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EPA Response to Scientific Advisory Panel Comments 

Related to the Proposed Repellency Awareness Graphic

Introduction

This document contains EPA’s responses to comments made about the proposed program for use 

of a repellency awareness graphic at a FIFRA Scientific Advisory Panel (SAP) Meeting held 

March 19- 20, 2013, on Draft Product Performance Data Needs Assessment for Products 

Claiming Efficacy Against Invertebrate Pests. EPA thanks the SAP for their comments and will 

carefully consider these comments in developing the program and any future guideline or data 

requirement revisions. The final SAP report, meeting minutes, the Technical Support Document, 

the charge questions, and other information about this meeting are available at 

http://www.epa.gov/scipoly/sap/meetings/2013/031913meeting.html. 

This document is not a complete response to all SAP comments. Only those comments related to 

the effort are included in this document. In preparing this document, first, EPA has included the 

charge question given to the Panel. Only certain of the charge questions or certain parts of the 

charge questions were applicable to the graphic: This includes charge questions 2b, 4a, 4c, 4d, 

and 10. Next, EPA included the portions of the SAP’s response to the applicable charge question, 

which is categorized here as “comment.” This is then followed by EPA’s response to the 

comment. 

Charge Question 2 to the Panel 

Establish pest groupings and identify representative taxa to support such groups in lieu of 

the submission of data for every species of significant public health and economic 

importance on a label 

The agency is considering establishing formal pest groupings that will permit defined, 

generalized label claims against assemblages of pests. These groups are taxonomically and 

biologically based to allow representative test organisms, where appropriate, and provide for 

generalized label claims against the pest grouping as a whole. Please discuss: 

(b) Whether the pest groups and/or sub-groups identified [in the TSD] are appropriate and 

adequate? If not, how should groups be developed? 

SAP COMMENT 2b-1: Ticks - Group 2 (including sub-groups 2a, b, and c) 

Suggest adding Dermacentor andersoni as a test species as it is easily reared 

under laboratory conditions and is common. 

EPA RESPONSE to COMMENT 2b-1: We are not aware of a study using Dermacentor 

andersoni as the test species being submitted to EPA. Historically, we are more familiar with the 
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American dog tick (Dermacentor variabilis), since we have reviewed and evaluated many of 

these studies. We are not aware of any unique advantages that Dermacentor andersoni offers 

over Dermacentor variabilis. Additionally, it is our understanding that Dermacentor andersoni is 

not commonly available at testing laboratories. Furthermore, the addition of Dermacentor 

andersoni as a test species could introduce another variable, and thus make comparisons of 

Complete Protection Time (CPT) more challenging. However, under the current regulations and 

guidelines, a researcher may conduct testing using different methodologies and submit the data 

to meet EPA’s requirements. Thus, if a registrant were to submit to EPA a well-conducted, 

scientifically-valid study using Dermacentor andersoni as the test species, which provided the 

information needed by EPA, then such a study would likely be considered acceptable. In the 

future, if EPA develops a rulemaking for product performance data requirements, then EPA 

would consider at that time whether to establish a requirement regarding which test species 

would be acceptable. 

Charge Question 4 to the Panel 

Evaluation of insect repellent efficacy data. 

With regard to skin-applied insect repellent products, EPA evaluates submitted efficacy data on 

mosquitoes and ticks and analyzes these data to determine protection times that are typically 

provided as claims on labels of the products. As noted in Unit VII.A of the TSD for this SAP, 

EPA is developing a standardized graphic for skin- applied insect repellent products that will 

highlight to consumers that a product works for an estimated period of time against mosquitoes 

and/or ticks when the product is used as directed on the label. EPA is undertaking this initiative 

in order to improve and clarify pesticide product labeling for consumers and promote public 

health protection. EPA provides recommendations for the design and execution of repellent 

efficacy studies in the EPA Office of Chemical Safety and Pollution Prevision (OCSPP) 

Harmonized Product Performance Test Guideline, OPPTS 810.3700: Insect Repellents to be 

Applied to Human Skin 

(http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series810.htm). Additionally, 

EPA has developed criteria that it believes are critical to analyzing submitted mosquito and tick 

efficacy data in such a way that consistent, reliable, informative, and health-protective estimates 

of Complete Protection Time (CPT) are produced. The intended criteria are as follows: 

• Based in part on discussions with the Human Studies Review Board, EPA will be using the 

median CPT determined using survival analysis to evaluate product efficacy/repellency for both 

mosquito and tick repellents. 

