UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
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Environmental News
O'Neill (202) 755-0344
FOR IMMEDIATE RELEASE MONDAY, JANUARY 7, 1974
EPA RELEASES INFORMATION ON FIELD STUDIES OF RODENTICIDES
The Environmental Protection Agency has Is9ued a sum-
mary statement on field studies it will initiate this year
to provide additional information on the effect of certain
rodent control products on non-target animals, such as the
American golden eagle, the kit fox, and the black-footed
ferret.
The rodenticides to be studied are those containing the
compounds calcium cyanide, strychnine, sodium monofluoro-
acetate (1080) and sodium cyanide. There are presently
registered with EPA for use in this country some 130 rodenti-
cides containing these compounds which are used to control
gophers, moles, and other rodent pests in the field, home
and urban areas.
The lack of hard scientific data on the environmental
impact of these products was part of the reason EPA recently
withdrew its intent to hold public hearings on whether cur-
rent uses of these products should be continued, cancelled
or somehow amended. (See December 7, 1973 Federal Register.)
A copy of the field studies summary is attached.
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EPA FORM 1810*1 (*EV, 8-72)
R-312

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Another study evisioned involves key questions on the
safety of strychnine baits on such wildlife species as the
burrowing owl, horned larks and other small birds normally
in the vicinity of ground applications of poisoned grain baits
used for the control of ground squirrels, prairie dogs, or other
rodents. These studies probably would not require radio-tele-
metry because of the rapidity with which strychnine acts, but
would require observations by trained field biologists. Place-
ment of bait by hand as well as by cyclone seeders is planned.
Other field studies will deal with 10 80 and strychnine upon
selected sensitive nontarget wildlife species. Study of certain
rare and endangered species such the California condor, American
golden eagle, and the black-footed ferret are believed to be
impractical for several reasons.
For example, risking the estimated 60 California condors
left in existence by toxicant research itself seems highly
undesirable. However, alternate species of even greater sensi-
tivity to these rodenticides but which are not endangered as a
species will be studied for this purpose.
Past field experience with cyanides, which as rodenticides
are used primarily to fumigate burrows, suggests that the appli-
cator is present during the time that the poison is released.
Only the species actually in the burrow is affected; any non-
target species are scared away by the presence of the applica-
tor. It is not thought that the cyanides remain in the general
environment after this type of rodenticide application in
quantities sufficient to cause other poisonings after the
applicator ha^ left the area. For this reason, EPA will attach
a higher priority to the field study of strychnine and 10 80
although we will continue to review new information on cyanides
as it appears in the literature.
Economic studies by EPA staff economists are continuing
in order to locate and develop further data to determine if need
and/or benefits derived from the rodenticides are sufficient to
justify their continued use. Further staff efforts are being
directed to defining hazards to man, his pets, and domestic
animals.
~Prepared by the Office of Pesticide Programs of the Office of
Hazardous Materials Control, Environmental Protection Agency..
December 19 73

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FIELD STUDIES WITH RODENTICIDES*
Over the last several months, EPA has held a series of
informal hearings on the use of 10 80, strychnine, calciuiu
cyanide, and sodium cyanide as rodenticides. The hearings
were held with a view toward gathering hard scientific data
which would support an informed decision on either the con-
tinued use or the cancellation of these chemicals as rodenti-
cides . After a review of the testimony presented at these
hearings, and an intensive EPA investigation of elsewhere
available scientific data, the Agency has concluded that
sufficient scientific information does not presently exist
to allow the Administrator to make a balanced and informed
decision. Accordingly, the Deputy Administrator issued a
Determination and Order on December 3 withdrawing the formal
hearings which were scheduled to begin in mid-December. EPA
is initiating a series of field studies on the wildlife effects
of these compounds in an attempt to remedy these data deficiencies.
The Environmental Protection Agency intends to undertake
this program of field investigations on rodenticides to clarify
some of the questions related to the unintentional poisoning of
wildlife species. In the laboratory, toxicity studies have
shown the theoretical possibilities of such unintentional
poisoning of several desirable wildlife species, such as the
San Joaquin kit fox, the black-footed ferret, and the American
golden eagle, by the use of compound 1080. Similarly, strychnine
grain baits have been shown in the laboratory to be more than
toxic enough to kill desirable species such as the burrowing owl
and numerous other avian species. In contrast to the carefully
controlled laboratory experiments, however, much of the field
data available are considered to be contradictory or unreliable
because some extraneous factor(s) frequently occurred that altered
the ecological vulnerability of the species to the pesticide.
The Agency plans to conduct field studies to gain information
on the following questions: Can operational (field) use of com-
pound 10 80 for rodent control produce mortality among nontarget
wildlife species by either primary or secondary poisoning?
Would these poisonings happen if the ground or aerial applications
of the pesticide were conducted according to officially accepted
procedures? Can operational use of strychnine in grain baits by
officially accepted rodent control procedures produce mortality
among nontarget wildlife species?
The Agency plans to conduct either through contract or
preferably, through interagency agreements, several studies in
19 74. If warranted, studies may continue into 19 75. One such
study being considered involves aerially applied compound 1080
for ground squirrel control and the observation of its effect
on the kit fox. A radio telemetering technique will probably
be used so as to obtain the most reliable data.

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