October 6, 2006
EPA-HSRB-06-03
George Gray, Ph.D.
Science Advisor
Office of the Science Advisor
1200 Pennsylvania Avenue, NW
Washington, DC 20460
Subject: June 27-30, 2006 EPA Human Studies Review Board Meeting Report
Dear Dr. Gray:
The United States Environmental Protection Agency (EPA or Agency) requested the
Human Studies Review Board (HSRB) to review scientific and ethical issues addressing a
human toxicity study involving one pesticide active ingredient-chloropicrin; guidelines for
conducting insect repellant efficacy testing; protocols for conducting two insect repellent
efficacy studies; and protocols for conducting five occupational handler exposure monitoring
studies. At the Chair's request, the Board developed scientific and ethics criteria for new
protocols. The enclosed HSRB report addresses the Board's response to EPA charge questions
for the Board's consideration at its June 27-30,2006 meeting. A summary of the Board's
conclusions is provided below.
Chloropicrin
Scientific Consideration
• The chloropicrin acute inhalation, human toxicity study, was scientifically sound
for the purpose of estimating a safe level of inhalation exposure to chloropicrin.
A LOAEL of 100 ppb was a scientifically justified point of departure (POD).
While the Board agreed that the BMCL10 data from the Phase III study was
scientifically sound to derive a benchmark concentration estimate, it stressed that
non-responders should not be excluded from such an analysis. The Board also
emphasized the importance of the inhalation data for irritation effects.
Ethical Considerations
• There was not clear and convincing evidence that the conduct of the research was
fundamentally unethical (e.g., the research was intended to seriously harm
participants or failed to obtain informed consent).
• There was not clear and convincing evidence that the conduct of the study was
significantly deficient relative to the ethical standards prevailing when the study
was conducted.
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Insect Repellent Product Performance Efficacy Guidelines
Actions to Minimize Risks to Human Subjects
• The consensus of the Board was that studies involving humans are necessary to evaluate
the efficacy of products to repel insects and other arthropods.
• Risk identification and minimization is also essential. In their protocols, investigators
should adequately identify risk to participants and describe adequate steps they will take
to minimize these risks.
Types of Toxicity Data That Should Be Generated
• The consensus of the Board was that the minimum set of toxicity data that should be
routinely generated before an investigator conducts repellent efficacy testing on human
subjects with a new product is that which will assure that subjects would not be at risk of
permanent or irreversible harm.
Self—experimentation
• It may not be a priori unethical or problematic from a scientific perspective for a
principal investigator to be a subject in hisfher own study ffi:
• The study was approved by an IRB in the same manner as was required for most
human subjects research;
• Scientific issues:
a. Principal investigator met all enrollment criteria;
b. The study was a well controlled trial with ajustified sample size adequate to
answer the study question with statistical surety;
c. The principal investigator was one of many subjects, accounting for normal
human variability, and allowing results to be generalized to a broad population;
and
d. The outcome measure is objective and measured by another (blinded, when
possible) investigator;
• A plan is in place to assure integrity and safety of the study while the principal
investigator was a subject;
• A plan is in place to ensure for study oversight if the principal investigator
becomes incapacitated;
• Participation of other research staff/employees should be allowed only if the
above criteria are satisfied and if issues of coercion/undue influence can be
addressed, which may or may not be possible;
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• The investigator justifies why he/she should be a research subject in the study.
Negative Controls
The Agency should modify the guideline to say that negative controls “may be”
needed (instead of “are”) and that examples be given both for when negative controls
are needed and when they are not. The language on positive controls may also
benefit from further expansion and clarification.
Design of Studies to Support Assessment of Repellent Efficacy
• The Board consensus was that the time to first confirmed bite, or the time to first
confirmed “intent to bite” (if ascertainable), has the advantage of minimizing risk of
vector-borne diseases. However, for some studies there is a statistical advantage for
the use of relative protection as an appropriate outcome measure. Since relative
protection procedures in field studies increases the risk of vector-borne diseases,
protocols must: (a) justify the level of risk by the probability and social value of the
benefits; (b) adequately identify all risks; (c) present a description of adequate steps
to minimize the risks; and (d) provide consent materials that include information
about the prevalence and risks of any vector-borne diseases, consequences of
contracting disease, and alternative effective repellents outside of the research.
Minimum number of subject to evaluate the level of repellent efficacy
• It is critical that the proposed number of subjects be justified on the basis of good
research design. Because experiments to test effectiveness of products to repel insect
and tick bites are likely to vary in terms of design, response variable, target
population of interest, detectable effect size and other important variables, requiring a
specific minimum sample size that guarantees sufficient accuracy in all cases might
be impractical. Instead, the guideline might require that registrants present their own
sample size calculations and that the methodology used in the calculations be justified
relative to the factors noted in the report.
Compensating Research Subjects For Research-Related Injuries
• It is appropriate that sponsors of repellent efficacy research studies should be required
to assure that if a subject is injured as a result of participating in a study, then the
subject will not have to assume the costs of medical care needed to treat such injuries.
Special Considerations in Informed Consent Materials
• To comply with the human studies rule, consent information for pesticide studies
must include: (a) detailed information on the procedure (e.g., number of insect bites
or landings anticipated, nature of apparatus or field context, length of time of
exposure); (b) a clear statement of the risks involved (e.g., discomfort from bites, risk
of vector-borne disease, medical consequences of the disease, treatments available for
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the disease); (c) the voluntary nature of participation (e.g., statements that eliminate
the perception of coercion for students or employees; specific instructions on how to
signal desire to withdraw from the study); (d) the fact that there was no immediate
direct benefit to the subject in participating as well as a description of alternative
available repellents; and (e) other steps outlined in the report. In addition, informed
consent information should be as detailed for experienced subjects as for naïve
subjects.
HSRB Protocol Criteria
• Before the Board reviewed the presented human studies proposals, the HSRB developed
scientific and ethical criteria as a guide for its evaluation of such studies. Such criteria
will be helpful for the Agency, study investigators, and other members of the public to
understand the Board’s approach for the review of proposed human studies.
Study EMD-003 from CarroH-Loye Biological Research
Scientific Considerations
The HSRB recognized three major limitations to the protocol as submitted to the HSRB for
review. These limitations included: (1) the lack of a clear rationale underlying the conduct of the
study; (2) the lack of identification and characterization of the formulations to be tested and (3)
the scientific design of the study. Of these issues, the design of the study was seen as the most
significant shortcoming of the proposed work.
Ethical Considerations
The Board concurred with the initial assessment of the Agency that the study submitted for
review by the Board failed to meet the requirements established in the Agency’s human studies
rule (40CFR26).
The Board determined the proposed research described in these studies did not comport with
the applicable requirements of 40CFR26, subpart K. The study documents submitted for review
also failed to comply with the requirements of 4OCFR §26.1125. However, the deficiencies
noted, while significant, were not irreparable.
Study EMD-004 from Carroll-Loye Biological Research
Scientific Considerations
• It was not clear whether new studies involving human subjects were necessary; however,
if the repellency had never been tested with North American mosquitoes, the tests were
probably necessary.
• The potential benefits of the study were clear, i.e., that an effective repellent would be
available that would have either greater efficacy and/or fewer drawbacks than what was
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currently approved. However, empirical evidence or procedures to determine risks to
subjects (e.g., of vector borne disease) were not adequate.
• It was not clear if the stated numbers of subjects would be repeated in both testing
locations. The basis for the dose levels and formulations was not provided. There were no
controls with just the formulation matrix without the repellent.
• These issues would need to be addressed before the protocol could be considered
acceptable.
Ethical Considerations
• The Board concluded that the proposed research did not comport with the applicable
requirements of 40 CFR 26, subpart K.
• The proposed research does comport with 40CFR26 subpart L, as pregnant women and
children were excluded.
• Although the ethical concerns identified by the Board could be remedied, there were
sufficient questions raised about the adequacy of the research design to cast doubt on
whether the proposed research would meet the criteria for IRB approval found under 40
CFR 26.1111(a) (1). In other words, absent a sound research design, any exposure of
human subjects to risk would be unnecessary and unjustifiable.
Occupational Handler Exposure Monitoring Studies
Scientific Considerations
• The occupational handler exposure monitoring studies were components of a large-
scale exercise to create a contemporary database on occupational exposure to
agricultural pesticides. The undertaking is in itself likely to be worthwhile in
quantifying and improving our understanding of the exposures and risks of pesticide
handlers.
• The potential benefits are large and the risks appear to be relatively modest. However,
the materials supplied for HSRB review failed to deal adequately with risks and
benefits. None of these protocols can be properly evaluated in regard to scientific
validity because they lack: (1) a developed rationale documenting the need for new
data; (2) a clear and appropriate plan for the handling of the data (including its
statistical analysis), and (3) an explanation of the uses to which the data will be put.
These points need to be addressed briefly at least in each specific protocol and, more
fully, in a separate and new “governing document” that is not simply a generic
description of the planned activities.
• Additional validation studies are recommended to determine the extent to which
dermal exposure measurements may underestimate true exposure. Laboratory-based
removal efficiency studies or field-based biomonitoring studies could be conducted to
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achieve this goal. Such studies should be published in the peer-reviewed literature.
Broader participation of the scientific community and of parties with a direct interest
in the database project, such as the labor community, would likely improve the
quality of the database and enhance the credibility of its use in risk assessments.
• The HSRB recommended that specific criteria for withdrawal from study
participation due to heat stress be included in these worker exposure protocols, and
that the protocols included a heat stress management plan. In addition, the length of
each study should be truly representative of a full workday, and each protocol should
document the basis for the proposed duration of the study.
• The HSRB was gratified to receive the Agency’s response to its query regarding the
use of diazinon in the AHE37. It is the understanding of the HSRB that the Agency
would inform the AHETF that it needs to identify a pesticide other than diazinon in
this protocol to evaluate exposures associated with open pour activities and
applications using open cabs, and that the Agency would ensure that future protocols
comply with the most current risk mitigation measures specified in IREDs and REDs.
Ethical Considerations
• The Board concurred with the initial assessment of the Agency that the studies
submitted for review failed to meet the requirements established in the 40CFR26.
• The Board determined the proposed research does not comport with the applicable
requirements of §40CFR26, subpart K. However, the deficiencies noted, while
significant, were not irreparable.
In conclusion, the EPA HSRB appreciated the opportunity to advise the Agency on the
scientific and ethical aspects of human studies research and looks forward to future opportunities
to continue advising the Agency in this endeavor.
Sincerely,
Celia B. Fisher, Ph.D. Chair
EPA Human Studies Review Board
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NOTICE
This report has been written as part of the activities of the EPA Human Studies Review
Board, a Federal advisory committee providing advice, information and recommendations on
issues related to scientific and ethical aspects of human subjects research. This report has not
been reviewed for approval by the Agency and, hence, the contents of this report do not
necessarily represent the view and policies of the Environmental Protection Agency, nor of other
agencies in the Executive Branch of the Federal government, nor does mention of trade names or
commercial product constitute a recommendation for use. Further information about the EPA
Human Studies Review Board can be obtained from its website at http:llwww.epa.gov/osa/hsrb/.
Interested persons are invited to contact Paul Lewis, Designated Federal Officer, via e-mail at
1ewis.pau1 epa.gov.
In preparing this document, the Board carefully considered all information provided and
presented by the Agency presenters, as well as information presented by public commenters.
This document addresses the information provided and presented within the structure of the
charge by the Agency.
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United States Environmental Protection Agency Human Studies Review Board
Chair
Celia B. Fisher, Ph.D., Marie Ward Do w Professor of Psychology, Director, Center for Ethics
Education, Fordham University, Department of Psychology, Bronx, NY
Vice Chair
William S. Brimijoin, Ph.D., Chair and Professor, Molecular Pharmacology and Experimental
Therapeutics, Mayo Foundation, Rochester, MN
Members
David C. Bellinger, Ph.D., Professor of Neurology, Harvard Medical School, Professor in the
Department of Environmental Health, Harvard School of Public Health, Children’s Hospital,
Boston, MA
Alicia Carriquiry, Ph.D., Professor, Department of Statistics, Iowa State University
Snedecor Hall, Ames, IA
Gary L. Chadwick, PharrnD, MPH, CIP, Associate Provost, Director, Office for Human Subjects
Protection, University of Rochester, Rochester, NY
Janice Chambers, Ph.D., D.A.B.T., William L. Giles Distinguished Professor, Director, Center
for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State
University, Mississippi State, MS
Richard Fenske, Ph.D., MPH, Professor, Department of Environmental and Occupational Health
Sciences, University of Washington, Seattle WA
Susan S. Fish, PharmD, MPH, Professor, Biostatistics & Epidemiology, Boston University
School of Public Health, Co-Director, MA in Clinical Investigation, Boston University School of
Medicine, Boston, MA
Suzanne C. Fitzpatrick, Ph.D., DABT, Senior Science Policy Analyst, Office of the
Commissioner, Office of Science and Health Coordination, U.S. Food and Drug Administration,
Rockville, MD
Kannan Krishnan, Ph.D., Professor, Département de sante environnementale et sante au travail,
Faculté de medicine, Université de Montréal, Montréal, Canada *
KyungMann Kim, Ph.D., CCRP, Professor & Associate Chair, Department of Biostatistics &
Medical Informatics, School of Medicine and Public Health, University of Wisconsin-Madison,
Madison, WI * *
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Michael D. Lebowitz, Ph.D., FCCP, Professor Emeritus of Medicine. University of Arizona,
Tucson, AZ
Lois D. Lehman-McKeeman, Ph.D., Distinguished Research Fellow, Discovery Toxicology,
Bristol-Myers Squibb Company, Princeton, NJ
Jerry A. Menikoff, M.D., Associate Professor of Law, Ethics & Medicine, Director of the
Institute for Bioethics, Law and Public Policy, University of Kansas Medical Center,
Kansas City, KS
Robert Nelson, M.D., Ph.D., Associate Professor of Anesthesiology and Critical Care,
Department of Anesthesiology and Critical Care, University of Pennsylvania School of
Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA “u
Sean Philpott, PhD, MS, Bioethics, Associate Director, Alden March Bioethics Institute, Albany
Medical Center, Albany, NY
Consultants to the Board
Col Raj K Gupta, Ph.D. BCE, Director, Science, Technology and Strategy, Headquarters, Walter
Reed Army Institute of Research, Silver Spring, MD
Daniel Strickman, Ph.D., National Program Leader, Veterinary, Medical, and Urban Entomology
United States Department of Agriculture, Agricultural Research Service, Beltsville, MD
Human Studies Review Board Staff
Paul I. Lewis, Ph.D., Designated Federal Officer, United States Environmental Protection
Agency, Washington, DC
* Recused from chloropicrin discussion and deliberation
**Not in attendance at the June 27-30, 2006 Public Meeting
** Resigned from Board effective September 27, 2006
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TABLE OF CONTENTS
INTRODUCTION 11
REVIEW PROCESS 12
CHARGE TO THE BOARD AND BOARD RESPONSE 14
1. Ch loropicrin 14
2. Insect Repellent Product Performance Testing Guideline 21
3. Insect Repellent Product Performance Efficacy Studies 43
4. Study EMD-003 from Carroll-Loye Biological Research 43
5. Study EMD-004 from Carroll-Loyc Biological Research 47
6. Occupational Handler Exposure Monitoring Studies 51
7. REFERENCES 67
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INTRODUCTION
On June 27-30, 2006, the United States Environmental Protection Agency’s (EPA or
Agency) Human Studies Review Board (HSRB) met to address scientific and ethical issues
surrounding a human toxicity study involving one pesticide active ingredient-chloropicrin;
guidelines for conducting insect repellant efficacy testing; protocols for conducting two insect
repellent efficacy studies; and protocols for conducting five occupational handler exposure
monitoring studies.
The Pesticide Registration Improvement Act (PR1A) requires that EPA complete its
decision-making process on certain types of applications to register a pesticide product within
specified amounts of time after receiving the application for registration. In addition, PRJA
established deadlines for EPA to complete “reregistration” of pesticide active ingredients that are
contained in pesticide products initially registered before 1984. Reregistration involves the
systematic reexamination of these older pesticides, applying contemporary scientific and
regulatory standards. When a pesticide active ingredient is approved for use on food, EPA
combines reregistration with the tolerance reassessment process mandated by the Food Quality
Protection Act of 1996 (FQPA).
Chloropicrin is undergoing reevaluation in the reregistration process. As part of the
review of the available toxicity data on chioropicrin, EPA had identified a study involving
intentional exposure of human subjects which EPA intends to use in its risk assessment. In
accordance with 40 CFR 26.1602, EPA sought HSRB review of this study.
EPA regulates pesticides intended for use on skin to repel arthropod pests. As part of the
application for registration of a new repellent, EPA requires data to demonstrate that the product
is effective. The Agency had developed a guideline for the conduct of such studies, and
presented it to the Board for comment. The Agency had also received protocols for two insect
repellent efficacy studies, and as required by the recently promulgated regulation, EPA is
required to submit the protocols to the HSRB for its review and comment. See 40 CFR 26.1601.
In addition, EPA routinely considers the human health risks of occupational handlers of
pesticides in both its reregistration program and as part of its review of an application for
registration pending under FIFRA and PRIA. EPA has received five protocols for conducting
new research involving human subjects to collect data on the levels of exposure received by
people when mixing, loading, and applying pesticides under various conditions. In accordance
with 40 CFR 26.1601, EPA sought HSRB review of these proposed protocols.
For the human studies or guidelines under consideration, the Agency provided the Board
with the complete study report or associated protocols and any supplements available to the
Agency. Similarly, guideline documents were included with appropriate background
information. Completed studies were assigned a unique identifier (e.g., the Master Record
Identifier-MRID), which the Agency uses to manage documents. When a company submits
multiple documents pertaining to a single study, each document is typically assigned a unique
tracking number.
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In addition, for each study, protocol or guideline to be evaluated, the Agency provided a
review of the ethical conduct. Each ethics review identified any deficiencies which were
identified compared to appropriate ethical standards. EPA has intentionally deferred making a
final determination of whether the chloropicrin study satisfies the ethical standards for
acceptability in 40 CFR sections 26.1704 — 26.1706, pending the advice of the Board.
