Document ID: EPA-HQ-ORD-2011-0953-0004
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2012-01-23T05:00Z

January 11, 2012

EPA-HSRB-11-03

Paul Anastas, PhD

EPA Science Advisor

Office of the Science Advisor

1200 Pennsylvania Avenue, NW

Washington, DC 20460 

Subject: October 19-20, 2011 EPA Human Studies Review Board Meeting
Report

Dear Dr. Anastas,

	The United States Environmental Protection Agency (EPA or Agency)
requested that the Human Studies Review Board (HSRB) provide scientific
and ethics reviews of two new protocols for studies involving
intentional exposure of human subjects to pesticides: a proposed
Antimicrobial Exposure Assessment Task Force II (AEATF) scenario to
determine dermal and inhalation exposures associated with the manual
pouring of liquid antimicrobial products (AEA-05); and a proposed
Agricultural Handler Exposure Task Force, LLC (AHETF) scenario measuring
dermal and inhalation exposure of workers who perform closed system
loading of liquid pesticides in non-returnable and returnable
containers.

	The Agency also requested that the HSRB review a completed study of
insect repellent efficacy conducted by Carroll-Loye Biological Research,
Inc. (CLBR). This study (No Mas-003) was conducted after publication of
the EPA’s expanded final rule for protection of subjects in human
research (40 CFR 26) on February 6, 2006, and was reviewed favorably at
the HSRB’s October 2010 meeting.

	Finally, the Agency asked the Board to review a published study
involving intentional human exposure study measuring dermal absorption
of nanosilver (Moiemen et al. 2011). The Agency proposes to rely on this
study, conducted after publication of the EPA’s expanded final rule
for protection of subjects in human research, for regulatory actions.

	The enclosed report provides the Board’s response to EPA charge
questions presented at the October 19-20, 2011 meeting.

Assessment of Proposed AEATF Research Study AEA05: A Study for
Measurement of Potential Dermal and Inhalation Exposure During Manual
Pouring of a Liquid Containing an Antimicrobial.

Science

The Board concluded that the protocol submitted for review, if modified
in accordance with EPA (Leighton, Sherman and Cohen 2011) and HSRB
recommendations, is likely to generate scientifically reliable data,
useful for assessing the exposure of individuals who manually pour
liquid antimicrobial products. 

In addition to providing several additional comments or suggestions, the
Board also pointed out two limitations not identified either within the
protocol or by the Agency: 1) the wider range of exposures that could
occur while pouring products outdoors than only indoors as proposed;
and, 2) the unknown impact of potential differences in exposures between
consumers and professionals. 

Ethics

The Board concluded that the protocol submitted for review, if modified
in accordance with EPA and HSRB recommendations, is likely to meet the
applicable requirements of 40 CFR 26, subparts K and L.

Assessment of Proposed AHETF Research Study AHE500: Exposure Monitoring
of Workers During Closed System Loading of Returnable and Non-Returnable
Containers in the United States.

Science

The Board concurred with the Agency’s assessment that the proposed
AHETF scenario and field study proposal AHE500, if revised as suggested
in EPA’s review and performed as described, is likely to generate
scientifically reliable data, useful for assessing the exposure of
workers using closed systems to load liquid pesticide products from
returnable or nonreturnable containers. 

The Board provided an additional set of recommendations for the Agency
and study sponsors to consider when collecting and analyzing data
concerning the exposure of workers using such closed load systems.

Ethics

The Board concluded that the protocol submitted for review, if modified
in accordance with EPA and HSRB recommendations, is likely to meet the
applicable requirements of 40 CFR 26, subparts K and L.

Assessment of Completed Carroll-Loye Biological Research Study No
Mas-003: Field Efficacy Test of 16% Para-menthane-3,8-diol (PMD) and 2%
Lemongrass Oil Based Repellent ‘No Mas’ Against Mosquitoes.

Science

The Board concurred with the Agency’s assessment that this study
provides scientifically valid results to assess the repellent efficacy
against mosquitoes for the formulation tested. 

Ethics

The Board concurred with the Agency’s assessment that the study
submitted for review was conducted in substantial compliance with
subparts K and L of 40 CFR 26.

Assessment of Published Research Study MRID 48607501: Moiemen et al.
(2011) Acticoat Dressings and Major Burns: Systemic Silver Absorption.

Science

Despite several deficiencies identified with the study design, the small
number of subjects, and the interpretation of the data, the Board agreed
with the Agency’s assessment that the Moiemen et al. (2011) study
provides some potentially useful baseline information on the dermal
absorption of silver from nanosilver-containing wound dressings. 

The Board concluded that the Moiemen et al. (2011) study could be used
to support the Agency’s conclusion that the dermal absorption of
silver is less than 0.1% as part of the overall weight of evidence, but
recommended that: 1) the Agency clarify its assumptions in estimating
the dermal absorption of silver from nanosilver; and 2) that the Agency
consider alternatives for estimating dermal absorption based on this
study.

Ethics

The Board concurred with the Agency’s assessment that there was
sufficient information regarding value of the research to society,
subject selection, risks and benefits, independent ethics review,
informed consent, respect for potential and enrolled subjects to
conclude that the study was conducted in substantial compliance with
procedures at least as protective as those in subparts A - L of EPA’s
regulation at 40 CFR Part 26.

Sincerely,

Sean Philpott, PhD, MSBioethics

Chair

EPA Human Studies Review Board

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 the mention of trade names or
commercial products constitute a recommendation for use.  You may obtain
further information about the EPA Human Studies Review Board from its
website at   HYPERLINK "http://www.epa.gov/osa/hsrb" 
http://www.epa.gov/osa/hsrb .  You may also contact the HSRB Designated
Federal Officer, via e-mail at   HYPERLINK "mailto:ord-osa-hsrb@epa.gov"
 ord-osa-hsrb@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.

US ENVIRONMENTAL PROTECTION AGENCY

HUMAN STUDIES REVIEW BOARD

Chair

Sean Philpott, PhD, MSBioethics, Director for Research Ethics, The
Bioethics Program of Union Graduate College and the Mount Sinai School
of Medicine, Schenectady, NY

Vice Chair (Acting)

Rebecca Parkin, PhD, MPH, Professorial Lecturer (EOH), School of Public
Health and Human Services, The George Washington University, Washington,
DC

Members

Janice Chambers, PhD, DABT, Fellow ATS, William L. Giles Distinguished
Professor, Director, Center for Environmental Health Sciences, College
of Veterinary Medicine, Mississippi State University, Mississippi State,
MS

George Fernandez, PhD, Professor of Applied Statistics, Director of the
University of Nevada-Reno Center for Research Design and Analysis,
University of Nevada-Reno, Reno, NV

Vanessa Northington Gamble*, MD, PhD, University Professor of Medical
Humanities, Professor of Health Policy and American Studies, The George
Washington University, Washington, DC

Sidney Green, Jr., PhD, Fellow of the ATS, Professor, Department of
Pharmacology, Howard University College of Medicine, Washington, DC

Dallas E. Johnson, PhD, Professor Emeritus, Department of Statistics,
Kansas State University, Manhattan, KS

Michael D. Lebowitz†, PhD, FCCP, Retired Professor of Public Health &
Medicine, University of Arizona, Tucson, AZ 

José E. Manautou, PhD, Associate Professor of Toxicology, Department of
Pharmaceutical Science, University of Connecticut School of Pharmacy,
Storrs, CT

Jerry A. Menikoff§, MD, JD, Director, Office for Human Subjects
Research, Office of the

Secretary, Department of Health and Human Services, Rockville, MD

William Popendorf, PhD, MPH, Professor Emeritus, Department of Biology,
Utah State University, Logan, UT 

 

Virginia Ashby Sharpe, PhD, Medical Ethicist, National Center for Ethics
in Health Care, Veterans Health Administration, Washington, DC

Linda J. Young, PhD, Professor, Department of Statistics, Institute of
Food and Agricultural Sciences, University of Florida, Gainesville, FL 

Human Studies Review Board Staff

Jim Downing, Executive Director, Human Studies Review Board Staff,
Office of the Science Advisor, United States Environmental Protection
Agency, Washington, DC

* Not present on October 19, 2011.

† Participated in the October 19-20, 2011 meeting via telepresence.

§ Not present on October 20, 2011.

INTRODUCTION 

On October 19-20, 2011, the United States Environmental Protection
Agency’s (EPA or Agency) Human Studies Review Board (HSRB) met to
address scientific and ethical issues concerning two new protocols for
research involving human participants: one new study measuring dermal
and inhalation exposures associated with the manual pouring of liquid
antimicrobial products, and one new study measuring dermal and
inhalation exposure of workers who perform closed system loading of
liquid pesticides in non-returnable and returnable containers. In
accordance with 40 CFR 26.1601, EPA sought HSRB review of these two
proposed studies. Each of these studies is discussed more fully below.

	In addition, the Agency has data from one completed study measuring the
efficacy of an insect repellent containing para-menthane-3,8-diol (PMD)
and lemongrass oil against mosquitoes under field conditions. In
accordance with 40 CFR 26.1602, EPA sought HSRB review of this completed
study. This completed study is discussed more fully below.

	Finally, the Agency sought HSRB review of one published study of dermal
absorption of silver (Ag) from silver nanoparticle-impregnated wound
dressings used to treat major burns. This study, conducted after
publication of the EPA’s expanded final rule for protection of
subjects in human research, was identified by Agency scientists from the
peer reviewed literature. This study, which the Agency proposes to rely
upon for regulatory actions, is discussed in detail below.

REVIEW PROCESS

On October 19-20, 2011, the Board conducted a public face-to-face
meeting in Arlington, Virginia. Advance notice of the meeting was
published in the Federal Register as “Human Studies Review Board;
Notice of Public Meeting” (76 Federal Register 187, 59697).

