United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-93-012
September 1993
R.E.D. FACTS
Pesticide
Reregistration
Use Profile
Regulatory
History
Sulfuryl Fluoride
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 which were first registered years ago 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, describing the human
health and environmental effects of each pesticide. The Agency imposes
any regulatory controls that are needed to effectively manage each
pesticide's risks. EPA then reregisters pesticides that can be used without
posing unreasonable risks to human health or the environment.
When a pesticide is eligible for reregistration, EPA announces this and
explains why in a Reregistration Eligibility Document, or RED. This fact
sheet summarizes the information in the RED for sulfuryl fluoride.
Sulfuryl fluoride is an insecticide used to fumigate closed structures
and their contents such as domestic dwellings, garages, barns, storage
buildings, commercial warehouses, ships in port, and railroad cars. It
controls numerous insect pests including termites, powder post beetles, old
house borers, bedbugs, carpet beetles, clothes moths and cockroaches, as
well as rats and mice. The end-use product is marketed as a liquid gas in
pressurized steel containers.
Sulfuryl fluoride was first registered in December 1959. In June
1985, EPA issued a registration standard entitled "Guidance for the
Reregistration of Pesticide Products Containing Sulfuryl Fluoride as an
Active Ingredient" (NTIS PB87-124392), requiring additional product
chemistry and occupational and residential exposure studies. Data Call-In
Notices issued in July 1990 and November 1992 required additional
toxicity data.
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Currently, no manufacturing use products and only one end-use
product containing the active ingredient sulfuryl fluoride are registered.
The single registered product, Vikane, contains 99% sulfuryl fluoride and
1% inert impurities. Vikane is classified as a restricted use pesticide due to
its inhalation toxicity.
Human Health Toxicity
Assessment In acute oral toxicity studies using rats and guinea pigs, sulfuryl
fluoride has been shown to be moderately toxic; it has been placed in
Toxicity Category II for these effects (Category I indicates the highest and
Category IV the lowest level of acute toxicity). Sulfuryl fluoride has been
placed in Toxicity Categories III and IV for acute inhalation and Category
IV for acute dermal vapor toxicity. A two-day neurotoxicity study using
rats showed no effects at the highest dose levels.
Four subchronic toxicity studies using rats, rabbits and dogs showed
similar results including fluorosis of the teeth, decreased body weights, and
effects to the lung, nervous system and brain. In developmental toxicity
studies using rats and rabbits, at the highest dose levels or in range-finding
studies, some maternal toxicity (reduced body weight gain) and
developmental toxicity (reduced fetal body weights) were observed. A
reproductive toxicity study using rats showed parental effects to the lungs
and brain, and reduced pup weights. Sulfuryl fluoride was negative in three
mutagenicity studies.
Several humans poisonings and two deaths have been attributed to
sulfuryl fluoride exposure. All resulted from reentering treated homes
before they had adequately aerated, inconsistent with label directions.
Dietary Exposure
Sulfuryl fluoride is not registered for any food- or feed-related uses.
No tolerances or exemptions from the requirement of a tolerance have been
established, and no dietary exposure is anticipated.
Occupational and Residential Exposure
Sulfuryl fluoride is dispensed as a pressurized gas from a steel
cylinder through a hose into the interior of an enclosed, sealed structure.
People must be evacuated from the structure before it is treated; chlorpicrin,
which produces a strong odor and eye irritation, is used as a warning agent
and is released within the structure 5 to 10 minutes before sulfuryl
fluoride is applied to ensure that the site is vacated. After treatment,
the structure remains closed for a period of time (refer to the
product label for specific times regarding target pest and environmental
conditions) after which the applicator reenters and begins to aerate the
area. People not wearing a respirator may not reenter the treated structure
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until air levels of sulfuryl fluoride have declined to 5 part per million (ppm)
or less. Because sulfuryl fluoride is a Restricted Use Pesticide, it may only
be applied by or under the direct supervision of a trained, certified
applicator.
Applicators may be exposed to sulfuryl fluoride while applying the
pesticide. However, sulfuryl fluoride is introduced as a gas into the target
area through a hose, thus, negligible exposure to the applicator is expected
until the time of reentry into the treated structure to monitor air levels.
Applicators and residents may be exposed to sulfuryl fluoride through
inhalation upon reentry and/or reoccupation of treated structures. Exposure
to workers is acute and intermittent, while exposure to residents is acute and
lasting. Current product labeling requires applicators to wear protective
clothing including respirators when reentering treated structures and
prohibits other people from reoccupying treated structures until air levels of
sulfuryl fluoride have declined to 5 ppm.
Human Risk Assessment
Sulfuryl fluoride poses no human dietary risks since no food- or feed-
related uses are registered and dietary exposure is not anticipated.
EPA is concerned with neurotoxicity associated with inhalation
exposure to sulfuryl fluoride. Residents and workers reentering treated
structures may be at risk for acute neurotoxic effects from this exposure,
which currently is limited to 5 ppm. The Agency has concern that the 5
ppm reentry level may not be appropriate based on the calculated Margins
Of Exposure (MOEs) which suggest 2 ppm for adults. In order to provide a
further safety measure for children, the current data and the limit of
detection of the monitoring devices suggest a reentry level of 1 ppm.
