United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-95-008
January 1995
R.E.D. FACTS
Pesticide
Reregistration
Use Profile
Polybutene
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 reregi strati on, 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 reregi strati on, EPA announces this and
explains why in a Reregistration Eligibility Decision (RED) document. This
fact sheet summarizes the information in the RED document for reregi strati on
case 4076, polybutene.
Polybutene is a non-drying, sticky polymer which is registered for use
as a bird and squirrel repellent. When birds land on treated objects or
surfaces, they dislike the unpleasant sticky sensation and usually do not
return. Polybutene's sticky quality therefore is the source of the repellent
action of pesticide products containing this active ingredient.
Polybutene products may be used outdoors or indoors, on buildings or
adjacent structures (for example, on girders, beams, ledges, windowsills,
gutters, trees, shrubs, and vines) where birds land or roost. Formulations
include a gel which is applied as a bead strip to surfaces with a ready-to-use
tube or caulking gun, and a liquid concentrate which is applied with a paint
brush or sprayed on using a hand or pressure sprayer.
Use practice limitations include prohibitions against applying the
product to surfaces where small protected bird species may become
entrapped, or where people walk or stand; and against applying the product in
wet, damp, or freezing conditions.
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Regulatory
History
Polybutene has been registered in the U.S. since 1960 as an insect
control agent, since 1963 as a bird repellent, and since 1967 as a tree squirrel
repellent. The insect repellent uses were deregulated because their mode of
action is more to trap than to repel insects. A Data Call-In notice issued in
July 1993 required only minimal studies to complete the database for
reregi strati on. Currently, six polybutene pesticide products are registered.
Human Health
Assessment
Toxicity
Polybutene generally is of relatively low acute toxicity. It has been
placed in Toxicity Categories III and IV respectively for acute dermal and
oral effects (these are the lowest of four categories, indicating the lowest
degree of acute toxicity). Polybutene is not irritating to the skin (Toxicity
Category IV), but is irritating to the eyes and has been placed in Toxicity
Category II for eye irritation effects.
Polybutene is not mutagenic in studies available at this time. Additional
information is required on an Ames study to upgrade it to an acceptable level.
Dietary Exposure
Dietary exposure to polybutene is not expected since no food-related
uses are registered.
Occupational and Residential Exposure
The potential for exposure to workers (mixers, loaders and applicators)
is low when using polybutene products in accordance with label instructions.
The potential for post-application exposure is minimal, based on polybutene's
use patterns.
Human Risk Assessment
Polybutene generally is of low acute toxicity but causes eye irritation
(Toxicity Category II). No other toxicological endpoints are of concern for
workers or homeowners exposed to polybutene.
No food-related uses are registered so dietary exposure is not of
concern. Worker exposure is low when products are used in accordance with
approved labeling. Risk to workers and homeowners from exposure to
polybutene is expected to be negligible.
Environmental
Assessment
Environmental Fate
Polybutene is a highly stable polymeric substance which is resistant to
physical or chemical change due to aging or temperature. The Agency
imposed no environmental fate data requirements for reregi strati on of
polybutene because of its physical properties and use patterns. The hydrolysis
data requirement was waived based on the limited environmental exposure
that results from its use.
Ecological Effects
Because of its properties and use patterns, honey bees, small mammals,
aquatic organisms, and other wildlife are not likely to ingest or otherwise be
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exposed to significant amounts of polybutene. Many of the studies usually
required for reregi strati on therefore have been waived.
Polybutene is practically nontoxic to birds on an acute oral and a
subacute dietary basis. It also is practically nontoxic to small mammals on an
acute basis.
Attempts to conduct acute toxicity studies with the rainbow trout and
Daphnia magna were thwarted by the test material, which was insoluble and
formed a surface slick in the test vessel, resulting in unacceptably low levels
of dissolved oxygen. After all appropriate means of increasing the solubility
of polybutene were exhausted, EPA waived the requirements for freshwater
fish and aquatic invertebrate toxicity studies.
Ecological Effects Risk Assessment
Based on the nature of polybutene, toxic exposure to birds is not likely.