Following welcoming remarks from Agency officials, the Board heard
presentations from EPA on the following topics: one new study protocol
to measure dermal and inhalation exposures associated with the manual
pouring of liquid antimicrobial products, and one new study protocol to
measure dermal and inhalation exposure of workers who perform closed
system loading of liquid pesticides in non-returnable and returnable
containers. A completed study measuring the efficacy of an insect
repellent containing PMD and lemongrass oil against mosquitoes under
field conditions was also reviewed, as was one published study measuring
dermal absorption of silver (Ag) from silver nanoparticle-containing
wound dressings applied to severely burnt human skin. 

The Board also asked clarifying questions of several study sponsors
and/or research investigators, including:

Dr. Michael Bartels, Scientist, Dow Chemical Company (representing the
Antimicrobial Exposure Assessment Task Force II)

Dr. Victor Cañez, Technical Chair, Agricultural Handler Exposure Task
Force

Dr. Scott Carroll, Study Director, Carroll-Loye Biological Research

Dr. Richard Collier, Administrative Committee Chair, Agricultural
Handler Exposure Task Force

Mr. Shawn King, Director of Operations, Carroll-Loye Biological Research

Ms. Leah Rosenheck, President, LR Risk Consulting, Inc. (representing
the Antimicrobial Exposure Assessment Task Force II)

Public oral comments were provided by: 

Dr. Michael Bartels, Scientist, Dow Chemical Company

Dr. Victor Cañez, Technical Chair, Agricultural Handler Exposure Task
Force

Dr. Scott Carroll, Principal, Carroll-Loye Biological Research

No written public comments were submitted.

For their deliberations, the Board considered the materials presented at
the meeting, oral comments, and Agency background documents (e.g.,
published literature, sponsor and investigator research reports, study
protocols, data evaluation records, and Agency science and ethics
reviews of proposed protocols and completed studies). A comprehensive
list of background documents is available online at   HYPERLINK
"http://www.regulations.gov"  http://www.regulations.gov . 

CHARGE TO THE BOARD AND BOARD RESPONSE

Assessment of Proposed AEATF Research Study AEA05: A Study for
Measurement of Potential Dermal and Inhalation Exposure During Manual
Pouring of a Liquid Containing an Antimicrobial.

Overview of the Study

AEATF II liquid pour protocol (AEA05) is designed to measure a typical
occupational handler’s daily exposure to various antimicrobial
products whose use and application requires the pouring of a liquid
product (e.g., an antimicrobial concentrate that may be measured and
diluted with water prior to use). This proposal presents two different
occupational exposure scenarios: one involving pouring of liquids from
conventional containers and one involving the use of containers designed
to reduce splashing.  

A total of 18 participants (described in the protocol as “Monitoring
Events” [MEs]) will be observed. Each volunteer will pour
antimicrobial products from both conventional and “reduced splash”
containers at a laboratory site in Concord, OH.  Didecyl dimethyl
ammonium chloride (DDAC; Maquat WP) and N-alkyl dimethyl benzyl ammonium
chloride (ADBAC; Maquat DS 1412-10%) will be the antimicrobial materials
used for the conventional pour and reduced splash scenarios,
respectively. These two commonly used products can be distinguished
analytically, thus allowing researchers to use a single participant to
monitor dermal and inhalation exposure to antimicrobial agents under
both a conventional pour and reduced splash scenario. For each scenario,
the study participants will be randomized to pour different amounts of
liquid; 40 ounces to 20 gallons in the conventional pour scenario, and
60 ounces to 30 gallons in the reduced splash scenario. A variety of
source and receiving containers will also be used, including 32 ounce
spray bottles, 2 and 4 gallon buckets, and 10 gallon basins.

	Participants will wear long sleeved shirts and long pants (provided by
the researchers), and shoes plus socks (provided by the subject). The
low toxicity and low concentration of the surrogate compounds used
eliminates the need to have participants wear additional protective
equipment, such as chemical resistant gloves or aprons. 

	Dermal exposure will be measured by a whole body dosimeter worn beneath
the subject’s outer clothing. Hand wash and face/neck wipe samples
will also be collected prior to, during, and after completion of the
liquid pour procedures. Airborne concentrations of the surrogate will be
monitored in the participant’s breathing zone using an OSHA Versatile
Sampler (OVS) tube sample collector connected to a personal sampling
pump. Additional measures will also record environmental conditions at
the time of monitoring, and observers will collect field notes, take
photographs, and record video of participant activity throughout the
monitoring event. 

These data will be used by the Agency generically to estimate dermal and
inhalation exposures and risks for other antimicrobial ingredients where
the product is packaged as a liquid concentrate in conventional or
reduced splash containers. 

Science

Charge to the Board

	If the AEATF liquid pour study proposal is revised as suggested in
EPA’s review and if the research is performed as described, is the
research likely to generate scientifically reliable data, useful for
assessing the exposure of individuals who manually pour liquid
antimicrobial products?

Board Response to the Charge

HSRB Recommendation 

	The Board concluded that the protocol submitted for review, if modified
in accordance with EPA (Leighton, Sherman and Cohen 2011) and HSRB
recommendations, is likely to generate scientifically reliable data,
useful for assessing the exposure of individuals who manually pour
liquid antimicrobial products. 

	Several comments or suggestions were made by the Board with respect to
the Agency’s proposed revisions to the protocol, the Task Force’s
proposal to use a single participant and a single dosimeter to assess
dermal and inhalation exposure in two scenarios, and the lack of
information provided within the protocol on the source containers to be
used. 

	The Board also pointed out two limitations not identified either within
the protocol or by the Agency: 1) the wider range of exposures that
could occur while pouring products outdoors than only indoors as
proposed; and, 2) the unknown impact of potential differences in
exposures between consumers and professionals. These limitations are
described in detail below.

HSRB Detailed Recommendations and Rationale

The AEATF-II liquid pour protocol is complicated and highly scripted,
but seems to be a feasible way to generate scientifically reliable
exposure assessment data that includes the effects of source container
size, size and type of receiving container, use of measuring cups or
not, and height of pouring. The Board had several recommendations,
however, as to how the study might be improved.

1. 	Proposed Revisions to the Protocol.

First, the Agency has proposed that the protocol be revised to randomize
the use of a measuring cup by participants in monitoring Group 2
(Leighton, Sherman and Cohen 2011, 17). The Board has no substantive
insight into the impact on dermal and inhalation exposures if Group 2
does or does not use a measuring cup. Indeed, the inclusion of the
measuring cup appears to be more of a policy decision based on perceived
future uses of the data than a question of science.  Nonetheless, the
Board made the following observations.  Because using a 4 ounce
measuring cup twice for each of 10 pours into a bucket means that only
80 ounces (~ ⅔ of a gallon) will comprise only 5-10% of the total of
7.5 to 14 gallons expected to be handled by each ME in Group 2, the
effect of this difference on exposures may be slight in either
direction.  The ability to detect a slight difference within two
subgroups of 3 MEs each is very small.  Given this, two alternatives for
assessing the effect of using a measuring cup were suggested by the
Board.  The first alternative is to consider having half of the
participants in Group 2 use a measuring cup to transfer all of their
assigned source volume into the receiving container, and the other half
to not use the cup.  Another alternative is for no one in Group 2 to use
a measuring cup, but instead to test for a difference in the unit
exposure values between Group 1 (all of whom use a measuring cup) and
Group 2 (all of whom do not use a measuring cup).

The second revision proposed by the Agency would be to allow study
participants to “fill the spray bottles from the source container and
with water in the order they would normally do as opposed to the
researchers directing them to fill with water after pouring the
concentrate from the measuring cup” (Leighton, Sherman and Cohen 2011,
17). This is probably a good revision.  However, the Agency should also
ensure that the protocol directs the handlers to follow the label
instructions.  The label information provided within this protocol was
not complete, and the lack of more specific instruction should be
confirmed among all applicable labels. Based on the information
available, however, the Board concurs with this proposed revision.  A
related but separate comment was made that since the bactericidal
solution to be used in the study has been pre-diluted by the study
director(s), none of the labeling instructions that would normally be
present on the original container will be present in the pouring
containers within this study.  The protocol thus should be amended to
specify what label information will be made available to study
participants.

Regarding the third revision proposed by the Agency -- to “provide a
description of how the different size source containers will be randomly
assigned to each ME” (Leighton, Sherman and Cohen 2011, 17) -- the
Board suggested adding statistical constraints to the randomization
process used to assign the different size source containers to each ME. 
Since the array of conditions is already scripted, it seems reasonable
to avoid creating statistical outliers that might result from a
completely random distribution.  For example, the study director could
generate the random array of size distributions beforehand and screen it
to assure that all distributions fall within the “to-be defined”
probability limits. 

The Board concurs with the Agency’s fourth proposed revision, namely
to request that the Task Force “provide details about how the airflow
in the laboratory room will be measured and what the target airflow will
be (e.g., will the airflow be minimized?)” (Leighton, Sherman and
Cohen 2011, 17). However, the focus of interest in ventilation should be
on the local air flow between the pouring operation (the purported
source of exposure) and the handler.  Analyses of the pattern of
exposures to applicators in the AEATF-II completed mopping protocol
showed that the amount of room ventilation seemed to have virtually no
effect on exposures (EPA HSRB 2010). Mopping is a mobile task, and
moving throughout a room can balance the effects of localized air
currents between the source of exposure and the handler.  In contrast,
someone pouring a liquid is likely to be relatively stationary.  Thus, a
consistent local air flow (its speed and especially its direction
between the pouring operation and the handler) is likely to bias the
measured exposures.  Because air flow patterns generated by a Heating,
Ventilation and Air Conditioning (HVAC) system are likely to be
consistent, at the very least, that pattern should be measured before
and/or after exposures and the orientation between the source and each
handler should be documented for each ME.  Alternatively, the room’s
setup and the orientation between the source and handler could be varied
(e.g., rotated 90°) either within or among MEs; this approach may
increase the variability in the resulting exposure data and is more
likely to include the higher downwind exposures than having only one
orientation for all MEs.  Increasing the variability independent of the
amount of the active ingredient handled (AaiH) may adversely affect the
ability to detect proportionality, akin to the effect discussed herein
regarding the Agricultural Handlers Exposure Task Force’s Closed
System Load Liquid (AHETF CSLL) study.  In addition, it was pointed out
that the airflow through laboratories is generally more than what would
be expected in many other work rooms in which such pouring would take
place; therefore, some steps to minimize the air flow should be
considered.  One possible, simple way to reduce the airflow through the
room is to close the laboratory fume hood’s sash door, although some
fume hoods have a bypass that prevents the sash’s position from
affecting the HVAC airflow. 

