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RED Fact Sheet: Chloropicrin
July 10, 2008

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RED Fact Sheet: Chloropicrin
July 10, 2008
Pesticide Reregistration
All pesticides sold or distributed in the United States must be
registered by EPA, based on scientific studies showing that they can be
used without posing unreasonable risks to people or the environment.
Because of advances in scientific knowledge, the law requires that
pesticides first registered before November 1, 1984, be reregistered to
ensure that they meet today's more stringent standards.
In evaluating pesticides for reregistration, EPA obtains and reviews a
complete set of studies from pesticide producers that describe the
human health and environmental effects of each pesticide. The
Agency develops any mitigation measures or regulatory controls
needed to effectively reduce each pesticide's risks. EPA then
reregisters pesticides that meet current human health and safety
standards and can be used without posing unreasonable risks to
human health and the environment.
When a pesticide is eligible for reregistration, EPA explains the basis
for its decision in a Reregistration Eligibility Decision (RED) document.
This fact sheet summarizes the information in the RED document for
the pesticide chloropicrin, case number 0040.
Concurrent to EPA's review of the soil fumigant uses of chloropicrin,
EPA assessed the risks and developed risk management decisions for
four other soil fumigant pesticides, including methyl bromide,
dazomet, metam sodium/metam potassium, and a new active
ingredient, iodomethane. Risks of a fifth soil fumigant, 1,3-
dichloropropene (1,3-D), were also analyzed along with the other soil
fumigants for comparative purposes. The RED for 1,3-D was
completed in 1998. The Agency evaluated these soil fumigants
concurrently to ensure that human health risk assessment approaches
are consistent, and that risk tradeoffs and economic outcomes were
considered appropriately in reaching risk management decisions. This
review is part of EPA's program to ensure that all pesticides meet
current health and safety standards.
Regulatory History
•	First registered in the U.S. in 1975
•	A Registration Standard was issued in 1982
Uses

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•	Chloropicrin is a broad-spectrum fumigant chemical that can be
used as an antimicrobial, fungicide, herbicide, insecticide, and
nematicide.
•	Chloropicrin is used as a pre-plant soil fumigant at agricultural
sites, tree replant sites, and greenhouses; a warning agent with
other soil fumigants including methyl bromide and iodomethane,
a warning agent in residential structures before sulfuryl fluoride
fumigations; and an antimicrobial for remedial wood treatment.
•	As a pre-plant soil fumigant chloropicrin is either injected (e.g.,
by shank) into the soil or applied via drip irrigation. These
applications can either be tarped or untarped.
•	For the orchard use, chloropicrin is used in existing orchards for
tree replant purposes in small treated areas (10' x 10'). It is
injected at least 18 inches into the soil using a replant wand and
the soil is compacted after the application wand is withdrawn.
•	When used as a warning agent prior to sulfuryl fluoride
residential structure fumigations, a tent must first be put up
around the structure. Chloropicrin is placed in the center of the
structure 5-10 minutes before sulfuryl fluoride is introduced.
•	For remedial wood treatment, chloropicrin is either
poured/injected or applied with encapsulated vials into pre-
drilled holes. For utility pole treatment, holes are drilled at a 45
degree angle and chloropicrin is poured/injected or applied with
encapsulated vials into all of the holes. After the chloropicrin
has been applied, the holes are immediately plugged
•	Approximately 10 million pounds of chloropicrin are used
annually for pre-plant soil fumigations.
Health Effects & Risks
Health Effects
•	Chloropicrin can cause eye, nose, throat, and upper respiratory
irritation. Results from a chloropicrin human sensory irritation
study indicate that eye irritation is the most sensitive effect.
•	The Agency selected a reversible acute endpoint using a human
sensory irritation study with a bench mark concentration level
(BMCLio) of 0.073 parts per million (ppm). At this level EPA
does not expect eye or nose irritation, upper respiratory
changes, or any other health effects. Most of the study
participants detected chloropicrin within 20-30 minutes at 0.15
ppm. This level corresponds to mild irritation without leading to
more severe irritation or respiratory effects. In addition, the
study shows that persons exposed to 0.15 ppm of chloropicrin,
did not experience irritation effects 1 hour after the exposure
ended, and also no effects were seen the following day.
