United States
                    Environmental Protection
Office of Pesticides »nd Toxic Substances
Office of Pesticide Programs ITS-' o6CI
Washington, DC 20460
&EPA       Pesticide
                    Fact  Sheet
                    Name of Chemical:zinc Borate (2zno.313203.3.51120)
                   Reason for Issuance:New Chemical  Registration
                    Date  Issued:  7/15/91
                    Fact Sheet Number:  225
  1.  Description

     Generic Names:

     Trade Name:

     EPA Shaughnessy Code:

     Year of Initial

     Pesticide Type:

     U. S. and Foreign

  2.  Use Patterns and Formulations
  Zinc Borate
  Firebrake® ZB




  U. S. Borax & Chemical Corp.
  3075 Wilshire Blvd.
  Los Angeles,  CA  90010
     Application sites:   Interior uses, such as PVC carpet backing,
        shower curtains,  wall coverings, etc.,  and exterior uses, such
        as PVC tenting and awnings,  polyolefin wire and cable coverings,

     Type of  formulation:  100% manufacturing grade formulation.

     Types and methods of application:  Granular product can be fed
        into  an extruder, calender machine, or injection molding mac-
        hine  for plastics or incorporated during pigment dispersion
        cycle for coatings.

     Application rates:  The effective additive level varies depending
        on fungal susceptibility of  the product and ultimate conditions
        for the use of the product.  For protection of plastics, a rate
        range of 3-30 parts product  per hundred parts resin is used.
        For coatings, rates range from 1.25 to 3.0 Ib/gal.


3.  Science Findings

    Summary Science Statement

     The toxicological data submitted for this active ingredient
included the full complement of acute studies.  Results of these
studies show that zinc borate is in the toxicity category III
(CAUTION) based on acute dermal and primary eye irritation studies
with rabbits.

     Zinc borate did not induce either genotoxic effects or chromosomal
aberrations in mutagenicity studies.

     Environmental fate data were waived because there is no direct
or indirect discharge resulting from production of this chemical.

     Chemical Characteristics

          Color:           V7nite
          Physical State:  Granular
          Melting Point:   Greater than 550°C
          Partical Size:   8-20 urn (mean)
          Density:         40 to 50 Ibs/cu. ft. (bulk)
          pH:              7.6 (In deionized

     Toxicological Characteristics

     Acute effects;
     1. Acute Oral (U^Q) in Rats -  The LDso in rats (males)  was
                found to be greater than 10 g/kg.   Zinc borate did not
                produce severe signs of toxicity in treated rats.

     2. Acute Dermal Toxicity (11)50) in Rabbits - The LD5Q was esti-
                mated to be greater than 10 g/kg in both male and
                female albino rabbits.

     3. Primary Eye Irritation in Albino Rabbits - Zinc borate was
                shown to be an eye irritant producing mild con-r
                junctivitis in albino rabbits.

     4. Primary Dermal Irritation/Corrosivity in Albino Rabbits -  The
                Primary Irritation Index of zinc borate in rabbits was
                found to be 0.  Therefore,  it is not considered to be
                an irritant or corrosive.

     Data from acute oral and acute dermal toxicity tests place the
chemical in Toxicity Categories IV and III, respectively.  These


results were duplicated in the primary eye and primary dermal irritation
studies.  Precautionary labeling language as follows is required for
this product:

     "Avoid skin and eye contact.  Avoid inhalation.  Wash after

Mutagenic effects;

     In the Salmonella/microsomal Assay (Ames Bioassay) for bacterial
mutagenic activity, zinc borate did not elicit any mutagenic response
in Salmonella tester strains when tested either with or without a
metabolic activation system.

Environmental Fate

     The Agency reviewed available data on fate and transport of
zinc and boron in the environment and concluded that no additional
data were warranted for the proposed pesticidal use.  The following
were among factors contributing to this position:

     1. According to the registrant,  there is no direct or indirect
        discharge of zinc borate into the environment from manufac-
        turing this chemical.