  Proposal to Monitor Two Scenarios Using the Same Dosimeters.

	The proposal for each ME to monitor two scenarios using the same set of
dosimeters seems novel and efficient.  There is no evidence to suggest
that the plan as proposed will not work, and precedents for collecting
and analyzing multiple active ingredients in the same environment were
discussed. The Board suggested that consideration be given to ways of
leveraging the data from two exposures to the same individual during the
analysis of the results.  However, the Board pointed out the potential
for a portion of a dosimeter (particularly an outer dosimeter) that
becomes locally saturated by a significant spill or splash to behave
differently from a fresh dosimeter in terms of its transmission and/or
retention of the handled mixture.  While such an event may not occur
during the study, such wetting of the outer clothing is likely to be
quite visible to the study observer.  Thus, a suggestion was made to
modify the protocol to allow the study observer to decide if someone’s
dosimeters should be changed between the two scenarios to avoid such a
foreseeable event from confounding the sample results of the second
scenario.  Discussion pointed out that this flexibility should be
implemented in a way that does not cause the handler to change his or
her behavior.  Finally, no rationale was provided for using DDAC in the
conventional pour scenario and ADBAC in the reduced-splash pour scenario
versus randomizing the two antimicrobial agents between the conventional
and reduced splash containers.

3.	Source Containers.

	The lack of information within the protocol about the source containers
to be used was noted.  Granted that the definition of reduced-splash
non-refillable containers is performance based rather than product
specific; however, neither the specific reduced-splash container(s) was
to be used in this study not identified, nor were a list of candidate
reduced-splash containers potentially to be used or a description of how
the final container(s) will be chosen provided.  A similar comment about
the lack of candidates or specificity (other than size) applies to the
refillable containers.  It seems prudent to agree upon the selection
process or final containers before beginning the study.

4.	Additional Study Limitations.

	The Board also pointed out two limitations not identified either within
the protocol or by the Agency: 1) the wider range of exposures that
could occur while pouring products outdoors than only indoors as
proposed, and; 2) the unknown impact of potential differences in
exposures between consumers and professionals. 

	First, pouring operations are likely to occur outdoors within three of
the eight ‘Use Categories’ identified by the Agency at which a
majority of liquid pouring operations are likely to occur (i.e.,
Agricultural, Swimming pools, and Aquatic areas), and it may occur
outdoors in a fourth (III Commercial / institutional / industrial
premises and equipment) (Leighton, Sherman and Cohen 2011, 5-6). Air
velocity outdoors is likely to be more variable (particularly on the
high-end) than indoors. The Agency should review and determine the
importance of the limitation of not assessing exposures outdoors.

	Second, while pouring a liquid product from a container may not be a
specialized task (see, e.g., Leighton, Sherman and Cohen 2011, 25), the
experience of a user may reduce the incidence of high exposure events.
This pattern leads to the hypothesis that a consumer (or less
experienced handler) may have a higher exposure on any given pour than a
professional (or more experienced handler).  Despite this, the Board did
not disagree with Agency’s conclusion that “because of greater
quantities of antimicrobial, professional handler exposure is expected
to be greater than that of consumers” [sic] (Leighton, Sherman and
Cohen 2011, 8). Professionals seem to be the appropriate group upon
which to later assess chronic risk, but having data only from highly
experienced (and nominally more proficient) handlers may underestimate
the acute hazards experienced by consumers who have potentially higher
but less frequent exposures.

Ethics

Charge to the Board

	If the AEATF liquid pour study proposal is revised as suggested in
EPA’s review and if the research is performed as described, is the
research likely to meet the applicable requirements of 40 CFR part 26,
subparts K and L?

Board Response to the Charge

HSRB Recommendation 

	The Board concluded that the protocol submitted for review, if modified
in accordance with EPA (Leighton, Sherman and Cohen 2011) and HSRB
recommendations, is likely to meet the applicable requirements of 40 CFR
26, subparts K and L.

HSRB Detailed Recommendations and Rationale

The submitted documents assert that the study will be conducted in
accordance with the ethical and regulatory standards of 40 CFR 26,
Subparts K and L, as well as the requirements of the US EPA’s Good
Laboratory Practice (GLP) Standards described at 40 CFR 160, and, for
research conducted in California, the California State EPA Department of
Pesticide Regulation study monitoring (California Code of Regulations
Title 3, Section 6710) (AEATF 2011). Requirements of FIFRA §12(a)(2)(P)
also apply. Researchers who participate in the study and interact with
study participants will be required to undergo ethics training.  The
training will include the successful completion of the course from the
National Institutes of Health (Protecting Human Research Participants)
and/or the Basic Collaborative IRB Training Initiative Course. 

	The protocol was reviewed and approved by an independent human subjects
review committee, IIRB, Inc. of Plantation, FL, prior to submission.
IIRB, Inc. is fully accredited by the Association for the Accreditation
of Human Research Protection Programs (AAHRPP). IIRB, Inc. is also
listed as an active Institutional Review Board (IRB) on the Office of
Human Research Protection (OHRP) website (Reg. #IORG0002954). Copies of
all correspondence with IIRB, Inc. (Shah 2011b, 2011c) and a copy of
IIRB, Inc. policies and membership roster were provided (IIRB, Inc.
2011a; 2011b). These documents indicate that IIRB, Inc. reviewed this
protocol pursuant to the standards of the Common Rule (45 CFR Part 46,
Subpart A). 

1.	The Board concurred with the conclusions and factual observations of
the ethical strengths and weaknesses of the study, as detailed in the
EPA’s Ethics Review (Evans, Sherman and Cohen 2011). The proposed
study is likely to meet the applicable ethical requirements for research
involving human subjects, in accordance with the following criteria: 

a. 	Societal value of the proposed research. The clearly stated purpose
of the proposed monitoring study is to determine potential dermal and
inhalation exposures to occupational workers and consumers associated
with the manual pouring of liquid antimicrobial products. Many consumers
and workers pour antimicrobial products, so the research question is
important and cannot be answered with confidence without new monitoring
data meeting contemporary standards of quality and reliability. 

b.	Subject selection and informed consent. The inclusion/exclusion
criteria are complete and appropriate. Pregnant or nursing women are
excluded from participation. Employees or relatives of employees of the
investigators and of cleaning product manufacturers are also excluded
from participation. Protections are adequate even if a subject were from
a vulnerable population. Informed consent will be obtained from each
prospective subject and appropriately documented in the language
preferred by the subject. Recruitment materials and interactions with
potential subjects will be conducted in English or Spanish, depending on
subject preference; the Board agrees with EPA’s suggestion that AEATF
identify the recruiting newspapers and specify “Spanish” rather than
“second alternate language.” Subjects will be recruited through
newspaper advertisements, which will minimize the potential for coercion
or undue influence, and the proposed monetary compensation is not so
high as to unduly influence participation. Candidates and subjects will
be repeatedly informed that they are free to decline to participate or
to withdraw at any time for any reason, without penalty.

c.	Risks to subjects. The proposed test materials are EPA-registered for
the use proposed, are of low toxicity to mammals, and will be used in
full compliance with the approved labels. All identified risks are
characterized as of low probability, and risks are further minimized by
exclusion of candidates known to be sensitive to quaternary ammonium
compounds or in poor health or with broken skin on hands, face, or neck;
testing in a controlled-temperature environment; alerting subjects to
signs and symptoms of heat stress; monitoring heat index with associated
stopping rules; allowing subjects to rest whenever they want or need to;
close observation of subjects; training of experienced technicians to
minimize embarrassment; incorporation of procedures to keep results of
pregnancy testing private and to permit discrete withdrawal; provision
of appropriate work clothing and Personal Protective Equipment (PPE).
Provision is made for discrete handling of the pregnancy testing that is
required of female subjects on the day of testing. The Board agreed with
the Agency’s suggestion to clarify the steps that participants should
take if participants have an adverse reaction within 24 hours.

d. 	Benefits to participants. This research offers no direct benefits to
the subjects. The principal benefit of this research is likely to be
reliable data about the dermal and inhalation exposure of people pouring
liquid antimicrobial products from conventional and reduced-splash
containers.  These data are intended to be used by EPA and other
regulatory agencies to support exposure assessments for a wide variety
of antimicrobial products and their uses. 

e.	Risk/benefit balance. Risks to subjects have been thoughtfully and
thoroughly minimized in the design of the research. The low residual
risk is reasonable, in light of the likely benefits to society from new
data supporting more accurate exposure assessments for antimicrobial
products. 

2.	In addition to this analysis, the Board recommended a few edits to
improve the clarity of the Informed Consent Form. These are listed
below, organized according to the section within the Informed Consent
Form in which they appear:

Introduction: 

“If you do In order to take part in this study, you must read and sign
this consent form” (Line 4).

Purpose of this Study:

“This study is being funded by the American Chemistry Council’s
Antimicrobial Exposure Assessment Task Force II (AEATF II) which. The
AEATF II is a …” (Line 1).

Purpose of this Study:

The last sentence of this section currently reads: “If you cannot read
or understand English, a Spanish speaking member of the research team
will read the Spanish translation to you and answer your questions.”
It is not clear what translated document(s) are being referred to here.
The protocol indicates that the forms and supporting documents will be
available in either English or Spanish and literacy is required, thus it
is not clear why someone would need to read to the participant. The
Board suggests clarifying this sentence.

