Partial*
Interim Reregistration Eligibility Decision
for
Phosmet
Case No. 0242
*Includes only kiwifruit, peas (dry and green), sweet potatoes, alfalfa, blueberries, cherries (sweet and
tart), cotton, cranberries, potatoes, pine seed orchards, ornamental nursery stock, household uses
(ornamentals and fruit trees), domestic pet uses, and fire ants.
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TABLE OF CONTENTS
Executive Summary 3
I. Introduction 6
n. Chemical Overview 8
A. Regulatory History 8
B. Chemical Identification 8
C. Use Profile 9
D. Estimated Usage of Pesticide 10
III. Summary of Phosmet Risk Assessment 13
A. Human Health Risk Assessment 13
1. Dietary Risk from Food 14
a. Toxicity 14
b. FQPA Safety Factor 14
c. Population Adjusted Dose (PAD) 15
d. Exposure Assumptions 15
e. Food Risk Characterization 16
2. Dietary Risk from Drinking Water 16
a. Surface Water 17
b. Ground Water 17
c. Drinking Water Levels of Comparison (DWLOCs) 18
3. Occupational and Residential Risk 19
a. Toxicity 19
b. Exposure 22
c. Occupational & Residential Handler Risk Summary 24
1) Occupational Handler Risk 25
2) Post-Application Occupational Risk 47
3) Residential (Homeowner) Handler Risk
52
4) Residential Post-Application Risk 54
4. Aggregate Risk 55
5. Incident Data Review 56
B. Environmental Risk Assessment 56
1. Environmental Fate and Transport 57
2. Risk to Birds and Mammals 57
3. Risk to Aquatic Species 58
4. Risk to Honey Bees 58
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IV. Interim Risk Management and Reregistration Decision for 17 Uses 58
A. Determination of Interim Reregistration Eligibility 58
B. Summary of Phase 5 Comments and Responses 59
C. Regulatory Position 60
1. Tolerance Summary 61
2. Human Health Risk Mitigation 61
a. Dietary (food and water) Risk Mitigation 61
b. Residential Risk Mitigation 61
c. Occupational Risk Mitigation 62
3. Environmental Risk Mitigation 79
V. What Registrants Need to Do: 80
VI. Related Documents and How to Access Them: 80
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PHOSMET TEAM
Office of Pesticide Programs:
Health Effects Risk Assessment
Jerome Blondell
Jeffrey Dawson
Virginia Dobozy
Christina Swartz
Linda Taylor
Environmental Fate Risk Assessment
Sid Abel
Dana Spatz
Use and Usage Analysis
Jihad Alsadek
William Gross
Registration Support
Richard Gebken
Risk Management
Diane Isbell
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GLOSSARY OF TERMS AND ABBREVIATIONS
AGDCI Agricultural Data Call-In
ai Active Ingredient
aPAD Acute Population Adjusted Dose
AR Anticipated Residue
BCF Bioconcentration Factor
CFR Code of Federal Regulations
cPAD Chronic Population Adjusted Dose
CSF Confidential Statement of Formula
CSFn USDA Continuing Surveys for Food Intake by Individuals
DCI Data Call-In
DEEM Dietary Exposure Evaluation Model
DFR Dislodgeable Foliar Residue
DWLOC Drinking Water Level of Comparison.
EC Emulsifiable Concentrate Formulation
EEC Estimated Environmental Concentration
EPA Environmental Protection Agency
EUP End-Use Product
FDA Food and Drug Administration
FFDCA Federal Food, Drug, and Cosmetic Act
FIFRA Federal Insecticide, Fungicide, and Rodenticide Act
FOB Functional Observation Battery
FQPA Food Quality Protection Act
G Granular Formulation
GENEEC Tier I Surface Water Computer Model
GLN Guideline Number
HAFT Highest Average Field Trial
IR Index Reservoir
LC5o Median Lethal Concentration. A statistically derived concentration of a substance that can be
expected to cause death in 50% of test animals. It is usually expressed as the weight of
substance per weight or volume of water, air or feed, e.g., mg/1, mg/kg or ppm.
LD5o Median Lethal Dose. A statistically derived single dose that can be expected to cause death in
50% of the test animals when administered by the route indicated (oral, dermal, inhalation). It is
expressed as a weight of substance per unit weight of animal, e.g., mg/kg.
LOAEL Lowest Observed Adverse Effect Level
LOC Level of Concern
LOD Limit of Detection
MATC Maximum Acceptable Toxicant Concentration
mg/kg/day Milligram Per Kilogram Per Day
mg/L Milligrams Per Liter
MOE Margin of Exposure
MRID Master Record Identification (number). EPA's system of recording and tracking studies
submitted.
MUP Manufacturing-Use Product
NA Not Applicable
NAWQA USGS National Water Quality Assessment
NOAEL No Observed Adverse Effect Level
NPDES National Pollutant Discharge Elimination System
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NR Not Required
OP Organophosphate
OPP EPA Office of Pesticide Programs
OPPTS EPA Office of Prevention, Pesticides and Toxic Substances
PAD Population Adjusted Dose
PCA Percent Crop Area
POP USDA Pesticide Data Program
PHED Pesticide Handler's Exposure Data
PHI Preharvest Interval
ppb Parts Per Billion
PPE Personal Protective Equipment
ppm Parts Per Million
PRZM/EXAMS Tier H Surface Water Computer Model
Qi* The Carcinogenic Potential of a Compound, Quantified by the EPA's Cancer Risk Model
RAC Raw Agriculture Commodity
RED Reregistration Eligibility Decision
REI Restricted Entry Interval
RfD Reference Dose
RQ Risk Quotient
SAP Science Advisory Panel
SCI-GROW Tier I Ground Water Computer Model
SF Safety Factor
SLC Single Layer Clothing
SLN Special Local Need (Registrations Under Section 24(c) of FIFRA)
TGAI Technical Grade Active Ingredient
TRR Total Radioactive Residue
UF Uncertainty Factor
USDA United States Department of Agriculture
USGS United States Geological Survey
UV Ultraviolet
WPS Worker Protection Standard
ug/g Micrograms Per Gram
ug/L Micrograms Per Liter
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Executive Summary
EPA has completed its review of public comments on the revised risk assessments and is
issuing a partial risk management decision for phosmet. The decisions outlined in this document do not
include all uses, nor do they include the final tolerance reassessments for all uses of phosmet; however,
they do include some tolerance actions that will be undertaken prior to completion of the final tolerance
reassessments. Five tolerances will be revoked when the IRED is issued, for citrus and corn, because
the registrant is not supporting these uses. The final tolerance reassessment decisions for this chemical
will be issued once the cumulative assessment for all of the organophosphates is considered. The
Agency may need to pursue further risk management measures for phosmet once the cumulative
assessment is finalized.
The revised risk assessments are based on review of the required target data base supporting
the use patterns of currently registered products and new information received. The Agency invited
stakeholders to provide proposals, ideas or suggestions on appropriate mitigation measures before the
Agency issued its risk mitigation decision on phosmet. After considering the revised risks, as well as
mitigation proposed by Gowan Company, the technical registrant of phosmet, and comments and
mitigation suggestions from other interested parties, including Wellmark International, the Natural
Resources Defense Council, several grower organizations, and an agricultural extension agent, EPA
developed its risk management decision for uses of phosmet that pose risks of concern. Seventeen
decisions are discussed fully in this document. Risk management decisions on the remaining 28
phosmet uses will be discussed in a future document.
Phosmet is an organophosphate insecticide used to control a variety of insects, first registered in
1966 for use on the following crops: Fruit trees (apple, apricot, crabapple, nectarine, peach, pear,
plum/prune, cherry (tart and sweet) and nut trees (almond, beechnut, Brazil nut, butternut, cashew,
chestnut, chinquapin, filbert, hickory, macadamia, pecan, pistachio, walnut), grapes, kiwifruit,
blueberries (highbush and lowbush), cranberries, peas (fresh and dried), potato, sweet potato (foliar
and post-harvest) alfalfa, cotton and clover. In addition, phosmet is registered for direct animal
treatments to control fleas, lice, hornflies, sarcoptic mange, and ticks on cattle, swine, and dogs. There
are other uses such as in forestry, pine seed orchards, pine seedlings, fire ants and for ornamentals,
including residential sites, that can be treated by professional applicators. Phosmet can also be used by
homeowners to treat trees, shrubs, ornamental plants, pets (dogs only) and home gardens. Use data
from 1988 to 1997 indicate an average of approximately 1,000,000 Ibs of phosmet are applied to
approximately 402,000 acres per year.
Overall Risk Summary
EPA's human health risk assessment for phosmet indicates some risk concerns. Food risk,
both acute and chronic, is well below the Agency's level of concern. Similarly, drinking water risk
estimates based on screening models, from both ground and surface water for acute and chronic
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exposures, are not of concern for all populations. There are, however, concerns for workers who mix
and load phosmet ("handlers") in the wettable powder form for aerial and chemigation applications to
fruit/nut trees, field and vegetable crops, grapes, and ornamental plants and forestry. Worker handler
risks are largely due to estimated dermal exposures. Following application of phosmet, there are also
concerns for workers re-entering treated fields. Additionally, there are concerns for homeowners who
apply phosmet to ornamental plants and fruit trees with a low pressure hand wand, and for adults and
youths harvesting and maintaining these fruit trees. There are significant risk concerns for toddlers
exposed to phosmet residues following contact with treated dogs. In addition, there are concerns for
continuous exposure to adults and youths in residential settings if exposure extends over a period of
time (greater than 30 days) following application to home gardens.
Phosmet was found to be moderately to practically non-toxic to avian species on an acute
basis; however, the application rates for some crops result in levels of concern that are slightly
exceeded. Use on most crops appears to pose a chronic risk to birds and for all crops, there is a high
chronic risk for mammals. For mammals, the acute levels of concern are exceeded mainly on short
grass for smaller animals. Acute and chronic risk to both freshwater and estuarine/marine fish is
relatively low. The acute risk to both freshwater and estuarine/marine invertebrates are of concern for
some crops. Use of phosmet on all crops (with potential for marine exposure) appear to pose a
chronic concern for marine invertebrates. Use of phosmet on many crops appears to pose a chronic
risk to freshwater invertebrates. In addition, phosmet is highly toxic to honey bees, and incidents of
honey bee toxicity have been reported.
To mitigate risks of concern posed by the uses of phosmet, EPA considered the mitigation
proposal submitted by the technical registrant, as well as comments and mitigation ideas from other
interested parties, and has decided on risk mitigation measures to address the worker, residential, and
ecological concerns for 17 phosmet use sites. Results of the risk assessments are presented in this
partial interim RED. Revised labeling and other actions needed to implement risk mitigation for all
phosmet uses will be outlined in a future document.
Dietary Risk
Acute and chronic dietary risk assessments for food and drinking water are not of concern;
therefore, no mitigation is warranted at this time for any dietary exposure to phosmet.
Occupational Risk
Occupational exposure to phosmet is of concern to the Agency, and it has been determined that
a number of mitigation measures are necessary. For the agricultural uses of phosmet, the Agency has
risk concerns, i.e., MOEs are less than 100, for occupational handlers mixing and loading wettable
powder products for aerial and chemigation applications to fruit and nut trees, field and vegetable
crops, grapes, ornamental plants, and forestry. The EPA believes most of these risks can be mitigated
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with the following label restrictions: addition of personal protective equipment, and the use of closed
systems, in addition to label restrictions and amendments detailed in this document. The Agency has
concerns about workers re-entering the agricultural field within 24 hours after treatment with phosmet,
which is the restricted entry interval on current labels. There are some remaining phosmet uses with
risks of concern, even after taking into account all feasible mitigation for these uses, EPA has conducted
a benefits assessment, and considered the benefits of continued use, as well as the risks, in its risk
management decisions. The benefits associated with these uses are discussed in Section IV of this
partial interim RED.
Residential Risk
Based on the phosmet use pattern, residential handler exposure is expected to occur through
either treatment of a dog or use in a home garden. The residential handler scenarios that involve the use
of a low-pressure handwand are of concern. There are concerns for continuous post-application
exposure to adults and youth in residential settings over an extended period of time (greater than 30
days); however, there is little information to determine if such extended exposures actually occur.
There are also concerns for short-term exposure to adults and youths harvesting and maintaining fruit
trees. In addition, there are significant risk concerns for toddlers exposed to phosmet residues
following contact with treated dogs, regardless of the duration of exposure. To mitigate the residential
risks of concern, the registrant has agreed to cancel all products that are used in or around the home or
on pets.
Ecological Risk
The Agency has some concerns with the estimated ecological risks. Studies suggest that on
certain crops, where there is a high application rate and frequent application of phosmet, expected
environmental concentrations can lead to acute risk for mammals; chronic risk for birds and mammals;
and acute and chronic risks to invertebrates. In addition, phosmet is highly toxic to honey bees.
With the implementation of the mitigation measures detailed in this document, the Agency has
determined that, until the cumulative risks for all of the organophosphates has been considered, kiwi,
peas (dry and green), sweet potatoes, alfalfa, blueberries, cherries (sweet and tart), cotton, cranberries,
potatoes, pine seed orchards, ornamental (nursery stock) and fire ant uses of phosmet may continue;
the use on dogs and the homeowner use of phosmet on ornamentals and fruit trees will be voluntarily
canceled.
The Agency is issuing this partial interim Reregistration Eligibility Document (RED) for phosmet,
as announced in a Notice of Availability published in the Federal Register. Because of extensive
public interest in phosmet, EPA is providing a 60-day comment period for this partial interim decision
document.
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No action is needed by registrants until EPA has completed its risk management decisions for
all phosmet uses and issues a complete IRED with time lines and instructions for complying with the
DCIs and other provisions of the IRED. Neither the tolerance reassessment nor the reregistration
eligibility decision for phosmet can be considered final, however, until the cumulative risks for all
organophosphate pesticides are considered. The cumulative assessment may result in further risk
mitigation measures for phosmet.
I. Introduction
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was amended in 1988 to
accelerate the reregistration of products with active ingredients registered prior to November 1, 1984.
The amended Act calls for the development and submission of data to support the reregistration of an
active ingredient, as well as a review of all submitted data by the U.S. Environmental Protection Agency
(referred to as EPA or "the Agency"). Reregistration involves a thorough review of the scientific
database underlying a pesticide's registration. The purpose of the Agency's review is to reassess the
potential hazards arising from the currently registered uses of the pesticide; to determine the need for
additional data on health and environmental effects; and to determine whether the pesticide meets the
"no unreasonable adverse effects" criteria of FIFRA.
On August 3, 1996, the Food Quality Protection Act of 1996 (FQPA) was signed into law.
This Act amends FIFRA to require tolerance reassessment of all existing tolerances. The Agency had
decided that, for those chemicals that have tolerances and are undergoing reregistration, the tolerance
reassessment will be initiated through this reregistration process. FQPA also requires that by 2006,
EPA must review all tolerances in effect on the day before the date of the enactment of the FQPA.
FQPA amends the FFDCA to require a safety finding in tolerance reassessment based on factors
including an assessment of cumulative effects of chemicals with a common mechanism of toxicity.
Phosmet belongs to a group of pesticides called organophosphates, which share a common mechanism
of toxicity - they all affect the nervous system by inhibiting the enzyme cholinesterase. Although FQPA
significantly affects the Agency's reregistration process, it does not amend any of the existing
reregistration deadlines. Therefore, the Agency is continuing its reregistration program while it resolves
the remaining issues associated with the implementation of FQPA.
This document presents the Agency's revised human health and ecological risk assessments,
and a partial interim decision on the reregistration eligibility of phosmet. It is intended to be only the first
set of reregistration decisions for phosmet. The Agency will eventually proceed with its risk
management decisions for all phosmet uses and its assessment of the cumulative risk of the OP
pesticides and issue a final reregistration eligibility decision for phosmet.