• The median CPT will be derived from the most conservative data set per pest (lowest CPT 

value among the tests performed for the pest) to calculate the hours of protection listed on a 

label. For mosquitoes, this would be the lower CPT from the typical two field study sites where 

testing was performed, and for ticks, this would be the lowest CPT of all the representative tick 

species tested. 
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• Standard arithmetic rounding conventions will be used to round to a whole number of hours 

when the calculated CPT is not a whole number. 1

• The minimum performance standard (using the raw median CPT, before rounding) as outlined 

in Unit IX (Table 12) will be two hours. If a product does not meet the minimum hours of 

protection EPA would not allow the graphic to be used on the label. 

Given EPA’s objectives to (1) ensure the reliability and consistency of claims made for skinapplied insect repellent products to keep mosquitoes and ticks away from the typical consumer 

for an estimated period of time and (2) to aid consumers in their decision-making by conveying 

to consumers that products differ in their duration of efficacy towards these vector-borne, 

disease-carrying insects, please discuss: 

Charge Question 4(a): Should some of the testing parameters in test guideline “OPPTS 

810.3700: Insect Repellents to be Applied to Human Skin” be described with greater 

specificity in order to derive consistent and reliable estimates of CPT for label claims? 

Please provide a supporting discussion and include references to any published literature 

that could inform our data collection. 

SAP COMMENT 4(a)-1: 

[The SAP described the definition of "crossing" as] "A crossing may be quantified 

either or both by the distance the tick or chigger moves onto treated skin or by 

how long the tick or chigger remains on treated skin." The Panel questioned 

whether the actions described in this statement are measuring the same thing. If 

not, allowing both to be an outcome of a test would confound the product labeling 

effort. Does the individual conducting the test decide? How does the statement 

account for a crossing, but then a drop off? The Panel recommended choosing one 

or the other as a measurable outcome to provide greater clarity to registrants. 

EPA RESPONSE to COMMENT 4(a)-1: 

The agency believes the existing guideline definition of “crossing” (page 5 of Guideline 

810.3700) is sufficiently clear. While the definition may offer some flexibility for quantifying 

the “crossing,” the descriptions in the guideline (page 30) refer to a “release point 3 cm distant 

from the treated area and scoring of a crossing when a tick moves at least 3 cm into the treated 

area.” Most of the protocols reviewed by EPA have used “crossing” as the measurable outcome 

for tick repellency testing. 

 In light of this definition, once the tick has crossed the “line,” whether the tick keeps moving 

forward on or over the treated skin, or remains static on the treated skin, or falls/drops off the 

treated area, the tick is not being repelled. Although a “drop off” could be considered further 

proof of repellency, as the tick would be removed from the host, EPA relies on the more 

conservative measure of a crossing. EPA also acknowledges that there could be circumstances 

 

1

 Based on the recommendations of the SAP, as discussed in response to comment 4(c)-1, EPA is changing this 

criterion to “round down.” 
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dependent on the chemical being tested when the use of a different measurable outcome could be 

more appropriate. 

SAP COMMENT 4(a)-2: 

In the guideline description of "dose determination," the Panel believed use of the 

words "multiple applications" is rather vague. A power analysis conducted by the 

registrant or at least a minimum number of subjects specified by EPA was 

suggested. The typical dose or "dosimetry" is the average application rate by 

consumers (test subjects) on themselves. There may be an opportunity for bias if 

consumers feel they must meet a certain expectation when doing the applications. 

Also, an application in an efficacy study (e.g., preparing for a field trial) may not 

accurately reflect what someone might really apply to themselves if they are 

anticipating an activity such as hiking, hunting or other outdoor activity when 

arthropod contact might be high. 

The Panel recommended that EPA establish the dose for spray-type formulations. 

