UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

APR 2 8 2014 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile (BCP) for Registration Review: Dipropyl 

isocinchomeronate (PC Code 04 7201) 

FROM: David 

Biological 

Brassard, 

Analysis 

Entomologist 

Branch 

) ~ ~ 

/ 

Sepehr Haddad, Environmental Protection Specialist ( ft ~ ,{, ' · 

Science Information and Analysis Branch Vf- ~~ 

Economic 

Michelle Ranville, 

Analysis 

Economist 

Branch V 

I f(\f 

~,_A__./ 

~ 

Biological and Economic Analysis Division (7503P) 

THRU: Arnet Jones, Chief /) · ,ri;;)l/'11'."""~ Biological Analysis Bran~-f 

DiannSims,ChiefA-~ f 0 .. /:n-4-/ 

Science Information and Analysts Branch ,. 

Timothy Kiely, Chief r\_ lA ~:Q, Economic Analysis Branch '-J_ ) _ V\1\J 1 

Biological and Economic Analysis Division ( 3P) 

TO: Molly Clayton, Chemical Review Manager 

Risk Management and Implementation Branch III 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel date: April 9, 2014 

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SUMMARY 

Dipropyl isocinchomeronate or Morpel® Repellent 326 (formerly MGK® Repellent 326) is 

never used as the sole active ingredient (a.i). Rather, it is used to expand the spectrum of 

repellency of other formulation components. For instance, when found in products intended for 

use on humans, dipropyl isocinchomeronate is always combined with DEET (N,N-diethyl-mtoluamide) and MGK® 264 at or below a concentration of2.5 percent by weight. Application 

methods include aerosols or towelettes. For companion animal use, dipropyl isocinchomeronate 

is used at a concentration of 4 percent for dip applications to dogs and cats and spray and 

towelettes products at a concentration from 0.2 to 1.0 percent that are applied to horses 

(Vertellus Specialities, Inc., 2014). 

INTRODUCTION 

The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an 

overview of the pest management roles and quantitative usage information for dipropyl 

isocinchomeronate. The BCP includes summaries of previous BEAD products and available 

public and/or private use and usage data for dipropyl isocinchomeronate to describe the role of 

this chemical in pest management. Additional information on use is available in the dipropyl 

isocinchomeronate LUIS Reports posted in the registration review public docket. Information 

provided in this BCP may be used by stakeholders (e.g., users and registrants), OPP risk 

assessors, OPP risk managers, and the general public during the Registration Review process of 

this pesticide. 

USE SITES 

Agricultural Use Sites 

There are no agricultural uses for dipropyl isocinchomeronate. 

Non-agricultural Use Sites 

Registered non-agricultural use sites for dipropyl isocinchomeronate include indoor non-food 

(i.e., pet living/sleeping quarters) and residential use (i.e., repellents for humans and companion 

animals). 

FORMULATIONS AND APPLICATION METHODS 

Application methods include aerosols and towelettes for humans, and dip and spray for 

application to cats and dogs, and spray and towelettes for horses. Application rates for insect 

repellent products are applied on an "as needed" basis for human and companion animal uses. 

IDSTORY OF DIPROPYL ISOCINCHOMEROATE AND BEAD PRODUCTS 

Dipropyl isocinchomeronate was initially registered by the USDA in 1957 as an insect repellent 

for livestock. Tolerances were established for meat and milk and are found in 40 CFR § 

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180.143. However, in 1993, McLaughlin Gormley and King Company, the technical registrant, 

elected to voluntarily cancel use on livestock intended for slaughter, which resulted in the 

chemical being limited to indoor non-food (i.e., pet living/sleeping quarters) and residential use 

(i.e., repellents for humans and companion animals). 

A Reregistration Eligibility Decision (RED) document was issued in September 2003. As per the 

RED, for the potential residential cancer risks associated with use of dipropyl isocinchomeronate 

over a lifetime, the Agency limited production and distribution of the chemical for personal insect 

repellents to 20,000 lbs of a.i. per year. Additionally, the Agency limited and reduced the maximum 

concentration of a.i. to 2.5 percent for end-use products containing dipropyl isocinchomeronate 

intended for use on humans. The Agency believed that these steps were necessary to provide 

assurance that human exposure to dipropyl isocinchomeronate in the U.S. would not increase 

beyond current levels. Further, to limit potential overexposure to young children, no more than 3 

applications per day of dipropyl isocinchomeronate is allowed on children ages twelve and under 

(US EPA, 2003). 

A search of the BEAD database for previous BEAD products for dipropyl isocinchomeronate 

indicates that there are no records of prior BEAD benefits assessments or Section 18 requests for 

this chemical. A lack of Section 18 requests does not indicate the relative importance of the 

chemical. 

USAGE 

Non-Agricultural Usage 

According to marketing data available at the time the RED for this chemical was issued, the total 

amount of dipropyl isocinchomeronate sold to customers with pesticide labels for use as 

"personal insect repellents" was approximately 15,000 to 20,000 pounds (lbs) of a.i. Whereas use 

on dogs/cats and horses averaged 2,100 and 14,000 lbs ofa.i., respectively (US EPA, 2003). 

