UNITED STATES ENVIRONMENTAL PROTECTION AGENCY W ASIDNGTON, D.C. 20460 

### MAR 2 8 

### 2014

MEMORANDUM SUBJECT: Denatonium Saccharide Alternati ve Assessment (129045) OFFICE OF CHE MIC AL SAFETY AND POLLUTION PREVENTION

FROM: David W Brassard , Senior Entomologist

## ~M{J**~ ~~**  Biological Analysis Branch Biological and Economic Analysis Division (7503P) THROUGH: Amet Jones, Chief Biological Analysis B ranch Biological and Economic Analysis Division (7503P TO: Cathyrn Britton, Team Leader Kevin Costello, Branch Chief Risk Management and Implementation Branch I Pesticide Re-Evaluation Division PRP Review Date March 12, 2014 

### Summary and Conclusions The purpose of this memorandum is to provide background informa tio n on the use of denatonium saccharide and to present informati on on alte rna tives. Denatonium saccharide is a bi ttering agent reg i stered for use by residential consumers as a squirrel, vole, dog, and cat repellent on outdoor surfaces, structures, seeds and bulbs. Only 1 1 0 pounds or less of denatonium saccharide active ingredient (a.i.) is sold in the U.S. annually. There are t hree animal repe ll ent alternatives to denatonium saccharide for protection of outdoor surfaces, structures, trees, seeds and bulbs: methyl nonyl ketone, capsaicin mixture, and thiram. However, because each of these alternatives can only be used on a subset of uses, us ers may only have one alternative for some uses. Some of the alternatives have constraints that may limit their usefulness. Methyl nonyl ketone has a shorter period of re si dual activity and needs to be reappli ed daily. The capsaicin/garlic oil/putrescent whole egg solid products have a strongaromatic smell that may be offensive to some users. Lastly, little is known about the comparative efficacy of the alternatives; therefore, the alternatives may n ot be as eff ective as denatonium saccharide. Background The purpose of this memorandum is to provide background information on use of denatonium saccharide and to present information on alternatives. Denatonium saccharide is a bittering agent registered for use as a squirrel, vole, dog, and cat repellent. Denatonium saccharide, a quaternary ammonium salt, is the bi tterest chemical compound known to man. Dilutions as low as 10 ppm are unbearably bitter to most humans. (CPSC, 1992; Clegg, 2013). There is currently one registered product, RO-PEL Tree Squirrel, Vo le, Dog, and Cat Repellent , EPA Registra tion Number 811 17- 1, a ready-to-use liquid formulation containing 0.065% denatonium saccharide and 0.035% thymol (NPIRS, 2014). Currently, only 50 Kg (110 pounds) per year or less of denatonium saccharide is imported, which is enough to formulate 20,400 gallons ofRO-PEL (Brown, 2012). Assuming that user households apply one gallon ofRO-PEL ann ually , thi s is enough to treat 0.017% of U.S. house ho ld s (U.S. Cens u s Bureau, 2012). The retail cost ofRO-PEL ranges from $25 for 24 fluid ounces (Sears 2013 ) to about $ 50 per gallon (Nix a li te 2013)

. RO-PEL is used mostly by consumers in residential areas (Becker, 2013). RO-PEL is used to repe l tree squirrels, dogs and cats on outdoor surfaces and structures such as trees, fences , poles, decks, planters, siding, garbage cans, and furniture. RO-PEL is also labeled for the protection of seeds and bulbs from tree squirre ls and voles. For struct ures, RO-PEL i s applied as a spray or with a paintbrush to the point of runoff at the rate of 1 gallon per 1,000 to 4,000 sq. ft. The labe l allows for a second application in 2 to 7 days to improve effectivenes s . Additionall y, the product can be sprayed onto seeds and bulbs before planting to repel tree squirrels and voles. The label does not list application rates for seeds and bulbs. The directions for these uses only state "Using rubber g loves, place seeds or bulbs in a plastic or metal container and spray thoroughly until soaked." Becker (2013) calculated an application rate for hyacinth bulbs of 4 ml product or 0.000006 lb a .i

. per bulb. Becker (2013) also calculated an application r ate for grass seed of 0.00008 to 0.0003 lbs a.i. per 1,000 sq. ft planted grass seed (equivalent to 2 to 8 fl. oz. product per 1 , 000 sq. ft).