EPA RESPONSE to COMMENT 4(a)-2: 

EPA follows recommendations from the Human Studies Review Board (HSRB) on dose 

determination by using dosimetry testing instead of establishing a standardized dose (see 

http://www.epa.gov/hsrb/files/oct2006-final-report-12107.pdf). Dosimetry testing is conducted 

separately from the repellency testing and seeks to estimate a “typical consumer dose.” Guideline 

810.3700 (page 7) indicates that the “typical dose” should be calculated as the mean of multiple 

applications. The number of subjects would be specified in the protocol reviewed by EPA and 

the HSRB. EPA agrees that each person applies different amounts of repellent based on factors 

such as the formulation, the part of body to which the repellent is applied, and their past 

experiences in using insect repellents. The differences in amount of repellent applied via the 

individual application techniques are precisely the information that EPA seeks. EPA believes 

that its approach to dose determination by using dosimetry testing is appropriate for all 

formulation types. 

EPA does not believe that there is an opportunity for bias when test subjects are instructed to 

apply the repellent as indicated on the label. It is possible that a test subject could apply the 

product at a lower dose than what some consumers could apply when they are “anticipating an 

activity such as hiking, hunting or other outdoor activity when arthropod contact might be high.” 

If such a lower dose is determined to be effective, then EPA assumes that the product will be at 

least as effective as when applied at a higher dose. 

SAP COMMENT 4(a)-3:
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The Panel believed that the only way that a median CPT can be estimated was with 

multiple study participants and, therefore, the emphasis should be on replication of 

study participants within each lab or field trial. 

EPA RESPONSE to COMMENT 4(a)-3: 

Guideline 810.3700 specifically includes information on complying with the new ethical 

requirements for research involving human test subjects. (EPA’s codification of the Common 

Rule is at 40 CFR part 26.) The testing methodologies were also upgraded to ethically justify the 

use of human subjects, since it would be unethical to employ human subjects for unreliable 

testing results. The current recommendations for product performance testing of skin-applied 

insect repellents, as specified in Guideline 810.3700, strike a balance between ethical 

considerations, cost of testing, and reliable results. 

The ethical considerations for conducting studies with human subjects are clear on the need to 

minimize human exposure when conducting needed research as well as assuring that there is a 

benefit to having such information. Guideline 810.3700 provides flexibility by not requiring a 

minimum sample size. Study directors must provide a rationale for the choice of sample size; 

however, we note that a sample size of 10 subjects is routinely used and accepted. 

The CPT is derived from the first confirmed landing and this measure is analyzed using a nonparametric survival analysis procedure, which is appropriate for right-censored data that is not 

normally distributed. The central CPT value is the median CPT derived from such analysis. The 

first confirmed landing is the most protective efficacy endpoint for human subjects exposed to 

mosquitoes during testing. It prevents bites and even probing since mosquitoes can transmit 

pathogens during probing activity. Testing parameters and study design are standardized for 

consistency. EPA notes that guideline recommendations are flexible enough to allow adoption of 

innovative technologies as they develop since this is an evolving field. Additionally, EPA will 

consider SAP advice in related policy formation in the future. 

SAP COMMENT 4(a)-4: 

Using the EPA definition of CPT ("the time from application of a repellent until 

efficacy failure, as defined in the protocol used to conduct the study"), a repellent 

would fail at the point in time when one mosquito bites or one tick crosses a line, 

or by successive bites or crossings within a 30 minute period. The CPT will likely 

underestimate repellency and use of CPT as a criterion for evaluating repellent 

efficacy may encourage the over-application of repellents because consumers may 

believe that they would be vulnerable to attack after the CPT period. 

Measuring percent repellency with 95% as the minimum allowable in estimating 

protection time for repellents applied to skin would likely yield more reliable 

results. A requirement of 100% repellency is too rigorous because it does not take 

into account the size of the mosquito population and intensity of activity. Using 

95% reduction in landing or biting is a more appropriate measure of the response 
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of a mosquito test population as a whole in comparison to CPT. CPT essentially 

records the activity of outliers and provides the time when the first outlier lands 

(or bites) or the landing (biting) followed by a landing (bite) of a second outlier. 

What would the CPT be for a repellent that achieved 99% repellency at 1 hour, 

100% at 1.5 hours, and 99% at 2 hours? 