For most studies and protocols, the Agency develops documents, called Data Evaluation
Records (DERs), containing a scientific review. The Board was provided with one or more
DERs for chioropicrin, the two proposed insect repellent efficacy protocols, and each of the five
Agricultural Handlers Exposure Taskforce (AHETF) protocols. DERs contain summaries of the
study design, methods and results, describe potential deficiencies, and provide conclusions about
the usefulness of the study in risk assessment.
In addition to the DERs, the Agency had prepared or included several other background
documents which address various elements of the issues to be reviewed by the HSRB. For
example, for the AHETF protocols, a number of types of documents had been provided including
transmittal documents and the charge questions, general background information pertaining to
the maimer in which the Agency completes exposure/risk assessments, the AHETF protocols
and various documents that the AHETF had developed related to the manner in which it intends
to conduct studies, the background documents related to the AHETF protocol review by the
Western Institutional Review Board of Olympia, Washington, and the EPA science and ethics
reviews of these protocols.
The Agency asked the HSRB to advise the Agency on a range of scientific and ethics
issues and on how proposed and completed studies should be assessed against the provisions in
40 CFR 26 of EPA’s final human studies rule. This report transmits the HSRB’s comments and
recommendations from its June 27-30, 2006 meeting.
REVIEW PROCESS
On June 27-30, 2006 the Board had a public face-to-face meeting in Arlington, Virginia.
Advance notice of the meeting was published in the Federal Register “Human Studies Review
Board: Notice of Public Meeting (71 Federal Register 32536 and 71 Federal Register 33747). At
the public meeting, following welcoming remarks from Agency officials, Celia B. Fisher, HRSB
Chair, proposed a set of scientific and ethics criteria consistent with the language of 71 Federal
Register 6137 to guide Board evaluation of completed studies. The Chair’s scientific criteria
asked the Board to consider the following two questions: (1) did the research design and
implementation meet scientific standards and (2) did the data generated by the study have
implications for the Agency’s Weight of the Evidence (WOE) review and, when applicable,
aspects of the risk assessment? The Chair reviewed the Chair’s science criteria and the Board’s
criteria for scientific standards for human dosing studies established at the Board’s May 2006
meeting. The Chair’s ethics criteria asked the Board to consider three questions: (1) did the
study fail to fully meet specific ethical standards prevalent at the time the research was
conducted; (2) was the conduct of the study fundamentally unethical (i.e., specifically was there
clear and convincing evidence that the research was intended to seriously harm participants or
failed to obtain informed consent); and (3) was the conduct of the study sign fIcantly deficient
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relative to the ethical standards prevailing at the time (i.e., was there clear and convincing
evidence that identified deficiencies that could have resulted in serious harm based on
knowledge available at the time the study was conducted or the information provided to
participants could seriously impair informed consent).
The Board then heard presentations from the Agency on the following topics: scientific
and ethical issues addressing a human toxicity study involving one pesticide active ingredient-
chloropicrin; guidelines for conducting insect repellant efficacy testing; protocols for conducting
two insect repellent efficacy studies; and protocols for conducting five occupational handler
exposure monitoring studies. At the Chair’s request the Board developed scientific and ethics
criteria for new human study protocols.
The Board heard oral public comments from the following individuals:
Chioropicrin
Robert Sielken, Ph.D., of Sielken and Associates and John Butala, Ph.D. of Toxicology
Consultants, Inc. on behalf of the Chloropicrin Task Force.
Jennifer Sass, Ph.D. on behalf of the Natural Resources Defense Council.
Guidelines For Conducting Insect Repellant Efficacy Testing
Scott Carroll, Ph.D., on behalf of the University California at Davis and Carroll-Loye Biological
Research.
Protocols For Conducting Insect Repellent Efficacy Studies: Study EMD-003 And Study EMD-
004
Scott Carroll, Ph.D., on behalf of Carroll-Loye Biological Research.
Mr. Dan Giambattisto on behalf of EMD Chemicals, Inc.
Mr. Niketas Spero on behalf of Insect Control and Research, Inc.
Protocols For Conducting Occupational Handler Exposure Monitoring Studies: Study AHE34.
Study AHE36. Study AHE37,. Study AHE38 And AHIE42
Victor Canez, Ph.D., Elliot Gordon, Ph.D., Mr. Curt Lunchick, and Mr. Larry Smith on behalf of
the Agricultural Exposure Handlers Task Force
Ms. She lly Davis on behalf of Farmworker Justice Fund
In addition, the Board received written public comments from the Agricultural Exposure
Handlers Task Force, Carroll-Loye Biological Research, the Farmworker Justice Fund, the FMC
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Corporation, Toxicology Consultants, Inc. and the Walter Reed Army Institute of Research,
Vector Control/Repellents Program.
For their deliberations, the Board considered the materials presented at the meeting,
written public comments and Agency background documents (e.g. pesticide human study,
Agency data evaluation record (DER) of the pesticide human study, weight of evidence review,
ethics review, pesticide human study protocol and Agency evaluation of the protocol).
CHARGE TO THE BOARD AND BOARD RESPONSE
Chioropicrin
Charge to the Board
Chioropicrin is a non-selective soil fumigant whose primary toxic effect is sensory
irritation in which stimulated free nerve endings mediate sensations and clinical signs in the
nose, eyes, throat, and upper respiratory tract. Chioropicrin is a unique soil fumigant in that it is
also used as an indicator chemical or warning agent (2% or less by weight in formulations). The
Agency is developing an assessment to estimate inhalation risk to bystanders and workers from
acute exposures to chioropicrin.
Scientific considerations
The Agency’s “Weight of Evidence” (WOE) document and Data Evaluation Records
(DER) for chioropicrin described the study design of the acute inhalation, human toxicity study.
The Agency had concluded that the human toxicity study was appropriate for developing a point
of departure for extrapolation of inhalation risk to bystanders and workers exposed to
chloropicrin.
Please comment on whether the study was sufficiently sound, from a scientific
perspective, to be used to estimate a safe level of inhalation exposure to chloropicrin.
Board Response to the Charge
Background of Study
To determine a subject’s sensitivity for the detection and characterization of feel to the
human eye, nose, and/or throat produced by chioropicrin vapors, as well as the odor threshold,
healthy volunteers (18 to 35 years of age, average 23 years) were exposed to a range of vapor
concentrations and exposure durations in a controlled laboratory setting. The investigation
consisted of three phases, very brief exposures (Phase I) and more extensive exposures (Phases II
and III). These phases are described in more detail below.
The study report cited Krieger (1996) as a review of the risks to workers from exposure
to chioropicrin in agricultural applications. It appeared that this reference was relied upon for
basing concentration and duration for the human sensory study. From this reference, a time-
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weighted average of 0.1 ppm (100 ppb) was indicated to evoke no response in humans. The
report then indicated concentrations of 0.15 to 0.3 ppm would evoke concentration-dependent
sensory detection via chemesthesis, as well as reflex tearing and cough. Concentrations above
0.3 ppm would evoke an increasing degree of irritation. Odor was noted as occurring at about 0.9
ppm. The extended phases were focused on concentrations of likely occupational relevance,
both below and just above 100 ppb, the ACGIH (American Conference of Governmental
Industrial Hygenists) threshold Limit Value (TLV) and OSHA Permissible Exposure Limit
(PEL).
Statistical analyses including all subjects for each phase of the study were provided in the
study report. The EPA provided a logistical regression when appropriate as well as an analysis
for only those subjects positively detecting chloropicrin for Phases I and II of the study.
Additionally, the EPA provided a summary of the benchmark concentration analysis that was
performed by TERA.
Phases of Study
Phase I: The objective of Phase I was the identification of chloropicrin by odor (both
nostrils, single sniff), eye feel (one eye, 25 seconds), or nasal feel (one nostril, 7 seconds) at 356
ppb, 533 ppb, 800 ppb and 1200 ppb generated from a vapor delivery device. Phase I consisted
of 62 subjects (32 male and 30 female) for odor and 63 subjects (32 male and 31 female) for eye
feel. The same subjects participated for both odor and eye feel. Confidence of feel was rated 1 to
5, with 1= very low, 3= moderate, and 5= very high confidence. Severity of feel was not rated in
Phase I. For Phase 1, approximately 10% to 13% of subjects failed to detect either odor or eye
feel after momentary exposures to chioropicrin over the range evaluated. Approximately 13% (8
of 62) of subjects (5/30 female and 3/32 male) failed to detect the odor of chioropicrin over the
range of concentrations evaluated. Approximately 11% (7/63) of subjects failed to detect eye feel
(two male and five female) at any concentration. The feel of chioropicrin in the nose was not a
reliable endpoint and was therefore dropped prematurely from the Phase I study by the study
director. The median concentration of all subjects for detection of eye feel was 900 ppb, or 790
ppb for males and 1010 ppb for females, although this gender difference was not significant. The
median for only those subjects detecting odor was 356 ppb while eye feel was between 356 ppb
and 533 ppb.
Phase II: The purpose of Phase II was the detection of chloropicrin in the eyes, nose,
andlor throat during exposure to 50 ppb, 75 ppb, 100 ppb, or 150 ppb chloropicrin vapor in a
walk-in chamber for 20-30 minutes. (Odor was not studied in Phase II). A total of 62 subjects
(32 male and 30 female) participated in Phase II. 12 of 30 female subjects and 14 of 32 male
subjects also participated in Phase I of the study. Subjects responded “yes” for a positive feel or
“no” for no feel. A level of confidence to each event (eye, nose, throat) was also recorded with
1 not certain, 2= moderately certain, and 3 very certain. The first exposure in a day consisted
of a known blank (air). This exposure served to acclimate the subjects to the task in the chamber.
The subjects were asked to perform ratings as they would for future blinded exposures. One
female subject left the exposure chamber after 16 minutes of chloropicrin at 75 ppb. An
explanation for this subject’s premature exit from the chamber was not provided. At 150 ppb,
this same subject along with another male in the chamber left the chamber after 15 minutes. On
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a separate day of testing, one female and one male subject also left the exposure chamber after
15 minutes of exposure to 150 ppb. Again, no explanation was given for these subjects’
premature departure from the chamber. No subjects left the chamber at 50 ppb or 100 ppb. The
results of Phase II indicated that eye feel was more sensitive than either nose or throat feel.
ANOVA results provided in the study report indicated that concentration and duration were
significant (p<0.0001) for the eye response only. As a group, subjects differentiated 50 ppb
chioropicrin in the eyes from the blank after 20 minutes of exposure. Differentiation from blank
occurred after 5 minutes at 75 ppb, 3 minutes at 100 ppb, and 2 minutes at 150 ppb. There were
no significant statistical interactions of response with sex for the eyes, nose, or throat responses.
On an individual basis, binary detection indicators (yes/no) developed by the Agency were
combined by participant across dose levels. Using eye feel as a marker of detection of the
chemical, 20 of the 62 participants (32%) could not detect chioropicrin at any concentration:12
of 30(40%) females and 8 of 32 (25%) males failed to make progress toward eye feeling over a
30 minute period of exposure. In addition, 46/62 (74%) and 48/62 (77%) subjects could not
detect the chemical via the nose or throat, respectively at any concentration, again indicating the
greater sensitivity of the eye.
Phase III: The goal of Phase III was the detection of chioropicrin vapor as evidenced by
irritation to the eyes, nose and/or throat after 1 hour (60 minute) exposures repeated over 4
consecutive days. Concentrations tested included blank (air), 100 ppb, and 150 ppb. This phase
included a clinical exam of the eyes, nose and throat, as well as pulmonary function testing with
the outcome variable FEV1 (Forced Expiratory Volume) and FVC (Forced Vital Capacity),
rhinomanometry, and nasal cytology. In addition, an assessment was performed based on ocular
cytology from samples of cells taken from the conjunctival membrane inside the lower eyelid
and from the concentration of exhaled nitric oxide sampled from the lung (eNO) and nose
(nNO). Subjects participated in 3 cycles [ (6 days per cycle) of 6 sessions, each beginning on
Friday and ending on the subsequent Friday] (no measurements taken on Saturday or Sunday).
Subjects remained in exposure chambers for 1 hour per session on Monday through Thursday (4
consecutive days). The 3 cycles included exposure to 100 ppb, 150 ppb, and just air (blank). The
order in which the subject was exposed to these concentrations was random to prevent
confounding. At least one week separated the end of one cycle of exposures and the beginning of
another for each subject. Subjects rated their symptoms in three setting: (1) severity of effect for
eye, nose, and throat while in the chamber (0= no symptom to 3 severe); (2) before and after
exposure in the chamber and at the beginning and end of each week of exposures; and (3) at the
beginning and end of a cycle of exposure. Symptoms were rated using the Rhinconjunctivitis
Quality of Life Questionnaire (RQLQ), a series of 28 questions in seven domains, where the
subjects used a seven point scale from Not Troubled to Very Troubled. The first two instruments
referred to how the subject felt at the time of rating, the RQLQ referred to how the subject felt
over the previous week. When in the exposure chamber, subjects rated symptoms (0 to 3) after
30 seconds, at 1 minute, and every minute until the end of the exposure at 60 minutes. Every 10
minutes, study personnel read and recorded the subjects’ blood oxygen saturation from a pulse
oximeter attached to the finger (data not included in report). A total of 15 males and 17 females
participated in Phase Ill. Two females in Phase III also participated in Phases I and II. One male
in Phase III also participated in Phases I and II and one male in Phase III participated in Phase II
only.
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Results of the Study
For Phase II, one female subject left at 75 ppb and again at 150 ppb with another male.
On a separate testing day, one female and male left the chamber prematurely at 150 ppb. 38% (8
males and 8 females) of subjects detected chloropicrin initially at 50 ppb and consistently up to
150 ppb. Subjects gave higher ratings to symptoms in the eye than to those in the nose and
throat. Subjects gave nominally slightly higher ratings in the nose than in the throat, but
expressed no symptoms of consequence at either site. There was no indication of intensification
of symptoms based on subject scoring for any parameter on the consecutive days of exposure.
For the eye, the study report ANOVA indicated Level of Exposure (p<0.00 1) and interaction of
Level of Exposure by Duration of Exposure was significant (p<0.001). An ANOVA also
revealed an effect of Level of Exposure by Day (p
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significance achieved. Exhaled nitric oxide by the lungs (eNO) equaled 37.8 before exposure
and 39.2 after exposure with no significance achieved. Sex was not significant for any of
interactions of the three lower respiratory variables. Two upper respiratory alterations, nNO
(nasal nitric oxide) and flow, were observed for one-hour exposures that occurred only day by
day. For the upper respiratory variables (nNO, inspiratory flow, expiratory flow), nNO was
significant for Level of Exposure by Order of Exposure with 399 ppb before exposure and 425
ppb after exposure (p=0.012). Level of Exposure by Order of Exposure by Day was not
significant. nNO increased 1% after exposure to blank, 10% after exposure to 100 ppb, and 8%
after exposure to 150 ppb. The effect of nNO did not continue from one day to the next.
Inspiratory flow and expiratory flow equaled 450 and 415 mL/sec, respectively, before exposure
and 435 and 406 mL/sec, respectively, after exposure.
Chioropicrin had a differential effect on flow. Level of Exposure by Order of Exposure
was nearly significant (p=0.087). However, Level of Exposure by Order of Exposure by Day
was not significant. Flow decreased 2% after exposure to blank and increased 2% after exposure
to 100 ppb chioropicrin, however, flow decreased by 8% after exposure to 150 ppb. Sex was not
significant in any of the relevant interactions for the upper respiratory variables. Physiological
effects such as changes in nNO and flow rate may indicate signs of nasal congestion and
engorgement.
Cell types and cell numbers from the Rhinoprobe samples were approximately the same
at the end of each cycle as at the beginning. For the RQLQ questionnaire results, nasal
congestion was the only parameter that reached a level where more than half of the subjects gave
a response above zero. 53% of subjects reported a non-zero response to congestion after 4 days
of exposure to the blank vs. 41% and 34% after exposures to 150 ppb and 100 ppb, respectively.
The average ratings equaled 0.53, 0.34, and 0.41 for the blank, 100 ppb, and 150 ppb,
respectively, where a rating of 1 signified hardly troubled at all. Watery eyes, sore eyes, and
swollen eyes were scored higher by subjects after exposure to either 100 or 150 ppb chioropicrin
than to the blank. The Q test revealed significance for the sore eyes only (p<0.05). The highest
rating given after exposure to swollen eyes was 0.47.
The LOAEL was determined to be 100 ppb, the lowest concentration tested, based on eye
irritation, increased nasal nitric oxide (nNO), and differential effect on inspiratory and expiratory
flow. A NOAEL was not established in Phase III.
Critiuue of the Study
Strengths:
This was an excellent scientific study of eye, upper and lower respiratory irritant effects
at various concentrations over various short term (i.e., acute effects) time periods. The objective
and subjective measurements and the statistics were reasonable. Most importantly, Phase III of
the study provided evidence of upper airway (nasal) respiratory effects and established a
LOAEL.
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Weaknesses:
Concentrations below 100 ppb were not investigated in Phase III so as to compare with
results from Phase II.
HSRB Consensus and Rationale
The chioropicrin acute inhalation, human toxicity study, was scientifically sound for the
purpose of estimating a safe level of inhalation exposure to chloropicrin. A LOAEL of 100 ppb
was a scientifically justified point of departure (POD). While the Board agreed that the
BMCLIO data from the Phase III study was scientifically sound to derive a benchmark
concentration estimate, it stressed that non-responders should not be excluded from such an
analysis. The Board also emphasized the importance of the inhalation data for irritation effects.
Charge to the Board
Ethical considerations
The Agency requests that the Board provide comment on the following:
a. Was there clear and convincing evidence that the conduct of the Cain study was fundamentally
unethical?
b. Was there clear and convincing evidence that the conduct of the study was significantly
deficient relative to the ethical standards prevailing at the time the research was conducted?