Study Procedures:

The numbered list under “Here’s exactly what will happen”
sequences the pregnancy test prior to checking for cuts and scrapes on
the hands.  Some (though not all) Board members were concerned that this
ordering might subject female participants to an unnecessary pregnancy
test and recommended that the sponsors consider conducting the skin
check earlier than any pregnancy test since evidence of any exclusion
factors here would make the pregnancy test unnecessary.  

Benefits:

Regarding the section of the informed consent form that discusses return
of results as a possible benefit of the study, the Board discussed:

Whether this adequately covers the issue of return of research results
to participants;

Whether this topic deserves its own section in the informed consent form
under “Receiving your Research Results”;  

Whether it should be presumed that receiving the results would be a
benefit; and

Whether the Board would recommend that the AEATF not offer to return
research results to participants.

Based on this discussion, the Board determined that at this time there
is neither a positive nor a negative duty to provide results to
participants of this study as there is not a clear rationale or benefit
to participants. The Board concluded that it would not be objectionable
if the Sponsor and the Agency decided not to return individual research
results and removed language relating to this from the Informed Consent
form. Likewise, if the sponsor chooses to return individual research
results to participants, the Board would offer guidance regarding
language in the Informed Consent form and to provide the sample letter
drafted and discussed during the May 2011 teleconference (EPA HSRB
2011b).

Right to Withdraw:

The Board recommended revising language consistent to clarify that “If
you withdraw from the study after the exposure monitoring begins, you
will still be paid for your time.”

Questions about this Study:

The Board recommends adding information to clarify what the IIRB is and
does (e.g., “The organization that reviewed and approved this study
meets requirements for the protection of research subjects”).

3.	The Board recommended that EPA and the sponsors consider breach of
confidentiality associated with photographs taken or video recorded as a
potential risk associated with study participation. For future studies,
this risk should be listed on the informed consent form and should be
considered by the Agency in its ethics review.

Assessment of Proposed AHETF Research Study AHE500: Exposure Monitoring
of Workers During Closed System Loading of Returnable and Non-Returnable
Containers in the United States.

Overview of the Study

	This proposal presents two agricultural handler exposure scenarios
involving loading of liquid pesticides packaged in non-returnable
containers and returnable containers respectively. 

The scenario calls for study participants to mix and load one of
thirteen possible surrogate pesticides using closed systems, which are
defined by the Agency’s Worker Protection Standard (WPS; 40 CFR 170)
as mixing and loading systems that are “designed by the manufacturer
to enclose the pesticide to prevent it from contacting handlers or other
people while it is being handled.”

	A total of 21 participants (described in the protocol as “Monitoring
Units” [MUs]) will be observed for the non-returnable container
scenario; three volunteers from each of seven geographically distinct
growing regions will be enrolled using a purposive sampling method (with
some elements of random selection). For the returnable container
scenario, a total of 15 participants (three volunteers from each of five
geographically distinct growing regions) will be observed; these data
will be combined with existing exposure data from two pre-Rule studies
involving two participants in California and seven participants in Texas
(see Collier 2011, 23-25). For each scenario, volunteers will be
randomized to mix and load a defined amount of active ingredient within
one of three strata. For the non-returnable container scenario, these
strata are: 12 to 30 pounds, 31 to 310 pounds, or 311 to 800 pounds of
active ingredient, respectively. For the returnable container scenario,
these strata are: 60 to 119 pounds, 120 to 1200 pounds, or 1201 to 2400
pounds of active ingredient.

	Although the use of closed mixing loading systems permits handlers to
wear less PPE than required by pesticide labeling for open
mixing/loading, including not wearing chemical resistant gloves in some
cases, for this protocol all participants will wear long sleeved shirts,
long pants, and shoes plus socks. Chemical resistant gloves and
protective eyewear will also be required when the study participants are
using closed systems that operate under pressure.	

	Dermal exposure will be measured by a whole body dosimeter worn beneath
the subject’s outer clothing. Hand wash and face/neck wipe samples
will also be collected prior to, during, and after completion of
pesticide loading and mixing procedures. Airborne concentrations of the
surrogate will be monitored in the participant’s breathing zone using
an OVS tube connected to a personal sampling pump. Additional measures
will also record environmental conditions at the time of monitoring, and
observers will collect field notes, take photographs, and record video
of participant activity throughout the monitoring event.

	The results of sample analysis under the closed system scenario will be
posted to the Agricultural Handlers Exposure Database (AHED®), where
they will be available to the EPA and other regulatory agencies for
statistical analysis. The proposed documentation will report a
confidence interval-based approach to determine the relative accuracy
for the arithmetic mean and 95th percentile of unit exposures. The
Agency proposes to use these data to estimate daily dermal and
inhalation exposures of agricultural handlers who are mixing and loading
pesticides using closed systems. 

Science

Charge to the Board

	If the AHETF closed system loading study proposal is revised as
suggested in EPA’s review and if the research is performed as
described, is the research likely to generate scientifically reliable
data, useful for assessing the exposure of workers using closed systems
to load liquid pesticide products from returnable or nonreturnable
containers?

Board Response to the Charge

HSRB Recommendation 

	The Board concurred with the Agency’s assessment that the proposed
AHETF scenario and field study proposal AHE500, if revised as suggested
in EPA’s review (Evans et al. 2011) and performed as described, is
likely to generate scientifically reliable data, useful for assessing
the exposure of workers using closed systems to load liquid pesticide
products from returnable or nonreturnable containers. The Board raised a
number of additional concerns, however, for the Agency and study
sponsors to consider when collecting and analyzing the exposure data.

HSRB Detailed Recommendations and Rationale

	The Board concluded that the research is likely to generate
scientifically reliable data, useful for assessing the exposure of
handlers who using closed systems to load liquid pesticide products from
returnable or nonreturnable containers. However, five additional
concerns were raised by the Board.

	First, the Board was concerned that the pre-Rule exposure study
conducted in 1991 (referred to as AH501 in the AHETF submission [Collier
2011, 23-25]) might not have been conducted with similar attention to
detail (e.g., careful observation and recording data about the workers,
work practices and equipment) as the proposed studies. The quality of
the older data might therefore not match the quality of the data
collected in the proposed studies. The Board thus urged the Agency and
sponsors to be cautious about including these older data in the AHED
exposure data, particularly if they are substantially different from the
data collected using the proposed design and protocols.

	Second, there is some concern that the proportionality premise
regarding levels of residues and amount of active ingredient handled
might not hold for these scenarios.  These scenarios are somewhat
reminiscent of the completed study of the closed cab scenario that the
HSRB reviewed at its January 2011 meeting (EPA HSRB 2011a). In the
closed cab scenario, the pesticide residues detected on the study
participants’ hands and clothing appeared to be more related to
incidental exposures than to the amount of active ingredient handled.
If, as designed, the engineering controls of the closed systems used in
this proposal are effective in restricting worker exposure to
pesticides, it would not be surprising if similar results were obtained
here.  Therefore, the HSRB strongly supports the EPA’s recommendation
(Evans et al. 2011) that detailed observations should occur during the
conduct of the exposure so that any incidental worker contacts with
contaminated surfaces are noted. Furthermore, the Board suggested that
the sponsors and Agency consider the value of measuring surface
contamination at the start of the study; if there were a background
residue present prior to the conduct of the study, this existing residue
would contribute to the total exposure and should be quantified. Because
the proportionality objective (objective 2) is crucial to the proposed
analysis, as described in Section C12 of the AHETF Governing Document
(AHETF 2010, 150), exposure and normalized exposure is interpretable
only when the proportionality constants are zero and one. The effect of
assuming the proportionality constant is one (or zero), when in fact it
may not be, should be also considered. Diversity selection will lead to
exposures being more uniformly spread than what would be observed from
random selection (e.g., Figure B2 in the AHEFT governing document [AHETF
2010, 119]). However, under the assumed model, it is not evident that
the normalized exposures would also have a more uniform spread. 

	Third, Board members raised some concerns about the necessity for and
the appropriateness of upper limits to the AaiH for those handlers to be
included in these studies.  While the rationale for the proposed upper
limit on study participants using closed systems to load liquid
pesticide products from returnable containers seemed sound (particularly
since existing data from the two pre-Rule studies was collected from
participants with very high AaiH values), it was suggested that no upper
limit be imposed on the AaiH of participants using closed systems to
load liquid pesticide products from nonreturnable containers.  Expanding
their range will increase the potential pool of acceptable participants,
expand the power of demonstrating proportionality, and also have the
potential to yield a better match in the AaiH from this portion of the
study with the data coming both from this study and from the previously
reviewed AHE80 open pour wettable powder mixer/loader protocol (EPA HSRB
2011a).

	Fourth, the Board recommended that criteria be developed before the
conduct of the study to ensure that the closed systems included within
these studies comply with the provision within the Agency’s WPS that
such systems must be functioning properly.  These criteria should
describe how ‘proper function’ will be (or were) determined and by
whom.  Such criteria are expected to be a part of scientifically
reliable data collection process and to ensure compliance with the WPS. 
 

	Finally, a suggestion was made to consider the addition of cotton
gloves, to be worn over the handlers’ chemical protective gloves. 
While the Board did not question the rationale to place the focus of
these studies on hand exposures inside chemical protective gloves, it
felt that being able to measure both unprotected and protected hand
exposures would greatly increase the value of this study.  In this case,
such cotton gloves would need to be tested to see if they would fit over
the chemical protective gloves and not interfere with the work tasks. 

Ethics

Charge to the Board

	If the proposed AHETF scenario and field study proposal AHE500 is
revised as suggested in the EPA’s review and if the research is
performed as described, is the research likely to meet the applicable
requirements of 40 CFR 26, subparts K and L?

Board Response to the Charge

The Board concluded that the protocol submitted for review, if modified
in accordance with EPA (Evans, Sarkar and Sherman 2011) and HSRB
recommendations, is likely to meet the applicable requirements of 40 CFR
26, subparts K and L. 