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Risks from Pre-Plant Soil Use
•	EPA has identified acute inhalation as the main risk of concern
for handlers (including persons involved in the application, and
also persons involved in tarp perforation and removal activities),
workers, and bystanders.
•	Monitoring and modeling data indicate that there can be risks of
concern associated with chloropicrin use at a broad range of
distances from treated fields, depending on application method,
emission control methods employed, application rate, and size of
the area treated.
•	Incidents from chloropicrin and other fumigants have occurred
involving handlers, workers and bystanders.
•	Bystander incidents from chloropicrin and other fumigants have
occurred to people who were located close to fields and up to
several thousand feet from the fumigated field.
Risks from Structural Warning Agent Use
•	As with other uses, EPA has risk concerns for inhalation risks to
handlers.
•	EPA does not have risk concerns for bystanders for this use.
Risks from Antimicrobial Remedial Wood Treatment Use
•	EPA has identified acute inhalation as the main risk of concern
for handlers and workers, and bystanders near the application.
Ecological Effects & Risks
•	EPA's ecological risk assessment indicates some risk concerns for
non-target organisms.
•	Chloropicrin is highly volatile and is a gas at room temperature.
Inhalation is the major exposure pathway for terrestrial animals.
•	Risks to mammals based on refined air modeling do not exceed
the Agency's level of concern (LOC); however, risks to birds
could not be quantified in absence of inhalation toxicity data.
•	Chloropicrin is highly soluble in water and has low adsorption in
soil, characteristics in common with chemicals that have been
detected in groundwater. Chloropicrin can potentially leach into
groundwater or reach surface water as a result of heavy rainfall
events. However, its high vapor pressure and high Henry's Law
Constant indicate that volatilization is the most important route
of dissipation. Chloropicrin is usually applied under tarps, which
reduces potential for movement to water.
•	Risks to aquatic organisms exceed EPA's acute LOCs for some
fish and invertebrate scenarios. Chronic risks to aquatic
organisms were not estimated due to lack of chronic data,
however, due to its volatility, chronic exposure to chloropicrin is
unlikely.
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•	There are several uncertainties in estimating ecological effects of
chloropicrin due to limited toxicity data and the limitations of
exposure models and crop scenarios.
Benefits
Due to the broad range of pests controlled, soil fumigants are used in
production of a wide variety of crops and provide high benefits for
many growers. Chloropicrin has benefits both as a methyl bromide
alternative and as a warning agent to make people aware of potential
exposures to other fumigants such as methyl bromide and sulfuryl
fluoride.
Risk Mitigation for Soil Uses
EPA has identified several measures which will work together to
protect fumigant handlers, reentry workers, and bystanders from risks
resulting from exposure to chlorpicrin. These are summarized below.
•	Buffer Zones: Buffer zones, of varying sizes based on
application method, application rate, application block size, and
emission control measures are required. Buffer zones will be in
effect from the time the fumigation begins until 48 hours
following the application.
•	Posting: EPA is requiring that buffer zones be posted at usual
points of entry and along likely routes of approach to the buffer
unless (1) a physical barrier such as a fence prevents access to
the buffer, or (2) all of the area within 300' of the buffer is under
the control of the owner/operator. The posting requirement is
intended to prevent passersby from entering a buffer zone.
•	Worker Protections: The following additional measures will be
required to protect those involved in handler activities.
Respiratory Protection - New labels will require air
monitoring at regular intervals. If concentrations detected
are above action levels on labels, handlers must wear
respirators.
Tarp Perforation and Removal -
>	tarps cannot be perforated (cut/punched) until a
minimum of 5 days (120 hours) have passed after the
fumigant application is complete;
>	a minimum interval of 24 hours must pass between
perforation and tarp removal;
>	use of respiratory protection is required for tarp
perforation if concentrations exceed labeled action
levels; and
>	use of mechanical devices (e.g., using all-terrain
vehicles with cutting implements attached) is required.