However, certain post treatment decline data are not available which might
enable the Agency to refine the reentry level. The sulfuryl fluoride
registrant has been given the option in the RED document to submit
exposure data and any other data that can be used to refine the decline rate
of sulfuryl fluoride. These data are due by August 1, 1994. By October 1,
1994, the Agency will make a decision on the reentry level but until these
data are evaluated the 5 ppm reentry level will remain in place. If these
new data are not useful or not received by August 1, 1994, the reentry level
will be established at 1 ppm and revised labeling will be implemented on an
accelerated basis.
In addition, a fact sheet must be provided in advance to an adult
occupant of each structure to be fumigated, describing why and how
buildings are fumigated, the potential risks and safety precautions, as well as
who to contact for more information.
Because of uncertainty about neurotoxic effects due to long term
exposure to sulfuryl fluoride, workers will be required to wear a NIOSH-
approved, self-contained breathing apparatus (SCBA) upon reentry,
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regardless of air levels of sulfuryl fluoride. EPA is requiring a 90-day
inhalation neurotoxicity study in rats to more fully assess human subchronic
and chronic effects. Assessment of risks to workers during their working
life span, and the need to continue wearing the SCBA upon reentry at all air
levels of sulfuryl fluoride, will be addressed after this study is received and
evaluated.
Environmental
Assessment
Environmental Fate
Since sulfuryl fluoride is registered for highly specialized uses, and
due to its chemical properties, EPA is not requiring the usual supporting
environmental fate data for reregistration. After fumigation and aeration of
treated structures, there is little likelihood that nontarget organisms would
be exposed to residues of sulfuryl fluoride, or that the pesticide would leach
to ground water. Residues of the parent chemical are not expected to
remain in the environment for any significant length of time.
Additional Data
Required
Product Labeling
Changes Required
Ecological Effects Risk Assessment
Based on its limited use sites and chemical properties, significant
environmental exposure is not expected to result from use of sulfuryl
fluoride. Therefore, wildlife toxicity data were not required for
reregistration, and an ecological risk assessment was not conducted.
The generic data base for sulfuryl fluoride is substantially complete.
However, EPA is requiring a new 90-day neurotoxicity study in rats, as
confirmatory data. Method validation data for indoor air monitoring
devices are also required.
EPA is not requiring product-specific data, but is requiring a revised
Confidential Statement of Formula and revised labeling for reregistration of
the pesticide product containing sulfuryl fluoride.
The end-use product must comply with EPA's current pesticide
product labeling requirements. In addition:
• The label must provide specific directions for the use of
chlorpicrin as a warning agent to be present in the structure during
fumigation at a level $ 0.25%. Instructions must be provided that the
chlorpicrin must be used by persons certified to apply sulfuryl fluoride
and that applicators must observe the precautionary statements and
safety recommendations appearing on the label of this product.
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• The label must require that a pesticide fact sheet be provided to
an adult occupant of the structure to be fumigated prior to the
initiation of the fumigation contract. This fact sheet, which is
labeling, must contain as a minimum of information the following:
a) Why buildings are fumigated.
b) How buildings are fumigated.
c) Potential health risks from overexposure.
d) Safety precautions and homeowner preparation.
e) A contact point for additional information.
• Add the following under the Environmental Hazards Statement:
"Pesticide wastes are toxic. Improper disposal of excess
pesticide is a violation of Federal Law. If these wastes
cannot be disposed of by use according to the label
instructions, consult your State Pesticide or Environmental
Control Agency, or the Hazardous Waste representative of
the nearest EPA Regional Office for guidance."
• Due to concern for neurotoxic effects from long term exposure
to sulfuryl fluoride upon reentry to treated structures, the Agency
requires the following:
Applicators must wear a NIOSH approved self-contianed
breathing apparatus (SCBA) when reentering a treated structure
regardless of air levels of sulfuryl fluoride.
Regulatory Use of the currently registered pesticide product containing sulfuryl
Conclusion fluoride as labeled and specified in the RED document will not pose
unreasonable risks or adverse effects to humans or the environment.
Therefore, all uses of this product are eligible for reregistration.
The sulfuryl fluoride product will be reregistered once the
confirmatory generic data, revised Confidential Statement of Formula and
revised labeling are received and accepted by EPA.
For More EPA is requesting public comments on the Reregistration Eligibility
Information Document (RED) for sulfuryl fluoride during a 60-day time period, as
announced in a Notice of Availability published in the Federal Register. To
obtain a copy of the RED or to submit written comments, please
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contact the Pesticide Docket, Public Response and Program Resources
Branch, Field Operations Division (7506C), Office of Pesticide Programs
(OPP), US EPA, Washington, DC 20460, telephone (703) 305-5805.
Following the comment period, the sulfuryl fluoride RED document
will be available from the National Technical Information Service (NTIS),
5285 Port Royal Road, Springfield, VA 22161, telephone (703) 487-4650.
For more information about sulfuryl fluoride RED document, EPA's
pesticide reregistration program, or reregistration of individual products
containing sulfuryl fluoride, please contact the Special Review and
Reregistration Division (7508W), OPP, 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 Pesticides Telecommunications Network (NPTN). Call toll-
free 1-800-858-7378, between 8:00 am and 6:00 pm Central Time, Monday
through Friday.
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