The implementation of FQPA has required the Agency to revisit some of its existing policies
relating to the determination and regulation of dietary risk, and has also raised a number of new issues
for which policies need to be created. These issues were refined and developed
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through collaboration between the Agency and the Tolerance Reassessment Advisory Committee
(TRAC), which was composed of representatives from industry, environmental groups, and other
interested parties. The TRAC identified the following science policy issues it believed were key to the
implementation of FQPA and tolerance reassessment:
Applying the FQPA 10-Fold Safety Factor;
Whether and How to Use "Monte Carlo" Analyses in Dietary Exposure Assessments ;
How to Interpret "No Detectable Residues" in Dietary Exposure Assessments;
Refining Dietary (Food) Exposure Estimates;
Refining Dietary (Drinking Water) Exposure Estimates;
Assessing Residential Exposure;
Aggregating Exposure from all Non-Occupational Sources;
How to Conduct a Cumulative Risk Assessment for Organophosphate or Other Pesticides with
a Common Mechanism of Toxicity;
Selection of Appropriate Toxicity Endpoints for Risk Assessments of Organophosphates; and
Whether and How to Use Data Derived from Human Studies.
The process developed by the TRAC calls for EPA to provide one or more documents for
public comment on each of the policy issues described above. Each of these issues is evolving and in a
different stage of refinement. Some issue papers have already been published for comment in the
Federal Register and others will be published shortly.
In addition to the policy issues that resulted from the TRAC process, the Agency issued, on
September 29, 2000, a Pesticide Registration Notice (PR 2000-9) that presents EPA's approach for
managing risks from organophosphate pesticides to occupational users. The Worker PR Notice
describes the Agency's baseline approach to managing risks to handlers and workers who may be
exposed to organophosphate pesticides, and the Agency expects that other types of chemicals will be
handled similarly. Generally, basic protective measures such as closed mixing and loading systems,
enclosed cab equipment, or protective clothing, as well as increased reentry intervals will be necessary
for most uses where current risk assessments indicate a risk and such protective measures are feasible.
The policy also states that the Agency will assess each pesticide individually, and based upon the risk
assessment, determine the need for specific measures tailored to the potential risks of the chemical.
The measures included in this interim RED are consistent with the Worker Pesticide Registration
Notice.
This document consists of six sections. Section I contains the regulatory framework for
reregistration/tolerance reassessment as well as descriptions of the process developed by TRAC for
public comment on science policy issues for the organophosphate pesticides and the worker risk
management PR notice. Section n provides a profile of the use and usage of the chemical. Section m
gives an overview of the revised human health and environmental effects risk assessments resulting from
public comments and other information. Section IV presents the Agency's partial interim decision on
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reregistration eligibility and risk management decisions for some phosmet uses. Section V usually
summarizes the label changes necessary to implement the risk mitigation measures outlined in Section
IV. However, for this partial decision document it is included only as a place holder. Instructions and
time lines for complying with the provisions of the IRED will be provided when EPA completes its risk
management decisions for all uses of phosmet and issues a complete IRED. Section VI provides
information on how to access related documents. Finally, no appendices are included in this document.
The complete IRED for phosmet will include appendices that list the uses that will be eligible for
reregistration, pending the cumulative assessment for the organophosphate pesticides, data that support
these decisions and Data Call-In (DCI) information.
The revised risk assessments and related addenda are not included in this document, but are
available on the Agency's web page www.epa.gov/pesticides/op, and in the OPP Public Docket
located in Room 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
II. Chemical Overview
A. Regulatory History
Phosmet was first registered in the United States in 1966 as a broad-spectrum insecticide for
control of a wide variety of pests including the alfalfa weevil, boll weevil, codling moth, grape
berrymoth, leafrollers, plum curculio, and oriental fruit moth. In addition, phosmet is registered for
direct animal treatments to control fleas, lice, hornflies, sarcoptic mange, and ticks on cattle, swine and
dogs. There are other uses such as in forestry and for ornamental plants, including residential sites that
can be treated by professional applicators. Phosmet can also be used by homeowners to treat trees,
shrubs, ornamental plants, home gardens and dogs.
Although there are existing tolerances for residues in sweet corn and citrus, the registrant has
indicated these uses will not be supported and they have been excluded from the risk assessment. The
associated tolerances will be revoked.
B. Chemical Identification
N-(mercaptomethyl) phthalimide-S-(O,O-dimethyl phosphorodithioate):
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Phosmet
Phosmet oxon
! Common Name:
! Chemical Name:
! Chemical family:
! Case number:
! CAS registry number:
! OPP chemical code:
! Empirical formula:
! Molecular weight:
! Trade and other names:
! Basic manufacturer:
Phosmet
N-(mercaptomethyl) phthalimide-S- (O,O-
dimethyl phosphorodithioate):
Organophosphate
0242
732-11-6
059201
CnH12N04PS2
317.32
Imidan
Gowan Company and Schering-Plough Animal Health
Inc.
Technical phosmet is a pink to white crystalline solid with a melting point of 66-69 C. Phosmet
is slightly soluble in water (20 mg/L at 20-25 C), more soluble in ethanol and kerosene (<1.0 g/100
mL), and readily soluble in acetone, chloroform, and xylene (>100 g/100 mL). Phosmet has a
relatively low vapor pressure of 3.72 x 10"7 mm Hg at 25 C.
C. Use Profile
The following information is based on the currently registered uses of phosmet.
Type of Pesticide: Insecticide
Summary of Use Sites:
Food and Feed: Fruit trees (apple, apricot, crabapple, nectarine, peach, pear,
plum/prune, cherry (tart and sweet) and nut trees (almond, beechnut, Brazil nut,
butternut, cashew, chestnut, chinquapin, filbert, hickory, macadamia, pecan, pistachio,
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walnut), grapes, kiwifruit, blueberries (highbush and lowbush), cranberries, peas (fresh
and dried), potato, sweet potato (foliar and post-harvest) alfalfa, cotton and clover.
Residential: Ornamentals, fruit and nut trees, blueberries, grapes, peas (fresh and dried),
potatoes, and pets (dogs only).
Public Health: Fire Ants.
Other Nonfood: Evergreen trees, nursery stock, pine seed orchards, and pine
seedlings. Direct animal treatments to cattle, swine, and dogs.
Target Pests: Moths, beetles, weevils, leafrollers, navel orangeworm, peach twig
borer, plum curculio, San Jose scale, lice, flies, ticks and sarcoptic mange.
Formulation Types Registered Dust, emulsifiable concentrate, soluble concentrate,
and wettable powder.
Method and Rates of Application:
Equipment - In agriculture, groundboom, airblast and aerial applications. Other
applications, dusting equipment, handheld equipment such as low pressure
handwand sprayers and backpack sprayers. Post- harvest application to sweet
potatoes can be made by hand held dusting equipment. Direct dermal
application to livestock is permitted via sprays and a backrubber. Dogs can be
treated with a dip or a dust.
Method and Rate - In agriculture, use rates range from 0.7 to 6 Ibs ai/A,
depending on the crop. Multiple foliar applications can be made to some crops
in a growing season. Applications can generally be made up to 7 to 14 days
prior to harvest. Post-harvest application of a dust formulation to sweet
potatoes is permitted, using 0.0125 Ib ai/50 Ib bushel. Direct dermal
applications to livestock range from 0.4 - 2.0 Ib ai/100 gallons spray.
Backrubber application to cattle rate is 1 Ib ai/50 gallons fuel oil. The use rate
for dusting dogs is 0.5 g dust/kg animal weight. The use rate for dipping dogs is
0.0076 Ib ai/gallon dip solution.
Timing - Delayed dormant, foliar applications for agricultural crops and post-
harvest use on sweet potatoes.
Use Classification: General classification.
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D. Estimated Usage of Pesticide
This section summarizes the best estimates available for many of the pesticide uses of phosmet,
based on available pesticide usage information for 1988 to 1997. A full listing of all uses of phosmet,
with the corresponding use and usage data for each site, has been completed and is in the "Quantitative
Use Assessment" document, which is available in the public docket. The data, reported on an
aggregate and site (crop) basis, reflect annual fluctuations in use patterns as well as the variability in
using data from various information sources. Approximately 1,000,000 Ibs active ingredient (a.i.) of
phosmet are used annually, according to Agency and registrant estimates.
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Table 1. Phosmet Estimated Annual Usage for Representative Sites
Crop
Blueberries
Apples
Apricots
Cherries
Kiwifruit
Nectarines
Peaches
Pears
Plums & Prunes
Grapes
Almonds
Pecans
Walnuts
Potatoes
Sweet Potatoes
Peas, Dry
Peas, Green
Alfalfa
Cotton
Other Crops
Woodland
Canine (Dog)
Cattle & Swine
Beef Cattle
Dairy Herd
Lbs. Active
Ingredient Applied
(Wt. Avg.)1
19,000
420,000
10,000
35,000
54
13,000
110,000
54,000
15,000
21,000
61,000
30,000
87,000
28,000
14,000
12,000
7,000
37,000
2,000
5,000
0
10,000
19,000
-
-
Percent Crop
Treated
(Likely
Maximum)
30
37
28
26
4
27
23
33
7
5
9
10
25
4
7
27
6
0.5
0.18
-
0.02
-
-
0.22
0.56
Percent Crop
Treated
(Wt. Avg.)
20
23
21
15
1
14
13
20
4
2
4
3
9
1
4
13
3
0.2
0.04
-
0.01
-
-
0.11
0.28
1 Weighted Average is based on data for 1988 to 1997; the most recent years and more reliable data are weighted
more heavily.
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III. Summary of Phosmet Risk Assessment
Following is a summary of EPA's revised human health and ecological risk findings and
conclusions for the organophosphate pesticide phosmet, as fully presented in the documents, "Phosmet
(Chemical ID No. 05920I/List A Reregistration Case No. 0242). HED Revised Human Health Risk
Assessment for the Reregistration Eligibility Decision Document (RED). DP Barcode No. D262365,"
dated February 9, 2000; "Phosmet: Revised Occupational Post-Application Exposure and Risk
Calculations [DP Barcode D268141, Chemical Code 059201, Case 818976]", dated August 15,
2000; and "Environmental Fate and Effects Division RED Chapter for Phosmet," dated April 24, 1998.
The purpose of this summary is to assist the reader by identifying the key features and findings of these
risk assessments, and to better understand the conclusions reached in the assessments.
These risk assessments for phosmet were presented at a February 10, 2000 Technical Briefing
in Pasco, WA, which was followed by an opportunity for public comment on risk management for this
pesticide. The risk assessments presented here form the basis of the Agency's risk management
decision for phosmet only; the Agency must complete a cumulative assessment of the risks of all the
organophosphate pesticides before any final decisions can be made.
A. Human Health Risk Assessment
EPA issued its preliminary risk assessments for phosmet on January 15, 1999, (Phase 3 of the
TRAC process). In response to comments and studies submitted during Phase 3, the risk assessments
were updated and refined. Major revisions to the human health risk assessment include recalculation of
restricted entry intervals based on new data from the Agricultural Reentry Task Force (ARTF) and
inclusion of a worker risk assessment for the liquid formulations.
The Agency has reviewed all toxicity studies submitted and has determined that the toxicity
database is complete, and that it supports an interim reregistration eligibility determination. Further
details on the toxicity of phosmet can be found in the February 9, 2000, Human Health Risk
Assessment.
Cancer Risk
Based on all available data for phosmet, the HED Cancer Assessment Review Committee
(CARC) concluded that phosmet should be classified as having "suggestive evidence of carcinogenicity,
but not sufficient to assess human carcinogenic potential". In a mouse carcinogenicity study, phosmet
caused increases in liver carcinomas/adenomas in males and increased mammary gland tumors in
females. Phosmet was not carcinogenic in rats. The CARC conducted a weight-of-evidence
evaluation of the mutagenicity and carcinogenicity data for phosmet (in accordance with the 1997 draft
Cancer Guidelines) on September 1, 1999. Additional data regarding tumor counts in the mouse
carcinogenicity study were discussed along with additional mutagenicity data submitted by the
registrant. The CARC recommended against completing a quantitative cancer risk assessment for
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phosmet. This recommendation is consistent with the previous recommendation to use the reference
dose (RfD) approach, in which chronic risks assessed using the RfD are considered to be protective of
any carcinogenic effect, as well as any systemic or other chronic effects.
Human Data
The Agency is currently evaluating an acute (ascending single oral dose) study with phosmet in
humans that was conducted by Inveresk Research in Scotland in 1999. The following observations can
be made on the potential impact of these data on the phosmet risk assessment. Because the study is a
single oral dose, it could be used in a weight-of evidence approach to inform the selection of the inter-
species uncertainly factor for acute risk assessments. That is, assuming it was conducted according to
appropriate scientific and ethical standards, the acute human study could be compared to existing acute
animal data to determine if the full ten-fold inter-species uncertainty factor is needed to account for
variation between species in the acute dietary assessment for phosmet and could provide a basis for
reduction of the uncertainty factor for acute dietary risk. However, because of its limited duration, the
human study would not likely be appropriate for use in short-term or intermediate-term assessments,
such as those used to estimate worker risk from phosmet use, nor would it be appropriate for the
chronic dietary assessment.
1. Dietary Risk from Food
a. Toxicity
A brief overview of the studies used for the dietary risk assessment is outlined in Table 2 below.
b. FQPA Safety Factor
The FQPA Safety Factor was reduced to 1 X. The toxicity database includes an acceptable
two-generation reproduction study in rats and acceptable prenatal developmental toxicity studies in rats
and rabbits. These studies show no increased sensitivity to phosmet among fetuses as compared to
maternal animals following acute in utero exposure in the developmental rat and rabbit studies and no
increased sensitivity among pups as compared to adults in a multi-generation reproduction study in rats.
There was no evidence of abnormalities in the development of the fetal nervous system in the pre/post
natal studies. In the subchronic neurotoxicity study in rats, an increase in the neuropathological
changes, characterized by digestion chamber in the sciatic and peroneal nerves, was seen in high dose
male rats. When compared to the controls, these changes could not be ruled out as a treatment-related
effect. Adequate actual data, surrogate data, and/or modeling outputs are available to satisfactorily
assess dietary and residential exposure and to provide a screening level drinking water exposure
assessment. The assumptions and models used in the assessments do not underestimate the potential
risk for infants and children. Therefore, the 10X factor as required by FQPA was reduced to 1, for
both acute and chronic risk assessments for all subpopulations. A developmental neurotoxicity study
(DNT) study has been required and is considered confirmatory.
14
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c.
Population Adjusted Dose (PAD)
The PAD is a term that expresses the dietary risk of a chemical, and reflects the Reference
Dose, (RfD) either acute or chronic, that has been adjusted to account for the FQPA safety factor (i.e.,
RfD/FQPA safety factor). In the case of phosmet, the FQPA safety factor is 1; therefore, the acute or
chronic RfD is equal to the acute or chronic PAD. A risk estimate that is less than 100% of the acute
or chronic PAD does not present a risk of concern.
Table 2. Summary of Toxicological Endpoints and Other Factors Used in the Human Dietary
Risk Assessment of Phosmet
Assessment
Acute
Dietary
Chronic
Dietary
Dose
LOAEL of
22.5 mg/kg/day
NOAEL of
4.5 mg/kg/day
LOAEL of
1.8 mg/kg/day
NOAEL of
1.1 mg/kg/day
Endpoint
Red blood cell,
plasma and brain
cholinesterease
inhibition and
decreased motor
activity
Red blood cell,
and serum
cholinesterease
inhibition
Study
Oral Acute
Neurotoxicity
Study on Rats
Oral Chronic
Toxicity/
Carcinogenicity
Study on Rats
UF
100
100
FQPA
Safety
Factor
1
1
PAD
0.045
mg/kg/day
0.011
mg/kg/day
d. Exposure Assumptions
Revised acute and chronic dietary risk analyses for phosmet were calculated using the Dietary
Exposure Evaluation Model (DEEM). The regulated residues consist of parent phosmet and its
metabolite, phosmet oxygen analog (oxon). For the revised phosmet risk assessment, the Agency
conducted highly refined (Tier 3) acute (probabilistic) and chronic dietary exposure analyses which
were based almost entirely on the available monitoring data, and incorporated additional refinements
such as processing and cooking factors and percent of crop treated. The DEEM analysis evaluated the
individual food consumption as reported by respondents in the USDA's 1989-91 Continuing Surveys of
Food Intakes by Individuals (CSFn) and accumulated exposure to the chemical for each commodity.