HSRB Detailed Recommendation and Rationale

The submitted documents assert that the study will be conducted in
accordance with the ethical and regulatory standards of 40 CFR 26,
Subparts K and L, as well as the requirements of the US EPA’s Good
Laboratory Practice (GLP) Standards described at 40 CFR 160, and, for
research conducted in California, the California State EPA Department of
Pesticide Regulation study monitoring (California Code of Regulations
Title 3, Section 6710) (AHETF 2010; Collier 2011). Requirements of FIFRA
§12(a)(2)(P) also apply. Researchers who participate in the study and
interact with study participants have or will undergo appropriate ethics
training.

	The protocol was reviewed and approved by an independent human subjects
review committee, IIRB, Inc. of Plantation, FL, prior to submission. As
described previously, IIRB, Inc. is fully accredited by AAHRPP, listed
as an active IRB on the OHRP website, and reviewed this protocol and
associated documents pursuant to the standards of the Common Rule (45
CFR Part 46, Subpart A. Copies of all correspondence with IIRB, Inc.
(Collier 2011) and a copy of IIRB, Inc. policies and membership roster
were provided (IIRB, Inc. 2011a; 2011b). 

1. 	Except as noted below, the Board concurred with the conclusions and
factual observations of the ethical strengths and weaknesses of the
study, as detailed in the EPA’s Ethics Review (Evans, Sarkar and
Sherman 2011). The proposed study is likely to meet the applicable
ethical requirements for research involving human subjects, in
accordance with the following criteria: 

a. 	Acceptable risk-benefit ratio. The risks as described in the study
protocol are fivefold: 

1)	The risk of heat-related illness. The study will likely involve an
increased risk of heat-related illness due to study participation. All
participants in the study will be wearing an extra layer of clothing
that they would not normally wear using closed systems to load liquid
pesticide products from returnable or nonreturnable containers. In
addition, loading activities might occur indoors or outdoors and some
locations and dates are likely to result in hot and/or humid conditions.

2)	The risk associated with scripting of field activities. In order to
ensure all monitoring units (MUs) fall within one of the AaiH strata,
AHETF may ask some workers to load more or less product than usual. For
some, this might lead to a slightly longer work period for those workers
which may increase the risks of acute toxicity associated with exposure
to the surrogate chemical or of heat-related illness. 

3)	Psychological risks. Participating in AHETF exposure monitoring
studies involves activities that are unusual and might cause subjects
psychological distress. These include performing an over-the-counter
pregnancy test prior to participation (females only) and allowing a
researcher to assist with the removal of the whole body dosimeter. 

4)	Exposure to surfactants. A very dilute surfactant solution (0.01% v/v
sodium dioctyl sulfosuccinate in water) is used as a surfactant for
face/neck wipes and hand washes for all MUs. This surfactant is in a
very dilute solution and its use represents a very short exposure
period, but the undiluted surfactant causes mild to moderate skin and
eye irritation in animals.

5)	Risk of exposure to surrogate chemicals.

AHETF has proposed several procedures to minimize these risks:

1)	Monitoring and stopping procedures will be instituted. The AHETF will
monitor ambient conditions to determine the heat index near the
mixing/loading station and base monitoring decisions on the current heat
index. Exposure monitoring will be discontinued if the heat index cutoff
of 105º F (adjusted for direct sun, if applicable) is reached or
exceeded. The Study Director or other researcher shall stop the
monitoring and/or move the worker to a cooler environment until
monitoring can be resumed. If necessary, some monitoring will take place
at night or early in the morning to avoid excessively hot and humid
conditions. 

2)	Clear inclusion/exclusion criteria have been established. Only
experienced pesticides handlers who consider themselves in good health
will be included in the study.  Experience with the mixing/loading
equipment to be used in the study will be required of all participants.
Participants must also understand Spanish or English, and appropriate
provisions have been made for participants who have low levels of
literacy.

3)	Workers will be reminded of safe chemical handing practices and
research staff will practice the face wipe and hand wash procedures with
each participant before pesticide handling begins. The use of PPE is
required of all participants, and in some cases will exceed the minimum
requirements established by the WPS. 

4)	Appropriate medical management procedures are in place.  Eye rinse
stations will be on hand in case of an accidental exposure. Medical
treatment facilities will be identified in case of an emergency. A
medical professional will be on site to observe study participants and
provide urgent care.

5)	Minors and pregnant or lactating women are excluded from
participation, with pregnancy status confirmed by over-the-counter
pregnancy testing within 24 hours prior to study participation.  All
female volunteers will be notified that an additional pregnancy test may
be required if there are any delays in the planned start of the study.
Only non-pregnant volunteers will be allowed to participate.

6)	Procedures have been instituted to decrease psychological risks. 
Pregnancy tests will be conducted in a private place and information
regarding pregnancy test will be kept confidential.  Private dressing
areas will be provided and researchers of the same gender will be
available to assist study participants. 

These risks are minimized appropriately and are justified by the
potential societal benefits associated with gathering data to determine
the potential exposure for workers who mix and load liquid pesticides
using closed systems in five regions of the United States.

b. Voluntary and informed consent of all participants:

1)	There is the possibility that the participants in this study might be
vulnerable (i.e., susceptible to coercion and undue influence). The
study protocol, however, includes several mechanisms designed to
minimize coercive recruitment and enrollment.

2)	The informed consent materials, if changed as recommended by the HSRB
below, will adequately inform the subjects of the risks, discomforts and
benefits from participation, and of their right to withdraw.

3)	Monetary compensation is not so high as to unduly influence
participants.

c. Equitable selection of study participants:

1)	AHETF will first determine a pool of growers and/or commercial
pesticide application companies who are eligible to participate in this
study. Agricultural workers who work for these eligible businesses will
be recruited as study participants. Employers will be required in
writing to affirm that they will not influence their employees’
decisions about whether to participate in this study. AHETF has
developed complete and appropriate inclusion/exclusion criteria. 

2. 	The Board recommended that the study protocol be modified to address
the concerns noted in the EPA’s Ethics Review (Evans et al. 2011). In
addition, the Board raised additional concerns:

a.	The Board concurred with the Agency’s recommendation (Evans et al.
2011) that a standard operating procedure (SOP) needs to be developed
which specifies the criteria by which study investigators will decide
that a participant is “too sick to make a decision about getting
medical treatment” (Collier 2011, 378). As mentioned in previous HSRB
reviews of similar AHETF protocols (e.g., EPA HSRB 2011a), appropriate
criteria for determining decision-making capacity can be found in the
clinical and clinical ethics literature (e.g., Appelbaum 2007) and
generally include all the following: The patient a) can appreciate the
situation and its consequences; b) can understand the relevant
information; c) can reason about the treatment decision; and d) can
communicate a choice.

b.	With regard to the return of exposure results to study participants,
the Board reiterated its opinion that there is neither a clear positive
nor a clear negative duty to provide results to participants at this
time. Although the Agency and sponsors have argued that the return of
individual exposure results may benefit research participants, based on
current debate within the bioethics community regarding the return of
individual study results, the Board felt that it was still unclear
whether or not this was indeed the case. Thus, the Board currently
neither recommends nor discourages the return of individual study
results. The Board remarked that it would not be objectionable should
the study sponsors chose to return individual exposure results to study
participants, nor would it be objectionable should they chose not to do
so. However, if the sponsor did elect to return individual exposure
results to study participants, the Board recommended that they look to
the letter developed by an HSRB working group (as discussed during the
Board’s May 2011 teleconference [EPA HSRB 2011b]) for an example of
how such information might be provided.

Assessment of Completed Carroll-Loye Biological Research Study No
Mas-003: Field Efficacy Test of 16% Para-menthane-3,8-diol (PMD) and 2%
Lemongrass Oil Based Repellent ‘No Mas’ Against Mosquitoes.

Overview of the Study

No Mas-003 was a field-based study to measure the effectiveness of a
lotion containing 16% PMD and 2% lemongrass oil (‘No Mas’) as a
repellent against three genera of mosquitoes (Culex, Anopheles and
Aedes). It was conducted after publication of the EPA’s expanded final
rule for protection of subjects in human research (40 CFR 26) on
February 6, 2006, and was reviewed favorably at the HSRB’s October
2010 meeting (EPA HSRB 2010).

	A total of 32 participants (selected from a pool of 92 volunteers
diverse in age and ethnicity) participated in this study. There were 10
participants (5 female and 5 male) in the dosimetry phase. Twenty
treated volunteers, 4 untreated experienced volunteers, and 6 alternates
participated in the field-based efficacy test. One female and 2 male
volunteers participated in both the dosimetry phase and the field-based
efficacy test.  The two untreated experienced volunteers from Site 1
also participated as treated subjects at Site 2. Finally, one of the
female alternates for the field-based efficacy test also participated in
the dosimetry phase of琠敨猠畴祤മ

Dosimetry data was collected from 10 participants (5 female and 5 male).
Each participant received an average of 1.20 μl/cm2 of product when
applied to the arms, and 1.04 μl/cm2 when applied to the legs. This is
equivalent to 1.14 mg/cm2 and 0.99 mg/cm2 of active ingredient for the
arms and the legs, respectively. Margin of Exposure (MOE) calculations
were based on an assumed 70 kg participant and an acute dermal LD50
value for PMD at the limit dose of greater than 5,000 mg/kg. For the
arms, the MOE was greater than 583 and for the legs the MOE was greater
than 287, both exceeding a target MOE of 100. 

The effectiveness of ‘No Mas’ as a mosquito repellent was determined
in a study conducted at two diverse field sites in the Central Valley of
California. Site 1 (Glenn County) was mature floodplain forest
surrounding some marshy areas with standing water; only Aedes spp. of
mosquitoes were detected at this site. Site 2 (Butte County) was a
relatively open landscape with hedgerows of willows growing along an
active stream; all three genera of mosquitoes were detected at this
site, with Aedes spp. predominant. Participants at Site 1 were treated
approximately 3.2 hours before field exposure, whereas participants at
Site 2 were treated approximately 6 minutes prior to field exposure.

