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Table of Contents

I. Introduction ................................................................................................................................. 3

A. General Background .............................................................................................................. 4

II. Scientific Assessments............................................................................................................... 4

A. Human Health Assessment .................................................................................................... 4

Dietary Exposure Assessment................................................................................................. 4

Food Tolerances ..................................................................................................................... 5

Hazard Characterization and Risk ......................................................................................... 5

Residential and Occupational Exposure................................................................................. 5

B. Environmental Assessment .................................................................................................... 5

Environmental Fate and Exposure ......................................................................................... 5

Ecological Risk Characterization........................................................................................... 5

Threatened and Endangered Species...................................................................................... 6

C. Endocrine Disruptor Screening Program ............................................................................... 6

III. Proposed Interim Registration Review Decision...................................................................... 6

IV. Next Steps and Timeline........................................................................................................... 7
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I. Introduction

This document is the Environmental Protection Agency’s (EPA or the Agency) Proposed 

Registration Review Decision for polybutene resins and is being issued pursuant to 40 CFR 

Sections 155.57 and 155.58. A registration review decision is the Agency's determination 

whether a pesticide meets, or does not meet, the standard for registration in the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA). Among other things, the proposed 

registration review decision states (1) the Agency’s proposed findings with respect to the FIFRA 

standard for registration and describes the basis for such proposed findings; (2) identifies 

proposed risk mitigation measures or other remedies as needed and describes the basis for such 

proposed requirements; (3) states whether additional data are needed and, if so, describes what is 

needed; (4) specifies proposed labeling changes; and (5) identifies deadlines for completing any 

required actions.

FIFRA, as amended by the Food Quality Protection Act (FQPA) of 1996, mandated the 

continuous review of existing pesticides. All pesticides distributed or sold in the United States 

generally must be registered by the EPA based on scientific data showing that they will not cause 

unreasonable risks to human health or to the environment when used as directed on product 

labeling. The registration review program is intended to make sure that, as the ability to assess 

and reduce risk evolves and as policies and practices change, all registered pesticides continue to 

meet the statutory standard of no unreasonable adverse effects to human health or the 

environment. Changes in science, public policy, and pesticide use practices will occur over time. 

Through the registration review program, the Agency periodically reevaluates pesticides to make 

sure that as these changes occur, products in the marketplace can continue to be used safely. 

Information on this program is provided as www.epa.gov/oppsrrd1/registration_review/.

In 2006, the Agency implemented the registration review program pursuant to FIFRA 

section 3(g) and will review each registered pesticide every 15 years to determine whether it 

continues to meet the FIFRA standard for registration.

Pursuant to 40 CFR section 155.50, EPA formally initiated registration review for 

polybutene resins1(case 4076). The following highlights significant events that have occurred 

during the registration review of polybutene resins:

 June 23, 2010 – Publication of Polybutene Resins Summary Document for a 60-day 

public comment period. The Summary Document (PWP) included the preliminary work 

plan and was accompanied by the scoping document and problem formulation.

 November 16, 2010 - Final Work Plan (FWP) for polybutene resins was signed -- no 

public comments were received during the 60-day comment period for the Polybutene 

Resins Summary Document; thus, the FWP did not modify the Summary Document. 

o In the PWP, EPA specifically solicited comments on environmental justice, water 

quality concerns, and trade irritants.

 

1 Also referred to as polybutene.
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o The FWP noted that no additional data were expected to be needed for the 

polybutene resins registration review because sufficient information was available 

to conduct a qualitative risk assessment to support a proposed registration review 

decision, pursuant to 40 CFR section 155.53(b).

 March 12, 2013 – The preliminary risk assessments, Human Health Risk Assessment to 

Support Final Registration Review Decision2and Preliminary Environmental Fate and 

Ecological Risk Assessment in Support of Registration Review of Polybutene3for 

polybutene resins published for a 60-day comment period. No comments were received 

during the comment period.

Additional information on polybutene resins can be found in EPA’s public docket, EPA-HQOPP-2009-0649, accessed at www.regulations.gov.

A. General Background

Polybutene is a sticky polymer registered for use as a bird and small mammal repellent. It 

is formulated as a non-drying liquid or gel that remains sticky after being applied. Polybutene's

tacky quality is the source of the repellent action of pesticide products containing the active 

ingredient. The product therefore differs from typical pesticides in that it is not intended to be 

ingested by the pest species. It was first registered in 1960 for use as an insect control agent and 

is currently registered for use to prevent pigeons, house sparrows, and starlings from roosting 

inside and outside of buildings, as well as to prevent beavers from damaging trees and shrubs. 

Animals that come in contact with surfaces treated with polybutene dislike the sticky sensation 

and usually do not return. Polybutene is registered for commercial and residential use. The 

Reregistration Eligibility Decision document (RED) for polybutene was issued in December, 

1994.4

II. Scientific Assessments

A summary of the Agency’s preliminary human health and environmental fate and 

ecological risk assessments published March 12, 2013 is presented below. For the detailed risk 

assessments, see the polybutene public docket (EPA-HQ-OPP-2009-0649) accessed at

www.regulations.gov.

A. Human Health Assessment

Dietary Exposure Assessment

There are no registered food/feed uses and existing use patterns are not expected to 

contaminate surface or ground water; thus, a dietary exposure assessment was not conducted.

 

2 Located at http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2009-0649-0011. 

3 Located at http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2009-0649-0010. 

4 Located at http://www.epa.gov/oppsrrd1/REDs/4076.pdf. 
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Food Tolerances

Polybutene is exempt from the requirement of a tolerance when used as a sticker agent in 

packaging of insect control products used on food crops.