Typically, the Agency will not use monitoring data which do not include all residues of lexicological
concern. Although both the PDF and FDA monitoring programs reported data for parent phosmet
only, these data have been used in the revised risk assessment for the following reasons: (i) field trial
data indicate that oxon residues, when detected, are generally an order of magnitude lower than parent
residues; (ii) residues in both PDF and FDA monitoring samples were significantly less than tolerance-
level residues; and (iii) phosmet oxon is relatively unstable in numerous commodities. Using the
monitoring data in acute and chronic dietary exposure analyses is not expected to underestimate risk.
15
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The acute dietary risk analyses for phosmet were calculated using a probabilistic analysis
(Monte Carlo), incorporating percent crop treated data, USDA's Pesticide Data Program data (PDF
monitoring data), the Food and Drug Administration's monitoring data, residue field trial data, cooking
study data, and processing factors, where available. Chronic dietary risk was calculated by using the
average consumption and residue values for foods.
e. Food Risk Characterization
Generally, a dietary risk estimate that is less than 100% of the acute or chronic Population
Adjusted Dose does not exceed the Agency's risk concerns. The phosmet acute dietary risk from food
is well below the Agency's level of concern; i.e., less than 100% of the acute PAD. For example, for
the most exposed subgroups, children (1-6 years) and infants (<1 year), the % acute PAD values are
7.5% and 6.5%, respectively, at the 99.9th percentile of exposure, based on food alone.
The chronic dietary risk from food alone is well below the Agency's level of concern. For the
most exposed subgroup, children (1-6 years), the % chronic PAD value is 0.7%.
The Agency has refined the dietary (food) analyses to the extent currently possible.
2. Dietary Risk from Drinking Water
Drinking water exposure to pesticides can occur through ground water and surface water
contamination. EPA considers both acute (one day) and chronic (lifetime) drinking water risks and
uses either modeling or actual monitoring data, if available, to estimate those risks. Modeling is
considered to be an unrefined assessment and provides a high-end estimate of risk. In the case of
phosmet, only limited monitoring data for either ground or surface water were available; therefore,
modeling was used to estimate drinking water risks from these sources.
The PRZM-EXAMS model was used to estimate surface water concentrations, and SCI-
GROW was used to estimate groundwater concentrations. Both models are considered to be
screening models, with the PRZM-EXAMS model being somewhat more refined than SCI-GROW.
Phosmet oxon is the only degradate of lexicological concern and was identified in a number of
the environmental fate studies that were conducted. Phosmet oxon appears to be less mobile than
phosmet, as evidenced by its absence in leachates in the aged and unaged mobility study. In addition
phosmet oxon was limited to the upper soil layer in the field studies while phosmet was detected as low
as the 10.5-inch soil layer. Phosmet was found to be moderately mobile to mobile in four different soil
classes.
The estimated concentrations for drinking water are for phosmet only. Phosmet oxon, which
has been included in the tolerance expression, is not included in the modeling due to the absence of fate
information. Considering the limited presence of phosmet oxon in the laboratory and field studies (soil
16
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extract of the mobility study and upper 0 - 3-inch soil layer in the field dissipation studies), phosmet
oxon should not add appreciably to the concentration of parent compound in ground or surface water
in most use areas.
a. Surface Water
A Tier n PRZM-EXAMS screening model was used to estimate the upper-bound
concentrations of phosmet in drinking water derived from surface water. This model, in general, is
based on more refined, less conservative assumptions than the Tier IGENEEC screening model.
Phosmet can contaminate surface water via runoff if runoff-producing rain events occur within
the first few days to weeks post application. Phosmet's water solubility (25 mg/1) and its partition
coefficient (Kads= 1.17-15.8) suggest that it will enter surface water via runoff. It appears that the
persistence of phosmet in surface water may be limited by its susceptibility to biodegradation especially
in water with moderate to high microbial activity and by abiotic hydrolysis under neutral to alkaline
conditions. In flowing water, its persistence is limited by the flow rate of the system more than by either
metabolism or hydrolysis. However, its persistence in lakes and reservoirs will be greater and
controlled more by metabolism and hydrolysis.
Limited monitoring data indicate that phosmet has been detected in surface water in known use
areas. However, these data suggest that phosmet concentrations do not exceed the very low ppb
range, well below the DWLOC. The three crops with the highest phosmet surface water
concentrations are pears, kiwi and cotton applied at 5, 2 and 1 Ib ai/A, respectively. The estimated
environmental concentrations (EECs) range from 0.4 ppb for application to apples at the western-low
rate (1.5 Ib ai/A) to 140 ppb for application to pears (5 Ib ai/A).
b. Ground Water
A Tier I screening model, SCI-GROW, was used to estimate the upper-bound drinking water
concentrations of phosmet in ground water. The SCI-GROW model is based on the fate properties of
the pesticide, the annual application rate, and the existing body of data from small-scale ground water
monitoring studies. The model assumes that the pesticide is applied at its maximum rate in areas where
ground water is particularly vulnerable to contamination. In most cases, a considerable portion of any
use area will have ground water that is less vulnerable to contamination than the areas used to derive the
SCI-GROW estimates. The estimated maximum concentration derived using these modeled estimates
should be considered a high-end to bounding estimate of acute and chronic exposure.
The maximum concentration (acute and chronic) for parent phosmet estimated using
SCI-GROW is approximately 0.4 ppb. No phosmet residues were reported in ground water
monitoring data at concentrations above the detection limits of 0.1 and 10 ppb. Phosmet is not
expected to pose a threat to ground water resources.
17
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c. Drinking Water Levels of Comparison (DWLOCs)
To determine the maximum allowable contribution of pesticide residues from drinking water
permitted in the diet, EPA first looks at how much of the overall allowable risk is contributed by food
(and if appropriate, residential uses) then determines a "drinking water level of comparison"(DWLOC)
to determine whether modeled or monitored levels exceed this level. The Agency uses the DWLOC as
a surrogate to capture risk associated with exposure from pesticides in drinking water. The DWLOC is
the maximum concentration in drinking water which, when considered together with dietary exposure
from food, does not exceed a level of concern.
The results of the Agency's drinking water analysis are summarized here. Details of this
analysis, which used screening models, are found in the HED Human Health Risk Assessment, dated
February 9, 2000.
For acute risk, the potential drinking water exposure derived from either ground or surface
water is not of concern for all populations. The table below presents the calculations for the acute
drinking water assessment.
Table 3. Summary of DWLOC Calculations for Phosmet Acute Risk
Population
Subgroup
U.S.
Population
Females
20+
Children
1-6
Ground Water
EECs (ppb)
(SCI-GROW)
0.4
0.4
0.4
Surface Water
EECs (ppb)
(PRZM-EXAMS)
3 - 140
3 - 140
3 - 140
DWLOC
(ppb)
1523
1308
416
For chronic risk, potential exposure to drinking water derived from either groundwater or
surface water is not of concern for all populations. The table below presents the calculations for the
chronic drinking water assessments.
18
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Table 4. Summary of DWLOC Calculations for Phosmet Chronic Risk
Population
Subgroup
U.S.
Population
Children
1 - 6
Females
13- 19
Ground Water
EECs (ppb)
(SCI-GROW)
0.4
0.4
0.4
Surface Water
EECs (ppb)
(PRZM-EXAMS)
1
1
1
DWLOC
(ppb)
384
110
330
3. Occupational and Residential Risk
Workers can be exposed to a pesticide through mixing, loading, applying a pesticide, and/or re-
entering treated sites. Residents or homeowners can be exposed to a pesticide through mixing, loading,
applying a pesticide, entering a treated area or performing other activities in a treated area.
Occupational handlers of phosmet include: individual farmers or growers who mix, load, or apply
pesticides, and professional or custom agricultural applicators. Residential handlers include homeowner
applicators treating their own home garden or dog. Risk for all of these potentially exposed populations
is measured by a Margin of Exposure (MOE) which determines how close the occupational or
residential exposure comes to a No Observed Adverse Effect Level (NOAEL). Generally, MOEs
greater than 100 do not exceed the Agency's risk concern.
a. Toxicity
The toxicity of phosmet is integral to assessing the occupational and residential risk. All risk
calculations are based on the most current toxicity information available for phosmet, including a 21-day
dermal toxicity study. An acceptable dermal absorption study conducted in rats indicates a dermal
absorption factor of 10 percent is appropriate for the phosmet risk assessment. The lexicological
endpoints, and other factors used in the occupational and residential risk assessments for phosmet are
listed below.
In the preliminary risk assessment for phosmet, the Agency selected a LOAEL of 1.5
mg/kg/day established in the subchronic oral neurotoxicity study in rats for the intermediate-term dermal
and inhalation exposures of >30 days in duration. In this study, a NOAEL was not established at the
termination of the study. Therefore, the Agency used the LOAEL in the risk assessment and added an
uncertainty factor of 3. The use of this uncertainty factor established the target MOE of 300 for these
assessments and lead to a value (0.5 mg/kg/day) lower than the one used for the chronic dietary RED
(1.1 mg/kg/day). Based on a consideration of the entire toxicity database, EPA determined that the 0.5
mg/kg/day value was not a representative subchronic endpoint. For this reason, the Agency selected
19
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the chronic rat study with a NOAEL of 1.1 mg/kg/day for the intermediate term >30 days exposure in
the risk assessment. This is appropriate because the same endpoint (cholinesterase inhibition) was
observed in both studies in the same species (rat) and the LOAEL of 1.5 mg/kg/day in the subchronic
study is comparable to the LOAEL of 1.8 mg./kg/day in the chronic study.
20
-------
Table 5a. Summary of Toxicological Endpoints and Other Factors Used in the Human
Occupational and Residential Risk Assessments for Phosmet
Assessment
Short-term
dermal
(Up to 7
days)
Intermediate-
term dermal
(>7 and < 30
days)
Intermediate-
term dermal
(>30 days)
Short-term
inhalation
(Up to 7
days)
Intermediate
-term
inhalation
(>7 and < 30
days)
Intermediate
-term
inhalation
(>30 days)
Non-dietary
ingestion -
Acute
(children)
Non-dietary
ingestion -
Chronic
(children)
Dose
NOAEL = 15
mg/kg/day
NOAEL = 15
mg/kg/day
NOAEL = 1.1
mg/kg/day
NOAEL= 4.5
mg/kg/day
NOAEL= 1.5
mg/kg/day
(At 3 week
interval)
NOAEL= 1.1
mg/kg/day
NOAEL = 4.5
mg/kg/day
NOAEL = 1.1
mg/kg/day
Endpoint
Cholinesterase Inhibition [brain
(females), plasma (males)] at the
LOAEL of 22.5 mg/kg/day
Cholinesterase Inhibition [brain
(females), plasma (males)] at the
LOAEL of 22.5 mg/kg/day
Cholinesterase Inhibition
(RBC and Serum) at the LOAEL
of 1.8 mg/kg/day
Cholinesterase Inhibition
(Plasma, RBC, Brain) and
Decreased Motor Activity at the
LOAEL of 22.5 mg/kg/day
Cholinesterase Inhibition [brain
(females), plasma (males)] at the
LOAEL of 2.7 mg/kg/day
Cholinesterase Inhibition
(RBC and Serum)
at the LOAEL of
1.8 mg/kg/day
Cholinesterase Inhibition
(Plasma, RBC, Brain) and
Decreased Motor Activity at the
LOAEL of 22.5 mg/kg/day
Cholinesterase Inhibition
(RBC and Serum)
at the LOAEL of
1.8 mg/kg/day
Study
21 -Day Dermal
Toxicity in Rats
21 -Day Dermal
Toxicity in Rats
Oral Chronic
Toxicity/
Carcinogenicity
in Rats
Oral Acute
Neurotoxicity
in Rats
Oral Subchronic
Neurotoxicity in
Rats
Oral Chronic
Toxicity/
Carcinogenicity
in Rats
Oral Acute
Neurotoxicity
in Rats
Oral Chronic
Toxicity/
Carcinogenicity
in Rats
Absorption
Factor
Not
Relevant
Not
Relevant
10%
100 %
100 %
100 %
Not
Relevant
Not
Relevant
21
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In acute toxicity studies, phosmet exhibits moderate toxicity via the oral and inhalation routes of
exposure. Phosmet is not acutely toxic in rats via the dermal route, is non-irritating to the skin, and is
not an eye irritant in the rabbit.
Table 5b. Acute Toxicity Profile for Phosmet
Guideline No.
870.1 100/ง81-1
870.1200/ง81-2
870.1300/ง81-3
870.2400/ง81-4
870.2500/ง81-5
870.2600/ง81-6
870.6100/ง81-7
870.6200/ง81-8
Study Type
Acute Oral - rat
Acute Dermal - rabbit
Acute Inhalation - rat
Primary Eye Irritation
Primary Skin
Irritation
Dermal Sensitization
Delayed
Neurotoxicity
Acute Neurotoxicity
MRIDs#
00046189
00046190
00063197
00046192
00046191
no study
44587601
44673301
Results
LD,n= 113 mg/kg
LD,n >5000 mg/kg
LC,0X).152mg/L
moderate eye irritant
not a skin irritant
unsteadiness, subdued behavior,
recumbency, salivation; no ataxia;
no decreases in brain or spinal
cord NTE; brain ChE decreased
63%; no neuropathology.
[All hens were dosed at 600 mg/kg
by oral gavage]
NOAEL 4.5 mg/kg LOAEL 22.5
mg/kg, based on cholinesterase
inhibition [plasma, RBC, brain] and
decreased motor activity in both
sexes.
Toxicity
Category
II
III
II
III
IV
N/A
N/A
N/A
b. Exposure
Chemical-specific exposure data were not available for phosmet, so risks to pesticide handlers
were assessed using data from the Pesticide Handlers Exposure Database (PHED). The quality of the
data and exposure factors represents the best sources of data currently available to the Agency for
completing these kinds of assessments; the application rates are derived directly from phosmet labels.
The exposure factors (e.g., body weight, amount treated per day, protection factors, etc.) are all
standard values that have been used by the Agency over several years, and the PHED unit exposure
values are the best available estimates of exposure. Some PHED unit exposure values are high quality
while others represent low quality, but all are the best available data. The quality of the data used for
each scenario assessed is discussed in the Human Health Assessment document for phosmet, which is
available in the public docket.
22
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Anticipated use patterns and application methods, range of application rates, and daily amount
treated were derived from current labeling. Application rates specified on phosmet labels range from
0.7 to 6 pounds of active ingredient per acre in agricultural settings. For agricultural applications, the
Agency typically uses acres treated per day values that are thought to represent 8 hours of application
work for specific types of application equipment. Phosmet may be used for direct animal treatments on
livestock and dogs. The application rates for the farm animal spray range from 0.4 to 2.0 Ib ai per 100
gallons. For the cattle backrubber, the application rate is 1 Ib ai per 50 gallons of fuel oil. Dogs may
be treated by either a dust or a dip solution. For the dog dust, the application rate is 0.5 grams of
formulated dust per kilogram of animal body weight. For the dog dip, the application rate is 0.0076 Ib
ai per gallon of dip solution.
For homeowner application, the rates are: 0.0098 Ib ai per gallon and 10 gallons of water per
fruit and nut tree; 0.0121b ai per 100 square feet for vegetables; 0.0075 Ib ai per gallon on ornamental
plants; and 0.009 Ib ai per square foot of fire ant mound. In addition, dogs may be treated by
homeowners; for the dust, the application rate is 0.5 grams of formulated dust per kilogram of animal
body weight and for the dog dip, the application rate is 0.0076 Ib ai per gallon of dip solution.