2Alternatives There are three animal repellent alternatives to denatonium saccharide f o r vertebrate pest control registered for use on outdoor surfaces, structures , trees , and bulbs: methyl nonyl ketone, capsaicin mixture , and thiram (NPIRS, 2014). There are 14 products containing methyl nonyl ketone is registered for use as an indoor / outdoor cat and dog repellent. The labeling specifies that it can be applied to furniture and rugs (indoors) and flower beds, lawns, trees, shrubbery, fences, patio furniture, and garbage cans/bags (outdoors). Methyl nonyl ketone has a shorter period of residual activity and needs to be reapplied daily. There are 9 registered products containing a mixture of capsaicin, garlic oil, and putrescent whole egg solids registered to repel squirrels and other animals from bulbs , flowers, grass, shrubs , plants , seedlings and trees (EPA Reg No 67356-1 ). These produ cts are not labeled for seeds. These products have a strong aromatic smell that may be offensive to some users. Thiram is registered for use on trees, ornamentals, seeds and bulbs to repel rodents (O'Brien , 1994; N PIRS , 2014 ; Thiram 480 DP label. 2012). In the absence of effective repellents , some users may resort to rodenticides for tree squirrel and vole control (Oregon State University, 2005) Non-chemical ways to control squirrels and voles include trapping , shooting, and tree removal (Jackson, 2005). Other control measures include placing chicken wire, hardware cloth , sharp gravel, or red pepper flakes over the planting area (O'Brien, 1994; Vanderlinden. 2012). Conclusions Denatonium saccharide is a bittering agent registered for use by residential consumers as a squirrel , vole, dog, and cat repellent on outdoor surfaces , structures , seeds and bulbs. Denatonium saccharide is used by only 0.017% of U.S. households. There are three alternatives to denatonium saccharide , however because each alternative can only be used on a subset of uses , users may only have one alternative for some uses (e.g. thiram for use on seeds). Some of the alternatives have constraints that may limit their usefulness. For example, methyl nonyl keto n e has a shorter period ofresidual activity and need s to be reapplied daily. The capsaicin , garlic oil , and putrescent whole egg solid products have a strong aromati c smell that may be offensive to some users. Lastly, little is known about the comparative efficacy of the alternatives ; therefore , the alternatives may not be as effective as denatonium saccharide.

3References Becker, J

.. 2013 [Revised] Application Rate Information for Uses ofRO-PEL, a Ready-To

- Use Liquid Bittering Agent Containing Denatonium Saccharide (PC Code 129045 ) , April24, 2013 Brown, R. 2012. Email correspondence from the registrant, Roger Brown, MCB , LLC , to Andrea Mojica, EPA, 10 / 8/2012. Clegg, B

. 2013. Denatonium benzoate. ChemistryWorld, Royal Societ y of Chemistry. http: //www .rsc.org/ chemi stryworld/20 13 /04/denatonium -b enzoate-podcast CPSC. 1992. "Final Report Study of Aversive Agents" Consumer Product Safety Commission United States of America. 18 N ovember 1992. http: //www . cpsc.gov /LIBRARY/FOIA /foia99 / os/aversive.pdf Jackson , J.J. 2005. T echniques to control and manage tree squirrel damage. Internet Center for Wildlife Damage Management. http: //icwdm.org/handbook/rodents/TreeSquirrels.asp Nix alite. 2013. Nixalite of America, Inc. website. Available at: h

ttp: //www .n ixal ite.cornlropel.aspx NPIR S. 2014. N ational Pesticide Information Retrieval System. http :/ /npirs.ceris.purdue.edu O ' Brien, J.M. 1994. Vo les. 

### [In Prevention and Control of Wildlife D am age) Cooperat i ve Extens i on Division , University of N ebras ka, Linco ln , NE

. http ://icwdm.org/handbook/rodents/ro b 177 .pdf Oregon State Univer sity. 2005. Voles and Their Control. Oregon State University. http: //extension.oregonstate.edu/lane / sites/ default /files/ documents/lc725vole control.pdf Pierce , R. A. 2003. Controlling Voles in Horticulture Plantings and Orchards in Missouri http: //extension.missouri.edu/explorepdf / agguides/ wildlife/ g09445.pdf Sears . 2013. S ears web s ite. Available at: http: //www.sears.com/search=four+paws+pet+products+keep+off + indoor+and + outdoor+ dog+and+cat+sp ray+repelle n t + 24+oz?vName = Pet+Supplies&cName = Dog+Supplies&au toRedirect=true&view Items=25&redirec t Type=CA T REC PRED Thiram 480 DP l abel. 2012. Labeling for Thiram 480 DP , E PA R eg. N o . 400

- 434. http: //www.epa.gov / pesticides/chem search/ppls / 000400

- 00434

- 20 12071 1.pdf U.S. Census Bureau. 2012. Statistical Abstract of the United States: 2012. http: //www . census.gov/compendialstatab/ 2012/tables/ 12s0059

. pdf 4Vanderlinden. 2012. How to Protect Bulbs from Squirrels. Organic Gardening. http ://organi cgardening.about.com/od/pestcont rol/a/How- To- Protect- But bs- F rom-Squirre l s.htm



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