Board Response to the Charge
The Cain study was conducted from 2002 through 2004. The study was performed in La
Jolla, California by researchers at the Chemosensory Perception Laboratory of the University of
California, San Diego. The study sponsor was the Chloropicrin Manufacturers Task Force,
whose mailing address is in care of Steptoe & Johnson, LLP, 1330 Connecticut Avenue, NW,
Washington, D.C. The documents provided by the sponsor specifically stated that the research
was to be conducted with the approval of an Institutional Review Board (IRB) at the University
of California, San Diego, and in compliance with the Human Subject’s Bill of Rights (a
provision of California law). The study was in fact reviewed and approved by an IRB at that
university, and the university had provided documentation that it held a Federalwide Assurance
with the Department of Health and Human Services. The documentation provided by the
university’s Human Research Protections Program indicated that it reviewed this study pursuant
to the standards of the Common Rule (45 CFR 46, Subpart A) and determined it to be in
compliance with that Rule.
Critique of Study
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The Board concurred with the factual observations of the strengths and weaknesses of the
Cain study, as detailed by the EPA (USEPA 2006a). The Board wanted to comment on several
specific aspects of the study:
1. The consent forms stated that ch loropicrin “is used commonly to fumigate fields for
planting and as a warning agent in structural fumigation.” It made no mention of prior uses of
this compound for the intentional purpose of harming and even killing people. As noted in one of
the documents supplied by the EPA (Prentiss 1937), chloropicrin “appears to have been the most
widely used combat gas” in World War I. That reference further notes that “as a war gas [ it] has
a number of desirable offensive properties,” and like phosgene gas, “it is a lethal compound.”
Some members of the Board concluded that in the context of being asked to participate in a study
to determine more information about the harmful effects of this gas on human beings, the
subjects should have been informed about the historical use of chloropicrin as a war gas. Others
concluded that the dose levels and other conditions were significantly distinct from the war use
that reference to those usages were not necessary for an infonned participation decision.
2. The consent forms, in describing the likely risks of participating in the study, noted
that “ [ e]xposure to chloropicrin in amounts greater than anticipated in the studies have resulted
in temporary tearing and painful stinging eyes and nausea and vomiting that are completely
reversible after the exposure.” Some members of the Board believed that this statement was
inaccurate in describing the possible risks of exposure to “greater” amounts of choloropicrin
(which, as noted in item 1 above, if in a sufficiently high dose, is well known to cause substantial
permanent effects, up to and including death). Those members concluded that the consent form
should have been more truthful in describing the possible consequences of exposure to high
doses of chloropicrin (though it could also have explained why it would not be the case that the
subjects could ever end up being exposed to such high doses as a result of participation in the
study).
3. The consent form, in describing the purpose of the study, stated that it was “intended to
provide information regarding safe levels of exposure.” This language might suggest to many
prospective subjects that the study was being conducted to see if it is important to create
increased restrictions on the use of this compound. Some members of the Board believed that
the consent form should have explicitly stated that this study was unlikely to lead to increased
restrictions and, in fact, its results, if they led to any regulatory changes, would more likely be
used to allow greater exposures of people to ch loropicrin.
HSRB Consensus and Rationale
The Board concluded that:
There was not clear and convincing evidence that the conduct of the research was
fundamentally unethical (e.g., the research was intended to seriously harm participants or failed
to obtain informed consent).
There was not clear and convincing evidence that the conduct of the study was
significantly deficient relative to the ethical standards prevailing when the study was conducted.
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The Board reached these two determinations on its conclusion that this study, based on
the evidence presented, deviated from, but was not significantly deficient relative to, the ethical
standards prevailing when the study was conducted.
Insect Repellent Product Performance Testing Guideline
Charge to the Board
The U.S. EPA Office of Pesticide Programs requested that the HSRB review and
comment on the draft “Product Performance of Skin-Applied Repel lents of Insects and Other
Arthropods” Testing Guideline in order to determine what changes, if any, are necessary for the
guideline to be made consistent with the requirements for protection of human research subjects
set forth in 40 CFR part 26. Below is a list of questions that focus on these topics.
a. What actions should an investigator routinely take to minimize the risks to human subjects
exposed during laboratory and field research on the efficacy of repellents?
Board Response to the Charge
The Board began its review by emphasizing that human studies are essential to assess the
efficacy of repelling insects and other arthropods. The only way to determine if these repellents
are effective is to test them on or near humans, since animals would not have the same level of
attractiveness to the arthropods as humans will.
The following comprehensive list of conditions should be considered by the investigator
in order to minimize risks to human subjects. The Board’s response to the Agency’s charge
focused primarily on the ethical considerations and only secondarily on the toxicity data base per
Se.
(1) IRB approval is required before initiating any human exposures.
(2) Initial human tests should be conducted in a laboratory setting, using insects and other
arthropods which are known to be disease-free.
(3) Healthy volunteers should be selected who are not sensitive to chemical reactions or
drug/cosmetic allergies, and not allergic or overly sensitive to arthropod bites and stings. The
subjects selected should not be known to experience any adverse drug reactions or allergies to
other substances or toxins, and the selected subjects should not be taking any drugs which might
elicit an adverse drug reaction (if the predictions from studies of metabolism of the repellent
suggest that drug-chemical interactions might occur at the level of metabolism).
(4) If no known information about exposures in humans is available, testing should begin with
the low dose levels and if no adverse reactions are displayed, rise gradually to the level of
exposure anticipated to be used in humans. The formulations should be the same as that
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expected to be applied on human skin. If another formulation is anticipated, such as a coil, then
it should also be tested in laboratory experiments.
(5) Although insect repellents would not be expected to yield adverse effects, test subjects should
be under close observation by an observer trained to detect, as well as listen to the subject, for
any adverse reactions. If such adverse reactions are observed, this would be grounds for
terminating the exposure as soon and as completely as possible.
(6) The laboratory results would need to show a substantial likelihood of repellency before field
tests should be initiated because of the possibility of subject exposure to disease-carrying
arthropods.
(7) The field region for tests should have as low as possible incidence of known disease-agent
infested insects or arthropods (prior trapping and microbial assays should document this minimal
risk).
(8) The lowest possible number of untreated controls needed to ensure scientific validity should
be used in field tests.
(9) The overall toxicity, in terms of both the toxic effects and the levels at which these toxic
effects occur, should be determined from the existing animal data base. The search on existing
animal data should include acute, chronic, reproductive, eye and skin irritation and dermal
sensitization, so that the most reliable information on potential human adverse effects is known.
(10) Any human data from controlled or inadvertent exposures, or from routine uses in the past
or in other countries should be accumulated. This information should be analyzed for evidence
of direct toxic effects or any adverse side effects, including allergic or sensitization reactions.
(11) The test compound should be compared to data bases on similar chemical classes of
compounds so that educated predictions can be made of types of toxicity that might be elicited in
humans, the likelihood of allergic or sensitization reactions, the likely disposition and
pharmacokinetics of the compound, including absorption, metabolism and clearance. In
addition, the metabolism of the compound should be known from in vitro tests using human liver
samples, in order to predict the toxicity or lack thereof of probable metabolites and to predict the
enzymes involved in the compound’s major routes of metabolism. This information on
metabolism would be useful to predict any likely interactions with drugs that an individual might
be taking.
HSRB Consensus and Rationale
The consensus of the Board was that studies involving humans are necessary to evaluate
the efficacy of products to repel insects and other arthropods. Risk identification and
minimization are also essential. In their protocols, investigators should adequately identifS risk
to participants and describe adequate steps they would take to minimize these risks.
Charge to the Board
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b. What types of toxicity data should be routinely generated before an investigator conducts
repellent efficacy testing on human subjects with a new product?
Board Response to the Charge
In response to the question, the Board proposed a set of data that would meet this
requirement:
• The initial evaluation of a compound should include an analysis of chemical structure
that emphasizes the detection of possible adverse effects. The analysis can be informed
by comparisons with repellents of similar chemotypes for which toxicity data exist. A
variety of computer applications and predictive models should be used to predict
potential alerts for metabolic activation, target organ toxicity or mutagenesis. This type
of evaluation can include the comparison to similar chemotypes of repellents for which
toxicity data exist.
• Acute (single dose) toxicity studies should be conducted, with emphasis on the intended
route(s) of exposure to the chemical.
• Dermal and ocular irritation should be evaluated. Characteristics of the potential for
dermal sensitization and nasal-pharyngeal sensitization or triggering should be
considered.
• Absorption of the compound after administration by the route of intended exposure, most
likely dermal, should be determined. This can be done in laboratory animals, but may
also be done using in vitro assessments of percutaneous absorption in human skin or
human skin surrogates. If conducted in animals, the study should include an assessment
of the routes of elimination of the compound.
• The mutagenic and clastogenic potential of the compound should be determined. At this
stage, this analysis could be an abbreviated battery of in vitro genetic toxicology tests.
• Some data on toxicity in a repeat dosing paradigm should be generated. This is
particularly important if the compound is available systemically.
• If the compound is available systemically, its metabolic fate should be investigated and it
should be determined whether humans are likely to metabolize the compound in a
manner that is qualitatively or quantitatively different from laboratory animals is
recommended.
It should be noted that, although the Board has made these recommendations for toxicity
data, it did not specify the precise methods by which the data set listed above should be
generated. The use of animal models, validated in vitro methods or robust predictive tools could
be used in combination to generate the recommended data set. Furthermore, if an investigator
desires to carry out multiple exposures of a given compound in human subjects, then additional
data, with emphasis on subacute and/or subchronic toxicity and the assessment of reproductive
hazard, should be included in the toxicology evaluation.
In addition to the toxicity data summarized above, information on the mode of action,
potency and projected human dose is useful adjunct information for assessing any potential risk
associated with human exposure. Dose selection for efficacy studies in humans should be
justified on the basis of animal toxicity studies and/or other relevant data (e.g., from in
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pharmaco-kinetic computer modeling, in vitro studies, and human case series). Present
guidelines specify that the amount applied should be up to the typical maximum dose applied by
consumers, with recognition that some clarification or comparison with the toxicology
benchmarks from animal studies will aid in dose selection (e.g., lowest NOAEL from sub-
chronic studies) and protect human health.
HSRB Consensus and Rationale
The consensus of the Board was that the minimum set of toxicity data (as delinieated above)
that should be routinely generated before an investigator conducts repellent efficacy testing on
human subjects with a new product is that which will assure that subjects would not be at risk of
permanent or irreversible harm.
Charge to the Board
c. In private and university research laboratories, investigators themselves have sometimes
served as research subjects when assessing chemicals for insect repellent activity. What scientific
and ethical issues would such a practice raise? Under what conditions, if any, would such a
practice be acceptable?
Board Response to the Charge
The topic of self-experimentation has been discussed and debated for many years, and the
debate is likely to continue. The scientific and ethical issues presented in the assessment of insect
repellents are not different from the issues of self-experimentation in clinical research in general.
There is not a clear overarching answer; each study may present a different situation.
Arguments in favor of self-experimentation
There is a long and noble history of investigators experimenting on themselves.
Experiments on yellow fever, pernicious anemia, morphine and cocaine as local anesthetics, H.
pylon as the causative agent for gastric ulcers, and many others have been instances of
researchers using themselves as research subjects.
The Nuremberg Code, written in 1947 as part of the criminal trials of the Nazi doctors,
states “5. No experiment should be conducted where there is an apnioni reason to believe that
death or disabling injury will occur; except, perhaps, in those experiments where the
experimental physicians also serve as subjects” (USOPO, 1949). If a researcher is not willing to
assume the risk of harm from research participation, how can that same researcher ask anyone
else to assume that same risk?
Ethical research in compliance with 40 CFR 26 requires voluntary informed consent.
Who better understands those risks than the researcher? Who best understands the societal or
scientific benefits of the knowledge to be gained from the experiment? There is no chance of
misunderstanding information in the consent process.
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If the ethical and scientific arguments against self-experimentation can be addressed
adequately, then self-experimentation seems quite reasonable.
Arguments against self-experimentation
Ethical Considerations
Many have objected to self-experimentation on scientific and ethical bases but their
arguments can all be addressed with proper planning and conduct of the research protocol. For
this reason, self-experimentation is not per se unethical or scientifically flawed per se.
One argument against self-experimentation is that researchers may take unreasonable
risks with their own health due to a blinding belief in the importance of the research question, as
well as personal incentives such as career advancement. Addressing this concern properly
requires independent review of the study in order to ensure that the risks are reasonable in
relationship to the potential benefits of the research. Therefore, the study must be IRB approved
prior to its conduct. As part of its review, the IRB must assure that “risks to subjects are
reasonable in relation to anticipated benefits, if any, to subjects, and the importance of the
knowledge that may reasonably be expected to result” as stated at 40CFR26.1 11 1(a)(2).
Potential coercion of co-investigators and research staff by the principal investigator is
another area of concern. For this reason, self-experimentation should be limited to the principal
investigator in most circumstances. Co-investigators and research staff (junior members of the
research team) should not be enrolled in a study if the principal investigator has power or
authority over them in the research setting or in any other setting (e.g., classroom or other work
environment). Situations such as these can lead to coercion or undue influence on subordinates
to participate in the research, and should be avoided, except when there is an IRB approved
protocol that would and allow for truly voluntary participation.
Scientific Considerations
There are many scientific issues that must be addressed in order for self-experimentation
to produce scientifically sound data that would be useful and generalizable at the end of the
experiment.
One issue involves the type of outcome measure used in the research. If the outcome
measure is a subjective one, then the expectation of the self-experimenter is likely to influence
the results. This bias may lead to an incorrect study conclusion. To address this problem, self-
experimentation should occur only in research protocols with objective outcome measures. The
investigator-subject should not assess their own outcomes. The outcome assessor should be
blinded to the subject’s identity, if possible. In addition, the burden of proof is on the principal
investigator to demonstrate how their participation does not introduce bias into the study results.
Oversight of the study is another issue of concern in self-experimentation. Since the
principal investigator is responsible for study oversight, this oversight can be compromised
during the time that the principal investigator is a research subject. Can the experiment be safely
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completed, for example, if the investigator became incapacitated while a research subject? This
objection can be addressed by identifying the person responsible for study oversight while the
principal investigator is a subject and if the principal investigator becomes unable to resume
study responsibilities.
Many of the stories of self-experimentation in the history of medicine have used a sample
of one; the researcher was the only subject. These studies thus lacked proper controls and did not
account for inter-individual variability. Such studies were poorly designed to answer a research
study question with rigorous methodology. To address this, a well-written protocol is required,
which must have a sample size that is adequate to answer the study question being asked.
Concern also has been raised about whether investigators are thorough in their evaluation
of whether they meet all of the study’s inclusion and exclusion criteria. If researchers are
convinced that they should be and really want to be subjects, they might not perform all
screening tests that are required by the protocol. This issue can be easily addressed by having
another investigator perform and assess the screening results. The principal investigator’s
eligibility to participate in the study should be assessed independently by someone outside the
research team, to avoid potential coercive influence of the principal investigator on the sub-
investigator.
HSRB Consensus and Rationale
It may not be a priori unethical or scientifically problematic for a principal investigator to
be a subject in his/her own study ff:
I. The study was approved by an IRB in the same manner as was required for most human
subjects research;
2. The following scientific issues were addressed:
a. Principal investigator met all enrollment criteria;
b. The study was a well controlled trial with a justified sample size adequate to answer
the study question with statistical surety (Occasionally a study with a small sample size may be
scientifically and ethically appropriate if it is a pilot or feasibility study. However, justification
for the sample size chosen is still necessary, although such justification may not be a statistical
one. In such a situation, (c) does not apply);
c. The principal investigator is one of many subjects, accounting for normal human
variability, and allowing results to be generalized to a broad population; and
d. The outcome measure is objective and measured by another (blinded, when possible)
investigator;
3. A plan is in place to ensure the integrity and safety of the study while the principal
investigator was a subject.
4. A plan is in place to ensure for study oversight if the principal investigator becomes
incapacitated;
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5. Participation of other research staff and employees is prohibited except in those cases where
issues of coercion/undue influence can be addressed, which may or may not be possible; and
6. The investigator justifies why he/she should be a research subject in the study.
Charge to the Board
d. Please comment on the scientific and ethical issues arising from the use of (or decision not to
use) negative controls groups in repellent efficacy studies, in both laboratory and field studies.
Board Response to the Charge
Scientific Considerations
Negative controls (i.e., untreated/unprotected) are used in repellant studies to show
“biting pressure”. This can be categorized as sufficient, insufficient, or it can be quantitatively
measured (bites/minute over time). Negative controls are also used in field studies to confirm
effectiveness that is shown in laboratory studies.
The use of a control group has been an essential characteristic of repellent efficacy
studies conducted in the laboratory, because a comparison of the data from the treatment and
control groups shows a measure of efficacy. The use of negative control groups in laboratory
studies appears to be a safe practice, since the insects involved are known to be disease-free. In
contrast, the uncontrolled nature of field studies means that the same assurances cannot be
provided to participants. Because negative controls are not exposed to the pesticidal active
ingredient, there is no risk of toxicity from the chemical. The risk of harm and discomfort for
subjects is primarily of two types. In laboratory and field studies, there is the discomfort of the
bite itself, which might include minor pain, itching and swelling. The discomfort experienced by
humans is variable, some having negligible reaction, others having a definite allergic response.
In addition to this risk, field trials have the added risk of subjects acquiring a vector-borne
infection. Fortunately, field procedures, such as capture of insects just prior to biting can reduce
such risk substantially. In addition, because negative controls are not exposed to the pesticidal
active ingredient, there is no risk of toxicity from the chemical.
Nonetheless, the Board failed to reach consensus regarding negative control groups in
field studies of repellent effectiveness. The basic scientific justification for such controls is to
confirm that “biting pressure” exists. If that is the only purpose, a single negative control may
suffice. As some Board members suggested, biting pressure might even be established through
trapping or other methods that did not involve an unprotected human subject. Other Board
members recognized, however, that it may be important to establish a particular level of biting
pressure in order to compare the extent and duration of repellency from trial to trial and
compound to compound. In fact, that condition appears to be essential for accurate product
labeling. In any case, since even one unprotected human subject could be at risk of vector-borne
disease, the use of negative control groups should not be a default component in the design of
repellency studies. Instead it should be justified in each protocol in which it is proposed.
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Ethical Considerations
By minimizing risk in the laboratory studies (e.g. screening for past sensitive reactions,
captive breeding of infection-free insects, and mechanical aspiration at bite), the use of negative
controls in the laboratory should not be considered ethically problematic as long as it is
scientifically justified. Steps can, and should be taken to minimize risk in field studies.
