodium and potassium nitrates

                  should be applicators, and they should be exposed only minimally.  These
                  chemicals are completely encased in cartridges, similar to flares. Unlike
                  many other pesticides, they do not splash, spill or create dust or spray
                  particles.  Further, once ignited, these products produce noxious gases
                  inside the pest burrow, which is sealed or covered.  Therefore, the
                  applicator's dermal and inhalation exposure to these pesticides and the gases
                  they produce should be negligible.
                        In the past, EPA received reports of incidents involving dermal burns,
                  caused by improper handling of ignited cartridges or by defective cartridges.
                  One fatality occurred as a result of gross misuse.  In 1982, the Agency
                  issued a Notice of Intent to Cancel sodium  and potassium nitrate products,
                  which elicited some  improvements in labeling and manufacturing processes.
                  However,  since then, EPA has received four more reports of injuries to
                  applicators, due mainly to defective cartridges.  The Agency is issuing a
                  Data Call-In Notice in conjunction with this RED, to address the issue of
                  defective cartridges and further improve the safety of these products.
                  Human Risk Assessment
                        EPA believes that sodium and potassium nitrates, as  currently
                  registered for use as pesticides, do not present any unreasonable adverse
                  effects to humans. As long as applicators use the gas cartridge products
                  properly, in accordance with approved labeling, they should  be exposed to
                  virtually none of the chemicals themselves, and to only negligible amounts
                  of the gases produced. EPA is requiring that registrants develop acute
                  toxicity data on the gases, and will make final  product reregistration
                  decisions after reviewing these data.

                        All environmental fate and ecological effects data requirements for
AsSGSSITIGnt  sodium and potassium nitrates have been waived, as explained below.

                  Environmental Fate
                        Sodium and potassium nitrates are naturally occurring  substances
                  whose physical properties are well understood.  The pyrolysis of these
                  products results in simple organic and inorganic compounds, mostly in the
                  form of gases, which diffuse through burrow openings  or into the soil.
                  Exposure  of the environment is limited and localized, however,  and
                  environmental fate studies are  not required.
                  Ecological Effects
                        The pesticide products containing these active ingredients are intended
                  to kill certain vertebrates and wasp pest species inhabiting burrows.  Since
                  these pesticides are applied below the surface of the ground, avian and

    Additional  Data
  Product Labeling
Changes Required
aquatic species are not exposed.  However, any organism in a properly
treated burrow is likely to be killed.  EPA is concerned about potential
impacts to non-target and endangered species.
     Several types of non-target organisms, including burrowing owls, may
inhabit the burrows of target pests. EPA is developing more extensive and
explicit labeling to modify the timing of applications, and to caution
applicators to observe signs indicating the presence of target pests and the
absence of non-target  organisms.
     Endangered species that inhabit burrows also are at potential risk.  As
a result of several earlier consultations with the Fish and Wildlife Service,
EPA already requires  endangered species  labeling to protect the six species
identified as being at risk. Another ongoing consultation may cause EPA to
require further label revisions in 1992.

     While EPA has all the  generic studies needed to support the
reregistration of sodium nitrate, the Agency still needs information
regarding potassium nitrate's composition, recovering and refining process,
and impurities. In addition,  product-specific data,  including accident
reports and information  on manufacturing processes and fuse burn times,
still are needed for products  containing both active  ingredients. EPA is
issuing a Data Call-in Notice in conjunction with this RED, to obtain this
generic and product-specific information.

     The labels  of end-use products containing sodium or potassium nitrate
must comply with EPA's current pesticide labeling requirements. In
addition, the Agency soon will issue detailed guidance on labeling for gas
cartridge products, which will address concerns regarding applicator safety
and protection of non-target  and endangered organisms.

      •    Registered pesticide products containing sodium and potassium
           nitrates can be used without causing unreasonable adverse effects
           in people or the environment. Therefore, they are eligible for
      •    The four end-use products containing sodium nitrate will be
           reregistered  once product-specific data and revised labeling
           are received and  accepted by EPA, and once any data and
           labeling needed for the other active ingredients in these products
           (sulfur and carbon) also are received  and accepted.

      •    The two end-use products containing  potassium nitrate will be
           reregistered  once generic and product-specific data and revised
           labeling are received and accepted by EPA, and once any data
           and labeling needed for the other active ingredients in these
           products (sulfur and carbon) also are received and accepted.

   For MorG        EPA is requesting public comments on the Reregistration Eligibility
Information   Document for sodium and potassium nitrates 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 and potassium nitrates 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 nitrate 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.