Occupational handler exposure assessments are conducted by the Agency using different levels
of personal protection. The Agency typically evaluates all exposures with minimal protection and then
adds additional protective measures using a tiered approach to obtain an appropriate MOE (i.e., going
from minimal to maximum levels of protection). The lowest tier is represented by the baseline exposure
scenario, followed by, if required (i.e., if MOEs are less than 100), increasing levels of risk mitigation
(personal protective equipment (PPE) and engineering controls (EC)). The levels of protection that
formed the basis for calculations of exposure from phosmet activities include:
Baseline: Long-sleeved shirt and long pants, shoes and socks.
Label: Long-sleeved shirt and long pants, waterproof gloves, shoes plus
socks, chemical resistent headgear for overhead exposure, and
dust/mist filtering respirator (most labels).
Minimum PPE: Baseline + chemical resistant gloves and a respirator.
Maximum PPE: Coveralls over long-sleeved shirt and long pants, chemical resistant
gloves, chemical-resistent footwear plus socks, chemical resistant
headgear for overhead exposures, and a respirator if risk is driven by
inhalation.
Engineering controls: Engineering controls such as a closed cab tractor for application
scenarios, or a closed mixing/loading system such as a closed
mechanical transfer system for liquids or a packaged based system
(e.g., water soluble packaging for wettable powders). Some
engineering controls are not applicable for certain scenarios (e.g., for
handheld application methods there are no known devices that can be
used to routinely lower the exposures).
23
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In addition to the tasks and activities associated with pesticide application and post-application
exposures, the Agency considers the expected duration and route of exposure and the associated
potential toxic effects as determined in the required toxicity testing. Based on the phosmet use pattern,
short-and intermediate-term exposures are expected to occur. For the phosmet risk assessment, short-
term exposures are from one to seven days; intermediate-term exposures were separated into two
distinct time-frames of between eight and thirty days and greater than thirty days in duration. The
reason for these distinctions is that the results of the toxicity testing indicate that effects associated with
exposure to phosmet become more severe over time (greater than 30 days).
For the residential handler risk assessment, all application of phosmet by homeowners to fruit
and nut trees, ornamental plants, vegetable plants, fire ant mounds and dogs is considered to be short-
term, and assumes that no protective clothing is used. The Agency does not require protective clothing
for residential handlers because there is no mechanism to ensure that the protective clothing is cleaned
and maintained appropriately or that it would routinely be used.
Finally, exposure to workers through entry into agricultural fields treated with phosmet, and
post-application exposure to homeowners entering treated areas, harvesting or maintaining fruit or nut
trees, or gardens are expected to occur. In addition, toddlers and others could be exposed to phosmet
after coming in contact with a treated dog.
c. Occupational & Residential Handler Risk Summary
Based on the phosmet use pattern, a total of 23 occupational handler scenarios were identified.
No chemical-specific handler exposure data were submitted for phosmet, and therefore daily dermal
and inhalation handler doses were calculated using data from the Pesticide Handlers Exposure
Database (PHED), Version 1.1. The database contains exposure values for over 1,700 monitored
exposure events, which have been evaluated by the Agency in order to characterize the quality of the
data.
Assumptions regarding the application rate and acres treated (including an assumption of an 8-
hour workday for occupational scenarios) were used in conjunction with the PHED unit exposure
values to determine phosmet handler exposures. For agricultural handler scenarios, the number of
acres treated per day assumed in the phosmet risk assessment are those typically used in risk
assessments. For pet handler exposures (vets and professional groomers), the Agency assumed that a
maximum of 8 dogs/day are dipped/dusted; risks were calculated for a range of dog body weights (5-
120 Ibs). In addition, it was assumed that 10% of the active ingredient applied during dipping/dusting
represented the total dose; this is a standard assumption taken from the 1997 Draft Standard
Operating Procedures (SOPs) for Residential Exposure Assessment. The average body weight of
an adult handler was assumed to be 70 kg, which is standard for these risk assessments. The hose-end
sprayer data were used to assess exposures associated with the fire ant mound treatment scenario.
Since there were no data to assess potential handler exposure associated with "charging" the cattle
24
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backrubber, data for open mixing of liquids were used; however, the Agency believes this approach
may underestimate exposure, based on information submitted by the registrant (Schering-Plough Animal
Health Inc.) about the operation of the cattle backrubber.
1) Occupational Handler Risk
The occupational handler scenarios are listed below:
Mixing/Loader
(la) mixing/loading liquid formulations for high pressure handwand applications;
(Ib) mixing/loading liquid formulations for airblast sprayer application;
(1 c) mixing/loading liquid formulations for groundboom sprayer;
(Id) mixing/loading liquid formulations for aerial application;
(2) mixing/loading wettable powders for treating pine seedlings
(2a) mixing/loading wettable powders for aerial application and chemigation;
(2b) mixing/loading wettable powders for groundboom application
(2c) mixing/loading wettable powders for airblast sprayer application;
(2d) mixing/loading wettable powders for high pressure handwand applications;
Applicator
(3) applying sprays with an airblast sprayer;
(4) applying sprays with a groundboom sprayer;
(5) aerial application of sprays with a fixed wing aircraft (fixed wing aircraft also accounts for
helicopter pilot exposure);
(6) applying using a high-pressure handwand;
(7) applying using a right-of-way sprayer;
(8) dipping pine seedlings;
Mixer/Loader/Applicator
(9) mixing/loading/applying with a power duster;
(10) dusting a dog;
(11) dipping a dog;
(12) use of a cattle backrubber;
(13 a) mixing/loading/applying liquids with a backpack sprayer;
(13b) mixing/loading/applying wettable powders with a backpack sprayer;
(14a) mixing/loading/applying liquids with a low pressure handwand;
(14b) mixing/loading/applying wettable powders with a low pressure handwand;
(15) mixing/loading/applying soluble concentrates for sprinkling; and
25
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r
flagging for aerial spray application.
26
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The Agency conducts occupational handler exposure assessments using different levels of personal protection. Minimal
protection is assumed at first, and a tiered approach to adding protective measures is used until an appropriate MOE is obtained, or until
all options are exhausted. The lowest tier is defined as the baseline exposure scenario; higher tiers include measures such as personal
protective equipment (PPE, e.g., gloves, extra clothing, and respirators) and engineering controls (e.g., closed cabs and closed loading
systems). The most practical option for risk reduction is generally considered to be the minimal level of protection adequate to address
the risks identified in the risk assessment. MOE calculations are shown in the table below. The footnotes describe the level of PPE used
in the assessment.
Table 6. Occupational Uses: Risk Estimates (combined dermal & inhalation MOEs)
Exposure Scenario
Crop Type or
Target
Acres
Treated or
Gallons per
Application
Application
Rate
(Ibs ai/A)
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
Intermediate
Term
< 30 days
Intermediate
Term
> 30 days
Necessary
level of
PPE or
Engineering
Controls
Occupational Mixer/Loader Estimates for MOE 100 or Highest Achievable MOE
(la) mixing/loading liquid formulations
for high pressure handwand
applications
livestock
livestock
ornamentals
1000 gal
1000 gal
400gal
0.004
0.02
0.008
9722 '
19941
1211
75001
15001
1201
55001
11001
7333' +
gloves
Baseline +
Gloves
Baseline +
Gloves
Baseline +
Gloves
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chemical-resistant gloves and a dust/mist respirator with a protection factor of 5 (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10 (OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
27
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Exposure Scenario
(Ib) mixing/loading liquid formulations
for airblast sprayer application
( 1 c ) mixing/loading liquid formulations
for groundboom application
Crop Type or
Target
ornamentals
blueberries
blueberries
potatoes,
alfalfa, cotton
alfalfa
alfalfa
alfalfa, cotton
Acres
Treated or
Gallons per
Application
50
80
80
80
80
200
200
Application
Rate
(Ibs ai/A)
0.06
0.47
0.94
1.02
0.78
0.78
1.02
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
1211
10341 +
gloves
517' +
gloves
477' +
gloves
623' +
gloves
249' +
gloves
191' +
gloves
Intermediate
Term
< 30 days
1201
798 ' + gloves
3991 + gloves
3681 + gloves
481 ' + gloves
192'+ gloves
1471 + gloves
Intermediate
Term
> 30 days
7333' +
gloves
5851 + gloves
293 ' + gloves
270 ' + gloves
3531 + gloves
141'+ gloves
108'+ gloves
Necessary
level of
PPE or
Engineering
Controls
Baseline +
Gloves
Baseline +
Gloves
Baseline +
Gloves
Baseline +
Gloves
Baseline +
Gloves
Baseline +
Gloves
Baseline +
Gloves
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chemical-resistant gloves and a dust/mist respirator with a protection factor of 5.
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
28
-------
Exposure Scenario
(Id) mixing/loading liquid formulations
for aerial application
Crop Type or
Target
Cotton
Cotton
Blueberries
Blueberries
Potatoes,
Cotton,
Alfalfa
Alfalfa
Alfalfa
Acres
Treated or
Gallons per
Application
80
200
350
350
350
350
1200
Application
Rate
(Ibs ai/A)
0.23
0.23
0.47
0.94
1.02
0.78
0.78
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
2114' +
gloves
845' +
gloves
236' +
gloves
118' +
gloves
109' +
gloves
143' +
gloves
1264
Intermediate
Term
< 30 days
1630' +
gloves
6521 + gloves
182'+ gloves
1262
1162
110'+ gloves
1194
Intermediate
Term
> 30 days
1196' +
gloves
478 ' + gloves
134'+ gloves
1152+ double
layer
1062+ double
layer
1112
874
Necessary
level of
PPE or
Engineering
Controls
Baseline +
Gloves
Baseline +
Gloves
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chemical-resistant gloves and a dust/mist respirator with a protection factor of 5.
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
29
-------
Exposure Scenario
(2) mixing/loading wettable powders
for high pressure handwand
application
(2a) mixing/loading wettable powders
for aerial application and
chemigation
Crop Type or
Target
Alfalfa,
Cotton
cotton
cotton
pine seedlings
various nut
trees
pears
fruit & nuts
Acres
Treated or
Gallons per
Application
1200
350
1200
100
350
350
350
Application
Rate
(Ibs ai/A)
1.02
0.23
0.23
0.35
5.95
5
3
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
974
483' +
gloves
141' +
gloves
1512
234
284
464
Intermediate
Term
< 30 days
914
3731 + gloves
109'+ gloves
1172
224
264
434
Intermediate
Term
> 30 days
674
273 ' + gloves
HO2
1032 + OV
respirator
164
194
314
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Minimum +
OV
Respirator
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chemical-resistant gloves and a dust/mist respirator with a protection factor of 5 (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10 (OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
30
-------
Exposure Scenario
Crop Type or
Target
grapes, fruit
trees &
vegetables
grapes, &
fruit trees
cranberries
cranberries
cranberries
cranberries
cranberries
Acres
Treated or
Gallons per
Application
350
350
10
25
80
10
25
Application
Rate
(Ibs ai/A)
1.5
1
1
1
1
2.8
2.8
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
924
1384
5292
2112
12384
1892
1043
Intermediate
Term
< 30 days
864
1284
4102
1642
10764
1472
12304
Intermediate
Term
> 30 days
634
944
3012
1202
7894
1072
9024
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chemical-resistant gloves and a dust/mist respirator with a protection factor of 5 (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10 (OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
31
-------
Exposure Scenario
(2b) mixing/loading wettable powders
for groundboom application
Crop Type or
Target
cranberries
cotton
pine seed
orchards
pine seed
orchards
forestry
noncrop/
field
perimeters
grapes,
vegetables,
etc.
Acres
Treated or
Gallons per
Application
80
1200
150
300
1200
10
80
Application
Rate
(Ibs ai/A)
2.8
0.4
1
1
1
2
1.5
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
4424
1004
6604
3304
404
1681
+ gloves
4014
Intermediate
Term
< 30 days
3844
944
5744
2874
374
2052
3744
Intermediate
Term
> 30 days
2824
694
4214
2104
274
1502
2744
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmrata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
32
-------
Exposure Scenario
(2c) mixing/loading wettable powders
for airblast sprayer application
Crop Type or
Target
grapes,
vegetables,
etc.
cotton
various nut
trees
pears
fruit & nut
trees
grapes, fruit
trees &
vegetables
grapes, tree
fruit, etc.