However, the risk of a significant life altering infection can never be reduced to zero. Thus, the
potential benefit from such studies must justify this risk. The science must be sound and
alternative approaches - such as live trapping or laboratory studies - must be shown to be
inadequate. The consent process must be truly informed and subjects must be volunteers with
the full right of withdrawal. These issues must be specifically and completely addressed in the
study protocol.
HSRB Consensus and Rationale
The HSRB suggested that the Agency modify the guideline to say that negative controls
“may be” needed (instead of “are”) and that examples be given both for when negative controls
are needed and when they are not. The language on positive controls may also benefit from
further expansion and clarification.
Charge to the Board
e. Please comment on the scientific and ethical issues raised by the design of studies to collect
data sufficient to support assessment of repellent efficacy using the two different efficacy
metrics: time to first confirmed bite (TFCB), and time providing x% protection of treated
subjects from bites relative to untreated controls (RP).
Board Response to the Charge
The distinction between efficacy and effectiveness is useful in answering the questions
about the Insect Repellent Product Performance Testing Guideline. Although the efficacy of a
repellent can be established using laboratory techniques, the effectiveness of a repellent can only
be established in the field under actual use conditions.
Scientific Considerations
A particular study design can either minimize risk to all subjects enrolled in a study (for
example by using only laboratory mosquitoes or ticks to eliminate the possibility of vector-borne
diseases, excluding those who might adversely react to the insect bites), and/or minimize overall
risks by reducing the number of “at risk” subjects to the lowest number possible while
maintaining scientific integrity, pretesting insects to confirm probable absence of vector borne
diseases, and/or utilizing techniques to remove insects prior to bite when feasible. Risk
minimization strategies will depend upon knowledge of variability in subject attractiveness, the
effectiveness of the repellent, the interaction of biting pressure to insect hunger and subject
attractiveness, characteristics of the test environment, and the scientific reliability of generalizing
insect performance from the lab to the field.
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A question was raised about the provision of prophylactic antibiotics or use of a
preventative vaccine in order to minimize risks. The difficulty with this approach is that the
effectiveness of these interventions would need to be established, and the dangers associated
with such treatments would become part of the overall assessment of whether the risks of the
research are offset by the importance of the knowledge to be achieved. The measurement of pre-
exposure and post exposure antibodies, unless done in a context to only include subjects who are
immune to the vector borne disease of concern, does not minimize risk other than documenting
the presence of the subject’s immune response. Overall, the best approach is to choose a study
design that either eliminates or minimizes the risk of vector-borne diseases.
Ethical Considerations
The time to first confirmed bite, or the time to first confirmed “intent to bite” (if
ascertainable), has the ethical advantage of minimizing the risk of exposure to vector-borne
diseases. However, based on the background materials for the meeting, the use of relative
protection can be an appropriate outcome measure based on statistical advantage. Relative
protection could thus be an appropriate outcome measure for a laboratory based efficacy study.
As long as there was a sufficient “biting pressure”, one could then do a measure of the duration
of relative protection for protected subjects in a field study and compare it to laboratory based
measurements. This could also be done using time to first confirmed bite.
Participation in insect repellent research offers no direct benefit to subjects when their
exposure to insects or arthropods is for the purpose of the study given the presence of existing
insect repellents on the market. As such, the sponsors of repellent efficacy research are obligated
to provide insurance to cover possible future medical costs that result from injury or illness
experienced by the subjects as a consequence of their participation in the research. It is less clear
whether sponsors would have an obligation to provide for lost income in such instances. As
noted previously, protocols must justify the level of risk by the probability and social value of
the benefits, adequately identify all risks, and present a description of adequate steps to minimize
the risks.
The informed consent materials also must provide information about the prevalence and
risks of any vector borne diseases (if applicable), the consequences of acquiring such a disease as
a result of the research, and the availability of effective insect repellents outside of the research.
HSRB Consensus and Rationale
The Board consensus was that the time to first confirmed bite, or the time to first
confirmed “intent to bite” (if ascertainable), has the advantage of minimizing risk of vector-borne
diseases. However, for some studies there is a statistical advantage for the use of relative
protection as an appropriate outcome measure. Since relative protection procedures in field
studies increases the risk of vector-borne diseases, protocols must: (a) justify the level of risk by
the probability and social value of the benefits; (b) adequately identify all risks; (c) present a
description of adequate steps to minimize the risks; and (d) provide consent materials that
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include information about the prevalence and risks of any vector-borne diseases, consequences
of contracting disease, and alternative effective repellents outside of the research.
Charge to the Board
f. Please comment on appropriate approaches for estimating the minimum number of subjects
needed to evaluate the level of efficacy of a repellent in laboratory and field studies.
Board Response to the Charge
Introduction
As written, the current draft of the Guidelines suggests that six should be the minimum
number of research subjects in laboratory or field experiments where the efficacy of an insect
repellent is investigated. It is not clear from the Guidelines whether the number refers to the
entire experiment or to the number of subjects allocated to each treatment under consideration.
The Board argues below that establishing a single sample size for all types of experimental
designs and objectives is not the most appropriate approach.
Critique
Correctly estimating the sample size that is needed in an experiment (conducted either in
a laboratory or in the field) is important to ensure reliable inferences about the treatment under
study. Sample size calculations can be carried out using several approaches, but the two most
common ones (at least in tenns of usage) are based on:
• Power calculations: sample size is chosen to guarantee that tests of hypotheses reach a pre-
determined power. Power is defined as one minus the probability of incorrectly failing to
reject the null hypothesis of no treatment effect. In other words, power is the probability of
finding a difference if such a difference is “true”. That is, in under-powered experiments,
investigators have a high chance of not detecting a “true” treatment effect.
• Confidence interval calculations: sample size is chosen so that the lOO(1-a)% (for a typically
chosen to be 0.05) confidence interval around a treatment effect estimate is sufficiently
small. The narrower the confidence interval, the more reliable the point estimate of the
treatment effect size.
While smaller than needed sample sizes result in under-powered studies and wide
confidence intervals for true effect sizes, excessively large samples are not desirable either. First,
resources are wasted when samples are larger than they need to be. While it is always possible
to increase the power of a study by increasing the sample size, at some point the cost of
obtaining an additional observation outweighs the potential gains in power. Second, very large
sample sizes may result in statistically significant results that have no practical implication.
Finally, including more subjects in an experiment than is required for statistical reasons may
unnecessarily place subjects at risk.
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Both the power of a test and the width of the confidence interval around a point estimate
depend on various design and data attributes, including:
• Sample size: power increases as sample size increases; the width of confidence intervals
decreases as sample size increases.
• Variance across experimental subjects: the smaller the variability in the response across
experimental subjects, the larger the power and narrower the confidence interval for a given
sample size.
• The size of the effect that needs to be detected: in experiments in which detecting a very
small difference between two treatments or between a treatment and a control, the minimum
required sample size for achieving a certain power or for keeping confidence intervals to a
desired width will be larger than when the difference to be detected is larger. In other words,
the smaller the difference sought between two groups, the larger the required sample size, all
other factors being held constant.
• Whether the design calls for replicate measurements obtained from the same individuals in
the study (which induces correlation across measurements) or for “true” replication involving
different individuals observed under the same conditions: correlation across measurements
(repeat measures in the same individual) in general decreases the power of an experiment.
The appropriate approach for estimating the minimum required sample size in insect
repellency studies in the laboratory or in the field will depend greatly on the design of the study.
Factors to be considered when estimating sample size include the following:
• Whether the experiment was conducted in the laboratory or in the field: a larger sample size
will typically be required for experiments conducted in the field because uncontrollable
factors that may affect the response increase the variance across test subjects.
• The number of treatments (e.g., potency formulations or modes of application of an insect
repellent) included in the study.
• The presence of control subjects, and whether the same volunteers will serve as both controls
and experimental test subjects (as in experiments in which one arm of each subject is treated
with a repellent while the other one is not). Experiments in which the same subjects act
simultaneously as controls and as tests require smaller sample sizes (all other factors being
equal) than those studies in which different individuals act as controls and tests.
• Whether the design calls for repeated measurements on experimental subjects.
• The outcome variable of interest: this relates to the between-subject variability mentioned
earlier. The variance across subjects might be larger for some outcome variables than others.
For example, the between-subject variance might be expected to be larger when the outcome
variable is repellency of a product over a long period than when the product’s repellency
over a shorter period is of interest. Thus, the minimum sample size for adequate study
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reliability (either in the power or the width of confidence interval senses) would be larger in
long-term studies than in short-term ones.
• The presence and potential effect of confounders that cannot be easily controlled via the
experimental design. For example, for repellency studies the intensity of a person’s odor
from carbon dioxide emissions contribute to the attractiveness of the person to blood-seeking
mosquitoes. The sample must be large enough to ensure that the variability in the general
population of consumers of the product is represented in the study.
• The heterogeneity of the target population from which the sample is drawn: if the product is
meant to protect all individuals (e.g., all ages and both genders) then the minimum sample
size might need to be computed within population strata, to ensure that each population sub-
group is adequately represented in the sample and that inferences about the effectiveness of
the product can be reliably drawn for the entire population.
• The heterogeneity of environments in which the product is expected to be used: if the product
is to be used in a variety of environments (e.g., open fields, forests, marshes, and the typical
backyard) where a different concentration of insects and ticks can be expected, the
environment must be included as a factor in the experimental design. In laboratory
conditions, field insect and tick concentrations can be mimicked by varying the density of
insects and ticks in experimental cages. The larger the number of environments in the study
design, the larger the minimum sample size needed to achieve the desired level of inferential
accuracy.
Actual calculation of minimum required sample size typically requires estimating the
sample variance of the point estimate of interest. Point estimates, in turn, follow different
sampling distributions depending on the quantity that is being estimated. In repellency studies,
various outcomes are of interest and these differ in the distributional assumptions that can be
justified:
• When the outcome or response variable is the time to first confirmed bite (TFCB), an
appropriate distribution for the response might be the exponential distribution (or the more
general gamma family). A point estimate of the mean response is given by the sample mean
of the response variable, but construction of a confidence interval for the true mean response
must be based on the correct sampling variance calculation.
• When the outcome variable is relative protection, the product passes the efficacy test if
treated subjects receive 95% fewer bites than control subjects. Because the number of bites
can be best modeled as a Poisson random variable, a point estimate of the number of bites
under different treatments and a standard deviation around that point estimate must be
estimated under that Poisson model. A normal approximation to the Poisson would be
reasonable only when the number of bites anticipated for each subject is large, a situation not
likely to be encountered in practice.
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HSRB Consensus and Rationale
It is critical that the proposed number of subjects be justified on the basis of good
research design. Because experiments to test effectiveness of products to repel insect and tick
bites are likely to vary in terms of design, response variable, target population of interest,
detectable effect size and other important variables, requiring a specific minimum sample size
that guarantees sufficient accuracy in all cases might be impractical. Instead, the guideline might
require that registrants present their own sample size calculations and that the methodology used
in the calculations be justified relative to the factors noted in the bullet list above.
Charge to the Board
g. Please comment on whether or not investigators should have an ethical obligation to provide
subjects of repellent efficacy research with insurance to cover possible future medical costs or
other losses that result from injury or illness experienced by the subjects as a consequence of
their participation in the research.
Board Response to the Charge
The broad issue of compensating research subjects for research-related injuries, together
with the somewhat narrower one of paying for the costs of medical care for such injuries, has
received substantial analysis. The report by the National Academy of Sciences on intentional
dosing studies (NAS 2004), the principles of which Congress specifically required to be reflected
in the EPA regulations on such studies, directly addressed this issue.
As the NAS Report notes:
Debate continues in the United States about whether compensation should be provided
for research-related injuries. The Common Rule requires only that when research involves more
than minimal risk, information should be disclosed regarding whether medical treatment and
other compensation will be provided for research-related injuries. Many critics of the U.S. policy
believe there should be more than disclosure of information about compensation and call for the
provision of medical care for research-related injuries without cost to the participants and, in
addition, for compensation for lost wages, disabilities, and death. These claims are based on the
belief that research participants, whatever their motivations, accept risk on behalf of society.
When participants are injured, justice, fairness, and gratitude mandate, at a minimum, the
provision of needed medical treatment without cost to the participant. Further study is needed
regarding the provision of other types of compensation. (NAS 2004.)
Based on this analysis, the NAS Panel examined the ethical issues associated with
intentional human exposure studies, adopting the following as one of its Recommendations:
Recommendation 5-5: Comyensation for Research-Related Injuries
At a minimum, sponsors of or institutions conducting intentional human dosing studies
should ensure that participants receive needed medical care for injuries incurred in the study,
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without cost to the participants. In addition, EPA should study whether broader compensation
for research-related injuries should be required. (NAS 2004)
The Board agreed with the reasoning and recommendations listed in the NAS Report
with regard to a research subject not being required to bear the costs of medical care needed to
treat injuries incurred as a result of participating in a research study.
Indeed, the conclusions of the NAS Report reflect a growing consensus that the provision
of such free medical care should be adopted as a requirement for many categories of research
studies. For example, in Volume 1 of its 1982 Report, Compensating for Research Injuries, the
President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and
Behavioral Research, concluded that “compensation of injured subjects is appropriate to the
research enterprise. A program to assure compensation is thus a desirable policy goal for a just
and compassionate government, both as the sponsor of most biomedical and behavioral research
and as the means through which society acts on matters of common interest, such as the search
for new biomedical discoveries” (at page 64). That Report did not specifically call for the
adoption for such a program, since it concluded that it did not have enough information about
whether subjects were indeed already receiving such compensation, and about the costs and other
practicalities relating to adopting a program.
More recently, in its 2001 report on Ethical and Policy Issues in Research Involving
Human Participants, the National Bioethics Advisory Commission (NBAC 2001) reviewed the
literature on this issue, concluding that a “comprehensive system of oversight of human research
should include a mechanism to compensate participants for medical and rehabilitative costs
resulting from research-related industries. The inclusion of this mechanism has long been
justified on ethical grounds” (at page 123). It echoed the President’s Commission’s call for a
study of the need for a compensation program.
Similarly, in 2003, the Institute of Medicine, in Responsible Research: A Systems
Approach to Protecting Research Participants, commenting that “ [ b]ecause the contributions of
science benefit society as a whole, it seems indisputable that society is obligated to assure that
the few who are harmed in government-sponsored scientific research are appropriately
compensated for study-related injuries The same argument applies to privately funded
research, perhaps even to a greater extent, as the economic survival of a company depends
largely on the availability of participants to test new therapies, drugs, and other products.
Because the participants are ultimately contributing to the profits of the company, any costs that
result from the research should be the responsibility of the sponsor” (at pages 188, 190). The
Institute of Medicine report also reviewed international standards relating to this issue, pointing
out that Guideline 13 of the Council for International Organizations of Medical Sciences
(CIOMS) requires that subjects be equitably compensated for “any temporary or permanent
impainnent or disability.” The report concluded that although laws vary, “most [ nations] make
some provision for compensation” (at page 189).
These arguments have special import in the context of the intentional dosing studies that
this Board will be reviewing, including repellent efficacy research. These studies will almost
never produce any direct benefits for study participants. On the other hand, there is frequently
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the possibility that subjects will suffer significant injuries as a result of their participation. In the
repellent efficacy studies, for example, subjects may be at risk or contracting a serious vector-
born illness as a result from insect bites received during the course of the study. Given the lack
of direct benefits to subjects, and the possibilities of very significant harm, the justification for
requiring sponsors to cover the costs of medical care for research-related injuries is heightened.
Three important points also need to be mentioned regarding issues raised by the wording
of the charge to the Board. First, the Agency asked for comments regarding whether
“investigators” should be required to pay for the costs of such medical care. In most cases, it
would be most appropriate for that obligation to be imposed upon the sponsors of research, who
are usually the most immediate beneficiaries of the research, rather than the investigator. The
investigators should only have this obligation when there is no external study sponsor (i.e., when
they are effectively acting as the sponsor of their own study).
Second, the Agency’s charge spoke of requiring that subjects be provided with
“insurance” to cover the relevant medical costs. The Board believed that sponsors should be
provided with some degree of flexibility in demonstrating how they will cover the medical costs
of subjects. A sponsor that has sufficient assets, for example, might be able to contractually
commit itself to pay for these costs. Given the possible substantial administrative costs of having
a sponsor purchase a special type of insurance for subjects, it does not appear appropriate to rule
out other ways for assuring that a subject’s medical costs are covered.
Third, the Agency’s charge raised the possibility of requiring payment for “other losses”
beyond the costs of medical care. Payment for such “other losses” (for example, the cost of lost
wages when a subject is not able to work for a period of time) is a more complicated and
controversial issue than covering medical expenses. With regard to this issue, the Board agreed
with the conclusions of the NAS Report that further study should be required in order to better
evaluate whether requirements to cover such “other losses” should be imposed.
HSRB Consensus and Rationale
For the reasons discussed above (including justice, fairness and gratitude), the Board
concluded that it is appropriate that sponsors of repellent efficacy research studies should be
required to ensure that if a subject is injured as a result of their participation, then the subject will
not have to assume the costs of medical care needed to treat such injuries.
Charge to the Board
h. Please comment on any special considerations that should be addressed in the informed
consent materials provided people who are candidates to become subjects in insect repellent
efficacy research.
Board Response to the Charge
The general requirements for informed consent are outlined in 40 CFR 26.116 of the
Agency’s final human studies rule. A basic element in seeking informed consent is that the
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subject should be told that the study involved research and given an explanation of the purposes
of the research, the expected duration of the research, a description of the procedures to be
followed, and an identification of any procedures that are experimental.
The informed consent should begin with a clear statement that this study is research, and
a statement as to whether the product being tested is approved and marketed in the test
formulation or still in the experimental stage. Information about the potential efficacy of the
product against the test insect should also be provided.
For the insect repellent studies, it is especially important to be very clear about the
experimental set-up, either the laboratory or the field, and what the expectations are for the
subject. Because there appears to be a tendency in these research studies to use “seasoned”
subjects (i.e., those who are in the scientific field or have participated in these studies before), a
detailed explanation of the procedures might seem to be unnecessary to the investigator.
