= Reregistration Eligibility Decision
US Environmental Protection
Prevention, Pesticides, Protection and Toxic Substances (7508W)
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
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.
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.
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.
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
Human Health 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
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
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
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 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
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
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, 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
Environmental Assessment Environmental Fate
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.
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.
Additional Data Required
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
Product Labeling Changes Required
The end-use product
must comply with EPA's current pesticide product labeling requirements.
• 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.
• 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
a) Why buildings
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-contained breathing
apparatus (SCBA) when reentering a treated structure regardless
of air levels of sulfuryl fluoride.
Use of the currently
registered pesticide product containing sulfuryl 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 Information
EPA is requesting
public comments on the Reregistration Eligibility 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
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)
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
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.