Acres
Treated or
Gallons per
Application
80
200
40
40
40
40
40
Application
Rate
(Ibs ai/A)
1
0.4
5.95
5
3
1.5
1
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
6024
6024
2024
2414
4014
1102 +
double
layer
1322
Intermediate
Term
< 30 days
5614
5614
1894
2244
3744
1013
1032
Intermediate
Term
> 30 days
4114
4114
1384
1654
2744
5484
1113
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmiata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
33
-------
Exposure Scenario
(2d) mixing/loading wettable powders
for high pressure handwand
applications
Crop Type or
Target
ornamentals
ornamentals
Acres
Treated or
Gallons per
Application
50
400
Application
Rate
(Ibs ai/A)
0.06
0.008
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
11171
+ gloves
11171
+ gloves
Intermediate
Term
< 30 days
5831
+ gloves
5831
+ gloves
Intermediate
Term
> 30 days
428 '
+ gloves
4281
+ gloves
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Baseline +
Gloves
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmiata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
34
-------
Exposure Scenario
Crop Type or
Target
Acres
Treated or
Gallons per
Application
Application
Rate
(Ibs ai/A)
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
Intermediate
Term
< 30 days
Intermediate
Term
> 30 days
Occupational Applicator Estimates
(3) applying sprays with an airblast
sprayer
various nut
trees
pears
fruit & nuts
trees
grapes, fruit
trees &
vegetables
grapes &
tree fruit
ornamentals
40
40
40
40
40
50
5.95
5
3
1.5
1
0.06
2154
2564
4274
8544
103' +
gloves
9331
1884
2234
3724
7454
1052
8641
1384
1644
2734
5464
8194
6341
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of clieinical-resistanl gloves and a dnsfeMiesjmiaita (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
35
-------
Exposure Scenario
(4) applying sprays with a
groundboom sprayer
Crop Type or
Target
pine seed
orchards
pine seed
orchard
noncrop/
field
perimeters
grapes, fruit
trees &
vegetables
grapes &
vegetables
cotton
blueberries
blueberries
Acres
Treated or
Gallons per
Application
10
40
10
80
80
200
80
80
Application
Rate
(Ibs ai/A)
1
1
2
1.5
1
0.4
0.47
0.94
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
51224
12804
31881
5311
7971
7971
16961
8481
Intermediate
Term
< 30 days
44684
11174
24531
4091
6131
6131
13051
6531
Intermediate
Term
> 30 days
32774
8194
17991
3001
4501
4501
9571
479 1
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Baseline
Baseline
Baseline
Baseline
Baseline
Baseline
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmrata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
36
-------
Exposure Scenario
Crop Type or
Target
cranberries
cranberries
cranberries
cranberries
cranberries
cranberries
potatoes,
alfalfa, cotton
alfalfa
alfalfa
alfalfa, cotton
cotton
Acres
Treated or
Gallons per
Application
10
25
80
10
25
80
80
80
200
200
80
Application
Rate
(Ibs ai/A)
1
1
1
2.8
2.8
2.8
1.02
0.78
0.78
1.02
0.23
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
63771
25511
7971
22771
9111
2851
7811
10221
4091
3131
34661
Intermediate
Term
< 30 days
49071
19631
6131
17521
701 '
2191
601 '
786 '
3151
241 '
26671
Intermediate
Term
> 30 days
35981
14391
4501
12851
5141
1611
441 '
5771
230.6
1761
19561
Necessary
level of
PPE or
Engineering
Controls
Baseline
Baseline
Baseline
Baseline
Baseline
Baseline
Baseline
Baseline
Baseline
Baseline
Baseline
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmiata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
37
-------
Exposure Scenario
(5) aerial application of sprays with a
fixed wing aircraft (fixed wing
aircraft also accounts for helicopter
pilot exposure)
Crop Type or
Target
cotton
various nut
trees
pears
fruit &
nut trees
grapes, fruit
trees &
vegetables
grapes &
fruit trees
Acres
Treated or
Gallons per
Application
200
350
350
350
350
350
Application
Rate
(Ibs ai/A)
0.23
5.95
5
3
1.5
1
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
13861
974
1154
1914
3834
5744
Intermediate
Term
< 30 days
10671
894
1064
1764
3524
5284
Intermediate
Term
> 30 days
782 '
654
784
1294
2584
3874
Necessary
level of
PPE or
Engineering
Controls
Baseline
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmrata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
38
-------
Exposure Scenario
Crop Type or
Target
cotton
forestry
blueberries
blueberries
potatoes,
alfalfa, cotton
alfalfa
Acres
Treated or
Gallons per
Application
1200
1200
350
350
350
350
Application
Rate
(Ibs ai/A)
0.4
1
0.47
0.94
1.02
0.78
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
4184
1674
12214
6114
5634
7364
Intermediate
Term
< 30 days
3854
1544
11244
5624
5184
6774
Intermediate
Term
> 30 days
2824
1134
8244
4124
3804
4974
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmiata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
39
-------
Exposure Scenario
Crop Type or
Target
alfalfa
alfalfa
cotton
cotton
pine seed
orchards
pine seed
orchards
Acres
Treated or
Gallons per
Application
1200
1200
350
1200
150
300
Application
Rate
(Ibs ai/A)
0.78
1.02
0.23
0.23
1
1
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
2154
1644
24964
7284
13394
6704
Intermediate
Term
< 30 days
1984
1514
22964
6704
12324
6164
Intermediate
Term
> 30 days
1454
1114
16844
4914
9044
4524
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnstfaiMiesjmiltawiiliimpasteEtlram&Etteardf 55. (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
40
-------
Exposure Scenario
(6) applying using a high-pressure
handwand
(7) applying using a right-of-way
sprayer
(8) dipping pine seedlings
Crop Type or
Target
cotton
livestock
livestock
ornamentals
ornamentals
pine seedlings
Acres
Treated or
Gallons per
Application
1200
1000
1000
400
400
100
Application
Rate
(Ibs ai/A)
1.02
0.004
0.02
0.008
0.008
0.35
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
1644
1271
1272 +
double
layer
1701
2671
no data
Intermediate
Term
< 30 days
1514
1011
1 01 2 + double
layer
1351
261 '
no data
Intermediate
Term
> 30 days
1114
1351 + gloves
883
188'+ gloves
1921
no data
Occupational Mixer/Loader/Applicator Estimates
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Maximum
Maximum
Maximum
Baseline
Maximum
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of clieinical-resistanl gloves and a dnstfaiMiesjiiailtawiiliimpasteEtlram&EttearrfS. (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
41
-------
Exposure Scenario
(9) mixing/loading/applying with a
power duster
(10) dusting on animal
(11) dipping a dog
(12) useofa cattle backrubber
( 1 3a) mixing/loading/applying liquids
with a backpack sprayer
Crop Type or
Target
sweet potatoes
dog
dog
dog
cattle
livestock
livestock
ornamentals
Acres
Treated or
Gallons per
Application
no data
8 animals
8 animals
8 animals
50 animals
100 animals
100 animals
40
Application
Rate
(Ibs ai/A)
0.0131b/ai/
bushel
0.003
0.066
0.0076
0.02
0.004
0.02
0.008
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
no data
468,750'
19,886'
172,697'
362'
26,250'
5250'
35,000'
Intermediate
Term
< 30 days
no data
468,750'
19,886'
172,697'
361'
8750'
1750'
11,667'
Intermediate
Term
> 30 days
no data
343,750'
14,583'
126,645'
264'
6417'
1283'
8556'
Necessary
level of
PPE or
Engineering
Controls
Maximum
Use
Canceled
Use
Canceled
Use
Canceled
Baseline
Baseline
Baseline
Baseline
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmiata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
42
-------
Exposure Scenario
(13b) mixing/loading/applying wettable
powders with a backpack sprayer
(14a) mixing/loading/applying liquids
with a low pressure handwand
(14b) mixing/loading/applying wettable
powders with a low pressure
handwand
(15) mixing/loading/applying soluble
concentrates for sprinkling
Crop Type or
Target
ornamentals
livestock
livestock
ornamentals
ornamentals
fire ants
Acres
Treated or
Gallons per
Application
40
100
100
40
40
24
Application
Rate
(Ibs ai/A)
0.008
0.004
0.02
0.008
0.008
0.009
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
35,000'
49531
9911
6604 '
2851
1581
Intermediate
Term
< 30 days
11,667'
35961
7191
4795 '
1791
1581
Intermediate
Term
> 30 days
85561
26371
5271
35161
1311
1151
Necessary
level of
PPE or
Engineering
Controls
Baseline
Baseline +
Gloves
Baseline +
Gloves
Baseline +
Gloves
Baseline +
Gloves
Baseline
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnsfeMiesjmrata (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
43
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Exposure Scenario
Crop Type or
Target
Acres
Treated or
Gallons per
Application
Application
Rate
(Ibs ai/A)
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
Intermediate
Term
< 30 days
Intermediate
Term
> 30 days
Occupational Flagger Estimates
(16) flagging for aerial spray
application.
various nut
trees
pears
fruit & nut
trees
grapes, fruit
trees &
vegetables
grapes &
fruit trees
cotton
forestry
350
350
350
350
350
1200
1200
5.95
5
3
1.5
1
0.4
1
20724
24664
41104
1641
2471
ISO1
35964
17394
20694
34484
1381
2071
1511
30174
12754
15174
25294
1011
1521
1111
22134
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
44
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Exposure Scenario
Crop Type or
Target
blueberries
blueberries
potatoes
alfalfa
alfalfa
alfalfa
Acres
Treated or
Gallons per
Application
350
350
350
350
1200
350
Application
Rate
(Ibs ai/A)
0.47
0.94
1.02
0.78
0.78
1.02
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
5251
2621
2421
3161
46104
2421
Intermediate
Term
< 30 days
440 '
2201
203 '
265 '
38684
203 '
Intermediate
Term
> 30 days
323 '
1611
1491
1951
28374
1491
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnstfaiMiesjmiltawiiliimpasteEtlram&Etteardf 55. (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
45
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Exposure Scenario
Crop Type or
Target
alfalfa
cotton
cotton
cotton
cotton
Acres
Treated or
Gallons per
Application
1200
350
1200
350
1200
Application
Rate
(Ibs ai/A)
1.02
0.23
0.23
1.02
1.02
Combined MOEs (dermal and inhalation)
Short
Term
< 7 days
35254
10721
3131
2421
35254
Intermediate
Term
< 30 days
29584
9001
2621
203 '
29584
Intermediate
Term
> 30 days
21694
6601
1921
1491
21694
Necessary
level of
PPE or
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
Engineering
Controls
1 Baseline PPE which represents typical work clothing with no respiratory protection. No chemical-resistant gloves are included in this scenario.
2 Minimum PPE which represents the baseline scenario with the use of chcmical-rcsistonl gloves and a dnstfaiMiesjmiltawiiliimpasteEtlram&Etteardf 55. (dust-mist respirator).
3 Maximum PPE which represents the baseline scenario with the use of an additional layer of clothing, chemical-resistant gloves, and an air purifying respirator with a protection
factor of 10.(OV respirator).
4 Engineering controls which represent the use of an appropriate engineering control such as a closed tractor cab or closed loading system for granulars or liquids. Engineering
controls are not applicable to handheld application methods.
46
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2) Post-Application Occupational Risk
The post-application occupational risk assessment considered exposures to workers entering
treated sites in agriculture. All of the post-application risk calculations for handlers completed in this
assessment are included in the HED chapter and the August 15, 2000 update entitled "Phosmet: Revised
Occupational Post-Application Exposure and Risk Calculations (DP Barcode D268141, Chemical Code
059201, case 818976)", which takes into account the most recent revisions of the policy on agricultural
transfer coefficients; the revisions to the post-application exposure and risk calculations, dated August 20,
2001; and information recently collected by the Gowan Company with regard to post-application
exposures.
Based on the phosmet use pattern, there is potential for both short-and intermediate-term (< 30
days) post-application exposure to phosmet residues for workers. Only dermal exposures were
considered in the post-application assessment, since the physical properties of phosmet suggest post-
application inhalation exposures would be minimal.
Agricultural post-application scenarios assessed for phosmet consist of adults harvesting and
maintaining fruit trees, grapes, and field and vegetable crops. The MOEs were calculated using chemical
specific data for pears and grapes. All of the chemical-specific data generated for post-application
exposure and risk assessment included residues of phosmet and the oxygen analog metabolite, which were
assumed to be equivalent in terms of toxicity. The results of the revised post-application assessment are
summarized in Tables 7 through 13, this assessment reflects the updated transfer coefficients as established
in the//ED Science Policy for Exposure 3.1: Agricultural Transfer Coefficients, dated August 7,
2000. These calculations indicate a concern for workers reentering treated fields following the 24-hour
REI on current labels for some scenarios.
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Occupational Reentry Risk Estimates for Phosmet
Low Berry Transfer Coefficient Group:
Table 7: Post-application Risks For Phosmet On Low Bush Blueberries and Cranberries
Days After
Treatment
(DAT)
Dislodgeable
Foliar Residue
Source
Pre-Harvest
Interval on
Current Label
(days)
MOEs( 100 target)
Low Exposure Activities:
scouting, hand weeding,
irrigation (early season, low
foliage), hand pruning (early
season, low foliage), and
thinning (early
season, low foliage)
High Exposure Activities:
hand pruning (late season,
full foliage) and hand
harvesting.
Low Bush Blueberries and Cranberries
0
10
Grape data at 1
Ib ai/acre, not
adjusted for
application rate
Blueberries - 3
Cranberries - 14
193
52 (blueberries only)
102 (blueberries only)
Cranberries
0
11
Grape data at 1
Ib ai/acre,
adjusted for
application rate
of 4 Ib ai/acre
Cranberries - 14
48
102
Not Applicable
Not Applicable
48
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Field/Row Crop Transfer Coefficient Group (low/medium height):
Table 8: Post-ap
Days After
Treatment
(DAT)
0
10
18
plication Risks For Phosmet on Alfalfa, Cotton and Peas
Dislodgeable Foliar
Residue
Source
Grape data at 1 Ib
ai/acre, not
adjusted for
application rate
Pre-Harvest
Interval on
Current Label
(days)
Alfalfa 7-14
Cotton -21
Peas - 7
MOEs( 100 target)
Low Exposure
Activities:
irrigation and
scouting of
immature plants
772
Medium
Exposure
Activities:
irrigation and
scouting of
mature plants
52
102
High Exposure
Activities:
hand harvesting
31
61
105
49
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Deciduous Tree Fruit Transfer Coefficient Group:
Table 9: Post-application Risks For Phosmet On Deciduous Tree Fruit Transfer Coefficient Group
Crop
Pears
West Coast
Apples
Apricots,
nectarines,
peaches,
plums/prunes
East Coast
Apples
Days
After
Treatment
(DAT)
0
21
37
52
0
17
34
49
0
13
30
45
0
3
19
34
Dislodgeable
Foliar
Residue
Source
Pear data at
5 Ib ai/acre,
not adjusted
for
application
rate
Pear data at
5 Ib ai/acre,
adjusted for
application
rate of 4 Ib
ai/acre
Pear data at
5 Ib ai/acre,
adjusted for
application
rate of 3 Ib
ai/acre
Pear data at
5 Ib ai/acre,
adjusted for
application
rate of 1.5 Ib
ai/acre
Pre-Harvest
Interval on
Current Label
(days)
7
7
Apricots - 14
Nectarines -
14
Peaches - 14
Plums - 7
Prunes - 7
7
MOEs (100 target)
Very Low
Exposure
Activities:
propping
260
325
434
868
Low
Exposure
Activities:
irrigation &
scouting
26
105
33
100
43
103
87
106
High
Exposure
Activities:
hand
harvesting
9
101
11
103
15
105
29
102
Very High
Exposure
Activities:
hand
thinning
3
102
4
104
5
107
11
103
50
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Evergreen Tree Transfer Coefficient Group:
Table 10: Post-application Risks For Phosmet On Christmas Trees
Days After
Treatment
(DAT)
0
13
28
Dislodgeable
Foliar Residue
Source
Pear data at 5
Ib ai/acre,
adjusted for
application rate
of 1 Ib ai/acre
Pre-Harvest
Interval on
Current Label
(days)
Not Specified
MOEs (100 target)
Low Exposure
Activities:
Irrigation,
scouting, hand
weeding, thinning
small trees
130
Medium Exposure
Activities:
pruning, thinning,
cone pruning, cone
harvesting
43
103
High Exposure
Activities:
hand harvesting,
shaking, topping,
training
16
104
Tree Nut Transfer Coefficient Group:
Table 11: Post-application Risks For Phosmet on Tree Nut Transfer Coefficient Group
Crop
Beech nut, brazil
nut, butternut,
cashew,
chestnut,
macadamia,
walnuts
Almonds,
pistachios,
pecans
Days After
Treatment
(DAT)
0
13
37
0
3
27
Dislodgeable
Foliar Residue
Source
Pear data at 5 Ib
ai/acre, adjusted
for application
rate of 5.95 Ib
ai/acre
Pear data at 5 Ib
ai/acre, adjusted
for application
rate of 3 Ib ai/acre
Pre-Harvest
Interval on
Current Label
(days)
14
Almonds - 30
Pistachios - 14
Pecans - 14
MOEs (100 target)
Low Exposure
Activities:
irrigation and
scouting
44
104
87
106
High Exposure
Activities:
hand harvesting,
poling, pruning
9
101
17
104
51
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Root Vegetable Transfer Coefficient Group:
Table 12: Post-application Risks For Phosmet On Potatoes and Sweet Potatoes
Days After
Treatment
(DAT)
0
10
18
Dislodgeable
Foliar Residue
Source
Grape data at 1 Ib
ai/acre, not
adjusted for
application rate
Pre-Harvest
Interval on
Current
Label
(days)
Potatoes - 7
MOEs (100 target)
Low Exposure
Activities:
irrigation and scouting
of immature plants
257
Medium Exposure
Activities:
irrigation and scouting
of mature plants
52
102
High Exposure
Activities:
hand harvesting only
for sweet potatoes
31
105
Vine/trellis Transfer Coefficient Group:
Table 13: Post-application Risks For Phosmet On Highbush Blueberries, Grapes, Kiwi, and Trellised Sweet Peas
Days After
Treatment
(DAT)
0
4
28
38
Dislodgeable
Foliar Residue
Source
Grape data at
1 Ib ai/acre, not
adjusted for
application rate
Pre-Harvest
Interval on
Current Label
(days)
Blueberries 3
Grapes 7 -14
Kiwi 21
Sweet Peas 7
MOEs (100 target)
Low Exposure
Activities:
hedging,
irrigation,
scouting
blueberries,
hand weeding,
training/tying
blueberries
154
Medium
Exposure
Activities:
grape/kiwi
scouting,
training
grapes, tying
kiwi
77
101
High
Exposure
Activities:
hand
harvesting,
thinning,
pruning,
training/tying
grapes
15
104
Very High
Exposure
Activities:
grape girdling
and cane
turning
8
103
3) Residential (Homeowner) Handler Risk
For homeowner handler exposure assessments, the Agency does not believe a tiered mitigation
approach like that used for assessing occupational handler risk is appropriate. Homeowners often lack
52
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access to personal protective equipment (PPE) and also do not possess expertise in the proper use of
PPE. As a result, homeowner handler assessments are completed using a single scenario based on the use
of short-sleeved shirts and short pants (i.e., common homeowner attire during the pesticide application
season). In addition, only short-term exposures were assessed, as the Agency does not believe
homeowners who apply phosmet will be exposed for more than 7 days. The exposure scenarios are:
Residential (homeowner) Direct Animal Treatments:
(1) dusting a dog;
(2) dipping a dog;
Residential (homeowner) Use on Terrestrial Crops:
(3b) mixing/loading/applying wettable powders with a backpack sprayer;
(4b) mixing/loading/applying wettable powders with a low pressure handwand sprayer;
(5b) mixing/loading/applying wettable powders with a hose-end sprayer;
Residential (homeowner) Treatments on Ornamental Plants:
(3a) mixing/loading/applying liquids with a backpack sprayer;
(3b) mixing/loading/applying wettable powders with a backpack sprayer;
(4a) mixing/loading/applying liquids with a low pressure handwand sprayer;
(4b) mixing/loading/applying wettable powders with a low pressure handwand sprayer;
(5a) mixing/loading/applying liquids with a hose-end sprayer;
(5b) mixing/loading/applying wettable powders with a hose-end sprayer; and
(6) mixing/loading/applying soluble concentrates to fire ant mounds.
