United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-94-008
June 1994
R.E.D. FACTS
Pesticide
Reregistration
N6-Benzyladenine
All pesticides sold or distributed 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, describing 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 unreasonable risks to human health or the environment.
When a pesticide is eligible for reregistration, EPA announces this and
explains why in a Reregistration Eligibility Decision (RED) document. This
fact sheet summarizes the information in the RED for reregistration Case
2040, N6-Benzyladenine.
N6-Benzyladenine is a plant growth regulator used on certain fruit and
white pine trees, calla lily tubers, and spinach grown for seed. It enhances
the size and shape of fruit, lateral bud break and lateral shoot growth,
leading to improved branching in fruit trees and fuller white pine trees. It
causes an increase in the number of calla lily flowers while decreasing time
lag between first and second flowering. It also causes uniform bolting and
increased seed production in spinach. N6-Benzyladenine is
formulated as a soluble concentrate/liquid, and is applied using spray,
brush-on and sponge-on techniques.
Regulatory N6-Benzyladenine was first registered as a pesticide in the U.S. in
History 1979. 1° January 1990, EPA classified it as a biochemical pesticide because
it resembles natural plant growth regulators and uses a non-toxic mode of
action. Currently, three products are registered and there are two Special
Local Need registrations.
Use Profile
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Human Health Toxicity
AsS6SSm6nt In acute toxicity studies, N6-Benzyladenine is slightly toxic by the oral
route and produces moderate eye irritation; it has been placed in Toxicity
Category III (the second-to-lowest of four categories) for these effects. It is
of relatively low acute dermal and inhalation toxicity, and is only a slight
irritant to the skin; it has been placed in Toxicity Category IV for these
effects. N6-Benzyladenine does not appear to be a skin sensitizer or
mutagenic.
In a subchronic toxicity study using rats, N6-Benzyladenine caused
decreased food consumption, decreased body weight gain, increased blood
urea nitrogen, and minimal changes in kidney tissue. It shows some
evidence of causing developmental toxicity and maternal toxicity.
Dietary Exposure
Although N6-Benzyladenine has two food crop-related uses (on fruit-
bearing apple trees and spinach grown for seed), it is exempt from the
requirement of a tolerance because it is a biochemical pesticide used at a
rate of less than 20 grams of active ingredient per acre. Therefore, the
Agency will revoke the existing tolerance and establish an exemption from
the requirement of a tolerance for the currently registered uses of this
pesticidal compounds on apples and spinach.
Because the use rate is low and application precedes harvest by
approximately four months, the potential for dietary exposure is considered
to be negligible.
Occupational and Residential Exposure
Pesticide workers (mixers, loaders and applicators) may be exposed to
N6-Benzyladenine during application. Dermal exposure is expected to be
moderate to high for workers who open, pour, mix and load the pesticide,
and to applicators using hand sprayers and air blast equipment.
To reduce worker exposure, EPA is requiring use of the personal
protective equipment (PPE) and Restricted Entry Interval set forth in the
Agency's Worker Protection Standard (WPS). Because formulated products
that contain N6-Benzyladenine are in Toxicity Category II, use of the
following PPE is required: long-sleeved shirt and pants, socks, chemical-
resistant footwear, chemical-resistant gloves, respiratory protection devices,
and protective eyewear. Although the PPE requirement is based on the
acute toxicity of the end-use product, it will mitigate exposure substantially
and thus will serve to protect pesticide handlers from potential
developmental toxicity effects. Further, the Restricted Entry Interval of 12
hours set forth in the WPS will be required, reducing the risks of post-
application exposure to N6-Benzyladenine.
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Human Risk Assessment
N6-Benzyladenine is of moderate to relatively low acute toxicity, but
has been demonstrated to cause developmental toxicity and maternal toxicity
in laboratory animals. The potential for dietary exposure is negligible.
Applicator exposure and risk of developmental and maternal toxicity will be
reduced through use of personal protective equipment (PPE) and the
Restricted Entry Interval (REI) set forth in the Worker Protection Standard
(WPS).
Environmental
Assessment
Additional Data
Required
Product Labeling
Changes Required
Environmental Fate
Environmental fate studies were not required for N6-Benzyladenine
because it is a biochemical pesticide. Soil metabolism studies indicate that it
has a half-life of 7 to 9 weeks.
Ecological Effects
N6-Benzyladenine does not cause adverse effects to nontarget avian or
aquatic species. It is practically nontoxic to birds, and slightly toxic to fish
and freshwater invertebrates.
Ecological Effects Risk Assessment
Use of N6-Benzyladenine is not expected to pose a significant risk to
terrestrial or aquatic organisms. Further, no risk to endangered species is
anticipated.
EPA is requiring several generic studies as confirmatory information,
including additional data for analysis of samples, a dermal sensitization
study, and a mutagenicity study.
The Agency also is requiring product-specific data including product
chemistry and acute toxicity studies, as well as revised Confidential
Statements of Formula (CSF) and revised labeling for reregistration.
All N6-Benzyladenine end-use products must comply with EPA's
current regulations and labeling requirements, and the following:
Worker Protection Standard (WPS) - All N6-Benzyladenine products
within the scope of the Worker Protection Standard (WPS) for Agricultural
Pesticides (see PR Notice 93-7) must, within the timeframes listed in PR
Notices 93-7 and 93-11, revise their labeling to be consistent with the WPS,
as directed in those notices and the requirements of the RED.
Restricted Entry Interval (REI) - The 12 hour REI set forth in the WPS is
required. Labels must bear this Reentry Restriction:
- Do not enter or allow worker entry into treated areas during the
restricted entry interval (REI) of 12 hours.
Personal Protective Equipment (PPE) Requirements - Pesticide handlers
must wear:
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—coverall over short sleeved shirt and short pants;
—chemical-resistant gloves;
—chemical-resistant footwear plus socks;
—chemical-resistant headgear for overhead exposure;
—respiratory protection devices;
—protective eyewear
—chemical-resistant apron when cleaning equipment, mixing, or
loading.
RGQLllatory The use of currently registered pesticide products containing
Conclusion N6-Benzyladenine in accordance with approved labeling will not pose
unreasonable risks or adverse effects to humans or the environment.
Therefore, all uses of these products are eligible for reregistration.
These products will be reregistered once the required confirmatory
generic data, product specific data, Confidential Statements of Formula and
revised labeling are received and accepted by EPA.
Products which contain active ingredients in addition to
N6-Benzyladenine will be reregistered when all of their other active
ingredients also are eligible for reregistration.
For MOTG EPA is requesting public comments on the Reregistration Eligibility
Information Decision (RED) document for N6-Benzyladenine 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 document or to submit written
comments, please contact the Pesticide Docket, Public Response and
Program Resources Branch, Field Operations Division (7506C), Office of
Pesticide Programs (OPP), US EPA, Washington, DC 20460, telephone
703-305-5805.
Following the comment period, the N6-Benzyladenine RED document
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 EPA's pesticide reregistration program,
the N6-Benzyladenine RED, or reregistration of individual products
containing N6-Benzyladenine, please contact the Special Review and
Reregistration Division (7508W), OPP, US EPA, Washington, DC 20460,
telephone 703-308-8000.
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, from 8:00 am to 6:00 pm Central Time, Monday
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through Friday.
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