However, in a personal communication, the sole registrant Vertellus Specialties, Inc. has 

provided more recent production data for the years 2010-2013 for dipropyl isocinchomeronate 

as shown in Table 1. Comparing the more recent production data to the data provided previous 

to the RED shows that average annual domestic use prior to the red (26,000 lbs annually for 

years 1997-2001) has decreased to just under 7,000 lbs per year. 

The only available usage data from public or private data bases was from USDA's National 

Agricultural Statistics Service. The Agricultural Chemical Usage survey showed that 500 lbs a.i. 

were used on dairy cattle in 2006 at a rate of 5.9 grams per head per year (USDA NASS, 2006). 

At this rate, approximately 38,000 head of dairy cattle would be treated. The 2001 survey 

showed 1,900 lbs a.i. applied at a rate of 13.2 grams per head per year. At this rate, 

approximately 65,000 head of cattle would be treated. The 1999 survey showed that 3,100 lbs 

a.i. were used on beef cattle (USDA NASS, 2000). This survey has not been updated. 

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Table 1. Total Production (lbs) and End Uses of dipropyl isocinchomeronate, 1997-2001 and 

2010-2013 

Year 1997-2001 2010-2013 

annual average annual average 

Total Production (lbs) Not Available 17,200 

Volume Exported Outside of US Not Available 10,500 (lbs) 

Total Domestic Usage (lbs) 26,000 6,800 

US Sales for Insect Repellent Use Not Available 4,800 on Humans (lbs) 

US Sales for Animal-only Insect Not Available 2,000 Repellent Uses (lbs) 

Sources: Vertellus Specialties, Inc. 2014; US EPA, 2003 

BIOLOGICAL ASPECTS RELEVANT TO DIPROPYL ISOCINCHOMEROATE 

Dipropyl isocinchomeronate is added to insecticide products because of its repellency properties 

and, in some cases, because of its ability to extend the period of repellency of other active 

ingredients. (Debboun et al., 2007) Dipropyl insosinchomeronate is formulated with a number of 

other active ingredients including diethyl toluamide (DEET), piperonyl butoxide, MGK 264, 

permethrin, and pyrethins in products labeled to repel fleas, ticks, flies, and other pests. 

ROLE OF DIPROPYL ISOCINCHOMEROATE IN PEST MANAGEMENT 

While there is limited information available for dipropyl isocinchomeroate, this chemical could 

play a role in public health protection to the extent that it improves the repellency of products 

used to repel insects which vector Lyme disease, West Nile virus, and other pathogens. Before 

the RED was issued in 2003, the Agency requested a consultation with the Centers for Disease 

Control and Prevention (CDC) regarding the potential public health benefits of dipropyl 

isocinchomeronate as an insect repellent. CDC indicated its support for the registration of the 

chemical despite a lack of data on its efficacy. 

One dated study on housefly (Musca domestica) repellency found that dipropyl 

isocinchomeronate was the most effective chemical tested and more effective than DEET for 

repelling houseflies (Campbell, 1983). In addition to improving the repellency ofDEET 

products by preventing evaporation, dipropyl isocincheromeronate might increase repellency 

against stable flies, horse flies, and malaria mosquitoes (Strickman et al., 2009). The ongoing 

usage on cattle indicates that the chemical is an important tool for fly control. 

DATA NEEDS 

The Agency currently does not have needed and important information on dipropyl 

isocinchomeronate. Obtaining the following information may improve future assessments 

conducted by the Agency related to the use and importance of this chemical: 

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Information on the importance of dipropyl isocinchomeronate for repellency 

- Alternatives to dipropyl isocinchomeronate 

REFERENCES 

Campbell, M. M. 1983. A Test for Repellency to Non-biting Flies and A Comparison of 

Repellents Using Musca domestica L. Pesticide Science 14: 199-212. 

Debboun, M., Frances, S. & Strickman, D. 2007. Insect Repellents: Principles, Methods, and 

Uses. New York: CRC Press. P. 376-377. Online: 

http:/ /www.crcpress.com/product/isbn/97808493 71967. Accessed 31 March 2014. 

Strickman, D., Frances, S., & Debboun, M. 2009. Prevention of Bug Bites, Stings, and Disease. 

New York: Oxford University Press. 

USDA NASS. 2007. Agricultural Chemical Usage, 2006 Dairy Cattle and Dairy Facilities 

Summary. Online: 

http:/ /usdaO 1.librruy.comell.edu/usda/current/ AgriChem U sDairv/ AgriChemUsDairy-05-23-

2007.pdf 

USDA NASS. 2002. Agricultural Chemical Usage, 2001 Dairy Cattle and Dairy Facilities 

Summary. Online: 

http:/ /usdaO 1.librruy.comell.edu/usda/nass/ Agri Chern U sDairy/ /2000s/2002/ Agri ChemU sDai 

ry-05-29-2002.pdf 

USDA NASS. 2000. Agricultural Chemical Usage, 1999 Cattle and Cattle Facilities. Online: 

http://usdaO 1.library.comell.edu/usda/current/ AgChemUsCa/ AgChemUsCa-04-26-2000. pdf 

U.S. EPA, Reregistration Eligibility Decision for Dipropyl isocinchomeronate (MGK Repellent 

326), 2003. Online: http://www.epa.gov/oppsrrd11REDs/mgl£ 326 red.pdf 

Vertellus Specialties, Inc. Personal communication with Beth Sullivan, Product Regulatory 

Manager, February 24,2014. 

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