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Entry - Only properly trained and equipped handlers can
be in the field during treatment and for 5 days after the
application is complete.
Good Agricultural Practices (GAPs): Mandatory GAPs must
be followed during all soil applications. GAPs specify appropriate
weather conditions, injection depth, soil sealing, soil
temperature, air temperature, soil moisture, soil preparation,
prevention of end row spillage, flushing of drip irrigation lines,
and calibration, set-up, repair and maintenance of application
equipment.
Fumigant Management Plans (FMPs): The certified applicator
supervising the application must verify that a site-specific FMP
exists for each application block which includes site information,
a map of the treated field, authorized personnel, application
procedures, posting plans, and emergency procedures. Within
30 days of completing the application portion of the fumigation
process, the certified applicator supervising the application must
complete a post fumigation application summary that describes
any deviations from the FMP that occurred, measurements taken
to comply with GAPs, as well as any complaints and/or incidents
that have been reported to him/her. The summary must include
the actual date of the application, application rate, and size of
application block fumigated.
Emergency Preparedness and Response: The Agency is
requiring emergency preparedness measures at the community
level in the form of information and education for first
responders, and site-specific response and management
activities. These measures will ensure early detection and quick
response to situations as they arise.
Notice to State and Tribal Lead Agencies: Assuring
compliance with new label requirements is an important part of
the package of mitigation measures. Therefore, before the
application, fumigators must notify State and Tribal Lead
Agencies for pesticide enforcement about applications they plan
to conduct. This information will aid states in planning
compliance assurance activities.
Outreach Program for Communities: Registrants must
disseminate health and safety information to communities,
including first responders, in areas where there is high use of
chloropicrin and areas with significant interface between
communities and fumigated fields.
Training Program and Training Materials: The registrants
must develop a training program approved by EPA that provides
information on how to correctly apply the fumigant including how

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to protect themselves, other handlers and bystanders, how to
determine buffer zone distances, how to develop an FMP, and
how to determine when weather and other site-specific factors
are not favorable for fumigant application.
Other Risk Mitigation
•	Antimicrobial Remedial Wood Treatment Use: EPA is
requiring that applicators and other handlers wear an approved
respirator at all times when handling chloropicrin during the
transfer of the product into vials and during the pouring/injecting
of chloropicrin into pre-drilled holes.
•	Structural Warning Agent Use: EPA is requiring respiratory
protection for handlers.
•	Ecological Risks: Many of the mitigation measures EPA is
requiring to address human health risk, such as GAPs, timing of
tarp perforation and removal, and RUP classification, will also
reduce potential ecological risks.
Regulatory Conclusion
EPA has concluded that the supported uses of chloropicrin for: 1) pre-
plant soil agricultural, greenhouse, and tree replant, 2) warning agent,
and 3) antimicrobial remedial wood treatment, are eligible for
reregistration provided the mitigation measures discussed above are
adopted and labels are amended to implement these measures.
For More Information
Electronic copies of the Chlorpicrin RED and all supporting documents
are available in Docket #EPA-HQ-OPP-2007-0350 at
http://www.requlations.gov. For more information about EPA's
pesticide reregistration program, the Chloropicrin RED, or
reregistration of individual products containing chloropicrin, please
contact the Special Review and Reregistration Division (7508C), Office
of Pesticide Programs, US EPA, Washington, DC 20460, telephone 703-
308-8000.
For information about the health effects of pesticides, or for assistance
in recognizing and managing pesticide poisoning symptoms, please
contact the National Pesticide Information Center (NPIC). Call toll-free
1-800-858-7378, from 6:30 am to 4:30 am Pacific Time, or 9:30 am
to 7:30 pm Eastern Standard Time, seven days a week. The NPIC
internet address is http://npic.orst.edu.
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