Nonetheless, the written details of the experimental procedure must be sufficient to
inform a potential subject who has never anticipated in this type of study and to remind one who
has done so. A video, PowerPoint presentation, or photographs might help the subject to
visualize what will occur to him/her during the study. If it is a laboratory study, it may help to
have the subject place their arm into the cage. If the subject is expected to use an aspirator,
training on its use should occur prior to the beginning of the study. A demonstration of what a
landing and probing feels like might be appropriate because the dermal sensitivity of individuals
will vary.
The length of time that the study would take should be clear in the informed consent
document, including whether the test would be repeated. The process for randomizing subjects
to the test or experimental group should be included. In field studies that take the entire day, it
might be explained whether food would be provided to the subjects.
A clear discussion of the stopping rules should be included, especially for the field
studies. For example, to discontinue participation, does the subject raise their hand, return to the
van, or find a study monitor to express a desire to stop.
Another basic element of informed consent is a description of any reasonably foreseeable
risks or discomforts to the subjects. Inclusion of a Material Data Safety Sheet is not sufficient to
adequately inform the subject as far as all the inherent risks and benefits of study participation.
For insect repellent studies, three types of risks are reasonably foreseen.
The first is the risk of being bitten. The informed consent document should give an
estimate of the potential number of bites that a subject could receive in the control and
experimental groups. A statement that the researcher strives for each subject to receive few to no
bites is not sufficient. Additionally, should a subject have an allergic reaction to the insect bites,
medical procedures and remedies that would be present should be clearly described in addition to
any available follow-up treatment (e.g. will subjects be given an antibiotic or steroid cream for
their bites?
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The second risk is that of a sensitivity or allergic reaction to the experimental product. A
synopsis of the animal studies and any human data should be given to the subject along with a
discussion of the theoretical risk of a reaction occurring. Emergency care procedures should be
presented for a subject who has a reaction to either the bite itself or the repellent.
The third and most serious risk is the potential for acquisition of vector-borne illness as a
result of insect bites. The severity of these illnesses should be clearly explained, even if the
researcher believes the risk is minimal to non-existent due to either through the use of disease-
free insects in a laboratory study or the selection a disease-free zone for the field study. The risk
of insect-borne diseases might not occur to a subject who normally does not work in the field.
The investigator should make sure that the subject clearly understands both the risks of disease
transmission and what symptoms to look for with any potential insect-borne diseases. One
suggestion might be to test the subject, either verbally or in writing, about their understanding of
the procedures and the risks.
Another basic element of the informed consent process is a clear and complete
description of any benefits to the subjects or others that are reasonably expected to result from
the research. It should be very clear in the informed consent document that there are likely to be
no direct benefits to the subject as a result of study participation. The only potential benefit is to
society at large to have an arsenal of insect repellents available. Additionally payment for
participation in a research study can not be considered a benefit of the study.
Each research participant should be told the extent, if any, to which confidentiality of the
records identifying the subject should be maintained. The researcher should be careful to only
include those organizations that have jurisdiction over the study and might therefore have the
right to inspect the records. It is equally important that access to the records is limited to as few
individuals as possible and that strict confidentiality procedures be developed and are strictly
adhered to.
Regardless of whether an insect repellent study is classified as involving minimal risk or
greater than minimal risk, the subject should be clearly told if the researcher will cover medical
treatment if an injury occurs (this issue was reviewed by the Board in more detail in response to
question g.), including not only treatment during the research study but long-term care, if needed
(e.g. in those circumstances in which a study subject contracts an insect-borne disease). A phone
number should be provided to volunteers so that they can obtain additional information about the
risks and benefits of study participation, and their rights as study subjects.
The subject should clearly be told that the study is voluntary and refusal will not result in
any loss of benefits or privileges. For studies that use only one control group, it is especially
important for a subject assigned to the control group to understand that they can withdraw even if
this withdrawal might invalidate the study. It should also be clear that the subject does not need
to give a reason for withdrawal from the study. The consequences of a subject’s decision to
withdraw from the study should be addressed, including how it will affect any payment for
participation in the study.
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Students or employees used as research subjects in this study are considered “vulnerable
subjects” because they might feel coerced into participating either by their supervisor, thesis
advisor, or even fellow students/employees. It should be clear That participation in these types of
studies is neither a condition of employment nor an academic requirement for students. An
explanation of whom to contact if the subject feels coerced should be provided. This contact
should not be associated with the investigator and the subject should be guaranteed anonymity.
Employees who report directly to the investigators or study sponsors, and students of the
investigator should be excluded from the study.
The subjects should also be told that they will be informed if any new information is
found during the course of the study that might affect the subject’s willingness to participate.
Additionally the subject should be told that they will be informed if it is found that either a test
site, or a laboratory strain of insects used is discovered to have a higher level of disease than
previously thought.
The informed consent document should be written in a language understandable to the
subjects and the subjects should be informed about any potential conflicts of interests that the
researchers have.
HSRB Consensus and Rationale
The consensus of the HSRB was that informed consent should comply with all of the
requirements of 40 CFR 26.1116 of the Agency’s final human studies rule. To comply with the
human studies rule, consent information for pesticides studies must include: (a) detailed
information on the procedure (e.g., number of insect bites or landings anticipated, nature
apparatus or field context, length of time of exposure); (b) a clear statement of the risks involved
(e.g., discomfort from bites, risk of vector-borne disease, medical consequences of the disease,
treatments available for the disease); (c) the voluntary nature of participation (e.g., statements
that eliminate the perception of coercion for students or employees; specific instructions on how
to signal desire to withdraw from the study); (d) the fact that there was no immediate direct
benefit to the subject in participating as well as a description of alternative available repellents;
and (e) other steps outlined above. In addition, informed consent information should be as
detailed for experienced subjects as for naïve subjects.
Charge to the Board
i. Does the HSRB recommend that the draft guideline be revised? If so, please explain what
aspects or sections might improve with revision.
Board Response to the Charge
The Board recommended that the Agency refer to Board responses to previous questions
to address revisions to the draft guideline.
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Review of IISRB Protocol Criteria
Before the Board reviewed the presented proposed human studies research, the Board
developed science and ethics criteria as a guide for its evaluation of such studies. Reference to
such criteria would be helpful for the Agency, study investigators, and other members of the
public to understand the Board’s approach for the review of proposed human studies. The
relative emphasis placed by the Board on each criterion may be applied case-by-case and may
vary with the nature of the chemical product, study design, and participants. Specific studies
may also call for additional criteria. A list of the science and ethics criteria identified by the
Board are provided below:
Science Criteria
The criteria for the evaluation of the scientific quality of studies involving human
subjects was based on a series of questions which the Board agreed needed to be addressed by
the details provided in the study protocol.
1) Is a valid scientific question addressed by the study?
2) Are existing data adequate to answer the scientific question?
3) Are new studies involving human subjects necessary to answer the question?
4) What are the potential benefits of the study?
5) What is the likelihood that the benefits would be realized?
6) What are the risks? Are they serious or irreversible?
7) Is the purpose of the study clearly defined?
8) Are there specific objectives/ hypotheses?
9) Can the study as described achieve these objectives or test these hypotheses?
10) What is the sample size and how is it derived?
11) What is the basis for the proposed dose levels and formulations in the study?
12) Is there a plan allocating individuals to treatment?
13) Can the findings from this study be generalized beyond the study sample?
14) Is there a justification for the selection of the target population?
15) Are participants representative of the population of concern? If not, why not?
16) Are the inclusion/exclusion criteria appropriate?
17) Is the sample a vulnerable group?
18) Will the measurements be accurate and reliable?
19) Are measurements appropriate to the question being asked?
20) Are adequate quality assurance procedures described?
21) Can the data be statistically analyzed?
22) Is the statistical method appropriate to answer the question?
23) Are point estimates accompanied by measures of uncertainty?
24) Do laboratory conditions simulate real-world conditions?
25) Are field conditions representative of intended use?
26) Does the protocol include a stop rule plan, medical management plan, and a safety monitor?
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Ethics Criteria
The criteria for the ethical acceptability of environmental research protocols involving
human dosing and intentional exposure proposed by the Board are grounded in the general
criteria for IRB approval found in Subpart K of the Agency’s human studies rule (40 CFR
26.1111 and 1116). This approach is similar to that taken by the National Academy of Sciences
(2004) in formulating the criteria for scientific and ethical acceptability (recommendation 5-1)
and participant selection (recommendation 5-2).
Scientific Validity and Social Value
One of the most important criteria for the ethical review of protocols in fact is scientific.
The research design must be sound (i.e., scientifically valid) and the risks of the research must be
reasonable (or balanced) in relation to the importance of the knowledge that may reasonably be
expected to result. Absent a sound research design, the prospect of the research generating
usable knowledge is severely diminished. Although the risks to research participants may be
balanced against anticipated benefits to these same subjects, much environmental research (such
as intentional exposure studies) will not offer any direct benefit to the research subjects
themselves (See NAS recommendation 3-1 .).
The risks to which research subjects may justifiably be exposed should be directly
proportional (i.e. reasonable or balanced) to the importance of the knowledge expected to be
gained. In other words, the information to be gained from the research study must be “worth
knowing”. The NAS took this approach in recognizing that scientific accuracy alone is
insufficient justification for exposing research subjects to anything more than “no identifiable
risk.” For example, there must be a “reasonable certainty of no harm” to research subjects if the
only benefit of the research is to improve the scientific accuracy of extrapolating animal to
human data (NAS recommendation 4-1). As such, a research protocol needs to describe the
benefits of the knowledge that may be obtained so that the reasonableness of the risks can be
judged against the importance of that knowledge. In addition to improved scientific accuracy of
risk assessment, such benefits may include a more stringent regulatory standard, new public
health measures that could be adopted, or new products that may protect public health.
Federal regulations state that an IRB should not consider the possible effects of the
research on public policy when evaluating those research risks that fall within the responsibility
of the IRB (40 CFR 26.1111(a) (2)). Nevertheless, the public policy implications of the
knowledge that may result from the research does affect the importance of that information. As
such, scientific accuracy alone may be an insufficient justification for the importance of a
research project. The protocol should address the potential benefit of improved scientific
accuracy, and to whom this benefit would accrue. As recognized by the NAS in
recommendation 4-2, studies that may have a potential public health or environmental benefit
could involve a somewhat higher level of risk while not causing any lasting harm to research
subjects.
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Minimizing Research Risk
The research should not expose any human subjects to unnecessary risk (40 CFR 26.1111
(a) (1)). This ethical principle has a number of important corollaries. First, the use of human
subjects must be absolutely necessary in order to answer an important scientific question that
could not otherwise be answered by using animal models. In addition, any intentional dosing
studies can only be justified if observational studies would neither answer the question nor be
feasible. Admittedly, the judgment of feasibility may be ethically difficult especially if the only
consideration is time and expense. Second, the elimination of unnecessary risk means that there
is no way to answer the scientific question that involves less risk if human subjects are to be
used. Third, the scientific protocol should involve no additional exposure of study participants to
risk unless absolutely necessary. The ethical responsibility for “using procedures already being
performed on the subjects” translates, in the environmental context, to studying those situations
in which human subjects are exposed to environmental toxins as part of their usual activities
without increasing their exposure to those same toxins. In addition to the ethical priority of
animal over human studies, there is an ethical priority for observational research over intentional
dosing research involving environmental toxins if scientifically appropriate. Whether a study
meets the scientific and ethical criteria necessary to justify the exposure of human subjects to
potential risk can only be evaluated in the context of a given research protocol if the investigator
and/or sponsor specifically addresses alternative means of obtaining the desired data.
Equitable Selection of Subjects
The selection of subjects should be equitable (40 CFR 26.1111(a) (3)). In practical
terms, this means that the selection of subjects should reflect the scientific purposes of the
research and not the availability of a particular population. This ethical criterion may be
especially problematic in the context of environmental hazards research. Often the exposure to
environmental hazards in the workplace or at home is greater for those who are either
socioeconomically or educationally disadvantaged. As such, subject selection based purely on
scientific design may be insufficient protection for the research subjects, with additional
safeguards. The need for such safeguards must be assessed within the specific context of a
particular protocols based on an in-depth knowledge of the community within which the research
will take place. The ability to “minimize the possibility of coercion or undue influence” (40 CFR
26.1116) may require the involvement of representatives from the community from whom the
research subjects will be drawn and within which the research will take place. A research
protocol also must include specific measures for assuring the equitable selection of subjects,
including recruitment practices, incentives (financial or otherwise), impact on employment, and
the possibility of retaliation. In addition, any incentive for participation (whether financial or
otherwise, such as time off from work) should not be included in the analysis of risks and
potential benefits of the research.
Informed Consent
The information that is included in the informed consent process and documentation
should include all of the information found under the general requirements for informed consent
in 40 CFR 26.1116. There are a few specific features of the informed consent information that
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are worth highlighting in the context of environmental research. First, EPA regulations do not
allow for a waiver of either informed consent or the written documentation of informed consent.
Second, the informed consent information must include the identity of the pesticide and its mode
of action if the research involves intentional exposure of subjects to a pesticide (40 CFR 26.1116
(e)). Given the vulnerability of the research subjects that are likely to be enrolled in
environmental research (as discussed above), the default position for any research on
environmental toxins (whether observational or intentional) should be that the risks of any
potential pesticide exposure be included in the informed consent information. However, if the
risks of the toxins are not part of the research, but instead are part of daily work life, this should
be made clear. Third, the alternatives to research participation (40 CFR 26.11 16(a)(4)) should
include all steps that might minimize the risk of exposure to environmental hazards, up to and
including removing oneself from that environment. Fourth, as noted previously, the HSRB
supports the view that research subjects should receive needed medical care for research related
injuries at no cost to themselves (consistent with NAS recommendation 5-5). As such, the oft-
used informed consent template statement that “no program of compensation is available” would
be unacceptable in human dosing or pesticide exposure research. The HSRB acknowledges that
the determination that any given injury may be research-related might be difficult when the
protocol combines observational or interventional procedures with non-research related exposure
to environmental toxins. Nevertheless, the principle of providing medical care for research
related injuries at no cost to research subjects must be affirmed. Fifth, the voluntary nature of
participation must be carefully and explicitly described during the consent process. Investigators,
study sponsors and pesticide registrants are obligated to ensure that neither employment status
nor economic need creates a coercive context for study participation. Finally, the process and
documentation of informed consent needs take into account special circumstances that may arise
in the context of any given research setting, including language barriers, literacy, comprehension,
employment status, and the confidentiality of screening tests such as for pregnancy.
Subject Safety
The research protocol must also discuss provisions for assuring the safety of subjects
enrolled in the research, both during and after the research has been completed. This obligation
goes beyond simply “monitoring the data collected” to include procedures for collecting real-
time exposure data to the environmental toxins during the research, and procedures for
intervening should the health of research subjects be at risk from the environmental toxins
(regardless of whether the exposure is intentional or not). The protocol should describe in detail
any procedures for reversing experimentally-induced harms.
IRB Approval
The HSRB believed that the ethical analysis of a research protocol requires information
concerning the potential risks to human subjects, measures proposed to minimize risks, the
nature and magnitude of all the expected benefits, and to whom they may accrue, alternative
means of obtaining information comparable to what would be collected for the proposed
research, and the balance of risks and benefits of the proposed research (40 CFR 26.1125(a)).
Further, the HSRB believes that an IRB is unable to make the determinations required under 40
CFR 26.1111 absent this information. As such, the HSRB expects this information to be found
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in the protocol submitted to the responsible IRB. Although an IRB may be able to gather this
information from other sources, the lack of this information in the protocol and the lack of a
substantive discussion of these issues in the IRB minutes would raise doubt about the adequacy
of the IRB review.
Insect Repellent Product Performance Efficacy Studies
Study EMD-003 from Carroll-Loye Biological Research
Charge to the Board
a. Does the proposed research described in study EMD-003 appear likely to generate
scientifically reliable data, useful for assessing the efficacy of the repellent?
Board Response to the Charge
The protocol submitted for review by the HSRB outlined studies to evaluate the efficacy
of 1R3535 as a tick repellent in human subjects. The protocol described a laboratory study in
which the movement of the Western black-legged tick (Ixodespac(/icus) up the forearm was to
be determined. Studies in humans are required to assess the efficacy of such repellents because
laboratory animals differ in their attractiveness to the pest, and therefore do not provide an
accurate assessment of efficacy in humans. A more general protocol (CL-OO1), which provided
additional information relevant to study conduct, was also submitted for review in combination
with protocol EMD-003.
Overall, the protocol for EMD-003 was poorly prepared; for example, the evaluation of
repellency against mosquitoes was indicated in the rationale provided for the study.
Furthermore, the protocol indicated that the dose to be applied was 1 mg formulationl600 cm 2 ,
when in fact, the authors of the protocol intended the applied dose to be 1 gram/600 cm 2 . These
mistakes were not considered to be fatal errors in the protocol, but suggested a lack of attention
to the details of protocol preparation and review by the investigators. Staffers from the USEPA
provided comments on the numerous shortcomings of the proposed study, and the HSRB fully
concurred with these weaknesses.
1R3535 is commercially available, and there is a large amount of toxicology data
suggesting that it is a compound of low toxic potential. Therefore, human subjects are unlikely
to be at risk of experiencing adverse effects relative to exposure to the proposed formulations.
The HSRB recognized three major limitations to the protocol as submitted to the HSRB
for review. These limitations include: (1) the lack of a clear rationale underlying the conduct of
the study; (2) the lack of identification and characterization of the formulations to be tested and
(3) the scientific design of the study. Of these issues, which are discussed in more detail below,
the design of the study was seen as the most significant shortcoming of the proposed work.
With respect to the clear rationale for the conduct of the study, the HSRB understood that
all new formulations must be evaluated for efficacy, and that such studies must be conducted in
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human subjects to be valid. However, the investigators failed to identify what was new about the
formulations being studied and failed to identify the potential benefit of the fonnulations. This
shortcoming was considered to be minor and could readily be addressed by providing such
additional information in the study protocol.
With respect to the formulations to be evaluated, the investigators provided tables listing
the percent of active ingredient along with incipients used to formulate the spray, aerosol and
lotion to be used in the study. However, there was no additional information regarding when the
formulations would be prepared relative to study execution, whether the formulations would be
characterized analytically to confirm active ingredient composition, and whether the stability of
the formulations was to be determined. This information is critical to the overall valid execution
of the study and could be remedied by providing such detail in the protocol.
