United States
Environmental Protection
Agency
Office of Pesticides »nd Toxic Substances
Office of Pesticide Programs ITS-' o6CI
Washington, DC 20460
540/FS-91-139
&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
Registration:
Pesticide Type:
U. S. and Foreign
Producers:
2. Use Patterns and Formulations
Zinc Borate
Firebrake® ZB
128859
1991
Fungicide
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,
etc.
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.
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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
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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
handling."
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,
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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.
Benefits
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.
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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.
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&EPA
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
First-Class
Postage and Fees Paid
EPA
Permit Nc. G-35
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