However, birds whose feathers contact the sticky material may become
temporarily entrapped, or their feathers may become coated with gel. When
such incidents occur they can be fatal, but usually involve only one or several
birds at a time. Risk to many nontarget, small birds probably is alleviated by
the fact that polybutene products are used primarily in/on urban commercial
and industrial buildings where small birds protected by the Federal Migratory
Bird Treaty Act are unlikely to be found.
EPA is concerned that the liquid formulation of polybutene poses some
risks to small nontarget bird species. The liquid product can be sprayed to the
point of runoff on trees, shrubs, bushes, vines, etc., where a variety of small,
legally protected bird species could be present. The Agency's concern is
lessened somewhat, however, because the liquid formulation generally is
available to and applied by commercial applicators.
EPA does not anticipate any undue risks to wild mammals or aquatic
animals from use of polybutene. Due to polybutene's nature and consistency,
mammals are unlikely to consume this material. Because polybutene is
insoluble, contamination of water bodies is not expected to occur.
In the future, when EPA implements the Endangered Species Protection
Program, the use of polybutene may be limited to protect endangered and
threatened species. However, these limitations have not yet been defined.
Risk MitiqatJOn EPA is requiring the following risk mitigation measures for polybutene,
as discussed earlier:
Because of the Agency's concern for potential harm to non-target birds,
especially small birds covered by the Federal Migratory Bird Protection
Treaty Act, a warning statement clarifying this risk is required to appear on
polybutene labels.
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Additional Data
Required
Product Labeling
Changes Required
EPA considered classifying the polybutene liquid product as a
Restricted Use Pesticide, to be applied only by trained, certified applicators.
However, this product already is sold through commercial channels and
generally is not available to retail customers and homeowners. It is sold only
in one gallon units and generally is applied using equipment that is not used
by homeowners. The Agency decided, therefore, that adding a Restricted Use
Pesticide classification would have little impact on reducing risk to non-target
species.
The generic data base supporting polybutene is substantially complete.
Additional information is required only to upgrade a mutagenicity study.
EPA also is requiring product-specific data including product chemistry and
acute toxicity studies, revised Confidential Statements of Formula (CSFs),
and revised labeling for reregi strati on.
All polybutene end-use products must comply with EPA's current
pesticide product labeling requirements, and with the following:
Environmental Hazards - All polybutene products must bear the following
statement in the Environmental Hazards section of the label:
"Small birds may become fatally entrapped by this tacky repellent. To
reduce hazards to legally protected species, and to avoid noncompliance
with the Federal Migratory Bird Treaty Act, follow all instructions in
the Directions For Use."
Worker Protection - All currently registered products containing polybutene
are outside the scope of the Worker Protection Standard for Agricultural
Pesticides (WPS). The personal protective equipment required for products
that contain polybutene will be determined by the toxicity of the end-use
product.
The Agency is requiring the following statement on the label of the
liquid formulation product:
"Do not apply liquid products in a way that will contact workers or
other persons, either directly or through drift. Only protected handlers
may be in the area during application."
Regulatory
Conclusion
Currently registered pesticide products containing the active ingredient
polybutene, labeled and used as specified in the RED document, will not pose
unreasonable risks or adverse effects to humans or the environment.
Therefore, all uses of these products are eligible for reregi strati on. Products
containing polybutene will be reregistered once the required product specific
data, revised Confidential Statements of Formula, and revised labeling are
received and accepted by EPA.
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For More
Information
EPA is requesting public comments on the Reregi strati on Eligibility
Decision (RED) document for polybutene 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.
Electronic copies of the RED and this fact sheet can be downloaded
from the Pesticide Special Review and Reregi strati on Information System at
703-308-7224. They also are available on the Internet on EPA's gopher
server, GOPHER.EPA.GOV, or using ftp on FTP.EPA.GOV, or using WWW
(World Wide Web) on WWW.EPA.GOV.
Printed copies of the RED and fact sheet can be obtained from EPA's
National Center for Environmental Publications and Information
(EPA/NCEPI), PO Box 42419, Cincinnati, OH 45242-0419, telephone 513-
489-8190, fax 513-489-8695.
Following the comment period, the polybutene RED document also 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 reregi strati on program, the
polybutene RED, or reregi strati on of individual products containing
polybutene, please contact the Special Review and Reregi strati on 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, between 8:00 am and 6:00 pm Central Time, Monday
through Friday.
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