     2. The water solubility for zinc borate at 23°C (average
        temperature under natural conditions) is very low (0.1% at
        pH 5 and 7, and 0.03% at pH 9).  The zinc borate will be
        incorporated into some synthetic matrix to act as an
        antifungal agent.  To be effective over time,  the chemical
        must not have a propensity to solubilize and leach out of
        the matrix.  Any movement of the chemical out of the
        matrix will either be by abrasion (wear) or leaching as •
        solubilized ions.  Therefore it is highly unlikely that
        large amounts of the chemical will get into the the environ-
        ment through its pesticidal use.  Leaching studies are being
        required to confirm that ion levels in the leachate would
        be of no toxicological concern.

     3. When reformulated into other products where it serves as
        a fire retardant and fungicide , i.e. in PVC products,
        ceramics, other chemicals,  cosmetics, etc.,  zinc borate
        becomes chemically incorporated into the finished products
        and loses its identity.

     4. The chemical reactions of zinc borate can form a composite of
        oxides of zinc and boron.   Both these chemicals occur naturally
        in soil and are essential micronutrients for plants.  Moreover,


        both  zinc and boron are used extensively in agriculture as
        soil  amendments to improve the vigor of plants.  As soil
        amendments, these chemicals are applied at levels
        substantially higher than would be anticipated from their use
        in plastics as a fungicide.  The Agency is unaware of any
        lasting adverse effects on the environment from the soil
        amendment uses of zinc and boron.  The Agency concluded that
        additional data requirements would not add any substantive
        information to the available scientific data base.

     Based on these facts, the registrant was granted a waiver from
all environmental fate data requirements including hydrolysis data.

Ecological Characteristics

     In avian dietary studies, the LCso value of zinc borate in
the mallard ducklings (Anas platyrhynchos) is estimated to be
greater than 5,620 ppm.  No mortality occurred in either the control
or treated groups.  A slight reduction in body weight was observed
at the 6,520 ppm concentration during the exposure period.  There
was no effect on feed consumption at any concentration tested.

     The acute toxicity of zinc borate to bluegill sunfish
(Lepomis macrochirus) was tested under static conditions at
mean concentrations of 94, 137, 182,  248, and 335 ppm.  The
96-hr LC5Q for bluegill sunfish was shown to be greater than
335 ppm.  These results indicate that zinc borate is practically
nontoxic to the fish species tested.


     Potential advantages to the general public appear to exist by
having Firebrake ZB available as a fungicide in view of the following:

    - Zinc borate has a relatively low toxicity with no demonstrated
      adverse public health effects following extensive long-term use
      as a fire retardant in applications including carpet backing,
      fabric coating,  wall covering,  urethane foam,  roofing
      PVC tenting and awnings, etc.

    - Zinc borate is a broad-spectrum fungicide with no demonstrated
      adverse environmental effects.  This chemical would provide
      protection of a variety of plastic products and may decrease
      the environmental burden of more toxic pesticides by acting as
      an alternative for protection of plastics.


Tolerance Assessment

     There are no proposed direct food or feed uses of zinc borate,
•therefore, EPA has not established tolerances or exemptions from
tolerances in raw agricultural commodities or processed food and feed
products under the Federal Food, Drug and Cosmetic Act (FFDCA).

Summary of_ Major Data Gaps

     A dermal sensitization study is required for this chemical.  The
study is outstanding at this time.  However, the registrant has agreed
to conduct this study as a condition for registration.  The results of
the study must submitted to EPA within nine (9) months of issuance of
conditional registration of this product.  Additionally,  a leachability
study is being required as a condition of registration.  This study must
also be submitted within nine (9) months of registration approval.

     Contact Person at EPA

     Susan T. Lewis
     Product Manager (21)                   .
     Fungicide-Herbicide Branch
     Registration Division (H7505C)            :
     Environmental Protection Agency
     401 M St.,  S.W.
     Washington,  D.C.  20460

DISCLAIMER:  The information presented in this Pesticide Fact Sheet
is for informational purposes only and may not be used to fulfill
data requirements for pesticide registration and reregistration.

     United States
     Environmental Protection Agency
     Office of Pesticide Program (H7504C)
     PMSD, Information Services Branch
     401 M Street. SW.
     Washington. DC 20460
     Official Business
     Penalty for Private Use S300
Postage and Fees Paid
Permit Nc. G-35