The major limitation with the scientific conduct of the study concerned the study design
and data collection. In particular, the protocol outlined a study using six test subjects for each
product formulation, with two additional subjects serving as a negative and a positive control.
No information was provided to justify the group sizes used in the research. Given the nature of
these studies to evaluate tick repellency, the HSRB considered that a test in which each subject
served as his own control (using one arm for the untreated, negative control and one arm for the
test) was a more appropriate design that would also be more powerful statistically and more
likely to generate reliable results.
Additional questions were raised by the HSRB concerning how subjects would be trained
to accurately and consistently collect information regarding the number of ticks crossing or
repelled from the arm skin. The protocol defined that a crossing is scored by the movement of a
tick by at least two centimeters toward the elbow starting from a line at the wrist, and that
subjects select a new tick from a pool of unused, prescreened ticks every 15 minutes. There was
no information made available to the Board as to how subjects were trained and qualified to
establish that they could collect accurate data on tick movement. The Board agreed that such
information was important for establishing good quality control of the data collection concerning
repellency.
HSRB Consensus and Rationale
Overall, the HSRB concluded that there were numerous technical deficiencies in protocol
EMD-003, and the information provided in the general protocol (CL-OOl) did not make up for
the deficiencies in the specific protocol. Therefore, the Board concluded that the available
protocol did not warrant moving forward with the study.
Charge to the Board
b. Does the proposed research described in Study EMD-003 from Carroll-Loye Biological
Research appear to comport with the applicable requirements of 40 CFR part 26, subparts K and
L?
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Board Response to the Charge
Background
The proposed study was to evaluate the efficacy of a compound known as 1R3535 as a
tick repellent in human subjects. The study is to be conducted by Carroll-Loye Biological
Research, a private research laboratory in Davis, California by using healthy volunteers and a
controlled laboratory environment. Two protocols were submitted for review, a general protocol
(CL-OO1) that provided considerable background information about tests of insect repellency in
general, and the protocol for analysis of the efficacy of 1R353 as a tick repellent evaluated here.
For this protocol, the efficacy of 1R3535 as a tick repellent would be determined by
placing Western black-legged ticks (Ixodespac flcus) on 1R3535-treated and —untreated forearms
and measuring the speed and distance that moving insects would penetrate into the treated area.
Strengths and Limitations
The Board concurred with the factual observations of the strengths and weaknesses of the
study, as detailed in the EPA’s Initial Ethics Review (USEPA 2006b). This study, it was argued,
would provide critical data on the efficacy of 1R3535 as a tick repellent. 1R3535 is commercially
available and has been used as a repellent in Europe for years with no evidence of toxicity, so the
subjects enrolled in this study were unlikely to be at increased risk of experiencing adverse side
effects upon exposure. The ticks used for the study also were bred and raised in a laboratory
environment and are considered to be pathogen-free, minimizing the risk of vector-borne
diseases.
The Board concluded, however, that given the deficiencies noted by the Agency, the
proposed research described in Protocol EMD-003 did not comport with the applicable
requirements of §40CFR26, particularly subpart K. Carroll-Loye Biological Research and the
IRB of record also failed to obtain or to provide all of the documents necessary to be in
compliance with the requirements of 4OCFR §26.1125. The IRB, for example, refused to release
copies of the minutes documenting the discussion of EMD-003 protocol, preventing the Board
from evaluating whether or not they considered fully the issues listed under the EPA’s Final
Human Studies Rule as part of their review. Furthermore, the protocol and supplementary
documents submitted to the Board were poorly written which, while not a fatal flaw in and of
itself, should have precluded IRB and HSRB review and approval.
The HSRB recognized several significant limitations to the protocol, as submitted to the
Board for review. There was, for example, lack of a clear rationale justifying the conduct of the
study as designed. The Board’s concerns about this are discussed in detail with respect to the
companion protocol submitted by Carroll-Loye, EMD-004, but it was felt that absent any clear
scientific rationale for conducting such a study, exposure of human subjects to the risks inherent
in this protocol would be unnecessary and unjustifiable.
Additional limitations of the study protocol provided to the Board can be grouped into
two broad categories: (I) concerns about equitable study subject selection and recruitment; and
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(2) questions about whether or not the documentation and process of study subject enrollment
was sufficient to meet prevailing standards of voluntary informed consent.
Subject Recruitment
The Board expressed concern about the potentially coercive nature of study subject
recruitment. Although the study is to be conducted by Carroll-Loye Biological Research, a
private research laboratory in Davis, California, the Principal Investigator of the study and Co-
Owner of the research laboratory, Dr. Scott P. Carroll, also is an adjunct faculty member of the
Department of Entomology at the University of California, Davis. As the majority of research
participants will be recruited from the University’s student population, including from Dr.
Carroll’s own department, the protocol and consent documents need to be altered to define
clearly the mechanisms in place to prevent any coercive enrollment, as well as the additional
concerns listed below.
Voluntary Informed Consent
The Board believed that the protocol and consent documents, as provided, lacked
sufficient information to ensure that all study participants were adequately informed about the
risks, benefits and alternatives to participation in the study. It was unclear, for instance, that
participation in the study would have no direct benefit for volunteers or that the study was being
conducted solely for development of data required for regulatory review by EPA. The major
risks of participation in the study also needed to be more clearly identified in the informed
consent form and in supplementary documents provided to study subjects. For example, one
additional risk that the study investigators may have failed to consider arises from the plan to
pre-screen female volunteers in order to exclude any subjects who may be pregnant. In
accordance with the newly promulgated provisions in the EPA’s final human studies rule
( 40CFR26.1701 - 26.1704), minors and pregnant women are explicitly excluded from
participation, the latter being confirmed by requiring all female volunteers to undergo a self-
administered over-the-counter pregnancy test on the day of the study. Because many of the
volunteers are undergraduate or graduate students at a nearby college, the unexpected revelation
that a subject may be pregnant could have a profound psychological or social impact; Dr. Carroll
also may have a professional relationship with these students through his affiliation with the
University. These risks should be specifically addressed, and the Board recommended that the
protocol needs to address how the consent form will appropriately communicate to prospective
subjects that pregnancy status will be tested and communicated to the participant and the
confidentiality procedures that will be put in place to protect the privacy of this pregnancy status
information. In situations, like this protocol, in which participants have another professional
relationship with the investigator and members of the research team, special efforts to protect
such privacy needs to be described (e.g., only a single investigator will have knowledge of the
test).
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Study investigators also may wish to provide either a more detailed explanation of the
study protocol — including a detailed method for manipulating the ticks used in the experiment
and a clear description of the study’s duration.
Finally, it was felt that the informed consent documents should be re-written to: (a)
comport with the reading and comprehension level of the likely subject population; and (b)
clarify the section on compensation for research related injury.
HSRB Consensus and Rationale
The Board concurred with the initial assessment of the Agency that the study submitted
for review by the Board failed to meet the requirements established in the Agency’s fmal human
studies rule ( 40CFR26).
The Board determined the proposed research described in this study did not comport with
the applicable requirements of §40CFR26, subpart K. The study documents submitted for review
also failed to comply with the requirements of 4OCFR §26.1125. However, the deficiencies
noted, while significant, were not irreparable.
Study EMD-004 from Carroll-Loye Biological Research
Charge to the Board
a. Did the proposed research described in Study EMD-004 from Carroll-Loye Biological
Research appear likely to generate scientifically reliable data, useful for assessing the efficacy of
a test substance for repellent ticks?
Board Response to the Charge
Introduction
The Board began its review noting that this protocol addresses repelling insects, not ticks.
The Board concluded that the proposed research should generate scientifically useful data for
assessing efficacy. Protocol EMD-004 describes a test of the efficacy of 3- [ N-butyl-N-acetyl]-
aminopropionic acid, ethyl ester (1R3535) to repel mosquitoes in field experiments. It describes
the formulation and dose of the repellent and the number of replications (6-10 for each
formulation). The components of the three formulations were provided by the Agency. There
would be one to two untreated controls and one to two positive (DEET-treated) controls. Two
locations would be used, in or adjacent to the Central Valley in California and the Florida Keys.
The experiment would be double-blinded. The compound has a very low toxicity profile in
animal tests and has been used in Europe for over 20 years as a repellent without reports of
adverse effects in humans.
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General Scientific Criteria
• The scientific question was stated (i.e., to test the efficacy of 1R3535 in repelling
mosquitoes).
• It was not clear whether existing data were adequate to answer the question.
• It was not clear whether new studies involving human subjects were necessary; however,
if the repellency had never been tested with North American mosquitoes, the tests may be
necessary.
• The potential benefits of the study were clear, i.e., that an effective repellent would be
available that would have either greater efficacy and/or fewer drawbacks than what was
currently approved.
• It was likely that the benefits would be realized (i.e., efficacy as a repellent) because there
was a long positive history on this compound from its European use.
• The risks were not specifically noted.
• The most likely relevant risk would be disease transmitted by the mosquitoes, if the
mosquitoes carried pathogens, and some mosquito-borne diseases (e.g., West Nile virus-
mediated disease) were serious. The protocol did not indicate the likelihood of the
mosquitoes in the two test areas to be carriers of disease organisms that could be
transmitted to humans. However, using the fewest number of untreated controls would
provide the least risk of disease to the participants. The protocol did not indicate whether
all the inert ingredients in the formulations are GRAS compounds or have documented
lack of toxicity at the exposure levels anticipated.
Study Design Criteria
• The purpose of the study was clearly defined (i.e., efficacy testing).
• There were specific objectives/hypotheses (i.e., that 1R3535 is an effective repellent).
• The study as described can test this hypothesis.
• The sample size and how it was derived was not clear, but seems to have been taken from
the guidelines. The number of subjects listed in section 9.1.3 of the protocol listed
potentially more subjects than in the table in section 8.3.2. It was not clear if the stated
number of subjects would be repeated in both locations. The basis for the dose levels and
formulations were not provided. There were no controls with just the formulation matrix
without the repellent.
• There was a plan allocating individuals to treatments.
• The findings from this study can probably be generalized beyond the study sample.
Participation Criteria
• There was partial justification for the selection of the target population.
• The participants were representative of the population of concern.
• The inclusion/exclusion criteria were appropriate.
• The sample was a representative population.
Measurement Criteria
• The measurements were expected to be accurate and reliable.
• The measurements were appropriate to the question being asked.
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• Quality assurances issues did not appear to be addressed.
Statistical Analysis Criteria
• The data should be able to be analyzed statistically if the efficacy with time was the
subject of the analysis and the comparisons are made across time. However, if there is
only one untreated control (which would be more protective against possible disease
transmission), then there would be difficulties with statistical analysis with comparisons
to the untreated control.
• The statistical method seems to be appropriate.
• Measures of uncertainty were not addressed.
Laboratory and Field Conditions
• No laboratory experiments were proposed in this protocol, probably because of the data
already available due to the compound’s long previous use.
• The field conditions were representative of the intended use.
• The protocol did not include a stop rule plan, medical management plan, and a safety
monitor.
HSRB Consensus and Rationale
It was not clear whether new studies involving human subjects were necessary. If the
repellency had never been tested with North American mosquitoes, however, the tests were
probably necessary. The potential benefits of the study were clear, i.e., that an effective repellent
would be available that would have either greater efficacy and/or fewer drawbacks than what
was currently approved. However, empirical evidence or procedures to determine risks to
subjects (e.g., risks of contracting a vector-borne disease) were not adequate. It was not clear if
the stated number of subjects would be repeated in both testing locations. The basis for the dose
levels and formulations were not provided. There were no controls with just the formulation
matrix without the repellent to ascertain whether the formulation might have repellent or
attractive properties. Should the formulation elicit a behavioral reaction in the mosquitoes, such
a property would need to be taken into account in the interpretation of the efficacy data. To
minimize risk, the Board recommended that the vehicle properties be tested in the laboratory.
Therefore, the Board concluded that some of the more critical deficiencies in the information
identified above would have to be adequately addressed before this protocol could receive a
positive recommendation.
Charge to the Board
b. Did the proposed research described in Study EMD-004 from Carroll-Loye Biological
Research appear to comport with the applicable requirements of 40 CFR part 26, subparts K and
L?
Brief Overview of the Study
The proposed study would evaluate the efficacy of three different skin applied
formulations of an already registered and marketed (in Europe) insect repellent 1R3 535. There
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would be two study sites, one located in central California and the other located in the Florida
Keys. The test compounds would be administered to a standardized skin surface area, with a
comparison to one positive control and one negative control. The subjects allocated to the
intervention groups would be blinded to the treatment. The chosen outcome measures are
“percent reduction in the rate of alightments” and “complete protection time.” The protocol
stated that there would be 6 to 10 subjects per treatment group, with one subject per control
group. However there was no discussion of sample size justification. As discussed below, the
protocol lacked any discussion of risks.
Ethics and Regulatory Compliance
Subpart K of the Agency’s final human studies rule requires that the investigator submit
to the EPA all information that pertains to the IRB review of proposed research (40 CFR
26.11 15a) as well as additional information specified in 40 CFR 26.1125, if not already included
in the IRB documentation. The information requested under 40 CFR 26.1125 includes a
discussion of the potential risks to human subjects, the measures proposed to minimize these
risks, expected benefits if any and to whom, alternative means to obtain comparable information,
and the balance of risk and benefits of the research. In addition, subject information sheets and
approved written informed consent agreements should be provided, along with any information
about recruitment and the presentation of this subject information. Finally, the investigator
should provide copies of all correspondence with the IRB, including official notification of IRB
review and approval.
The Board expressed concern about the potentially coercive nature of study subject
recruitment. Although the study is to be conducted by Carroll-Loye Biological Research, a
private research laboratory in Davis, California, the Principal Investigator of the study and Co-
Owner of the research laboratory, Dr. Scott P. Carroll, also is an adjunct faculty member of the
Department of Entomology at the University of California, Davis. As the majority of research
participants will be recruited from the University’s student population, including from Dr.
Carroll’s own department, the protocol and consent documents need to be altered to define
clearly the mechanisms in place to prevent any coercive enrollment, as well as the additional
concerns listed below.
In the case of this protocol, the principal investigator made a request to the reviewing
IRB (Independent Investigational Review Board Inc. located in Plantation, Florida) for the
documents required under 40 CFR 26.1125. The response from the IRB, dated May 12, 2006,
did not include the minutes of IRB meetings at which the protocol was discussed. As a result,
the Board was unable to assess whether the IRB discussed or was even aware of the controversial
issues raised by this protocol. The IRB did provide templates of two different forms, the EPA
Protocol Checklist and Research Evaluation Form. Although these forms were fairly
comprehensive, the Board was not provided with copies of the forms used for the specific
protocol review and thus cannot assess whether or not the forms were used or the content of the
IRB analysis and discussion. The membership roster of the IRB was included. Although the
membership was diverse and meets the regulatory requirements, there was no scientific member
that appeared to have sufficient expertise in the scientific issues involved in field testing of insect
repellents to assure that the IRB was qualified to make an adequate assessment of this protocol.
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The scientific and ethical assessment may have been adequate, but the lack of IRB minutes made
this determination impossible. In effect, the IRB response was to provide procedural
documentation of the IRB’s compliance with 40 CFR 26.1115 but to withhold any substantive
documentation that this procedural compliance resulted in an adequate ethical and scientific
review of the submitted protocol. As such, the proposed research failed to meet the requirements
of 40 CFR part 26, subpart K.
The investigator, to his credit, remedied some of these deficiencies in a supplementary
document submitted to the EPA as part of the Board’s review. This undated document was
presumably written after the IRB review. In this document, the investigator addressed the
potential risks to human subjects, the measures proposed to minimize these risks, the nature and
magnitude of all expected benefits of the proposed research and to whom they would accrue, the
balance of risks and benefits of the proposed research, and alternative means of obtaining
information comparable to what would be collected through the proposed research.
Several observations are in order. First, none of this material, including the discussion of
risks and benefits can be found in the protocol submitted to the IRB. The absence of this
information in the protocol further compounds the uncertainty created by the absence of minutes
showing how the IRB made the determinations required under 40 CFR 26.1111. The
information about the potential risks to human subjects, the measures proposed to minimize these
risks, the nature and magnitude of all expected benefits of the proposed research and to whom
they would accrue, and the balance of risks and benefits of the proposed research should be part
of the research protocol submitted for initial IRB review. Otherwise, the IRB lacked sufficient
information to make an appropriate assessment of the proposed research. This was not to say
that the protocol would fail to meet the criteria for IRB approval, only that there was no evidence
that the IRB had sufficient information or expertise to make these determinations. Second, the
protocol did minimize the risk of vector-borne diseases by limiting the untreated control group to
a single subject who was experienced in field biology or entomology. The risk was minimized
further by using an outcome measure that does not require biting, but rather preparatory activities
on the part of the mosquito after lighting on the subject followed by aspiration and removal of
the mosquito. However, this approach raised concerns about the scientific adequacy of the
protocol design. Third, the investigator addressed the question of alternative means of obtaining
information by arguing that the protocol was designed in compliance with previous EPA
guidelines for registration of these products. The Board did not take a position on whether the
protocol was indeed in compliance with these previous guidelines. However, there was
sufficient discussion by the Board of the new draft EPA guidance on “Insect Repellent Product
Performance Testing” to cast doubt on the scientific adequacy and necessity of the approach
taken in this protocol.
Finally, the Board agreed with the ethical deficiencies noted by the EPA (USEPA 2006c).
With the exception of amending the protocol to include the applicability of additional standards
of ethical conduct and the process of informing appropriate regulatory authorities of any
amendments or deviations from the approved protocol, all of these deficiencies related to the
informed consent discussion and document. These included a more accurate discussion of
subject assignment, a more extensive discussion of the risks (with specific information about the
risk of vector borne diseases), the correction of an important typographical error in the
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pregnancy section, a clarification of the section on compensation for research related injury, a
clarification of the lack of direct benefit to research subjects and additional information under the
heading of confidentiality. The Board also discussed the topic of pregnancy testing and whether
there should be a separate consent for such testing. The Board recommended that the protocol
needs to address how the consent form will appropriately communicate to prospective subjects
that pregnancy status will be tested and communicated to the participant and the confidentiality
procedures that will be put in place to protect the privacy of this pregnancy status information.
