UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

SEP 2 0 2011 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile for Registration Review: Tetramethrin (PC Code: 

069003) 

FROM: 

THRU: 

TO: 

Nikhil Mallampalli, Entomologist 

Biological Analysis Branch 

Rafael A. Prieto, Environmental Protection S~~ J A· . Science Information and Analysis Branch f //'f yv . 

Elizabeth Hill, Economist 

Economic Analysis Branch 

Biological and Economic Analysis Division (7503P 

Arnet Jones, Chief /),../ } 

Biological Analysis Brancl~ 

Diann Sims, Chief ~ 1 . Science Information and Analysis Branch 

Timothy Kiely, Chief 91 ~. 1

0 

Biological 

Economic Analysis 

and Economic 

Branch 

Analysis ivision (7503P) 

~ 

Monica Wait, Chemical Review Manager 

Risk Management and Implementation Branch 3 

Pesticide Re-evaluation Division (7508P) 

BEAD Product Review Panel date: August 24, 2011 

INTRODUCTION 

The purpose of this document is to convey usage information and a broad overview of the pest 

management roles of pesticides that are beginning to undergo registration review. The 

anticipated audience consists of the team of EP A staff currently evaluating the registration status 

of tetramethrin, and eventually the general public. This document builds upon the data already 

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provided in the "Usage and Label Use Data Packages" that are also provided to Registration 

Review teams by BEAD. However, for tetramethrin the usage and label use package will be 

provided at a later stage of registration review because product reregistration is ongoing, and all 

product labels are expected to be revised as a result of that process. The document is based on 

information and data available to BEAD as of August 2011. 

Tetramethrin was the subject of an Agency Reregistration Eligibility Decision (RED) in 2008, 

and the RED was amended in April 2010 (go to 

http://www.epa.gov/oppsrrd1IREDs/tetramethrin-revised-red.pdffor the document). To quote the 

RED: "tetramethrin is part of the pyrethroid class of pesticides and was first registered in 1968. It 

is a broad spectrum, non-systemic, synthetic pyrethroid used to control flying and crawling 

insects in a number of commercial, horticultural and residential applications." 

The Insecticide Resistance Action Committee (IRAC), comprised of technical personnel from 

various large agrochemical and public health companies, classifies tetramethrin as a member of 

the Mode of Action Group 3 (subgroup 3A). This group of insecticides acts as sodium channel 

modulators, thus causing disruption of nerve impulses in the target insects. All pyrethroids 

"initially stimulate nerve to produce repetitive discharges and subsequently cause paralysis" 

(Narahashi, 1976). Like other compounds derived from the chemical structure of pyrethrum, it is 

most toxic to the target pest on contact, and has a quick "knockdown" effect, which is the initial 

paralysis and quick intoxication caused by nerve stimulation (Doull 1976). Tetramethrin is 

sometimes formulated with a synergist compound, usually piperonyl butoxide (PBO) or MGK264, to extend its active life and increase its toxic effect on target insects (Jones 1998). It is also 

sometimes formulated with pyrethrins or synthetic pyrethroids for the same purpose. 

USE SITES 

This information was summarized well in the amended RED and that list has not changed. To 

quote the relevant text from the amended RED document: 

"Commercial [uses] include space sprays, broadcast surface treatments, and crack and crevice 

treatments in a variety of industrial and institutional sites including: indoor non-food areas; 

animal premises (not used for human consumption); and outdoors as localized space and contact 

sprays on ornamental plants and perimeter treatments (sidewalks, entranceways, outside surfaces 

of buildings, etc.). 

Residential uses include: pest control in homes as a space spray, general surface spray, spot and 

crack and crevice applications, on house plants, clothing and bedding, pet premises, and direct 

applications to pets. [In the residential use context] outdoors it is used as localized space and 

contact spray on ornamental plants and perimeter treatments (sidewalks, decks, patios, outside 

surfaces of buildings, etc.). 

Horticultural [uses] include foliar and fogger treatment on non-food plants. There are no 

registered food use applications for tetramethrin." 

COMMON FORMULATIONS AND APPLICATION METHODS 

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Tetramethrin products are formulated as emulsifiable concentrates, pressurized gases and liquids, 

and ready-to-use solutions. These products are applied as a crack and crevice treatments, surface 

treatments, aerosols, fogs, and sprays. 