Prior to the field-based efficacy tests, each study participant received
training in proper observation and aspiration of mosquitoes using
pathogen-free laboratory-raised insects. During the field-based test, 10
participants (5 female and 5 male) at each site exposed a treated limb
to mosquitoes for one minute every 15 minutes. Two additional
experienced volunteers (1 male and 1 female) served as untreated
controls to measure mosquito biting pressure. Participants were
partnered in groups of two and each partner monitored the front of their
own exposed limb and the back of their partner’s exposed limb.
Mosquitoes landing with intent to bite (LIBe) were recorded, aspirated
into containers, and identified in the laboratory. Participants remained
in the test until the repellent failed as determined by the first
confirmed LIBe, or until the end of the test period, whichever came
first. The time at which the repellent failed equaled the Complete
Protection Time (CPT) for each subject. 

	All 10 of the treated volunteers at Site 1 experienced a confirmed
LIBe, versus 4 of the treated volunteers at Site 2. Weibull mean CPT
values were not significantly different at the two sites, with mean CPT
calculated at 9.8 hours (h) (lower and upper 95% = 9.0 h and 10.6 h) at
Site 1 and 10.2 h (lower and upper 95% = 8.2 h and 12.5 h) at Site 2.
The normal mean CPT values were 9.2 h (lower and upper 95% = 8.1 h and
10.2) and 8.5 h (lower and upper 95% = 7.8 h and 9.2 h) at Sites 1 and
2, respectively. Kaplan-Meier median CPT was 9.6 h (lower and upper 95%
= 6.4 h and 10.5 h) at Site 1. Neither the Kaplan-Meier median CPT nor
the upper 95% confidence limit could be determined for Site 2, but the
lower 95% confidence limit was estimated to be 6.8 h.

Science

Charge to the Board

	Is the CLBR completed study No Mas-003 sufficiently sound, from a
scientific perspective, to be used to estimate the duration of complete
protection against mosquitoes provided by the tested repellent?

Board Response to the Charge

HSRB Recommendation 

	The Board concurred with the Agency’s assessment (Fuentes 2011) that
this study provides scientifically valid results to assess the repellent
efficacy against mosquitoes for the formulation tested.  

HSRB Detailed Recommendations and Rationale

The Board agreed in full with the Agency’s assessment (Fuentes 2011)
of the completed CLBR study No Mas-003. The study was conducted
consistently with the protocol and produced results which are
sufficiently sound, from a scientific perspective, to be used to
estimate the duration of complete protection provided by the tested
repellent against three genera of mosquitoes. 

During the meeting, the Agency also asked the Board to consider the
question of which of statistical methods -- parametric (with Weibull
distribution or normal distribution) or non-parametric (Kaplan-Meier) --
would be appropriate to calculate the CPT for the No Mas repellent. The
Board considered the fact that parametric methods based on a normal
distribution are not suitable to estimate the CPT due to right-censored
and heavily skewed data.  Because of this, the HSRB previously
recommended the use of survival analysis methods to estimate the mean
CPT and its confidence intervals (CI) (see, e.g., EPA HSRB 2010). 

The Board concluded that Parametric Survival Analysis based on a Weibull
distribution is one form of survival analysis methods and is suitable
for predicting right-censored CPT if the Weibull distribution assumption
is validated before estimating the mean CPT and its confidence
intervals. This type of parametric analysis can be performed using
SAS/STAT LIFEREG or SAS/QC PROC Reliability procedures. However, if the
Weibull distributional assumption is not confirmed, a Non-Parametric
right-censored Survival Analysis method based on the product-limit
method (also called the Kaplan-Meier method) should be used to estimate
the CPT median and percentiles and the 95% CI, with relatively smaller
samples (10 subjects/group or stratum). Furthermore, a separate survivor
function can be estimated for each stratum, and tests of the homogeneity
among the groups can be conducted using this method. This type of
non-parametric analysis can be performed using SAS/STAT LIFETEST
procedures.

Ethics

Charge to the Board

	Does available information support a determination that the studies
were conducted in substantial compliance with subparts K and L of 40 CFR
Part 26?

Board Response to the Charge

HSRB Recommendation

The Board concurred with the Agency’s assessment (Sherman 2011a) that
the studies submitted for review was conducted in substantial compliance
with subparts K and L of 40 CFR Part 26. 

HSRB Detailed Recommendation and Rationale

The documents provided by Carroll-Loye Biological Research (Carroll
2011) state that the study was conducted in compliance with the
requirements of the US EPA Good Laboratory Practice Regulations for
Pesticide Programs (40 CFR 160); 40 CFR 26 subparts K, L and M; FIFRA §
12(a)(2)(P); and the California Code of Regulations Title 3, Section
6710. The study was reviewed and approved by a commercial human subjects
review committee, Independent Institutional Review Board Inc. (IIRB,
Inc.) of Plantation, FL. Documentation provided to the EPA indicated
that IIRB, Inc. reviewed this study pursuant to the standards of the
Common Rule (45 CFR Part 46, Subpart A) and found it in compliance
(Carroll 2011; IIRB, Inc. 2010; IIRB, Inc. 2011). IIRB, Inc. also
reviewed and approved Amendment 1 of November 15, 2010 (Carroll 2011;
Sherman 2011a).

1.	The Board concurred with the conclusions and factual observations
relating to the study, as detailed in the EPA’s Ethics Review (Sherman
2011a). Specifically:

a. 	Prior HSRB and Agency Review. The requirements of 40 CFR §26.1125
for prior submission of the protocol to EPA and of §26.1601 for HSRB
review of the protocol were satisfied. The study (Carroll 2011) was
conducted in accordance with the protocol previously reviewed by the
Agency (Fuentes and Sherman 2010) and by the HSRB (EPA HSRB 2010).
Neither the Agency’s nor the HSRB’s ethics reviews identified
significant deficiencies requiring correction relative to 40 CFR 26,
subparts K and L, or to FIFRA § 12(a)(2)(P) (Carley 2010a). Because the
study was conducted in California, the approval of the California
Department of Pesticide Regulation (CDPR) was also required before the
study could be initiated. CDPR granted final approval of the amended
protocol and supporting documents on March 21, 2011.

b.	Responsiveness to HSRB and Agency Reviews. Following the HSRB review,
the protocol and consent form were modified through Amendment 1 of
November 15, 2010 (Carley 2010a; Carroll 2010c). This amendment
incorporated changes responsive to the comments of EPA, the HSRB, and
CDPR, as well as additional corrections initiated by the investigators.
Only two Agency and HSRB suggestions were not incorporated into the
revised protocol: the addition of “child/minor” to the list of
exclusion criteria and the definition of the acronym ‘PMD’ in the
protocol and informed consent document. Failure to incorporate these
suggestions into study protocol and informed consent documents, however,
is unlikely to compromise the informed consent process or place the
study participants at risk. IIRB, Inc. granted approval to Amendment 1
and supporting documents on November 16, 2010 (Carroll 2011; Sherman
2011a). 

c.	Substantial Compliance with Reporting Requirements (40 CFR Part 26
subpart M). CLBR’s submission (Carroll 2011), along with the
separately submitted documents describing the procedures and roster of
the IRB (IIRB, Inc. 2010; 2011), fully meet the requirements of 40 CFR
§26.1303 to document the ethical conduct of the research were fully
satisfied.

2.	The Board concluded that this study met all applicable ethical
requirements for research involving human participants, in accordance
with the following criteria that had been stated in the Board’s prior
review of this study protocol:

a.	Acceptable risk-benefit ratio. The risks to study participants were
minimized appropriately and were justified by the potential societal
benefits, particularly data on the efficacy of these new formulations as
personal insect repellents.

Minors and pregnant or lactating women were excluded from participation,
with pregnancy confirmed by over-the-counter pregnancy testing on the
day of study or by opt-out. The potential of stigma resulting from study
exclusion was also appropriately minimized. 

Based on toxicological data currently available for ‘No Mas’,
coupled with appropriate exclusion criteria, study participants were
unlikely to be at risk of adverse side effects with exposure. 

Clear stopping rules and medical management procedures were in place,
and no adverse events related to product exposure were reported.

The study was designed to minimize the likelihood of mosquito bites.

The field-based trials were conducted only in areas where known
vector-borne diseases like West Nile Virus had not been detected by
county and state health or vector/mosquito control agencies for at least
two weeks. Mosquitoes collected during the field studies also were
subjected to molecular analyses to confirm that they were free of known
pathogens.

b.	Voluntary and informed consent of all participants

The study protocol included several mechanisms designed to minimize
coercive recruitment and enrollment. Monetary compensation was not so
high as to unduly influence participation.

There was one minor protocol deviation reported: use of a reformatted
lotion dosimetry data form without prior IRB review. The Board
concluded, however, that this deviation did not affect the integrity of
the research or the safety of participants.

Assessment of Published Research Study MRID 48607501: Moiemen et al.
(2011) Acticoat Dressings and Major Burns: Systemic Silver Absorption.

Overview of the Study

	In the Moiemen et al. (2011) study, 6 human volunteers being treated
for severe burns (defined as burns covering greater than 20% of the
total body surface area) were exposed to antimicrobial wound dressings
containing silver in nanocrystalline form.  The study was conducted at
the Selly Oak Hospital Burns Unit (also known as the Midlands Burn
Center) in Birmingham, United Kingdom (UK), between May 2006 and May
2007. One female subject and five male subjects, ranging from 22 to 56
years of age, were enrolled. As part of their treatment, participants’
burns were dressed with either Acticoat® antimicrobial barrier
dressings and/or Acticoat® Absorbent; this represents standard of care
for patients with severe burns. 