In situations, like this protocol, in which participants have another professional relationship with
the investigator and members of the research team, special efforts to protect such privacy needs
to be described (e.g., only a single investigator will have knowledge of the test).
HSRB Consensus and Rationale
The Board thus concluded that the proposed research described in Study EMD-004 from
Carroll-Loye Biological Research did not comport with the applicable requirements of 40 CFR
part 26, subpart K. Although the ethical concerns identified by the Board could be remedied,
there were sufficient questions raised about the adequacy of the research design to cast doubt on
whether the proposed research would meet the criteria for IRB approval found under 40 CFR
26.1111(a) (1). In other words, absent a sound research design, any exposure of human subjects
to risk would be unnecessary and unjustifiable.
Occupational Handler Exposure Monitoring Studies
Charge to the Board
The Agricultural Handlers Exposure Task Force (AHETF) had submitted protocols for
five pesticide exposure studies that are part of a larger research program the AHETF is
conducting. The premise of the AI-IETF research program is that data can be used generically by
various stakeholders (e.g., applicants, registrants, EPA, and others) for calculating exposures for
the occupational handlers of pesticides. The scope of the AHETF research progr am was very
broad in that it intends to address exposures related to many job functions in agriculture and also
to assess generally the impacts of various parameters on exposure (e.g., How do changes in the
pounds of pesticide handled or acres treated affect exposure levels?). The protocols submitted
for HSRB review described studies to measure exposures for five specific scenarios.
The Agency believed these studies had the potential to improve EPA ’s ability to assess
the risks of using pesticides because the data would reflect current agricultural practices,
equipment and techniques and would allow for more refined exposure estimates. Further, the
monitoring techniques to be used for these studies have been standardized for use across the
AHETF research program. These more refined and reliable data would allow the Agency to
estimate better how worker exposure levels are affected by changes in various factors such as the
amount of active ingredient handled, type of application equipment used, application rate used,
volumes handled, and personal protective equipment used.
It should be noted, however, that the use of the data generated in this study by the EPA
and other stakeholders would depend upon the nature of the results. For example, the adequacy
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of the field or laboratory quality control data may dictate that correction factors are applied to
adjust monitored exposure levels to account for losses from field samplers or low performing
analytical methods.
1. AHETF Closed System Mixing/ Loading of Liquids Protocol (AHE34)
a. Does the proposed research described in Study No. AI-1E34 from the Agricultural Handlers
Exposure Task Force appear likely to generate scientifically reliable data, which would be
useful, together with other data, for assessing the potential levels of pesticide exposure received
by people when mixing, loading or applying a liquid pesticide with closed systems? [ Note: In a
few cases, corresponding application events are also to be monitored; the same question applies
to those elements of the study.]
b. Does the proposed research described in Study No. AHE34 from the Agricultural Handlers
Exposure Task Force appear to comport with the applicable requirements of 40 CFR part 26,
subparts K and L?
2. AHETF Airbiast Application to Trellis Crops in the West Protocol (A1-1E36)
a. Does the proposed research described in Study No. AHE36 from the Agricultural Handlers
Exposure Task Force appear likely to generate scientifically reliable data, which would be
useful, together with other data, for assessing the potential levels of pesticide exposure received
by people when making an airblast application of a pesticide to a trellis crop under conditions
found in the western United States? [ Note: In a few cases, corresponding mixing/loading events
are also to be monitored; the same question applies to those elements of the study.]
b. Does the proposed research described in Study No. AHE36 from the Agricultural Handlers
Exposure Task Force appear to comport with the applicable requirements of 40 CFR part 26,
subparts K and L?
3. AHETF Airbiast Application to Trellis Crops in the East Protocol (AHE37)
a. Does the proposed research described in Study No. AI-1E37 from the Agricultural Handlers
Exposure Task Force appear likely to generate scientifically reliable data, which would be
useful, together with other data, for assessing the potential levels of pesticide exposure received
by people when making an airbiast application of a pesticide to a trellis crop under conditions
found in the eastern United States? [ Note: In a few cases, corresponding mixing/loading events
are also to be monitored; the same question applies to those elements of the study.]
b. Does the proposed research described in Study No. AHE37 from the Agricultural Handlers
Exposure Task Force appear to comport with the applicable requirements of 40 CFR part 26,
subparts K and L?
4. AHETF Closed Cab Airbiast Application to Orchards Protocol (AHE38)
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a. Does the proposed research described in Study No. AFIE38 from the Agricultural Handlers
Exposure Task Force appear likely to generate scientifically reliable data, which would be
useful, together with other data, for assessing the potential levels of pesticide exposure received
by people when making an airbiast application of a pesticide to orchard crops? [ Note: In a few
cases, corresponding mixing/loading events are also to be monitored; the same question applies
to those elements of the study.]
b. Does the proposed research described in Study No. AHE38 from the Agricultural Handlers
Exposure Task Force appear to comport with the applicable requirements of 40 CFR part 26,
subparts K and L?
5. AHETF Fixed-Wing Aerial Application Protocol (AHE42)
a. Does the proposed research described in Study No. AHE42 from the Agricultural Handlers
Exposure Task Force appear likely to generate scientifically reliable data, which would be
useful, together with other data, for assessing the potential levels of pesticide exposure received
by people making an aerial application of a pesticide from fixed-wing aircraft? [ Note: In a few
cases, corresponding mixing/loading events are also to be monitored; the same question applies
to those elements of the study.]
b. Does the proposed research described in Study No. AHE42 from the Agricultural Handlers
Exposure Task Force appear to comport with the applicable requirements of 40 CFR part 26,
subparts K and L?
Board Response to the Charge
For the Board’s review of the agricultural handler protocols, the Board decided to focus
its analysis addressing the common strengths, limitations and overall conclusion of the five
protocols.
Scientific Considerations
Study Overview
The pesticide handler exposure study protocols submitted to the HSRB were part of a
larger project that was initiated in December 2001 by the Agricultural Handler Exposure Task
Force (AHETF). The project will produce a generic agricultural handler exposure database
(AHED TM ). EPA and other regulatory agencies would use this database to calculate pesticide
handler exposures across a wide range of work conditions. All of the protocols follow a similar
pattern. They involve personal measurements of inhalation and dermal exposure among a group
of workers who conduct what is referred to as a “scenario”; that is, the study participant would
conduct a specified job task with specified equipment, handling a particular product formulation
that contains one of six pesticides.
These studies can be referred to as scripted, so as to distinguish them from purely
observational studies. Workers are asked to conduct their work activities under a set of scripted
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conditions similar , but maybe not identical, to those they experience in their normal work
activities. The overall plan for the exposure database had been discussed with regulators from
EPA, California EPA, and Health Canada on a regular basis. The presentation of these protocols
to the HSRB is the first independent scientific review of the task force project.
The task force had proposed 33 handler exposure scenarios, distinguished by equipment
type, work task, and pesticide formulation. The task force has already conducted or initiated 14
exposure studies, and has sponsored four studies. In addition to the five protocols presented to
the HSRB, the task force planned to conduct approximately 40 additional studies over the next
several years.
Each of the protocols focuses on one primary exposure scenario, but all of the protocols
include more than one scenario. The five protocols reviewed by the HSRB are summarized in
Table 1.
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Table 1. Exposure Scenarios Included In The Five AHETF Protocols (N = anticipated number of
independent observations for a particular scenario based on monitoring events proposed by
AHETF for the 2007 growing season)
AHE34
ARE 36
AffE37
AHE38
AHE42
Scenario
1
Closed
system mix-
load of a
liquid
Open cab
trellis crop
airbiast
application
Open cab
trellis crop
airblast
application
Closed cab
orchard crop
airbiast
application
Closed cockpit
fixed-wing
aircraft
application
N
10
5
5
8
7
Scenario
2
Open or
closed cab
airbiast
application
Closed cab
trellis crop
airbiast
application
Closed cab
trellis crop
airblast
application
Open pour
mix-load of a
liquid
Open pour
mix-load of a
liquid
N
0-3
4
4
not specified
0-3
Scenario
3
Closed
cockpit
fixed-wing
aircraft
application
Open pour
mix-load of a
liquid
Open pour
mix-load of a
wettable
powder
Closed system
mix-load of a
liquid
N
0-3
0-4
4
0-3
Scenario
4
Closed
cockpit
rotary-wing
aircraft
application
Closed
system mix-
load of a
liquid
N
0-3
0-4
Total N
13
13
13
not specified
10
Chemical
Malathion 8
(80% a.i.)
Malathion 8
(80% a.i.)
Diazinon
50% WP
Carbaryl
4lb a.i./gal
Chlorothalonil
6lb a.i./gal
Location
CA
West (CA)
East (NY)
FL and GA
Pacific NW
The task force studies are using six different pesticides: three organophosphorus
insecticides (acephate, diazinon, malathion), one carbamate insecticide (carbaryl), one
organochiorine fungicide (chlorothalonil), and one triazine herbicide (simazine). A description of
the selection criteria for these compounds was provided as a part of the task force documentation
package. These selection criteria did not include the toxicity of the compounds, and toxicity was
not discussed in the Agency reviews of the protocols. However, oral comments from task force
representatives at the June HSRB meeting indicated that the formulations of these pesticides
have been selected such that they all fall into EPA toxicity categories III or IV; i.e., relatively
low toxicity formulations. It was also stated that all workers in these studies wear long-sleeve
shirts, long-legged pants, as well as socks and shoes. Protective equipment, such as chemical-
resistant gloves and eye protection, are provided to the workers if required by the pesticide label.
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The database to be developed from the task force studies is intended to supersede an
existing database — the Pesticide Handler Exposure Database (PHED). This database was
developed in the late 1980’s and early 1990’s through the compilation of existing data. These
data were drawn from both registrant-sponsored studies and studies published in the scientific
literature. The studies included in PHED used a different method for measuring dermal exposure.
This method, known as the “patch technique” (deposition coupons distributed over body regions
attached to the outer layer of clothing), has served as the standard method for such studies since
the 1960’s. When coupled with a hand rinse technique, it provides an estimate of exposure to all
body surfaces.
The documents submitted by the AHETF in support of the proposed exposure studies
consisted of the following:
• Cover letter dated May 24, 2006
• Analytical method validation reports for 5 of the 6 pesticides (missing simazine)
• List of 33 exposure scenarios
• Description of selection requirements for surrogate compounds
• 32 standard operating procedure (SOP) documents
• A generic field exposure monitoring protocol
• 5 exposure study protocols: AHE34, 36, 37, 38, and 42
• IRB documents related to each protocol
In addition, the HSRB received an EPA review for each protocol, EPA, Office of Pesticide
Program guideline documents, and several general documents on pesticide handler exposure.
Finally, the A1-IETF provided public comments (AHETF 2006) containing comments on the
EPA review of the five protocols.
Criticiue of Study
General Scientific Criteria
The primary aim of these studies is to generate personal measurement data on pesticide
handlers suitable for use in an agricultural handler exposure database. The notion that such a
generic database for pesticide handlers can be developed is supported by substantial scientific
evidence. This evidence indicated that occupational pesticide exposure in agriculture is largely
process rather than chemical-dependent (excluding chemicals with high volatility). Thus, if
sufficient data can be collected on the key variables that influence exposure, then a database can
be developed to estimate exposure for a wide range of exposure scenarios. A major concern of
the HSRB was that these protocols included too many variables, and that, even when combined
with the full complement of studies proposed, the database would be inadequate for meaningful
exposure estimates.
The process that has guided the exposure database project had some significant
limitations. The database project has been developed over the past 5 years by a pesticide industry
task force with the input of regulatory staff from EPA, California, and Canada. Such an
ambitious undertaking would have benefited from an initial independent scientific peer review,
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particularly of the study design and statistical plan, as the HSRB finds itself raising some
fundamental questions mid-stream in the project. Input from the labor community would also
have enhanced the project regarding procedures such as subject recruitment, selection of
pesticides to be used in individual studies, and informed consent. The purpose of the project,
after all, is to develop data to estimate worker risks. It seems reasonable to give those who would
be taking the risks an opportunity to contribute to the design of the project.
In regard to justification for new human studies, the Agency currently uses an existing
generic pesticide handler exposure database, known as PFIED. It is recognized that new data
have not been added to P1-lED in a number of years, and that the existing data have a number of
scientific limitations. However, the inadequacy of PHED was not documented in the protocols.
The Agency had not provided a compelling justification for these new human studies in the
materials provided.
Benefits of the study were not described in the protocols. However, the AHETF
comments (AHETF 2006) and the EPA review documents provided some general information
regarding the role of a handler exposure database in EPA’s regulatory process. It was not
possible to determine the likelihood that the benefits would be realized, since the protocols did
not include a description of the full database and how it would be used.
Study Design Criteria
The purpose of these studies was clearly defined. The objective was to collect high
quality personal measurement data for use in a generic exposure database. The protocols
reviewed by the Board should be able to produce such data.
Approximate sample sizes were presented in the protocols and discussed in more detail in
the Agency reviews of the protocols. Within each protocol, the sample sizes for particular
scenarios were quite small. All of the protocols contained multiple scenarios, with sample size
per scenario ranging from 1-10 (see Table 1). The inability to define exactly how many samples
would be collected in each proposed study was understandable, since the task force was
attempting to take advantage of ‘real-world’ conditions. Weather, logistical challenges, and
grower decisions regarding pest management can all affect the number of workers available for a
given study. The effort to study exposures under realistic conditions required expenditure of
significant resources, and was viewed by the HSRB as highly commendable. The HSRB
understood that these protocols should not be viewed as “stand-alone” studies, since data from
these studies would be combined with other similar studies. Presumably all of the data collected
in these five studies would be allocated to one of the 33 exposure scenarios outlined by the task
force. Under these circumstances, there was insufficient information for the HSRB to evaluate
the adequacy of the sample size.
In regard to dose levels, participants would be handling varying amounts of pesticides
under variable exposure conditions. The HSRB presumed that the conditions outlined in the
protocols and reviewed by the Agency all fall within parameters on the label. Actual dose during
these studies would likely be lower than normal, due to the wearing of a whole-body cotton
garment, and strict observance of label instructions.
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ParticiDation Criteria
Participants are referred to as ‘replicates’ both in the AHETF protocols and in the Agency
reviews. This term is problematic from a scientific perspective, since it is used to refer to both a
series of independent observations (e.g., three persons doing the same thing one time) and a
series of repeated measures (e.g., one person doing the same thing three times). This language
needs to be altered such that different terms are used for repeated measures on one person as
compared to observations on unique individuals. The AH1E34 protocol, for example, indicated
that “ten different mixer/loader workers (or replicates) will be monitored.. . each mixer/loader
replicate should be performed by a separate worker.” This type of awkward description could be
eliminated through use of unambiguous terminology.
The protocols indicated that the participants would be “experienced workers” recruited
through their employers, but there was no detailed description of the recruitment procedures, nor
were there clear inclusion/exclusion criteria other than age and pregnancy status. It was hard to
tell whether the workers who volunteer for a protocol exposure study would be representative of
the typical worker. Random sampling from a group of eligible workers would improve this
aspect of the protocols.
Measurement Criteria
AHETF investigators are using three different methods to measure skm exposure: cotton
garments (whole body dosimeters), hand rinse, and face/neck wipes. The cotton garments should
be able to capture pesticide that would normally be deposited on skin. However, no method for
preventing or monitoring garment breakthrough was presented. If breakthrough occurs, the
dermal exposure measurements would underestimate true exposure. The hand rinse method and
face/neck wipe both measure the amount of material that can be removed from the skin at the
particular time of the sampling. This amount is some fraction of the total material deposited on
the skin, since some of the material would have been absorbed into the skin. This method is
likely to underestimate the true exposure. Published laboratory and field studies have indicated
that the fraction of the amount deposited on skin that can be removed by rinsing or wiping can be
quite variable, depending on the nature of the chemical, its formulation, skin characteristics, and
the length of time the chemical has been in contact with the skin. In particular, the face/neck
wipe method may seriously underestimate exposure to these surfaces. This method was not
among the methods presented by the Agency in its 875 guidelines (Occupational and Residential
Exposure Test Guidelines: OPPTS 875.1100 Dermal Exposure — Outdoor), and has not been
validated. The accuracy of these measurements could be improved through the conduct of
laboratory removal efficiency studies. The 875 guidelines do not require removal efficiency
studies, but they do indicate that investigators should address this concern. If such method
validation studies are contemplated, the HSRB recommended that they be conducted as
independent scientific studies published in the peer-reviewed literature.
In summary, all of the methods for dermal exposure measurements have the potential to
underestimate exposure. The study investigators should acknowledge this problem in the
protocols, and explain what steps, if any, they have taken to improve or verify the accuracy of
the measurements.
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The protocols stated that hand rinse and wipe samples may be collected multiple times
during the work period (e.g., prior to eating, whenever a worker would normally wash hands),
and that this would vary from worker to worker. The protocols did not explain how multiple
measurements from a single worker would be combined. They also did not discuss whether or
not samples across workers with different rinse/wipe regimens can be considered comparable.
For example, can the amount of pesticide recovered in a single hand rinse from a worker at the
end of the study period be put in the same database as that from a worker who had four hand
rinses across the study period? The answer would seem to be “no” from a sampling perspective,
given the nature of dermal absorption processes.
The quality assurance components of the protocols are of high quality. There was
substantial documentation regarding the reliability of analytical methods available for each of the
sampling media to be used. There were detailed standard operating procedure documents for
field and laboratory quality assurance activities.
Statistical Analysis Critera
An inadequate statistical analysis plan was provided in the protocols. The HSRB
identified this deficiency as the most critical scientific limitation for these protocols. There was
a need for a more professional and comprehensive treatment of statistical issues in the analysis of
data, and in the design of individual protocols. Chief among these issues was the question of
statistical power. It is critical to address the HSRB’s concern that the present design calls in most
cases for a single observation per experimental condition. In other words, it appears that the
present studies are intended to be parsed in terms of formulation, container size, frequency of
worker activity, equipment, air temperature, wind speed, relative humidity, amount of cloud
cover, rainfall, crop, amount of material handled, rate of application, acreage treated, and
geographic location (along with other possible qualifiers). As a result, the number of variables to
be evaluated appears to approach or even exceed the total number of subjects for a given
scenario. One may hope that some useful information might yet emerge from a properly
performed analysis of the fill data set coming from studies involving different chemicals, sites,
and conditions. What is needed now, however, is a cogent and thoughtful discussion, in the
protocol, ofjust what can be accomplished along these lines, and an explanation of how it can be
accomplished. Further thought may lead to the conclusion that the current data-gathering plan is
in fact overly optimistic in regard to the issue of statistical power. It would then be essential to
restructure the plan and change the study design to ensure that the enormous effort in this large
and important project would not be wasted.
