United Stttv Offiet of Pwtieidw and Toxic SubMnoM
Environmental Protection Office of P«ticMe Program (TS-766C)
Aoancy Washington, DC 2O460
xvEPA Pesticide
Fact Sheet
Name of Chemical: oiazinon
Reason for Issuance:
Date Issued: September, 1986
Fact Sheet Number:
1. Description of chemical
Chemical name: O,O-Diethyl O-(2-isopropyl-6-methyl-4-pyrimidinyl)
phosphorothioate
Common name: Diazinon
Trade name: Spectracide, AG500, Alfa-tox, Sarolex,
D-Z-N Diazinon 14G, Geigy Spectracide Lawn
and Garden Insect Control, etc.
EPA Shaughnessy code: 057801
Chemical abstracts service (CAS) number: 333-41-5
Year of Initial Registration: 1952
Pesticide type: Insecticide
Chemical family: Organophosphate
2. Use patterns and formulations
Application sites: Field, fruit, nut, vegetable (including
seed treatment) and nonfood crops
(ornamentals and tobacco); forestry
(including Christmas tree plantations);
greenhouse food crops (vegetable bedding
plants and ornamentals); livestock; range,
pasture, and grassland; animal premises;
lawns and turf; domestic outdoor and indoor
(household); commercial indoor (including
food handling establishments and processing
plants); commercial and industrial
outdoor sites.
vrypes of formulations: Wettable powder, wettable powder/dust,
eraulsifiable concentrate, dust,
microencapsulate, soluble concentrate,
granular, oil solution, aerosol spray,
spray concentrate, impregnated materials,
soluble concentrate, liquid ready-to-use,
and pressurized liquid.
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Types and methods of application: Ground, aerial, and those
methods unique to the
formulation, such as aerosols.
3. Science ...Findings
Physical and Chemical Characteristics—
Physical state: Liquid
Color: Colorless (Technical is amber to brown)
Odor: Typical of organophosphates
Boiling point: 83—84° C
Melting point: Not applicable
Flash point: 82° F for AG500
>105° F for 4E and 4S
Human Toxicology Characteristics—
Acute rat oral LD 50 : 66—635 mg/kg for females and
96—967 mg/kg for males, Toxicity
Category II
Acute rabbit Dermal LD 50 : >2,000 mg/kg, Toxicity Category III
Acute rat inhalation LD 50 : 3.5 mg/i, Toxicity Category III
Dermal rabbit irritation: Toxicity Category IV
Eye rabbit irritation: data gap
Ecological characteristics—
Hazards to aquatic invertebrates and wildlife:
Avian subacute dietary LCçfl (ppm )
191 for Mallard Ducks
245 for Bobwhite Quail
Avian acute oral LDcO (mg/kg )
3.5 for Mallard Ducks
10 for Bobwhite Quail
These values characterize diazinon as very highly toxic
to birds.
Aquatic invertebrate LCcp
0.079 ppm for bluegill sunfish
0.635 ppm for rainbow trout
0.522 ppb for Daphnia sp .
These values characterize diazinon as very highly toxic
to fish and aquatic invertebrates.
4. Summary of regulatory position and rationale
On January 15, 1986, a FEDERAL REGISTER Notice was published
concerning the Special Review of all pesticide products
containing diazinon registered for use on golf courses and sod
farms. The Special Review was based on the hazard to non—
target birds from diazinon’s use on these two sites. The
Notice announced (1) the initiation of the Special Review on
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these two siteS, (2) the Preliminary Determination proposing
to cancel registrations and deny applications for diazinon
products used on these two sites, and (3) the availability of
the Support Document. The Support Document contained a
risk/benefit analysis, which was the basis for the Agency’s
action.
In evaluating the hazard to birds, the Agency considered
(1) acute toxicity studies which indicated that diazinon is
very highly toxic to birds, (2) residue level and dose estimates
on grass and seed which indicated a potential hazard, and
(3) bird kills reported to the Agency in which diazinon was either
confirmed or implicated as the primary cause. These kills
have involved 23 species of birds and occurred throughout the
country and throughout the year.