If landings were allowed (or bites or crossings), then why not use percent 

repellency as the measure instead? EPA allows the study design to use either 

landing or bites, but then goes on to strongly recommend landings. The Panel 

recommended not offering a choice. When would measuring "bites" be justified, 

according to EPA? Furthermore, use of landing rather than biting as an endpoint 

in repellent tests would require formulators to increase the volatility of their 

formulations to increase the repellent activity of their end use products. Increased 

volatility would decrease CPT unless the concentration of the active ingredient 

was increased. Some, if not most, repellents work as a contact irritant rather than 

a spatial repellent (altering seeking behavior). Therefore, landing as an endpoint 

should be defined in terms of a "touch time" such as greater than 2 seconds rather 

than as a simple touch with immediate lift off. Use of biting as an endpoint must 

be carefully considered for field studies due to risk of disease transmission to 

volunteers. 

The Panel agreed that from a consumer perspective, when reading a product label, 

it is more likely that the average consumer would understand repellency when 

stated in terms of CPT rather than as "percent repellency over time". However, 

duration of percent repellency could be written on a product label in a common 

sense way to enhance understanding by a consumer. 

EPA RESPONSE to COMMENT 4(a)-4: 

EPA recommends the use of landings (for mosquitoes) or crossings (for ticks), not bites, as the 

measurement of repellency appropriate to the repellency awareness graphic. As previously 

discussed, the ethical considerations for conducting studies with human subjects are clear on the 

need to minimize human exposure when conducting needed research as well as assuring that 

there is a benefit to having such information. While there is a clear benefit to understanding how 

long and how well a skin applied insect repellent works, exposure of the human test subjects 

must be minimized. Bites potentially put human subjects at risk since one bite can contain 

enough pathogenic material to transmit disease. Thus bites should not be used as a measurement 

of repellency for efficacy studies measuring effectiveness against mosquitoes. This also 

comports to advice given by the HSRB during its review of a draft version of Guideline 

810.3700. (see http://www.epa.gov/hsrb/files/june2006mtgreportfinal100606.pdf) 

EPA agrees that the CPT may underestimate repellency, but notes that underestimation of 

repellency would be more protective for consumers than overestimation. The agency assesses the 

risk associated with exposure to the repellent as part of the risk assessment and the exposure 
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includes re-application of the product. Any limitations to application (e.g., number of 

reapplications) are required to be part of the product label. 

EPA disagrees that using 95% repellency would be more reliable or appropriate. EPA believes 

that the CPT is more protective since it is indicative of 100% protection, i.e., no confirmed 

landings. EPA has considered the use of percent repellency statements for skin-applied insect 

repellent products. However, we believe that a statement such as “repels mosquitoes for up to 4 

hours” is easily understandable. While there is, of course, variability from person to person on 

how long the repellent works, the focus groups conducted by EPA indicated that consumers do 

have an understanding of such variability. A statement such as “repels 99% of mosquitoes at 1 

hour, 100% of mosquitoes at 1.5 hours, and 99% at 2 hours” offers little practical information to 

consumers. EPA is concerned that such detailed information offers a false precision to 

consumers because of these variability issues. Additionally, using percent repellency could 

require measurement of a sample of untreated negative subjects exposed to mosquitoes which 

makes it impossible to prevent multiple bites from happening. Given the need to minimize 

exposure for the test subjects, EPA does not believe that percent repellency is workable. 

In general, EPA allows registrants the flexibility to define efficacy failure in a study protocol; 

however, specifically for skin-applied insect repellent studies, the first confirmed landing or 

crossing is used to determine efficacy, thus providing consistency across registrant studies. With 

test species other than mosquitoes or ticks, efficacy failure may need to be defined differently, 

and the guideline allows this flexibility. For instance, biting flies such as stable flies will bite 

immediately upon landing on skin, thus bites are more appropriate as an endpoint instead of 

landings. EPA will continue to consider this SAP advice in future policy discussions. 

SAP COMMENT 4(a)-5: 

One or two untreated persons are used to verify landing pressure in CPT tests. 

This is not a true negative control because untreated persons are not to be 

compared to treated persons. The Panel recommended clarification. Further, 

multiple negative controls are required for studies of relative protection or percent 

repellency. If the Agency uses CPT as the endpoint or measure of repellency 

(which is not recommended), it creates confusion or ambiguity in the guidelines 

for registrants. This comment also applies to other places in the guidelines that 

describe "untreated controls". 

EPA RESPONSE to COMMENT 4(a)-5: 

EPA acknowledges that an untreated person used to verify landing pressure is not a true negative 

control. EPA believes that it is not necessary to have a replicated negative control group for 

statistical purposes. 