	Acticoat dressings consist of an absorbent inner core of rayon and
polyester fabric sandwiched between two layers of silver-coated, low
adherent polyethylene mesh. Acticoat Absorbent is a silver-coated
calcium alginate fabric. Both products release silver slowly over
several days. Silver nanoparticles are an effective microbiocide, and
Acticoat and Acticoat Absorbent have established antimicrobial efficacy
and are licensed for use as wound dressings.

	Serum levels of silver were determined prior to enrollment in the
study, during treatment with wound dressings, and after treatment
discontinuation. Hematology, clinical chemistry, and clinical
observations were also performed in order to identify any adverse
effects of treatment with the wound dressing. No treatment related
adverse effects on hematology, clinical chemistry, wound healing, or
clinical signs of toxicity were observed. 

	Serum levels of silver increased during the wound dressing treatment
periods, but there was no apparent relationship between the Total Body
Surface Area (TBSA) of the wound and the amount of silver absorbed.
Serum levels of silver also remained elevated after discontinuation of
wound dressing treatment, suggesting continued systemic absorption of
skin-associated silver and/or slow clearance of circulating serum
silver. The study authors calculated a median half-life of 46.4 days for
elimination of serum silver, which was extrapolated to give a median
reduction of 1.5% per day. 

	Using the data reported in the Moiemen et al. (2011) study, in
conjunction with in vitro data from the Larese et al. (2009) study, EPA
scientists have estimated that the maximum amount of silver absorbed
from nanosilver on human skin is approximately 0.1% per day. The Agency
proposes to use this estimated 0.1% absorption factor as part of the
overall weight of evidence to estimate dermal exposure for pesticide
formulations that contain nanosilver.

Science

Charge(s) to the Board

	1) Is the Moiemen et al. (2011) study scientifically sound, providing
reliable data?

	2) If so, can the Moiemen et al. (2011) study be used to support the
Agency’s conclusion that the dermal absorption factor for silver from
nanosilver on human skin is less than 0.1%?

Board Response to the Charge

HSRB Recommendation 

Despite several deficiencies identified with the study design, the small
number of subjects, and the interpretation of the data, the Board agreed
with the Agency’s assessment that the Moiemen et al. (2011) study
provides some potentially useful baseline information on the dermal
absorption of silver from nanosilver-containing wound dressings. 

The Board noted that the calculated values for the dermal absorption of
silver from nanosilver in the Moiemen et al. (2011) study were higher
than values previously reported by another study using in vitro intact
and abraded skin (Larese et al. 2009). Despite this, the Board concluded
that the Moiemen et al. study could be used to support the Agency’s
conclusion that the dermal absorption of silver is less than 0.1% as
part of the overall weight of evidence. 

The Board recommended, however, that the Agency clarify its assumptions
in estimating the dermal absorption of silver from nanosilver. The Board
also suggested that the Agency consider alternatives for estimating
dermal absorption based on the Moiemen et al. (2011) study, such as
using the less-conservative approach suggested by one Board member and
which will be detailed in a separate memorandum to the Agency.

HSRB Detailed Recommendations and Rationale

The estimates for dermal absorption of silver from nanosilver-containing
wound dressings in patients with various degrees of skin burns reported
in the Moiemen et al. (2011) are within the range of values previously
reported in some articles but higher than that seen in others (see,
e.g., Larese et al. 2009). This may be due to limitations in the design
and execution of the study, as well as the interpretation of the
results, as described in detail below:

1. 	Study design and execution. The authors did not include hematologic
and blood chemistry data in their article, so it was difficult to assess
whether or not changes in normal organ physiological and biochemical
functions (e.g., liver or kidney) may have influenced plasma values of
silver for each patient. Although the Agency had access to this
information, it was not at liberty to share it with the Board.  However,
based on their review of these data, the Agency believed that no
treatment related adverse effects on hematology, clinical chemistry,
wound healing or clinical signs of toxicity were observed.  

	The Board noted that the clustering of patients with partial thickness
and full thickness wounds might have masked any potential dose-response
relationship.  Unfortunately, the number of patients in each of these
two main categories of wound thickness seemed insufficient to study them
separately.

2.	Interpretation. The authors of the Moiemen et al. (2011) study
calculated a plasma half-life for silver of 46.4 days and a median
elimination rate of 1.5% per day upon cessation of Acticoat treatment;
in other words, after treatment was stopped, the daily reduction rate of
serum silver levels was estimated to be at 1.5% of the total amount
measured in blood. In its discussion of these estimated half-life and
median elimination rates, however, the Board viewed the lack of urinary
excretion measures as a shortcoming. Urine data are needed to obtain an
accurate measurement of the total amount of chemical actually absorbed
by the worker via all routes (see, e.g., AEATF 2011, 52). Any estimation
of dermal absorption from blood serum samples would be more reliable if
urinary excretion data are available.    

	The pattern of silver elimination from plasma for most patients was
described as biphasic.  The study investigators concluded that this
apparent biphasic elimination involved biliary excretion at low serum
silver levels and urinary excretion levels greater than 100 µg/L. The
Agency considered the possibility that this biphasic response may
reflect competing processes of systemic absorption of any
skin-associated silver present after the wound dressings were removed.
The Board argued that, for this biphasic response to be valid,
saturation of biliary excretion pathways should occur under the
conditions reported in the study. As this is unlikely when considering
the maximal plasma levels of silver achieved and that the fraction of
silver eliminated daily was ~1.5% of what was present in blood, the
Board suggested two alternative interpretations. 

	First, the biphasic mode of elimination suggests that two forms of
silver -- silver nanoparticles and silver ions -- were being absorbed
from the skin.  The particles can be subjected to uptake and storage in
a tissue compartment(s) from which these particles can be dissociated,
leading to a slow release of silver ions into the blood, while the
silver ions absorbed from the skin provide the more rapid phase of
elimination.  The authors did not report whether they considered the
likelihood that two forms of silver were being absorbed from the wound
dressing. 

	Alternatively, deposition of ionic silver itself (not necessarily
nanoparticles) in tissue reservoirs may explain the apparent biphasic
elimination mode. A recent review article by Lansdown (2010) describes
how ionic silver that is absorbed into the body readily binds to
intracellular proteins, such as serum albumin and macroglobulin, and to
intracellular cysteine-rich proteins like metallothioneins.  Bone is
also described as a potentially relevant storage site for silver --
along with soft tissues such as the eye, brain, liver, kidney spleen,
and bone marrow -- following systemic absorption.  Slow release from
these tissues/cellular reservoirs can contribute to the slow elimination
phase of silver seen in the Moiemen et al. (2011) study.

	The dermal absorption analysis described in Appendix 1 of the
Agency’s science review (Ryman 2011) was based on the conservative
assumption that the blood serum silver levels on any given day are due
to that day’s absorption. Implicit in that assumption is that each
prior day’s serum silver is removed from the blood and sufficient new
silver is absorbed to reach the next day’s level. As described above,
such an assumption is not based on a realistic pharmacokinetic model and
its results are inconsistent with the median of 9.5 days that it took
for patients’ serum levels to reach their maximum level and with the
estimated 46.4-day half-life serum levels after treatment was
discontinued. 

	Despite these limitations, this absorption factor calculated by the
Agency appears to be greater than any of the absorption factors
estimated by Board members using alternative approaches, or the
absorption factors seen in other studies in the current literature. Use
of such a conservative dermal absorption factor is likely to provide
greater protections when used for regulatory decision-making purposes.
Thus, the Board concluded that the Moiemen et al. (2010) study could be
used as part of a weight-of-evidence approach to support the Agency’s
conclusion that the dermal absorption factor for silver from nanosilver
on human skin is equal to or less than 0.1%. 

Ethics

Charge to the Board

	Is there adequate information to support a determination that the study
was conducted in substantial compliance with procedures at least as
protective as those at subparts A-L of 40 CFR Part 26?

Board Response to the Charge

HSRB Recommendation 

	The Board concurred with the EPA’s Ethics Review (Sherman 2011b),
that there was sufficient information regarding value of the research to
society, subject selection, risks and benefits, independent ethics
review, informed consent, respect for potential and enrolled subjects to
conclude that the Moiemen et al. (2011) study was conducted in
substantial compliance with procedures at least as protective as those
in subparts A-L of EPA’s regulation at 40 CFR Part 26. 

HSRB Detailed Recommendations and Rationale

	This is the second time that the Agency has asked the HSRB to review a
study that was located in the public literature and which was conducted
after promulgation of the Final Human Studies Rule in April 2006 (c.f.
EPA HSRB 2011a). This study was conducted in Britain and was reviewed
and approved by the Sandwell and West Birmingham Local Research Ethics
Committee, in accordance with the policies and procedures of the British
National Research Ethics Service.

1.	Standards Applicable to EPA’s Reliance on the Research.

	As noted in the EPA’s Ethics Review (Sherman 2011b), the Agency’s
Final Human Studies Rule (40 CFR part 26 subpart Q) defines standards
for EPA to apply in deciding whether to rely on research―like this
study―involving intentional exposure of human subjects. The applicable
acceptance standards are: 

	§26.1703. Prohibition of reliance on research involving intentional
exposure of human subjects who are pregnant women (and therefore their
fetuses), nursing women, or children. Except as provided in §26.1706,
in actions within the scope of §26.1701 EPA shall not rely on data from
any research involving intentional exposure of any human subject who is
a pregnant woman (and therefore her fetus), a nursing woman, or a child.

	§26.1705 Prohibition of reliance on unethical human research with
non-pregnant, non-nursing adults conducted after April 7, 2006. Except
as provided in §26.1706, in actions within the scope of §26.1701, EPA
shall not rely on data from any research initiated after April 7, 2006,
unless EPA has adequate information to determine that the research was
conducted in substantial compliance with subparts A through L of this
part, or if conducted in a foreign country, under procedures at least as
protective as those in subparts A through L of this part. This
prohibition is in addition to the prohibition in §26.1703.