The Agency’s concern for the hazard to non—target birds
included a concern for the impact on populations of species
at risk. The Agency reviewed information which indicated
that diazinon caused a reduction of a local population of
Atlantic Brant Geese when applied according to label directions
to a golf course in New York. —
The Agency also reviewed information concerning the
avian and human hazards of the five major alternatives.
Based on a comparative avian hazard assessment, the Agency
determined that the major alternatives are not likely to be
of greater hazard to birds than diazinon. Based on the
available data concerning the hazard to humans, the Agency
determined that the alternatives do not appear to pose a
greater human health hazard than diazinon.
In the Support Document the Agency also reviewed the
benefits of diazinon on golf courses and sod farms. Estimates
indicate that at least 512,000 pounds are used per year on
golf courses and 60,000 pounds on sod farms. The impact of
cancellation that results would be a cost increase of $937,200
for golf courses and $300,000 for sod farms. The Agency
anticipates that these impacts would be minor when compared
to the maintenance cost of $1,900,000,000 for golf courses
and the gross revenue of $210,000,000 on sod farms.
In weighing risks and benefits, the Agency reviewed a
number of options to reduce the risk to birds. However, the
Agency determined that cancellation was the only option that
would •reduce the hazard to birds adequately. The Agency
concluded that the risks outweigh the benefits and proposed
cancellation of all products registered for use on sod farms
and golf courses.
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During the comment period that followed publication of
the FEDERAL REGISTER Notice, the Agency received additional
information on the hazard to birds, which included reports of
26 additional bird kills. These kills once again confirm
that the hazard from diazinon is widespread throughout the
country and throughout the year. In addition the Office of
Endangered S ecies, U.S. Department of the Interior, commented
that certain endangered species could be seriously affected
by the use of diazinon on golf courses and sod farms.
The Agency also received data concerning diazinon residues
on grass and effects on Canada Geese penned on turf. The
data demonstrated that birds foraging on treated turf would
be exposed to lethal diazinon residues within a very short
period of time and that these residues would be high enough
to cause death to foraging waterfowl.
During the comment period the Agency also received
information regarding the benefits of diazinon use, which
included efficacy data on diazinon and its alternatives. The
results indicated that the efficacy of the major alternatives
is about the same as diazinon.
The Office of Pesticide Programs (OPP) transmitted the
Support Document to the Scientific Advisory Panel (SAP) and
the U.S. Department of Agriculture (USDA). The SAP’s comments
supported the Agency’s conclusions concerning the avian
hazard from diazinon application to golf courses and sod
• f arms. The USDA commented that the proposed cancellation
action was premature and could be inappropriate. The FEDERAL
REGISTER Notice responds point—by—point to each of their
comments.
The Agency also received 96 comments during the public
comment period, most of which supported the proposed action.
The Agency carefully reviewed all of the new information
and all of the comments that were submitted. The Agency
still concludes that the hazard to birds from diazinon use on
golf courses and sod farms outweighs the minor benefits and
that cancellation is the only appropriate action.
5. Summary of major data gaps
The Agency is concerned about the hazard to birds from
diazinon use on other sites. The data base is inadequate to
evaluate the hazard on all of the remaining sites at this
time. Consequently, the Agency is requiring the data necessary
to fully evaluate this problem through the reregistration
process. A Registration Standard is scheduled to be completed
by the end of this year.
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6. Contact person at EPA: Ingrid M. Sunzenauer
EPA
Office of Pesticide Programs
Registration Division -(TS—767C)
401 M Street, S.W.
Washington, D.C. 20460
DISCLAIMER: The information in this Chemical Information
Sheet is for informational purposes only and may not be used
to fulfill data requirements for pesticide registration or
reregistration.
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