Based on the recommendations of the HSRB, Guideline 810.3700 encourages the use of positive 

controls (page 9) and only discusses negative controls (page 35) as part of the consideration for 

statistical design. As previously discussed, the ethical considerations for conducting studies with 

human subjects are clear on the need to minimize human exposure when conducting needed 
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research as well as assuring that there is a benefit to having such information. Exposure to 

infected mosquitoes in the field is possible, and EPA does not want subjects to be bitten or to 

encourage the use of bite data to determine repellency. 

The type of statistical analysis that has been used to estimate CPT (based on the First Confirmed 

Landing) is a non-parametric test which is not intended to compare treatment groups. This means 

that a negative control is not needed to determine whether there is any statistically significant 

difference which demonstrates that the treatment effect is significant. The experiment is not 

designed for testing such hypothesis. The objective of the test is to measure time of repellency 

using a sample of treated subjects and having one person, fully covered, to monitor whether there 

is enough mosquito activity at the site during testing. 

SAP COMMENT 4(a)-6: 

Guideline 810.3700 states that for testing DEET (N,N-diethyl-meta-toluamide) 

lotion formulations, the standard dose was 1 g per 600 cm2

 . The guideline stated 

only that this was through many tests of repellency; therefore, it was not clear 

how the dose was determined. Has this been established over time, as a "typical 

consumer dose," using methods described by EPA? If so, the guideline should 

include a description or clarification. Why would this dose not also be a standard 

for other active ingredients? The only reason given was that no comparable 

standard dose had been identified. When was the standard dose for DEET 

identified by EPA? In public comments made by the DEET Task Force, it was 

noted that variable dosing would have an impact on CPT. This could lead to an 

overestimation or underestimation of CPT, which may provide inaccurate 

information to the consumer for protection against a public health pest and could 

complicate EPA's efforts to begin a repellent mark/graphic program. Data should 

be easily comparable across studies, registrants, etc. 

EPA RESPONSE to COMMENT 4(a)-6: 

The use of this DEET dose and formulation as a positive control is also used by the World 

Health Organization (WHO) and is also included in the WHO “Guidelines for Efficacy Testing 

of Mosquito Repellents for Human Skin.” 

(http://whqlibdoc.who.int/hq/2009/WHO_HTM_NTD_WHOPES_2009.4_eng.pdf) For other 

ingredients and formulations no comparable standard dose has been identified, and it is 

recommended that a “typical consumer dose” be estimated through empirical dose-determination 

testing as described in the test guideline. 

SAP COMMENT 4(a)-7: 
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EPA specifies which mosquito species should be used for conducting laboratory 

studies. However, this does not agree with the recommendations proposed in 

Appendix 5 of the TSD. The Panel recommended that guideline 810.3700 be 

revised to reflect the Panel's recommendations to Appendix 5 (for mosquitoes) 

that EPA chooses to accept (e.g., differentiating between field and laboratory 

studies, repellent requirements versus other types of pesticides). 

EPA recommended two distinct habitats for field testing sites where the 

predominant mosquito species differ, but it did not provide any specific guidance 

on what species should be targeted for these field studies. A registrant must 

provide field data (which EPA prefers) to support a product label claim against 

mosquitoes; however, field data on some of the specific species identified in 

Appendix 5 of the TSD could not readily be obtained in the U.S. Any adopted 

"test requirements" from the TSD should be harmonized with preexisting 

published guidelines.

EPA RESPONSE to COMMENT 4(a)-7: 

The Panel is correct that page 25 of Guideline 810.3700 provides specific species for laboratory 

studies of mosquito repellency. For field testing, EPA does not believe it possible to prescribe 

the species and genera that would be encountered in a given field test. Instead, EPA recommends 

field testing at two distinct habitats where predominant mosquito species differ and would 

presumably cover several different genera. 

Guideline 810.3700 specifies that insects should be aspirated or trapped, and then identified by 

genus and species (page 27). Field studies that have been submitted to EPA since 2006 include a 

complete listing of all species collected at the field sites as well as the number of individual 

species collected. EPA evaluates the identified species to make sure that sufficient disease vector 

species were present. As appropriate, EPA has required additional lab studies of one or more 

disease carrying species to supplement the field study when insufficient species were present. 