Combined dermal and inhalation MOEs for mixing/loading/applying phosmet to fruit trees and
ornamentals using a low pressure handwand were of concern (42 and 83, respectively). Very limited data
were available to assess exposure risks for handlers for the direct application to dogs scenario (dip/dust);
therefore, data and procedures specified in the 1997 SOPs for Residential Exposure Assessment were
used. The SOPs assume combined dermal and inhalation exposure of 10% of the amount applied. This
assessment estimated that handler risks for direct application to dogs (dip/dust) were not a concern.
53
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Table 14. Estimated Risks from Residential Uses of Phosmet
Phosmet MOEs Attributable to Combined Short-term
Homeowner Handler Dermal and Inhalation Exposures
Scenario
1
2
3a
3b
4a
4b
5a
5b
6
Scenario
Description
Dusting an Animal
Dipping a Dog
Mixing/loading/applying
Liquids With a Backpack
Sprayer
Mixing/loading/applying
Wettable Powders With a
Backpack Sprayer
Mixing/loading/applying
Liquids With a Low
Pressure Handwand
Mixing/loading/applying
Wettable Powders With a
Low Pressure Handwand
Mixing/loading/applying
Liquids With a Garden
Hose-End Sprayer
Mixing/loading/applying
Wettable Powders With a
Garden Hose-End Sprayer
Mixing/loading/applying
Soluble Concentrates For
Sprinkling
Assumptions
Used in
Assessment
1 dog/day
1 dog/day
1 dog/day
5 gallons
5 gallons
150ft2
250 ft2
10 gallons
5 gallons
5 gallons
150ft2
250 ft2
10 gallons
5 gallons
5 gallons
150ft2
250 ft2
10 gallons
20 gallons
(5 - 2 ft2 mounds at
4 gallons per mound)
Crop Type
or Target
Dog
Dog
Dog
Ornamentals
Ornamentals
Peas
Potatoes
Fruit Trees
Ornamentals
Ornamentals
Peas
Potatoes
Fruit Trees
Ornamentals
Ornamentals
Peas
Potatoes
Fruit Trees
Fire Ants
Dermal
MOEs
(Target
100)
3,750,000
159,091
1,381,579
5,490
4,118
11,438
11,438
2,101
280
84
233
233
43
933
700
1,944
1,944
357
389
Inhalation
MOEs
(Target
100)
No Data
No Data
No Data
280,000
210,000
583,333
583,333
107,143
280,000
5,727
15,909
15,909
2,922
884,211
663,158
1,842,105
1,842,105
338,346
368,421
Combined
MOEs
(Target
100)
No Data
No Data
No Data
5,385
4,038
11,218
11,218
2,060
280
83
230
230
42
932
699
1,942
1,942
357
388
4) Residential Post-Application Risk
Phosmet can be used on residential fruit and nut trees, home gardens, ornamental plants, and dogs
where exposure to adults and children may occur. Exposure may result from entering the treated garden;
54
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maintaining fruit or nut trees; harvesting fruits, nuts or vegetables; or petting treated dogs. As a result, both
toddler and adult risks were considered in the risk assessment.
Residential post-application scenarios assessed for phosmet consist of adults and children (aged
10-12) harvesting and maintaining pears and apples at maximum application rates, and toddlers after
dermal contact with treated dogs, including incidental hand-to-mouth transfer. There are concerns for
continuous post-application exposure to adults and youth in residential settings over an extended period of
time (greater than 30 days); however, there is little information to determine if such extended exposures
actually occur. There are also concerns for short-term post-application exposure to adults and youths
harvesting and maintaining fruit trees. In addition, there are significant risk concerns for toddlers exposed
to phosmet residues following contact with treated dogs, regardless of the duration of exposure.
For short- and intermediate-term (less than 30 days) exposures to adults and youths harvesting
and maintaining apples and pears in home gardens, the MOEs were less than 100 on the day of phosmet
application, with the exception of apples treated at 1.5 Ib a.i./A. An MOE greater than 100 was achieved
4-8 days after application for adults and 3-6 days after application for youths. For this residential post-
application scenario, the Agency assumes that home gardening activities would take place for 0.67 hours
per day. The Agency does not have enough information to determine if intermediate-term (more than 30
days) exposures to phosmet occur in home gardens. However, empirical dissipation data suggest that
phosmet residues persist, and that it may be possible for individuals to be exposed over an extended
period of time.
The Agency has concerns for short- and immediate-term (less than 30 days) post-application risk
for toddlers exposed to phosmet through dermal contact with treated dogs, as well as through non-dietary
ingestion of residues associated with hand-to-mouth behaviors. For this assessment, the Agency has
assumed that toddlers would engage in hand-to-mouth activity for 2 hours per day. The Day 0 MOEs
calculated for petting small and large dogs ranged from <1 to 8, with the target MOE being 100. An
MOE of more than 100 was not achieved even after 30 days, when re-treatment could occur. For toddler
mouthing behaviors, as well as for combined exposure to dogs (i.e., dermal + hand-to-mouth exposures),
Day 0 MOEs were 1 or less than one after contact with small and large dogs, and did not go above 100
after 30 days. Intermediate-term (more than 30 days) aggregate (i.e., dermal + hand-to-mouth) MOEs
calculated for toddlers following contact with treated dogs were <1.
4. Aggregate Risk
An aggregate risk assessment looks at the combined risk from dietary exposure (food and drinking
water routes) and residential exposure (dermal exposure, inhalation exposure for homeowner applicators,
and incidental oral exposure for toddlers who pet treated dogs and engage in hand-to-mouth activities).
55
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The aggregate dietary (food and water) risks are not of concern. Generally, all risks from these exposures
must have MOEs of greater than 100 to be not of concern to the Agency.
Results of the aggregate risk assessment are summarized here, and are discussed extensively in the
HED chapter, dated February 9, 2000. Aggregate risks including food, water, and residential exposure
were not of concern except for the following residential scenarios: toddler contact with treated dogs;
harvesting from home gardens treated at higher application rates; and homeowners applying wettable
powder to ornamentals and fruit trees using low-pressure handwand sprayers.
5. Incident Data Review
Incidents involving exposure to phosmet are reported in the four sources reviewed; OPP's
Incident Data System (IDS), Poison Control Centers (PCC), California Department of Pesticide
Regulation (CDPR), and the National Pesticides Telecommunications Network (NPTN). In addition, the
EPA has reviewed several literature studies, two of which describe an exposure incident in detail, and one
which consists of a telephone survey of animal groomers/veterinary workers to determine the type of
products used, PPE used, and incidents associated with exposure to flea control products.
The Agency is concerned about exposures associated with treatment of dogs because the majority
of the serious cases reported in the incident data involved systemic illnesses to pet owners,
groomers and veterinary assistants.
EPA's comparative analysis of incident data shows that residential exposures to phosmet were
more likely to result in treatment in a health care facility than other organophosphate insecticides;
phosmet ranked third for hospitalizations, and first for admission to intensive care units.
In 1996 several mitigation measures were implemented in an attempt to reduce the number of
incidents to homeowners, veterinary workers and pets, associated with the use of phosmet. Specifically,
product labels were amended to discourage application to certain dog breeds, and to smaller dogs and
specifically exclude use on cats.
B. Environmental Risk Assessment
A summary of the Agency's environmental risk assessment is presented below. For detailed
discussions of all aspects of the environmental risk assessment, see the Environmental Fate and Effects
Division chapter, dated April 24, 1998, available in the public docket.
To estimate potential ecological risk, EPA integrates the results of exposure and ecotoxicity using
the quotient method. Risk quotients (RQs) are calculated by dividing exposure estimates by ecotoxicity
56
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values, both acute and chronic, for various species. Risk characterization provides further information on
the likelihood of adverse effects occurring by considering the fate of the chemical in the environment,
communities and species potentially at risk, their spatial and temporal distributions, and the nature of the
effects observed in studies. The higher the RQ the greater the concern. Reported incidents to nontarget
organisms, such as fish and birds, involving the use of a pesticide can provide meaningful information to
confirm the results of risk assessments and to help characterize ecological risks.
1. Environmental Fate and Transport
Phosmet is stable to soil photolysis and appears to be stable to aqueous photolysis. Phosmet is
subject to rapid hydrolysis under alkaline and neutral conditions and to a much lesser extent, under acidic
conditions. Microbial degradation is a major route of dissipation. In soils where microbial activity is
minimal, leaching may be a significant route of dissipation for this chemical. Phosmet degrades rapidly
under aerobic conditions in soil (3 days) and more slowly under anaerobic conditions (15 days). Phosmet
was not detected below the 10.5-inch soil layer in any of three field dissipation studies and dissipated to,
or below, the level of detection prior to the study's completion.
Phosmet oxon is the only known degradate of lexicological concern identified in a number of
environmental fate studies conducted. Studies have indicated that phosmet oxon is less mobile than
phosmet because it was not detected in the leachate in aged and unaged mobility studies. In addition,
phosmet oxon was limited to the upper soil layer in field studies while phosmet was detected as low as the
10.5-inch soil layer.
Based on laboratory studies and field studies, phosmet and phosmet oxon might appear to pose a
threat to groundwater resources. However, the short time-frame in which these chemicals degrade,
reduces the migration in most microbially active soils and it does not appear that phosmet or phosmet oxon
will pose a significant threat to ground water resources. Phosmet and possibly phosmet oxon, may
contaminate surface waters in the dissolved phase, mainly as a result of runoff-producing storm events
shortly after field applications. Surface and ground water monitoring data were very limited for phosmet
and were not used in the risk assessment.
2. Risk to Birds and Mammals
Phosmet was found to be moderately to practically non-toxic to avian species (acute). However,
the application rates and number of applications for various crops have produced acute RQ values that are
in the 0.3 to 2.9 range. Use on most crops appears to pose a chronic risk to birds with RQ values that
range from 0.3 (for alfalfa seed) to 19.9 (for apples at high rates in short grass).
For mammals, the acute levels of concern are exceeded mainly on short grass for smaller animals.
The highest acute RQs are for pears (RQ = 10) and walnuts (RQ = 12). The application rates and
57
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frequency of applications result in high chronic risk concerns for all crops (RQs for short grass, the worst
scenario, range from 13 - 73).
3. Risk to Aquatic Species
Acute and chronic risk to both freshwater and estuarine/marine fish is relatively low. The highest
RQ is 3.4, for chronic risk to estuarine/marine fish, using the eastern apple high application rates.
The RQs for acute risk to both freshwater and estuarine/marine invertebrates range from 0.2 for
apples (low western rate) to 13.4 for apples (high eastern rate), excluding the two highest values. The two
highest RQ values are 68.7 and 70 for acute risk to freshwater invertebrates for application to kiwifruit
and pears, respectively. It should be noted that use on kiwifruit is extremely low (54 Ibs/year)
All crops, which have the potential to expose marine environments, appear to be a chronic
concern for marine invertebrates (except alfalfa and cherries) with RQs ranging from 0.39 to 10.5.
Chronic risk to freshwater invertebrates appears to be of concern for the following crops: apples, grapes,
kiwifruit, peaches, pears, pecans and sweet potatoes.
4. Risk to Honey Bees
Phosmet is highly toxic to honey bees. Incidents of toxicity to honey bees have been reported.
IV. Interim Risk Management and Reregistration Decision for 17 Uses
A. Determination of Interim Reregistration Eligibility
Section 4(g)(2)(A) of FIFRA calls for the Agency to determine, after submissions of relevant data
concerning an active ingredient, whether products containing the active ingredient are eligible for
reregistration. The Agency has previously identified and required the submission of the generic (i.e., active
ingredient specific) data required to support reregistration of products containing phosmet as an active
ingredient.
The Agency has completed its assessment of the occupational and ecological risks associated with
the use of pesticides containing the active ingredient phosmet, as well as a phosmet-specific dietary (food
+ water) risk assessment that has not considered the cumulative effects of organophosphates as a class.
Based on a review of these data and public comments on the Agency's assessments for the active
ingredient phosmet, EPA has sufficient information on the human health and ecological effects of phosmet
to make a partial interim decision on 17 uses as part of the tolerance reassessment process under FFDCA
and reregistration under FIFRA, as amended by FQPA.
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Although the Agency has not yet completed its cumulative risk assessment for the
organophosphates, the Agency is issuing this partial interim decision now in order to identify risk reduction
measures that are necessary to support the continued use of phosmet for 17 uses discussed in Table 15.
Because this is a partial interim RED, the Agency will take further actions to finalize the
reregistration eligibility decision for the remaining 28 phosmet uses after completing its risk/benefit
deliberations.
Because the Agency has not yet completed the cumulative risk assessment for the
organophosphates, this reregistration eligibility decision does not fully satisfy the reassessment of the
existing phosmet food residue tolerances as called for by the Food Quality Protection Act (FQPA). When
the Agency has completed the cumulative assessment, phosmet tolerances will be reassessed in that light.
At that time, the Agency will reassess phosmet along with the other organophosphate pesticides to
complete the FQPA requirements and make a final reregistration eligibility determination. By publishing
this partial interim decision on reregistration eligibility and requesting mitigation measures now for the 17
uses identified in this partial IRED, the Agency is not deferring or postponing FQPA requirements; rather,
EPA is taking steps to assure that uses which exceed FIFRA's unreasonable risk standard do not remain
on the label indefinitely, pending completion of assessment required under the FQPA. This decision does
not preclude the Agency from making further FQPA determinations and tolerance-related rulemakings that
may be required on this pesticide or any other in the future.
If the Agency determines, before fmalization of the RED, that any of the determinations described
in this partial interim RED are no longer appropriate, the Agency will pursue appropriate action, including
but not limited to, reconsideration of any portion of this partial interim RED.
B. Summary of Phase 5 Comments and Responses
When making its partial interim reregistration decision, the Agency took into account all comments
received during Phase 5 of the OP Pilot Process. These comments in their entirety are available in the
docket. A brief summary of the comments and the Agency response is noted here.
Fifty two comments were received during the public comment period. Of these, comments
specific to phosmet were received from the registrants (Gowan Company and Wellmark International
Corporation), and the remaining fifty comments were from various organizations and private citizens.
Many of these comments were testimonials to the effectiveness of phosmet. Commentors emphasized that
phosmet is an important tool for integrated pest management, and that without it, resistance would develop
quickly because of limited effective alternatives. Many commentors indicated that phosmet is not harmful
to beneficial insects. In addition, the Natural Resources Defense Council submitted comments that were
specific to phosmet, but also included comments on other OPs and any pesticide used on food.