If the goal of these studies was to estimate the distribution of exposures across a variety
of application scenarios, it would be important to include true repeated measures for at least
some of these scenarios to assess the extent of within-worker variability.
Laboratory and Field Conditions
The protocol states that the field conditions were selected to be representative of real-
world use of pesticides. In this regard, participants are experienced workers, are allowed to wear
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their own clothing, and conduct normal work activities in an actual agricultural setting. Studies
are distributed across the U.S. and across the year in an attempt to develop a range of exposure
conditions. While laudable in scope, it is important to restate the concern that the large number
of variables included in these studies may prove extremely problematic for analysis.
The issue of potential heat stress was discussed at length at the HSRB public meeting.
The HSRB concluded that the protocols should include explicit criteria for halting a study due to
heat stress risk.
The protocols stated that workers would be monitored “during a period of time
representative of a full day’s work”. The protocols also indicated that monitoring times would
conform to a “typical” workday. However, none of the protocols defined the typical work period
for the specific tasks to be studied. Instead, the protocols stated that monitoring time “will
involve work periods with a target of 4 hours.” This language suggested that even four hours of
monitoring might not be achieved in some cases, and there was no indication that workdays as
long as 8 or 9 hours would ever be monitored. It was not clear to the HSRB that these studies
would necessarily reflect a full workshift or a “typical” workday. Many factors can influence the
length of the workday, including weather conditions, and the need to “get the job done” due to
pest pressures or the stage of crop development. Fatigue is an important factor that can affect
exposure, and usually inattention occurs at the end of the day. The HSRB recommended that the
protocols document the time of a typical workday (or the range of these times) for each scenario,
and that the monitoring time be based on this information.
Special Concerns Regarding Use of Diazinon in Protocol AI-1E37
Protocol A1{E37 involves handling a wettable powder (5OWP) formulation of diazinon.
Workers would be monitored during open cab trellis crop airbiast applications and open pour
mixing-loading operations. The HSRB was concerned that these practices are not consistent with
current Agency policy. The Agency’s May 2004 interim registration eligibility document
(IRED) for diazinon stated that engineering controls are required during handling. The “IRED
Facts for Diazinon” states, “All application equipment must use lock and load engineering
controls. All wettable powder formulations must be packaged in water-soluble bags. Closed cabs
are required for all ground equipment, except for applications to apples.” The IRED Executive
Summary further stated, “Occupational exposure to diazinon is of concern to the Agency. For
agricultural uses of diazinon, most mixer/loader/applicator risk scenarios currently exceed the
Agency’s level of concern (i.e., MOEs are less than 100 for dermal exposure and MOEs are less
than 300 for inhalation exposure). Taking into consideration both the risks and benefits of these
uses, EPA has determined that most agricultural uses may continue with the adoption of the
following mitigation measures:.. . engineering controls for mixers and loaders and closed cabs
for applicators for all application scenarios.. .“ The above statements indicate that open pouring
of diazinon is not permitted, and that open cab airbiast applications are not permitted in trellis
crops.
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HSRB Consensus and Rationale
The five studies presented for HSRB review were components of a large-scale exercise to
create a contemporary database on occupational exposure to agricultural pesticides. The
undertaking is in itself likely to be worthwhile in quantifying and improving our understanding
of the exposures of and risks to pesticide handlers. The potential benefits are large and the risks
appear to be relatively modest. However, the materials supplied for HSRB review failed to deal
adequately with risks and benefits. None of these protocols can be properly evaluated in regard
to scientific validity because they lacked: (I) a developed rationale documenting the need for
new data; (2) a clear and appropriate plan for the handling of the data (including its statistical
analysis), and (3) an explanation of the uses to which the data would be put and adequate sample
sizes and protocols for repeated measures to appropriately estimate exposures within individuals
and between scenarios. These points need to be addressed, at least briefly, in each specific
protocol and, more fully, in a separate and new “governing document” that is not simply a
generic description of the planned activities.
Additional validation studies are recommended to determine the extent to which dermal
exposure measurements may underestimate true exposure. Laboratory-based removal efficiency
studies or field-based biomonitoring studies could be conducted to achieve this goal. Such
studies shouLd be published in the peer-reviewed literature. Broader participation of the scientific
community and of parties with a direct interest in the database project, such as the labor
community, would likely improve the quality of the database and enhance the credibility of its
use in risk assessments.
The HSRB recommended that specific criteria for cessation due to heat stress be included
in these worker exposure protocols, and that the protocols include a heat stress management plan.
In addition, the HSRB recommended that the length of each study should be truly representative
of a full workday, and that each protocol should document the basis for the proposed duration of
the study.
The HSRB was gratified to receive the Agency’s response to its query regarding the use
of diazinon in the AHE37. It is the understanding of the HSRB that the Agency would inform the
AHETF that it needs to identify a pesticide other than diazinon in this protocol to evaluate
exposures associated with open pour activities and applications using open cabs, and that the
Agency would ensure that future protocols comply with the most current risk mitigation
measures specified in IREDs and REDs.
Board Response to the Charge
Ethical Considerations
Background
These five studies are part of a series of studies that are to be conducted by the AHETE, a
coalition of 19 pesticide registrants that was fonned in December 2001 to share resources in the
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design, evaluation, and development of a proprietary agricultural mixer/loader and applicator
exposure database for use in regulatory risk assessments.
The study protocols were designed by AHETF investigators after joint discussions with
the US EPA, Health Canada, and the California Department of Pesticide Regulation, in
accordance with the recommendations of such guidance documents as: 1) US EPA, Occupational
and Residential Exposure Test Guidelines, Series 875.1000 through 875.1600 (1996); and 2) US
EPA, Working Draft - Occupational and Residential Exposure Test Guidelines, Series 875
Group-B, Postapplication Exposure Monitoring Test Guidelines Version 5.4 (1998). The
supporting and supplementary study documents also assert compliance with the Good
Laboratory Practice (GLP) Standards established by the 1972 amendment to the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA) ( 40CFR160). Finally, these protocols
were reviewed and approved by the Western Institutional Review Board (WIRB) of Olympia,
Washington, prior to submission to the Agency.
The aims of these studies are to provide critical exposure information for individuals who
mix, load, and apply agricultural pesticides. Agricultural producers (“growers”) would be
recruited by the study coordinators several months prior to initiation of the study; in exchange
for their participation in the study, each grower would receive, free of charge, an amount of
liquid pesticide equivalent to the normal quantity mixed and loaded into closed-mixing systems
and spray rigs for the duration of the study (expected to be a single day). Participating growers
also may be asked to recruit other growers and pesticide applicators into the research study.
Study investigators would recruit agricultural handlers on-site; volunteers would receive
$100/day for their participation in addition to their regular pay. Voluntary informed consent
would be solicited by study investigators, and will be documented using a standardized informed
consent form. Because the study participants would be recruited from a pooi of experienced
agricultural workers who routinely mix and load liquid pesticides as part of their normal duties,
the AHETF had argued that participation in this study presents a negligible increase in pesticide
exposure risk to volunteers. In accordance with the newly promulgated provisions in the EPA’s
Final Human Studies Rule ( 40CFR26. 1701 - 26.1704), minors and pregnant women are
explicitly excluded from participation, the latter being confirmed by requiring all female
volunteers to undergo a self-administered over-the-counter pregnancy test on the day of the
study.
Dermal exposure to pesticides would be ascertained through hand rinses and face/neck
wipes, as well as the use of long cotton underwear — as a surrogate for skin — to be worn under
the study participant’s clothing. In addition to the long underwear, all participants would be
required to wear long sleeved shirts and long pants, shoes plus socks, in accordance with
accepted worker protection standards. Volunteers may wear their own clothing provided they are
freshly laundered; alternatively, the AHETF would provide freshly laundered clothing. Any
personal protective equipment (PPE) that may also be required, such as chemical resistant gloves
and protective eyewear, will be provided. At the conclusion of the four-hour study observation,
the long underwear would be removed and subjected to laboratory analyses to estimate whole-
body dermal pesticide exposure. Study participants would also be asked to wear OSHA Versatile
Samplers (OVS) outfitted with glass filters, XAD-2 sorbent, and tygon tubes to measure
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inhalation exposure. The tubes would be attached to the volunteer’s collars with the openings
positioned in their breathing zones. By using such state-of-the-art monitoring techniques, the
AHETF argues, this study would provide critical exposure information for individuals who
mix/load liquid agricultural pesticides.
Strengths and Limitations
These studies would provide critical exposure information for individuals who mix/load
and apply agricultural pesticides. It is also believed that the monitoring techniques proposed for
these studies represent the current state-of-the-art. However, the Agency also recognized that use
of the data resulting from this studies would take careful scrutiny and may require a number of
adjustments depending upon the results. Finally, the overall design of these studies should be
considered in the context of the goals of the AHETF which are to develop a broad-based
database that can be generically used as a predictive tool for estimating exposures to pesticide
handlers and that the interpretation of the results of these studies may or may not necessitate the
need for additional monitoring data.
The Board concurred with the factual observations of the strengths and weaknesses of the
studies, as detailed in the EPA’s Initial Ethics Review of the A1-IETF Template Protocol and
each individual study protocol. The Board concluded that, given the deficiencies noted by the
EPA, the proposed research described in the AI-IETF Template Protocol and each individual
study protocol do not comport with the applicable requirements of §40CFR26, subpart K.
Furthermore, the AHETF and WIRB failed to provide all of the documents necessary to be in
compliance with the requirements of 4OCFR §26.1125.
Although public comments from several members of the AHETF helped assuage some of
the Board’s concerns, the members of the HSRB believed that further comments about this
protocol were warranted. The comments below are grouped into four broad categories: (1)
whether the study was designed to adequately minimize risk to study participants; (2) whether
the documentation and process of study subject enrollment was sufficient to meet prevailing
standards of voluntary informed consent; (3) whether study participants would be adequately
compensated in the event of a study-related injury; and (4) whether appropriate alternatives to
participation are provided.
Minimization of Risks to Study Participants
This study proposes to measure dermal and inhalation exposure to liquid pesticides by
agricultural handlers who usually perform pesticide mixing, loading, and application as part of
their daily routine. However, it was unclear to Board members, given the semi-scripted nature of
the protocol provided, as to whether or not study participants would be exposed to greater
quantities of these compounds than would normally occur. Are the studies proposed purely
observational in nature, or are study investigators intervening by requesting that study
participants use different types and quantities of pesticide, or different mixing, loading, and
application methods, than they normally would? If the latter is true, the assumption that this
study represents a negligible increase in pesticide exposure risk to volunteers may be unfounded.
Several Board members also expressed concern that the additional requirements for donning and
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removing the equipment used to measure pesticide exposure may inadvertently lengthen the
participant’s normal work day. If so, this should be clearly described during the consent process,
as should the question of whether the $100 paid for study participation is expected, in whole or
in part, to compensate for the extension of the work day.
The protocol failed to detail the approach taken to ensure that agricultural handlers are
adequately trained in the proper mixing, loading, and application of these compounds. Although
pesticide mixing instructions and Material Safety Data Sheets are made available to study
participants, given that many agricultural workers may not be fluent in English (or may even be
illiterate), a clear plan for ensuring that volunteers are properly educated in minimizing their
exposure to these compounds should be included. Furthermore, study investigators may want to
make arrangements to provide volunteers with the results of the study following completion.
One of the greatest risks to study participants is heat-related illness, given that dermal
exposure to pesticides will be determined by asking volunteers to wear long underwear in
addition to their normal protective equipment (e.g., long sleeved shirts and long pants, and other
applicable protective gear). Although study coordinators are expected to be vigilant for signs of
heat-related illness among volunteers, in order to minimize the risks posed to the study
participants the protocol also should include: a) explicit starting and stopping criteria based on a
quantifiable measure like ambient temperature or heat index; and b) a clear description of the
symptoms of heat-related illness in the informed consent documents. There should also be a clear
plan for reporting any heat-related illness (or, for that matter, any other adverse event) to the
study investigators, Western IRB, and the EPA.
Because some of the study participants may be undocumented immigrants, measures to
ensure strict confidentiality should be developed. Many undocumented workers, for example,
may be loathe to report any adverse study-related event requiring medical attention or
hospitalization if they believe that their illegal status will be reported to immigration authorities.
Alternatively, study investigators may wish to require documentation of citizenship or
immigration status as part of the inclusion criteria for recruiting study participants. In addition,
because many pregnant day-laborers may fear job loss in the event that their employer learns of
their condition, extra care should be taken to keep the results of over-the-counter pregnancy tests
private.
Voluntary Informed Consent
Several Board members felt that the AHETF protocol, as provided, lacked sufficient
safeguards to ensure that all study participants were adequately informed about the risks, benefits
and alternatives to participation in the study. For example, it was felt that the informed consent
documents provided were written at too high of a reading and comprehension level. Given the
sociodemographic characteristics of the farm worker population, many of the study participants
may have limited education, may speak English as a second or even a third language, or may
even be illiterate. Study investigators should develop a clear consent document which — in
addition to including a more detailed description of risks (including the risks of the pesticides
being handled) as described previously, as well as a clear distinction between what comprises
research versus normal activities — is written at a lower grade-level and translated into the
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various languages likely to be spoken by study participants. A brief oral test of comprehension
should also be developed, with volunteers required to demonstrate a clear understanding of the
purposes and the risks of the study prior to enrollment.
The Board also expressed concern about the potentially coercive nature of the study,
given the potential for study participants to believe that there is a direct relationship between
study investigators and growers. Absent additional safeguards, the “gift” of study pesticide to the
growers may contribute to undue influence on employees to participate in the research. Western
IRB, in its initial review of several of the AHETF protocols, recommended that “extra care” be
taken during the recruitment and consent process to minimize coercion or undue influence on
study participants. However, no documentation was provided to the HSRB as to how the AHETF
addressed WIRB’s concern. For example, there was no evidence to suggest that AHETF
researchers solicited the help of the farm-workers themselves or other community leaders to
ensure that study participants would not be covertly or overtly coerced into participating in the
study. The rights of participants to withdraw from the study at any time also should be
emphasized. It is unclear from the informed consent or other study documents, for instance, as to
whether volunteers are entitled to receive monetary payment even if they chose to withdraw
during the course of the study. Although the Board was reassured during the discussion that
sufficient alternate work was available, the protocol also failed to specify that workers would
still be paid for a day’s labor even if they refused to participate in the research.
Compensation for Injur y to Study Participants
The study protocol and informed consent documents state that: “If [ a study participant is]
injured as a result of being in this study, treatment will be available from a health professional at
a nearby medical facility. The costs of such treatment will be covered by the AHETF. This does
not cover any injuries resulting from [ the volunteer’s] normal activities.” Given the nature of the
study design, however, it is unclear whether a distinction between injuries resulting from normal
work activities versus participation in this study can be made. Two of the symptoms of heat
exhaustion, for example, are dizziness and loss of coordination — will study coordinators be able
to distinguish between an accidental injury caused by clumsiness versus an injury resulting from
potentially-unrecognized symptoms of heat-related illness? In light of these concerns, the Board
recommends that the AEHTF cover medical treatment for all participant illness and injury
occurring during the study period (i.e., the day of the test).
Alternatives to ParticiDation
As noted above, the design of this study involves collaboration between the researchers
and growers in which the growers receive, free of charge, a particular pesticide that they are
required to apply to their fields on the day of the study. That arrangement will lead in many
circumstances (except of the few coincidental instances when the grower had already planned to
use that chemical on that day) to a change in the pesticide being applied by the grower.
The following question thus arises: What alternatives are offered to agricultural handlers
working for that grower who choose not to participate in the study? One option is that they could
be offered the choice of applying that pesticide that day, but not needing to participate in any
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other study procedures (such as wearing the long underwear). Some members of the Board
believed that if that is the only alternative to participation, then this aspect of the study would not
comply with 40 C.F.R. Part 26, Subpart K.
Some members of the Board accordingly concluded that for agricultural workers who had
pre-existing expectations of earning money working for the grower on the day of the study
(either as employees or as independent contractors with contractual expectations of working that
day), the protocol must provide them alternatives for earning that same amount of money that do
not require them to apply the pesticide used in the study. Acceptable alternatives could include
applying some other pesticide they have in the past applied, performing some other task they
regularly perform, or being paid their expected earnings without needing to work. Absent such
alternatives, the protocol would appear to be inappropriately coercing such persons into applying
the study compound or else losing the money they expected to earn that day.
HSRB Consensus and Rationale
The Board concurred with the initial assessment of the Agency that the studies submitted for
review failed to meet the requirements established in the 40CFR26.
The Board determined the proposed occupational handlers exposure studies do not comport
with the applicable requirements of 40CFR26, subpart K. However, the deficiencies noted,
while significant, were not irreparable.
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REFERENCES
AHETF 2006. Comments to the Human Studies Review Board (HSRB) Regarding Five
Protocols Submitted for Review. June 20, 2006.
NAS 2004. Intentional Dosing Studies for EPA Regulatory Purposes: Scientific and Ethical
Issues. National Academy Press.
NBAC 2001. Ethical and Policy Issues in Research Involving Human Participants. National
Bioethics Advisory Commission. www.bioethics.gov
Prentiss AM. 1937. Chemical in War: A Treatise on Chemical Warfare. McGraw-Hill Book
Company, Inc. New York.
USEPA 2006a. Human Studies Review Board. Weight of Evidence Determination for
Chloropicrin. June 7, 2006
USEPA 2006b. Ethics Review of Protocol for Human Study of Tick Repellent Performance.
June 9, 2006.
USEPA 2006c. Ethics Review of Protocol for Human Study of Mosquito Repellent Performance
June 9, 2006.
USGPO. 1949. Trials of War Criminals before the Nuremberg Military Tribunals under Control
Council Law No. 10, Vol. 2, pp. 181-182. Washington, D.C.
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