 

If EPA develops a rulemaking for product performance data requirements, then most of the 

Guidelines would be revised at that time to accommodate what is codified in the regulations (and 

therefore required), and what is recommended in the guidelines. At that time EPA will consider 

which recommendations of the SAP are codified and which are placed in guidance. 

SAP COMMENT 4(a)-8: 

The guideline states “subjects may work in pairs.....;” however, working in pairs 

would likely interfere with a true measurement on the actual test subject for many 

reasons. A second person acting as "collector" would create an additional 

attractant (if not wearing repellent) or repellent (if required to wear repellent to 

minimize risk). It is entirely possible to adequately train test subjects to use an 
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aspirator and collecting cup prior to execution of a field study thus eliminating the 

need to work in pairs. 

In Unit VII, Part A of the TSD, EPA stated that they are planning to implement a 

voluntary repellency mark program and that information derived from this SAP 

may be used to further refine the criteria for this voluntary program. Registrants 

would have to demonstrate CPT ≥ 2 hours (the current endpoint or measurement 

for efficacy) in order to use a proposed graphic or repellency mark on a product 

label. In Table 12 of the TSD, EPA states that a CPT ≥ 2 hours would be required 

for any repellent, implying a minimum standard for registration. This does not 

entirely agree with the statements in Unit VII Part A, which is likely an oversight, 

but should be made clear by EPA. The Panel inquired whether a CPT ≥ 2 hours is 

required for registration of a repellent product or merely required to use the 

voluntary graphic on labels. The Panel thought that EPA's concept for the 

repellency mark program was a good idea since it aims to help consumers by 

reflecting protection times supported by data generated through performance 

testing and they thought that it should ultimately be a mandatory program. 

A Panel member noted that there is a discussion in the EU concerning protection 

times and the current line of thought is to work with average protection times 

because there can be large differences in responses between tested individuals. 

EPA's proposal to put whole hours of protection time on a product label would 

require calculation of the average protection time. Due to the high variability in 

individual protection time, the 100% criterion cannot be applied as the only 

criterion for the derivation of the protection time. If all users are to be protected at 

100% during a claimed period, the protection time on the label would need to be 

very low. The Panel members, therefore, suggested deriving a mean value to use 

as the protection time on a product label. It should somehow be stated on the 

product label that the declared hours of protection represent a mean value (e.g., 

“protects on average X hours”). For the calculation of the mean value, the EU 

uses only those studies which fulfill the requirements of the official guidelines 

(EPA, WHO) and which were conducted with at least 10 test persons. If test 

methods deviate from official guidelines and are less rigorous, the labeling should 

be adjusted, for example, by subtracting a certain amount of declared hours (e.g., 

5 instead of 6 hours). 

EPA RESPONSE to COMMENT 4(a)-8: 

Guideline 810.3700 (page 29) offers the option of subjects working in pairs to assist each other. 

While EPA continues to believe that this is an acceptable method of collecting and reporting 

data, EPA also recognizes that test subjects can be trained to accomplish this on their own. Test 

subjects do not need to see around their entire bodies to be able to count the number of landings 

(not bites) because there is only one small section of the forearm or leg that is treated and 

exposed to mosquitoes. That is the only area that needs supervision. Therefore, each test subject 

should be capable of counting/aspirating his/her own mosquito landings. 
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With regard to a minimum of two hours for CPT, EPA agrees that two hours should be the 

minimum for product registration, not just for participation in the voluntary program. 

EPA continues to believe that the median CPT value from the chosen data set is more 

appropriate for deriving the CPT used on the graphic. Most of the data sets submitted to EPA 

and reviewed by both EPA and the HSRB are right censored. This means that the data are not 

normally distributed and therefore the mean is effectively meaningless. 

As previously described, Guideline 810.3700 provides flexibility by not requiring a minimum 

sample size. Study directors must provide a rationale for the choice of sample size; however, we 

note that a sample size of 10 subjects is routinely used and accepted. 

EPA does not believe that it needs to consider adjusting labels by subtracting hours if test 

methods are less rigorous. Given the current process used by EPA for evaluating skin applied 

insect repellent testing protocols, in which the draft protocol is discussed during a public meeting 

of the HSRB, EPA finds it unlikely that any submitted study would have significant deviations. 

Charge Question 4 (c) to the Panel

Given our intended criteria, would the whole number derived from the data analysis 

represent a realistic method of approximating protection times for the typical consumer?