USAGE 

BEAD has very limited usage data for tetramethrin. Tetramethrin is active against most insects 

upon contact; the labeled uses suggest that urban and nuisance pests such as cockroaches, wasps, 

flies, and ants are frequent targets of use. In 2005, the most recent year for which BEAD has 

data, approximately 310,000 lb of tetramethrin was used by consumers of indoor residential 

treatments. Data for earlier or more recent years were not available to EPA. Usage was not 

reported in the available reports on food handling establishments; however, usage may be 

occurring below the reporting threshold. (Kline and Company 2005). 

BIOLOGICAL ASPECTS RELEVANT TO TETRAMETHRIN 

Tetramethrin is among the earliest synthetic pyrethroids developed (Casida 1980). While 

tetramethrin has better powers of knockdown than other older pyrethroids such as pyrethrins or 

allethrin, it has only about "equal powers of killing" as these materials (Incho 1970). Like these 

older pyrethroids, tetramethrin is also susceptible to quick degradation in sunlight (Soderlund 

2008). Given its short-lived residual activity, it is perhaps not surprising that usage of 

tetramethrin is currently low and apparently largely limited to indoor settings. Newer 

pyrethroids, such as deltamethrin, bifenthrin, and cyfluthrin have taken over agricultural markets 

once dominated by early pyrethroids, since the newer products are much less photo-labile 

(Casida 1980, Soderlund 2008). 

Due perhaps to its long history of use, resistance has been reported in the scientific literature for 

a number of insects in the U.S.A. and globally. For example, the Arthropod Pesticide Resistance 

Database maintained by Michigan State University (on the web at 

http://www.pesticideresistance.orgQliststheGermancockroach.chicken mite, cotton bollworm, 

and common housefly as showing confirmed resistance both within the U.S. and in other 

countries. It is not clear to BEAD exactly how quickly or widely resistance to tetramethrin, 

,specifically, spreads in pests, or how persistent it is. However, resistance problems may also be a 

factor in the apparently low usage of tetramethrin that is suggested by the limited data BEAD has 

available. 

HISTORY OF BEAD ASSESSMENTS FOR TETRAMETHRIN 

BEAD's Official Records indicate no formal assessments on tetramethrin were conducted. The 

EPA Section 18 Action Database also indicates that no Section 18 requests were made for the 

use of this chemical (EPA, 2011). 

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DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ON TETRAMETHRIN 

Obtaining additional information on the following items would improve future BEAD 

assessments of the importance of tetramethrin and may be required as part of the registration 

review of this pesticide. 

1) Usage data (pounds AI applied and area treated) for indoor/outdoor consumer use, use in 

food handling establishments/food processing establishments, and use in and around 

commercial and institutional facilities. 

2) Usage data (pounds AI applied and area treated) for horticultural plant production. 

REFERENCES 

Casida. J. 1980. Pyrethrum Flowers and Pyrethroid Insecticides. Environmental Health 

Perspectives Vol. 34, pp. 189-202. 

Doull, J. 1976. The Treatment of Insecticide Poisoning. Ch. 16 in: C.F. Wilkinson (ed.), 

Insecticide Biochemistry and Physiology. 753 pp. Plenum Press, New York. 

Environmental Protection Agency (EPA). 2011. Section 18 Action Database. Located at: 

http:// cfpub l.epa. gov / oppref/section 18/search.cfm 

Incho, H.H. 1970. New insecticide for aerosols. Soap & Chemical Specialties Vol. 46 (2): 37-

40. 

Jones, D.G (ed.). 1998. Piperonyl Butoxide: The Insecticide Synergist. 323 pp. Academic Press, 

San Diego, CA. 

Narahashi, T. 1976. Effects of Insecticides on Nervous Conduction and Synaptic Transmission. 

Ch. 9 in: C.F. Wilkinson (ed.), Insecticide Biochemistry and Physiology. 753 pp. Plenum 

Press, New York. 

Soderlund, D. 2008. Pyrethroids, knockdown resistance and sodium channels. Pest Manag. Sci. 

64: 610-616. 

Kline and Company, Inc. 2005. 

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