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Specifically, comments were received from the USA Dry Pea and Lentil Council; several sweet
potato farmers, sweet potato industry representatives and academia; the Wild Blueberry Commission of
Maine; a cherry farmer, Oregon Cherry Growers Association, the Cherry Marketing Institute; and Oregon
State University Hermiston Agricultural Research and Extension Center.
C. Regulatory Position
EPA has determined that the continued use of phosmet on the uses discussed below is warranted under
the conditions specified in this document. Dietary (food and drinking water) risks are not of concern.
Residential risks have been addressed by voluntary cancellation of phosmet uses in the home. Further, the
Agency finds that the risks posed to workers and the environment by the uses addressed in this document
are acceptable taking into account mitigation measures and the benefits of phosmet use. In arriving at
these decisions, EPA has considered all relevant risk mitigation options. In addition to personal protective
equipment and engineering controls for workers, EPA has considered reductions in the rate and frequency
of applications and precautionary labeling.
According to EPA's worker risk management policy (PR Notice 2000- 9), when calculated MOEs
are below the target MOE after all baseline mitigation has been considered, in this case 100, EPA will
characterize uncertainties in the risk assessment, assess the potential of additional data to reduce the
uncertainty, and consider benefits, i.e., the cost, availability and relative risk of alternatives in making its
regulatory decisions. These factors are addressed below and deal primarily with risks related to re-entry
workers, since some MOEs for re-entry tasks are less than 100.
Uncertainty in the Occupational Risk Assessment
In the case of phosmet, the uncertainty associated with its toxicity is low. For example, the endpoint
used for the reentry worker assessment is cholinesterase inhibition in both blood and brain. The 21-day
dermal rat study that was used for this assessment is appropriate both in terms of route and duration of
likely exposures. There is less than a 2-fold difference between the LOAEL (22.5 mg/kg/day) and the
NOAEL (15 mg/kg/day). Additional toxicity data are not likely to impact the hazard assessment.
On the exposure side, EPA's assessment reflects the most recently updated transfer coefficients based
on the Agricultural Reentry Task Force data and dislodgeable foliar residue (DFR) data from a phosmet-
specific study. Additional DFR data are not likely to impact the exposure assessment. However, there are
some protective assumptions built into the post-application exposure assessment for phosmet. For
example, EPA assumes that no protective clothing is worn, that workers are exposed for up to 30 days,
and that every field a worker enters has been treated with phosmet at the same maximum rate. User
survey information provided by the registrant and others indicates that the actual frequency and duration of
the post application activities of concern for the uses discussed below may be more intermittent, i.e.,
generally less than standard assumptions, and that maximum application rates are not always used.
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Benefits
Table 15 contains a brief summary of benefits information for each site and proposed decision. The
complete benefits assessments are available in the OPP public docket and on the Internet. In general,
EPA's assessments have found little or no impact on crop production from the measures proposed in this
document. However, USD A, the registrant and others have voiced the concern that extending the REI for
some uses could have the effect of growers shifting to more hazardous alternatives. Stakeholders are
urged to provide EPA with factual information related to potential shifts in use and the impacts of these
shifts, e.g., increased cost, increased pesticide use, environmental impacts, etc., as well as any appropriate
documentation.
EPA is providing a 60-day public comment period on the risk management decisions contained in this
Partial IRED. Any comments on the benefits assessments supporting these decisions and future phosmet
decisions should be provided to the Agency as soon as possible to ensure their consideration.
1. Tolerance Summary
The Agency will commence proceedings to revoke the five existing tolerances for phosmet use on citrus
and corn and related animal feed at a future date, after the IRED is issued. The corn and citrus uses are
not on any current product labels. The establishment of new tolerances or raising existing tolerances will
be deferred, pending consideration of the cumulative assessment.
2. Human Health Risk Mitigation
a. Dietary (food and water) Risk Mitigation
Taking into account all currently registered uses of phosmet, dietary (food and water) risks are not of
concern. No risk mitigation is necessary. However, additional studies will be required to reassess the
tolerance for residues in sweet potatoes following post harvest application of the dust formulation.
b. Residential Risk Mitigation
The registrant has agreed to voluntarily cancel all products used in the home gardens, all products used
on dogs, and prohibit use of fire ant treatment products in a residential setting except for fire ant mound
drenches for public health purposes by licensed applicators.
c. Occupational Risk Mitigation
The risks associated with the dipping of pine seedlings and post harvest application to sweet potatoes
have not been quantified, but the registrants have agreed that it is prudent to require handlers to wear a
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long-sleeved shirt and long pants, shoes, an additional layer of clothing, socks, chemical-resistant gloves,
and an air purifying (OV) respirator to mitigate risks.
To reduce risks to workers harvesting potatoes and sweet potatoes, the registrant agreed to require
that phosmet is only to be used on potatoes that will be harvested by machine.
The registrant has agreed to limit use of liquid products to the following crops: alfalfa, cotton,
blueberries, and potatoes.
EPA has determined that worker risks from exposure to phosmet in the scenarios listed below would
be adequately mitigated through use of the following PPE: long-sleeved shirt and long pants, shoes and
socks.
Applying sprays with a groundboom sprayer;
Applying using a right-of-way sprayer;
Use of a cattle backrubber
Mixing/loading/applying liquids with a backpack sprayer;
Mixing/loading/applying wettable powders with a backpack sprayer;
Mixing/loading/applying soluble concentrates for sprinkling.
EPA has determined that worker risks from exposure to phosmet in the scenarios listed below would
be adequately mitigated through use of the following PPE: long-sleeved shirt and long pants, shoes, socks
and chemical-resistant gloves.
Mixing/loading liquid formulations for high pressure handwand application;
Mixing/loading liquid formulations for airblast sprayer application;
Mixing/loading liquid formulations for groundboom application;
Mixing/loading/applying wettable powders with a low pressure handwand; and
Mixing/loading/applying liquids with a low pressure handwand.
EPA has determined that worker risks from exposure to phosmet in the scenarios listed below would
be adequately mitigated through use of the following PPE: long-sleeved shirt and long pants, shoes,
additional layer of clothing, socks, chemical-resistant gloves, and an air purifying respirator (OV) to
mitigate risks from exposure to phosmet.
Applying using a high-pressure handwand;
Dipping pine seedlings;
Mixing/loading wettable powders for high pressure handwand application; and
Mixing/loading/applying a dust formulation.
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EPA has determined that worker risks from exposure to phosmet in the scenarios listed below would
be adequately mitigated through use of engineering controls such as a closed tractor cab or closed loading
system for granulars or liquids.
Mixing/loading wettable powders for aerial application and chemigation;
Mixing/loading wettable powders for groundboom application;
Mixing/loading wettable powders for airblast sprayer application;
Mixing/loading liquids for aerial application;
Applying sprays with an airblast sprayer;
Aerial application of sprays with a fixed wing aircraft (fixed wing aircraft also accounts for helicopter
pilot exposure); and
Flagging for aerial spray application.
The only mixer/loader/applicator scenarios that remain of concern after the standard mitigation of PPE
and engineering controls are considered include:
mixing/loading liquid formulations for aerial application; and
mixing/loading wettable powder formulations for aerial application and chemigation.
These uses are discussed in the table below with the relevant crops.
In considering worker risks and benefits, the Agency considered the timing of field activities that are
critical to crop production. For many of the phosmet uses discussed below, scouting and irrigation are
critical activities in crop production, and these activities routinely need to be performed no later than three
days after application. In evaluating the restricted entry intervals, the Agency considered the exceptions to
the Worker Protection Standard that could inform the decision. EPA's proposed REIs take into account
the flexibility already provided by these exceptions. Scouting is a handler activity under the WPS, so
anyone performing this activity may legally enter the treated field during the REI provided they use the
handler personal protective equipment (PPE) specified on the label. In addition, if the scout is a certified
crop advisor as defined in the WPS (40CFR170.112(e)), the individual can determine the appropriate
PPE to be used. For many of these crops, irrigation equipment is not routinely moved by hand. For these
methods, the primary activity involves entering the field to turn the watering equipment on and off. This
activity is allowed during the REI under the no contact exception to WPS (40CFR170.112(b)). This
exception applies to mechanical harvesting and often applies to mowing. Should irrigation equipment need
unexpected repairs during the REI, WPS allows workers to enter a treated field provided early entry PPE
isused(40CFR170.112(c)).
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Table 15. Occupational Risk Mitigation and Rationale
The following is a summary of the rationale for managing risks associated with 17 uses of phosmet.
Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Kiwifiuit
21
High exposure activities (hand
harvesting):
MOE = 17 at current REI of 24 hours
MOE 100 @ 28 days
MOE 65 @ 21 days
Medium exposure activities (scouting
and tying kiwifruit):
MOE = 83 at current REI of 24 hours
MOE 100 @4 days
Because the boxelder bug is
an early season pest, a 28-day
pre-harvest interval (PHI) is
not expected to have an
impact on kiwifruit
production.
28-day PHI (high exposure:
harvesting), MOE >100)
7-day REI (medium, exposure:
scouting and tying,
MOE > 100)
Rationale:
For Kiwifruit, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for wettable
powder formulations and closed mixing/loading systems for liquid formulations.
The boxelder bug sporadically appears in kiwifruit (CA), and no alternative controls exist. This pest can cause bud and fruit drop and
malformation to the fruit, resulting in yield and quality losses. Because of the low volume of use, benefits are generally considered to be
low; however, for one sporadic but serious pest, there is no similarly efficacious alternative.
With a 28-day pre-harvest interval, risks from harvesting are not of concern. With a 7-day REI for the remaining activities, risks from
postapplication exposures are not of concern.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Peas (Green)
7
High exposure activities (hand
harvesting):
MOE = 33 at current REI of 24 hours
MOE 100@ 18 days
Medium exposure activities (irrigation
and scouting of mature plants):
MOE = 55 at current REI of 24 hours
MOE = 100 @ 10 days
Little phosmet use is reported
on this crop. Extending the
PHI to 18 days is expected to
have little impact on
harvesting of green peas.
Increasing the REI to 5 days
for all activities other than
hand harvesting is expected to
have little impact on the crop.
18dayPffl(MOE>100)
5-day REI (MOE = 72 for
irrigation, scouting, all other
worker activities >100)
Rationale:
For green peas, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for wettable
powder formulations and closed mixing/loading systems for liquid formulations. With a 18-day PHI and a 5-day REI, risks from
postapplication exposures are not of concern.
Stakeholder comments have suggested that scouts have minimal contact with treated foliage because of use of all terrain vehicles during
scouting activities. However, the Agency has received a study conducted in conjunction with the Agricultural Re-entry Task Force
(ARTF) that indicates that there is exposure to scouts performing those activities. Therefore, scouting and irrigating mature plants is
considered a "medium" exposure activity in the risk mitigation.
Under the Worker Protection Standard, scouting is a handler activity which means that scouting can be performed during the REI
provided the appropriate handler PPE is used. In addition, certified crop advisors can determine the appropriate level of PPE used during
the REI. Irrigation is often fixed in place, which is a no contact activity as defined by the Worker Protection Standard.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Peas (Dry)
7
High exposure activities (hand
harvesting):
MOE = 33 at current REI of 24 hours
MOE 100@ 18 days
Medium exposure activities (irrigation
and scouting of mature plants):
MOE = 55 at current REI of 24 hours
MOE = 100 @ 10 days
Use of phosmet on dry peas
(ID) has high benefits for
control of the pea weevil and
the pea leaf weevil.
Increasing the REI to 5 days is
expected to have little impact
on the crop.
5-day REI (MOE = 72 for
irrigation and scouting of
mature plants, all other worker
activities >100)
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Rationale:
For dry peas, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for wettable
powder formulations and closed mixing/loading systems for liquid formulations. With a 5-day restricted entry interval, risks from
postapplication exposures are not of concern.
Phosmet controls the pea weevil and the pea leaf weevil. Adult leaf weevils cause significant damage and economic loss by damaging
leaves, terminate buds, and ultimately destroying the plants.
Stakeholder comments have suggested that scouts have minimal contact with treated foliage because of use of all terrain vehicles during
scouting activities. However, the Agency has received a study conducted in conjunction with the Agricultural Re-entry Task Force
(ARTF) that indicates that there is exposure to scouts performing those activities. Therefore, scouting mature plants is considered a
"medium" exposure activity in the risk mitigation.
Phosmet use will be limited to dry peas that are mechanically harvested, which is a no contact activity as defined by the Worker
Protection Standard Under the Worker Protection Standard. Scouting is a handler activity which means that scouting can be performed
during the REI provided the appropriate handler PPE is used. In addition, certified crop advisors can determine the appropriate level of
PPE used during the REI. Irrigation is often fixed in place, which is a no contact activity as defined by the Worker Protection Standard.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Sweet
Potatoes
7
Medium exposure activities (irrigation
scouting of mature plants)
MOE = 55 at current REI of 24 hours
MOE 100 @ 10 days
Benefits very high - for
control of the white fringe
weevil, spotted and banded
cucumber beetle. Quarantine
use: for control of the sweet
potato weevil.
Increasing the REI to 5 days is
expected to have little impact
on the crop.
5-day REI (medium, exposure:
irrigation and scouting of
mature plants,
MOE = 72)
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Rationale:
For sweet potatoes, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for wettable
powder formulations and closed mixing/loading systems for liquid formulations.
Because sweet potatoes are mechanically harvested, the estimated risk for hand harvesting is not considered for setting the REI; therefore,
exposures to individuals performing scouting tasks on mature plants have calculated MOEs <100. However, EPA believes a 5-day REI
is acceptable with an MOE of 72 because of the low volume of phosmet use and scouting activities occur intermittently.
Phosmet is essential in controlling the sweet potato weevil, white fringe weevil, banded and spotted cucumber beetle.
exposures have MOEs over 100 and thus are not of concern.
All other worker
Phosmet is also used post-harvest on stored sweet potatoes for controlling the sweet potato weevil, a quarantine pest. The risks
associated with the post-harvest application to sweet potatoes have not been quantified, but the registrants have agreed that it is prudent to
require handlers to wear long-sleeved shirt and long pants, shoes, additional layer of clothing, socks, chemical-resistant gloves, and an air
purifying (OV) respirator to mitigate applicator risks associated with the use of the 5% dust product.
All sweet potatoes are mechanically harvested, which is a no contact activity as defined by the Worker Protection Standard Under the
Worker Protection Standard, scouting is a handler activity which means that scouting can be performed during the REI provided the
appropriate handler PPE is used. In addition, certified crop advisors can determine the appropriate level of PPE used during the REI.
Little irrigation is needed for sweet potatoes.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Alfalfa
7-14
MIL Aerial MOE=67-97 @ 1 Ibs.
Medium exposure activities (irrigation
and scouting of mature plants)
MOE = 55 at current REI of 24 hours
MOE 100 @ 10 days
Usage of phosmet on this field
crop is extremely low.
Increasing the REI to 5 days is
expected to have little impact
on crop production.
5-day REI (medium exposure:
scouting and irrigation of
mature plants,
MOE = 72)
For alfalfa, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for wettable powder
formulations and closed mixing/loading systems for liquid formulations. For mixing and loading for aerial application, it is unlikely that
the use of phosmet would exceed 7 days (MOE = 97) because of the low volume of phosmet used. Therefore, risks to mixers and
loaders are not of concern.
With a 5-day restricted entry interval (MOE=72), risks from postapplication exposures (scouting and irrigation of mature plants) are not
of concern because phosmet is not frequently used on alfalfa and most of the irrigation systems used are stationary thus resulting in no
worker contact with treated foliage, allowing re-entry consistent with the Worker Protection Standard. No impact on alfalfa production is
expected from extending the REI to 5 days because of the limited use and few hand activities that would occur during this period.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Blueberries
(lowbush)
High exposure activities (hand
harvesting)
MOE = 55 at current REI of 24 hours
MOE 100@ 10 days
Benefits are high to medium
high, because alternatives are
less effective than phosmet.