2.	Compliance with Applicable Standards.

	As noted in the EPA’s Ethics Review (Sherman 2011b), this research
did not involve intentional exposure of any pregnant or nursing female
subjects or any children. Reliance on the research is therefore not
prohibited by 40 CFR §26.1703. 

	EPA is forbidden by 40 CFR §26.1705 to rely on data from research
involving intentional exposure―such as this study― “unless EPA has
adequate information to determine that the research was conducted in
substantial compliance with subparts A through L of [40 CFR part 26], or
if conducted in a foreign country, under procedures at least as
protective as those in subparts A through L of [40 CFR part 26].” This
research was approved by an independent ethics review committee, the
Sandwell and West Birmingham Local Research Ethics Committee and
conducted in accordance with requirements under the UK Central Office
for Research Ethics Committees and the Medicine for Human Use Clinical
Trial Regulations.  The Board observed that the protocol provides that
the research “will be performed in accordance with the guidelines of
the Declaration of Helsinki (1964) and subsequent revisions,” but
noted that the Declaration of Helsinki is not regulatory in nature.
Rather, the fact that the protocol was reviewed and performed in
accordance with specific UK requirements for the conduct of ethical
research ensures that the research was conducted under procedures as at
least as protective as subparts A through L of the Agency’s Final
Human Studies Rule.

	EPA’s regulations governing third-party human research for pesticides
at 40 CFR part 26 subpart K permit consent for a subject’s
participation in research to be given by the subject’s “legally
authorized representative” when the subject lacks the capacity to
consent for himself or herself. Subpart K is consistent with the Common
Rule, which was drafted to protect subjects in a wide variety of
research settings, including, for example, research into emergency
procedures to save lives of unconscious patients.

3.	Additional Board Comments and Concerns.

	In order to ensure that quality of data regarding Acticoat absorption,
the protocol prohibited the use of other silver-based products in these
burn patients.  One question that was raised concerned whether or not
the quality of care provided to these patient/subjects may have been
adversely affected because of this prohibition. Based on clinical
information on silver-based products in burn care, and additional
research by the Agency and Board members regarding standard-of-care for
burn patients, the Board was satisfied that the silver-based wound
dressing being tested would have been the only silver-based product
used. All study participants were thus treated using an appropriate
standard of care.

	Finally, one member of the Board observed that the reference in this
study to obtaining “retrospective consent” is a misnomer. Informed
consent is a prospective decision made by and individual or surrogate to
consent for treatment and/or study participant. It is not possible for a
study participant or their surrogate to agree to something that happened
in the past.

REFERENCES

Agricultural Handler Exposure Task Force (AHETF). 2010. Governing
Documents for a Multi-Year Pesticide Handler Worker Exposure Monitoring
Program (Version 2). Dated August 12, 2010. Unpublished document
prepared by the AHETF. 156p.

Antimicrobial Exposure Assessment Task Force II (AEATF II). 2011.
Governing Document for a Multi-Year Antimicrobial Chemical Exposure
Monitoring Program (Version 3). Dated July 8, 2011. Unpublished document
prepared by the AEATF. 129p.

Appelbaum, P.S. 2007. Clinical Practice. Assessment of Patients'
Competence to Consent to Treatment. New England Journal of Medicine
357(18): 1834-40. 

Carroll, S. 2011. Field Efficacy Test of a PMD and Lemongrass oil- Based
Repellent ‘No Mas’ Against Mosquitoes. Dated August 14, 2011.
Unpublished document prepared by Carroll-Loye Biological Research. 411p.

Collier, C.H., for the Agricultural Handler Exposure Task Force (AHETF).
2011. Closed System Loading of Liquids in Returnable and Non-Returnable
Containers (AHETF Study No. AHE500). Dated August 2, 2011. Unpublished
document prepared by the AHETF. 438p.

Coombs, C.J., A.T. Wan, J.P. Masterton, R.A. Conyers, J. Pedersen, and
Y.T. Chia. 1992. Do Burn Patients Have a Silver Lining? Burns 18(3):
179-84.

EPA Human Studies Review Board. 2010. October 27-28, 2010 Human Studies
Review Board Meeting Report. 31p.

EPA Human Studies Review Board. 2011a. January 17, 2010 Human Studies
Review Board Meeting Report. 24p.

EPA Human Studies Review Board. 2011b. April 13-14, 2010 Human Studies
Review Board Meeting Report. 31p.

Evans, J., B. Sarkar, K. Sherman, and S. Knizer. 2011. Science and
Ethics Review of AHETF Scenario Design and Protocol AHE500 for Exposure
Monitoring of Workers During Closed System Loading of Returnable and
Non-Returnable Containers in the United States. Dated September 26,
2011. Unpublished document prepared by the Office of Pesticide Programs,
United States Environmental Protection Agency. 59p.

Fuentes, C. 2011. Science Review of Completed Carroll-Loye Mosquito
Repellent Field Efficacy Study No Mas 003. Dated September 29, 2011.
Unpublished document prepared by the Biopesticides & Pollution
Prevention Division, Office of Pesticide Programs, United States
Environmental Protection Agency. 8p.

Fuentes, C., and K. Sherman. 2010. Science and Ethics Review of Protocol
for Human Study of Mosquito Repellent Performance: Proposed Carroll-Loye
Field Efficacy Test of PMD and Lemongrass Oil-Based Repellent ‘No
Mas’ Against Mosquitoes. Dated October 1, 2010. Unpublished document
prepared by the Office of Chemical Safety and Pollution Prevention,
United States Environmental Protection Agency. 30p.

Independent Institutional Review Board, Inc. (IIRB, Inc.). 2010. Human
Research Protection Program Plan (HRPP Plan). Dated November 3, 2010.
Unpublished document prepared by IIRB, Inc. 131p.

IIRB, Inc., 2011. IRB Membership Roster. Dated September 12, 2011.
Unpublished document prepared by IIRB, Inc. 1p.

Lansdown, A.B.G. 2010. A Pharmacological and Toxicological Profile of
Silver as an Antimicrobial Agent in Medical Devices. Advances in
Pharmacological Sciences 2010: Article ID 910686, 16p. doi:
10.1155/2010/910686.

Larese, F.F., F. D’Agostin, M. Crosera, G. Adami, N. Renzi, M.
Bovenzi, and G. Maina. 2009. Human Skin Penetration of Silver
Nanoparticles Through Intact and Damaged Skin. Toxicology 255(1-2):
33-7.

Leighton, T., K. Sherman, and J. Cohen. 2011. Science and Ethics Review
of AEATF II Liquid Pour Scenario Design and Protocol for Monitoring.
Dated September 23, 2011. Unpublished document prepared by the Office of
Pesticide Programs, United States Environmental Protection Agency. 54p.

Moiemen, N.S., E. Shale, K. J. Drysdale, et al. 2011. Acticoat Dressings
and Major Burns: Systemic Silver Absorption. Burns 37(1): 27-35. MRID
48607501.

Ryman, J. 2011. Data Evaluation Record: SILCRYST™. Dated October 3,
2011. Unpublished document prepared by the Health Effects Division,
United States Environmental Protection Agency. 16p.

Shah, H., for the AEATF II. 2011a. A Study for Measurement of Potential
Dermal and Inhalation Exposure During Manual Pouring of a Liquid
Containing an Antimicrobial. Volume 1 of 4: Transmittal Letter; 40 CFR
26.1125 Checklist for Study AEA05; Liquid Pour Study Design Document.
Dated July 28, 2011. Unpublished document prepared by the AEATF II. 33p.

Shah, H., for the AEATF II. 2011b. A Study for Measurement of Potential
Dermal and Inhalation Exposure During Manual Pouring of a Liquid
Containing an Antimicrobial. Volume 2 of 4: Study Protocol; IIRB
Approval Letter and Supporting Documents. Dated July 28, 2011.
Unpublished document prepared by the AEATF II. 177p.

Shah, H., for the AEATF II. 2011c. A Study for Measurement of Potential
Dermal and Inhalation Exposure During Manual Pouring of a Liquid
Containing an Antimicrobial. Volume 3 of 4: Records of IIRB Review of
Study AEA05. Dated July 28, 2011. Unpublished document prepared by the
AEATF II. 224p.

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During Manual Pouring of a Liquid Containing an Antimicrobial. Volume 4
of 4: CVs and Ethics Training Records; SOPs Referenced in AEA05
Protocol. Dated July 28, 2011. Unpublished document prepared by the
AEATF II. 173p.

Sherman, K. 2011a. Ethics Review of Completed Carroll-Loye Mosquito
Repellent Field Efficacy Study No Mas 003. Dated September 29, 2011.
Unpublished document prepared by the Office of the Director, Office of
Pesticide Programs, United States Environmental Protection Agency. 7p.

Sherman, K. 2011b. Ethics Review of Intentional Exposure Human Toxicity
Study (Ref: Moiemen, N.S., Shale, E., Drysdale, K.J., Smith, G., Wilson,
Y.T., Rapini, R. Acticoat dressings and major burns: Systemic silver
absorption. The Midlands Burn Centre, University Hospitals Birmingham
Foundation Trust, United Kingdom. Burns, 37, 27-35 [2011]. [MRID
48607501]). Dated October 3, 2011. Unpublished document prepared by the
Office of the Director, Office of Pesticide Programs, United States
Environmental Protection Agency. 10p.

 	Possible surrogate pesticides include carbaryl, chlorothalonil,
Dacthal (DCPA), fosamine, glyphosate, imazapyr, imidacloprid, Malathion,
simazine, sulfur, thiophanate-methyl, 2,4-Dichlorophenoxyacetic acid,
and 4-(2,4-dichlorophenoxy)butyric acid. The choice of surrogate
pesticide will be determined by the preference of the grower involved in
the study and the pest pressure on the crop at the time of monitoring.

 	This value is the same as that originally reported by Coombs et al.
(1992) in a prospective clinical study that determined the absorption
and effects of the silver ion from sliver sulfadiazine in the context to
hepatic and renal function.

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