COMMENT 4(c)-1: 

The Panel believed that use of the whole number is realistic for expressing CPT, 

but asked whether the CPT would be rounded up or down. Standard rounding 

conventions would lead to an overestimation of CPT when numbers are rounded 

up. Therefore, the Panel recommended rounding numbers down. 

A typical statement on a product label might read, "This product protects for an 

average period of 6 hours from biting mosquitoes." One Panel member did not 

think such a statement provided useful information to consumers. In parts of the 

EU, there are only Culex species, but many consumers take DEET products with 

them on vacations to the tropics. Therefore, the EU has adopted label instructions 

that say: "This product protects for an average period of 6 hours from biting 

mosquitoes in the Netherlands, for an average period of 3 hours against yellow 

fever mosquitoes and 5 hours against malaria mosquitoes." This provides more 

useful information to a consumer. A CPT would reduce the claimed protection 

time while in practice the product may be effective for a longer period. 

It was also suggested that consumer activity and behavior be part of labeling 

considerations and the Panel asked if there should there be something on the 

product label that differentiates between types of consumer activities. EPA 
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responded that some companies are already making this distinction on their 

product packaging. 

EPA RESPONSE to COMMENT 4(c)-1: 

EPA agrees that a whole number is realistic for expressing CPT and also agrees with the SAP 

recommendation to round down when estimating CPT so that overestimation does not occur. 

EPA disagrees with listing multiple CPTs on the label by species and consumer 

activity/behavior. EPA’s registration of an insect repellent product can mean that the product can 

be distributed and used nationally. The variation of geographic habitats and species is wideranging. Given these variations EPA believes that using the lowest CPT is protective of almost 

any geographic or species variation that could be encountered in the US. Additionally, the 

agency believes that most consumers are not be able to visually distinguish the difference in 

mosquito species and therefore providing multiple CPTs on the label could be confusing. It is 

more practical and effective to require that the lowest CPT be stated on the label, which will 

cover all species and is the most conservative and protective approach. 

Charge Question 4 (d)

Is [there] additional or alternative scientific advice that EPA should consider to improve 

the analysis of efficacy data for mosquitoes and ticks?

COMMENT 4(d)-1: 

One Panel member recommended using different CPTs on the product label for 

different mosquito species. In general, Aedes are the most aggressive species, and 

have a much shorter CPT than Culex species. Anopheles is between Aedes spp. 

and Culex spp. with regard to aggressive feeding behavior. Depending on the 

climatic zone and country, different mosquito species may be present and 

different CPTs may be relevant. Are consumers aware that there are different 

mosquito species at "home" or when traveling? It was suggested that a map 

indicating regions with different mosquito species using different colors could be 

useful. 

EPA RESPONSE to COMMENT 4(d)-1: 

EPA agrees with the SAP comment regarding the different behaviors in mosquito species but, as 

described in response to comment 4(c)-1, disagrees with using different CPTs on the product 

label. Since species can respond differently to a repellent, using the lowest CPT rather than a 

CPT for each species is more protective. EPA does not believe the use of a map on repellent 

labels is feasible. Given that repellent containers tend to be small, a map would have to be very 

small and may not be understandable. In addition, a map may be limiting, as vectors may move 

due to climate changes or other external factors. EPA will continue to consider this advice for 
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policy formation in other areas related to communicating product efficacy. The use of graphics 

such as maps may be more appropriate for other communication outreach activities such as 

websites. 

Charge Question 10

Please provide comments on the overall clarity, accuracy and completeness of the agency’s 

consideration of product performance data that might be needed as discussed in the TSD 

and EPA guidelines. 

COMMENT 10-1: 

Pesticides registered under 25(b): As discussed earlier, efficacy data is 

important for minimum risk pesticides in order to avoid false or misleading 

statements. There is an industry demand for applying the same or similar 

performance standards to 25(b) products as for any other registered products to 

prove their efficacy as reliable products. 

EPA RESPONSE to COMMENT 10-1: 

As a point of clarification, EPA wishes to emphasize that minimum risk products that qualify for 

an exemption are not registered products. EPA agrees that such products should fulfill product 

performance testing requirements in order to use the repellency awareness graphic. EPA intends 

to encourage producers of these products to apply to register their product under FIFRA if 

interested in participating in the repellency awareness program.