7-day PHI (high exposure:
hand harvesting MOE = 83)
3-day REI (MOE>100 for
remaining activities)
For lowbush blueberries, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for
wettable powder formulations and closed mixing/loading systems for liquid formulations.
Growers have indicated a need to re-enter treated fields to monitor pest infestations and replace pheromone traps, consistent with
Integrated Pest Management Programs and that the use of alternatives (malathion and carbaryl) requires more frequent treatments.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Cherries,
Sweet
7
MIL Aerial MOE = 63-92
High exposure activities (hand
harvesting):
MOE = 31 at current REI of 24 hours
MOE 100@ 19 days
Low exposure activities (irrigation and
scouting):
MOE = 93 at current REI of 24 hours
MOE 100 @ 3 days
Benefits are high to growers in
OR for Syneta beetle use.
Limited alternatives. (24(c)
registration in OR)
Increasing the PHI to 19 days
and the REI to 3 days is
expected to have little impact
on crop production.
19-day Pffl (MOE > 100)
3-day REI (remaining
activities, MOE > 100)
Aerial application (using engineering controls) only occurs when rain has softened the orchard floor to the extent that a tractor could not
pass through the orchard without damaging the orchard. Given that aerial applications are rarely performed, and when aerial applications
are performed, it is unlikely that they would occur for up to seven consecutive days, actual risk is anticipated to be lower than the
calculated short-term MOE of 92. Therefore, risks to mixers and loaders are not of concern.
Damage from syneta beetle is fruit-scarring, and causes deformed fruit. Application to control this beetle is early-season (end of bloom).
Because critical activities are not anticipated in the early season, a 19-day pre-harvest interval is not expected to have an impact on sweet
cherry production. With a 3-day REI, the risks are not of concern for all other activities. The 3-day REI is not expected to have any
impact on sweet cherry production.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Cherries, Tart
7
MIL Aerial MOE = 63-92
High exposure activities (hand
harvesting):
MOE = 31 at current REI of 24 hours
MOE 100@ 19 days
Low exposure activities (irrigation and
scouting):
MOE = 93 at current REI of 24 hours
MOE 100 @ 3 days
Benefits are high for the use of
phosmet in tart cherries. Pests
are the cherry fruit flies.
3 day REI (low exposure:
irrigation and scouting) for all
activities -no hand harvesting,
MOE > 100
Aerial application (using engineering controls) only occurs when rain has softened the orchard floor to the extent that a tractor could not
pass through the orchard without damaging the orchard. Given that aerial applications are rarely performed, and when aerial applications
are preformed, it is unlikely that it would occur for up to seven consecutive days, actual risk is anticipated to be lower than the calculated
MOE of 92. Therefore, risks to mixers and loaders are not of concern.
Pests are the cherry fruit flies. Truckloads with maggots are rejected at the distributor level. Many alternatives are less efficacious.
Exposure to workers is limited because all tart cherries are mechanically harvested. Consequently, the re-entry exposures of concern are
scouting and irrigation. With a 3-day REI, these risks are not of concern and the increased REI is not expected to have any impact on tart
cherry production.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Cotton
21
Aerial MOE MIL 67-97 @ 1 Ib a.i./A
Medium exposure activities (irrigation
and scouting of mature plants):
MOE = 55 at current REI of 24 hours
MOE 100 @ 10 days
Usage of phosmet on cotton is
extremely low. No impact on
cotton production is expected
from extending the REI to 5
days.
5-day REI (medium, exposure:
scouting and irrigation, MOE
= 72)
Only 5000 acres are treated with phosmet. There is an interest in keeping for over wintering boll weevil. For cotton, handler risks are
not of concern provided engineering controls are employed; that is, water soluble bags for wettable powder formulations and closed
mixing/loading systems for liquid formulations. For mixing and loading for aerial application, it is unlikely that the use of phosmet would
exceed 7 days (w/ MOE=97) because of the limited use. Therefore, risk to mixers and loaders are not of concern.
No field activities are critical within 5 days after application. Because of the extremely low use of phosmet, it is unlikely that a individual
would be engaged in scouting and irrigation activities in phosmet treated fields for a number of consecutive days for eight hours a day, so
the calculated MOE of 72 probably overstates the actual risk for this crop. No impact on cotton production is expected from extending
the REI to 5 days because of the limited use and few hand activities that would occur during this period.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Cranberries
14
All activities (2.8 Ibs a.i./A rate):
MOE = 74 at current REI of 24 hours
MOE 100 @ 6 days
MOE 85 @ 3 days
New use registered in 2000.
EPA has no data to determine
the importance of phosmet in
cranberries.
3-day REI (all activities,
MOE = 85)
For cranberries, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for wettable
powder formulations and closed mixing/loading systems for liquid formulations. With a 3-day restricted entry interval, risks from
postapplication exposures are not of concern. The calculated MOE of 85 is based on the maximum rate of 2.8 pounds a.i. per acre. This
is a new registration and EPA does not have use data for phosmet. Phosmet may be applied at a lower rate, which would result in lower
worker exposure (MOEs > 85). The phosmet labeled use rates range from 0.93 to 2.8 Ibs a.i. per acre.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Potatoes
7
Medium exposure activities (scouting
and irrigation of mature plants):
MOE = 55 at current REI of 24 hours
MOE 100 @ 10 days
Usage of phosmet is low. No
impact on potato production is
expected from extending the
REI to 5 days.
5-day REI (medium, exposure:
irrigation and scouting of
mature plants, MOE =72)
For potatoes, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for wettable
powder formulations and closed mixing/loading systems for liquid formulations. Because potatoes are mechanically harvested, the
estimated risk for hand harvesting is not considered for setting the REI; therefore, exposures to individuals performing scouting tasks on
mature plants have the risk of greatest concern.
The Agency has received comments indicating that scouting has limited exposure because the workers drive around the perimeter of the
field, stopping to sample for pests at 3 or 4 sites. Therefore, EPA believes that the calculated MOE of 72 at 5 days may overstate the
actual risk to scouts. In addition, comments have indicated that the warm climate would prohibit workers from wearing full PPE to enter
treated fields for scouting and irrigating purposes as provided for by the existing low contact exemption in the Worker Protection
Standard. No impact on potato production is expected from extending the REI to 5 days.
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Crop
Current
PHI
Risks of Concern
Benefits
Proposed Mitigation
Pine Seed
Orchards
NA
High exposure activities (hand
pollination, harvesting, staking,
topping, and training):
MOE = 17 at current REI of 24 hours
MOE 100 @ 28 days
Medium exposure activities (pruning,
thinning, cone pruning, and cone
harvesting):
MOE = 46 at current REI of 24 hours
MOE100@ 13 days
New use registered in 2001.
EPA has no data to determine
the importance of phosmet in
pine seed orchards.
28-day REI
For pine seed orchards, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags for
wettable powder formulations and closed mixing/loading systems for liquid formulations. These estimates are based on the value for
aerial application of 150 - 300 acres treated per day which is a reasonable high-end estimate of the number of acres treated.
With a 28-day restricted entry interval, risks from postapplication exposures are not of concern. In pine seed orchards, mowing is a no
contact activity and thus could be performed during the REI. The Agency understands that there are some critical low exposure activities
that may need to be performed during the 28-day REI. Such activities will be considered in the final decision for this use.
Ornamental
(Nursery)
NA
MOE > 100 at current REI of 24 hours
for low exposure activities
Not assessed - risks not of
concern.
Acceptable with engineering
controls
For ornamental trees in nurseries, handler risks are not of concern provided engineering controls are employed; that is, water soluble bags
for wettable powder formulations and closed mixing/loading systems for liquid formulations. Postappli cation risks are not of concern at
the current 24 hour REI.
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Crop
Fire Ant
Control
Current
PHI
NA
Risks of Concern
Mixer/loader MOEs on day of
treatment range from 115 - 158
Benefits
Public health use.
Proposed Mitigation
Retain this use on agricultural
label, limited to use by a
certified pest control operator
Voluntary Use Cancellation
Household
Ornamental
Household
Fruit Tree
Domestic Pet
NA
NA
Mixing/loading/applying wettable
powders with a low pressure
handwand: MOEs = 42 -83
Mixing/loading/applying wettable
powders with a low pressure
handwand: MOEs = 42 -83
Post application risk to children is
high.
Not assessed
Not assessed
Not assessed
Accept cancellation
Accept cancellation
Accept cancellation
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3. Environmental Risk Mitigation
To reduce ecological exposure, the Agency usually requests that registrants assess the maximum
treatments allowed on product labels by evaluating the amount of pesticide applied either per season or
per application and treatment intervals. The phosmet registrant has agreed to limit applications for the
crops in this partial IRED, as indicated in the list below and to add a precautionary statement on all labels
indicating that phosmet is highly toxic to bees.
The following are maximum use rates or intervals proposed for labels:
Cherries - 5.25 Ibs a.i. per acre per season,
Deciduous Shade and Ornamental Trees - 3 applications per season
Woody Evergreens - 3 applications per season
Pine Trees - 3 applications per season
The following statements will be added to end use product labels:
"This pesticide is toxic to fish and aquatic invertebrates. Do not apply directly to water or to
areas where surface water is present or to intertidal areas below the mean high-water mark.
Drift and runoff may be hazardous to aquatic organisms in neighboring areas. Do not
contaminate water when disposing of equipment washwater or rinsate."
"This product is highly toxic to bees exposed directly to treatment of residues on crops. Do not
apply this product or allow it to drift to blooming crops or weeds if bees are visiting the
treatment area. Protective information may be obtained from your cooperative Agricultural
Extension Service."
"This chemical can contaminate surface water through aerial and ground spray applications.
Under some conditions, it may also have a high potential for runoff into surface water after
application. These include poorly draining or wet soils with readily visible slopes toward
adjacent surface waters, frequently flooded areas, areas overlying extremely shallow ground
water, areas with in-field canals or ditches that drain to surface water, areas not separated from
adjacent surface waters with vegetated filter strips, and areas overlying tile drainage systems
that drain to surface water."
The following statements will be added to manufacturing use product labels:
"This pesticide is toxic to fish and aquatic invertebrates. Do not discharge effluent containing
this product into lakes, streams, ponds, estuaries, oceans or other waters unless the action is in
accordance with the requirements of a National Pollutant Discharge Elimination System
(NPDES) permit and the permitting authority has been notified in writing prior to the discharge.
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Do not discharge effluent containing this product to sewer systems without previously notifying
the local sewage treatment plant authority. For guidance, contact your State Water Board or
Regional Office of the EPA."
The uses addressed in this partial decision are generally low volume, i.e., on the average less than
40,000 Ibs a.i. applied annually. Because of the low volume of usage, the potential exposure to non-target
organisms is somewhat less than for the major uses of phosmet, such as orchard crops. Additional
ecological mitigation may be warranted when these larger volume uses are considered.
V. What Registrants Need to Do:
When the Agency completes the IRED for phosmet, a complete set of instructions for complying
with the necessary risk mitigation, label amendments and data call-in will be issued at that time.
VI. Related Documents and How to Access Them:
This partial interim Reregistration Eligibility Document is supported by documents that are
presently maintained in the OPP docket. The OPP docket is located in Room 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. It is open Monday through Friday, excluding legal holidays from
8:30 am to 4 pm.
The docket initially contained preliminary risk assessments and related documents as of January
15, 1999. Sixty days later the first public comment period closed. The EPA then considered comments,
revised the risk assessment, and added the revised risk assessment to the docket on March 20, 2000.
All documents, in hard copy form, may be viewed in the OPP docket room or downloaded or
viewed via the Internet at the following site: "http://www.epa.gov/pesticides/op."
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Supporting Documents for the Phosmet
Partial Interim Reregistration Eligibility Decision
Human Health Risk Assessment, Issued in February 2000
"Phosmet - Review of Incident Reports for ProTICallฎ Derma-Dip (Reg. No. 773-79)," [V.
Dobozy memorandum dated 4/17/97, DP Barcode No. D234382].
"Revised Product and Residue Chemistry Chapters of the HED RED," [C. Swartz memorandum
dated 11/23/98, DP Barcode No. D250029].
"Review of Phosmet Incident Reports," [J. Blondell memorandum dated 12/7/98, DP Barcode
No. D251247].
"Phosmet-Report of the FQPA Safety Factor Committee," [B. Tarplee memorandum dated
7/21/99].
"Phosmet Toxicology Chapter for the HED RED," \L. Taylor memorandum dated 7/26/99, DP
Barcode No. D257925, HED Document No. 013586].
"HED Response to Public Comments on the Preliminary Human Health Risk Assessment," [C.
Swartz memorandum dated 7/29/99, DP Barcode No. D258140].
"HED Review of the Gowan Co. Probabilistic (Monte Carlo) Acute Dietary Exposure and Risk
Assessment," [C. Swartz memorandum dated 7/30/99, DP Barcode No. D254657].
"Phosmet: Revised Report of the Hazard Identification Assessment Review Committee," [L.
Taylor memorandum dated 8/4/99, HED Document No. 013604].
"Phosmet: Revised Dietary Exposure and Risk Analyses for the HED Human Health Risk
Assessment," [C. Swartz memorandum dated 9/8/99, DP Barcode No. D258080].
"The Revised Occupational and Residential Exposure Aspects of the HED Chapter of the
Reregistration Eligibility Document (RED) for Phosmet," [J. Dawson memorandum dated 1/27/00,
DP Barcode No. D262366].
"Cancer Assessment Document: Evaluation of the Carcinogenic Potential of Phosmet (3rd
Review)," [S. Diwan memorandum dated 9/30/99].
"Phosmet: Revised Report of the Hazard Identification Assessment Review Committee," [L.
Taylor memorandum dated 12/20/99, HED Document No. 013921].
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Updates to the Human Health Risk Assessment:
"Phosmet: Revised Occupational Postapplication Exposure and Risk Calculations," [J. Dawson
memorandum dated 8/15/2000, DP Barcode No. D268141].
"Phosmet: Response to Comments from Stakeholder Organizations on Phosmet Risk
Assessment," [J. Dawson memorandum dated 9/14/2000, DP Barcode No. D268565].
"Phosmet: Response to Comments from The Gowan Chemical Company on Phosmet Risk
Assessment," [J. Dawson memorandum dated 9/14/2000, DP Barcode No. D268563].
"Response to Comments from The Wellmark Chemical Company on Phosmet Risk Assessment,"
[J. Dawson memorandum dated 9/28/2000, DP Barcode No. D266418].
"Review of Wellmark International's Response to USEPA HED Phase 4 Human Health Risk
Assessment concerning: Memorandum: Review of Phosmet Incidence Reports" [J. Blondell
memorandum dated September 25, 2000, DP Barcode No.269221].
"Phosmet: Toxicology Chapter for RED - Revised" \L. Taylor memorandum dated
July 13, 2000, DP barcode No. D266419].
"Response to National Resources Defense Council (NRDC) Comments on Phosmet Risk
Assessment Included as Docket #OPP-34173B," [J. Dawson/C. Swartz/L. Taylor memorandum
dated 11/27/2000, DP Barcode No. D266418].
"Phosmet - Addenda to Previous Occupational and Residential Risk Assessment Completed on
January 27, 2000," [J. Dawson memorandum dated 2/6/2001, DP Barcode No. D271240].
"Phosmet: Further Revisions to the Occupational Exposure and Risk Calculations"
[J. Dawson memorandum dated 8/20/01, DP Barcode No. D277160].
"Phosmet: Cranberry and Forestry Occupational Exposure and Risk Calculations" [J. Dawson
memorandum dated August 31, 2001, DP Barcode No. D277440].
Ecological Risk Assessment, Issued April 24,1998:
"Environmental Fate and effects Division RED Chapter for Phosmet" [S. Abel/M. Rexrode/D.
Spatz/T. Steeger, memorandum dated 4/24/1998, DP Barcode Numbers D188325, D187058,
D236030].
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"Phosmet Tier II EECs," [S. Abel memorandum dated 8/9/99].
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