Polybutene is approved by the US Food and Drug Administration (FDA) as an indirect 

food additive and is used as an ingredient in cosmetic products that are applied directly to the 

skin such as sun block or moisturizer, and that may be incidentally ingested, such as lipstick. The 

use of polybutene in cosmetic products is considered safe, according to a review of available 

toxicity information by the Cosmetic Ingredient Review5(CIR) Expert Panel report6.

Hazard Characterization and Risk

The toxicological database was considered adequate for characterizing hazard and 

assessing risk from polybutene. No additional studies were required for registration review. No 

toxicological endpoints of concern were identified for dermal or inhalation exposure to 

polybutene.

Residential and Occupational Exposure

Although the registered end-use products of polybutene are intended for professional and 

commercial application, there are no restrictions limiting their use by homeowners. Therefore, 

both residential and occupational applicator and post-application exposures were considered in 

the assessment. Although exposure may occur during application of these products, quantitative 

exposure assessments were not performed for polybutene because dermal or inhalation endpoints 

of concern were not identified.

B. Environmental Assessment

Environmental Fate and Exposure

Polybutene is a highly stable, viscous, and extremely insoluble inorganic material. 

Because of its extremely low solubility, and application methods that would produce little-to-no 

spray drift, polybutene is not expected to be transported to aquatic environments in significant 

amounts. Any leaching to ground water is also expected to be negligible. Since aquatic exposure 

is expected to be negligible, no aquatic exposure or drinking water exposure assessment was

conducted when evaluating the pesticidal uses of this chemical. Polybutene is also expected to be 

immobile in the terrestrial habitats. Therefore, exposure to terrestrial plants and animals is 

expected to be limited to the immediate treatment site.

Ecological Risk Characterization

Considering the low toxicity observed in birds and mammals, and the lack of any known 

toxic mode of action to aquatic species, any potential exposure to polybutene through direct 

contact or ingestion is expected to have negligible toxicological effects. Furthermore, because of 

 

5 The Cosmetic Ingredient Review was established in 1976 by the industry trade association (then the Cosmetic, 

Toiletry, and Fragrance Association, now the Personal Care Products Council), with the support of the U.S. Food 

and Drug Administration and the Consumer Federation of America. Although funded by the Council, CIR and the 

review process are independent from the Council and the cosmetics industry. More information is available at 

http://www.cir-safety.org/about. 

6 Cosmetic Ingredient Review: Final Report on the Safety Assessment of Polybutene. J. Am. Coll. Toxicol. 

1(4):103-118, 1982.
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the very low solubility of polybutene, the amount of dissolved residues in aquatic environments 

is expected to be negligible, far below levels that might be toxic to aquatic organisms.

The use of polybutene is not expected to result in any significant risk to terrestrial 

wildlife through any toxic mode of action, but may pose some limited hazard to small wildlife 

species that may become entangled or entrapped in the product. Furthermore, product labels limit 

application to times that are less attractive to invertebrates (such as prohibiting applications to 

woody plants while they are in bloom). Exposure to terrestrial plants is expected to be minimal,

being limited to the plants that are directly treated with the product, or that lie immediately 

beneath treated plants. In addition, the use of polybutene is not believed to cause any significant 

damage to terrestrial plants even when directly exposed.

Threatened and Endangered Species

There is no reasonable expectation for any registered use of polybutene repellents to 

cause direct or indirect adverse effects to threatened and endangered species. No adverse 

modification of any designated critical habitat for such species is expected from the use of 

polybutene. This is because the treated area is very small relative to the range of species, most of 

the product use is expected to occur outside of areas inhabited by listed species, and the viscosity 

and very low solubility of polybutene makes it unlikely to runoff or leach from the target 

application site into non-target areas. Furthermore, since polybutene is an effective physical 

repellent, listed animals are generally expected to avoid treated application sites. EPA has made

a “no effect” determination under the Endangered Species Act (ESA) for all listed species and 

designated critical habitat for such species and has therefore concluded that consultation with the 

Fish and Wildlife Service and the National Marine Fisheries Service under ESA section 7(a)(2) 

is not required.

C. Endocrine Disruptor Screening Program

Pursuant to FFDCA Section 408(p)(4), EPA has exempted polybutene from the 

requirements of the EDSP in an Administrative Order entitled Exemption of Polybutene from the 

Requirements of the Endocrine Disruptor Screening Program, April 11, 2014. The Order is

available in the docket for this registration review at EPA-HQ-OPP-2009-0649. The 

Administrative Order describes the analysis and rationale that the Agency used to evaluate 

polybutene in order to determine that it qualifies for the exemption.

III. Proposed Registration Review Decision

In accordance with 40 CFR Sections 155.57 and 155.58, the Agency is issuing this 

Proposed Registration Review Decision document. The Agency has made the following

proposed decision: (1) no additional data are required at this time; and (2) no changes to the 

affected registrations or their labeling are needed at this time. In addition, EPA does not expect 

polybutene to have direct or indirect adverse effects to non-listed and listed species or to 

adversely modify any designated critical habitat for such species and has made a “no effect” 

determination under the Endangered Species Act for all listed species and designated critical 

habitat for such species. Further, EPA has determined that due to the chemical structure of 

polybutene, it is exempt from the EDSP requirement. EPA’s Proposed Registration Review 

Decision determination for polybutene is that the pesticide meets the standard for registration 

under FIFRA.
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IV. Next Steps and Timeline

A Federal Register Notice will announce the availability of this Proposed Registration 

Review Decision for polybutene and allow a 60-day comment period. If there are no significant 

comments or additional information submitted to the docket during the comment period that 

leads the Agency to change its decision, EPA will issue its Registration Review Decision for 

polybutene (case 4076).