United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-97-009
August 1997
R.E.D. FACTS
PROPOXUR
Pesticide
Reregistration
Use Profile
Regulatory
History
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 before November 1, 1984, be
reregistered to ensure that they meet today's more stringent standards.
Under the Food Quality Protection Act of 1996, EPA must consider
the increased susceptibility of infants and children to pesticide residues in
food, as well as aggregate exposure of the public to pesticide residues from
all sources, and the cumulative effects of pesticides and other compounds
with a common mechanism of toxicity in establishing or reassessing
tolerances.
In evaluating pesticides for reregi strati on, EPA obtains and reviews a
complete set of studies from pesticide producers, describing 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 the safety
standard of the FQPA and can be used without posing unreasonable risks to
human health or the environment.
When a pesticide is eligible for reregi strati on, 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
reregi strati on case 2555, propoxur.
Propoxur is a carbamate insecticide used to control ants, roaches and
hornets in and around residences and commercial food handling
establishments. The formulations include aerosols, baits, emulsifiable
concentrates, wettable powders formulated into aerosol cans, dusts and
powders, pest strips, shelf paper, ready-to-use solutions, granular baits,
containerized baits, and pet flea collars.
Propoxur was first registered as a pesticide in the U.S. in 1963. In
December, 1987, the Agency issued a DCI to call in data needed to support
the continued registration of propoxur products. The DCI required
additional data to support the outdoor uses of propoxur as well as studies to
examine potential risks to applicators and persons living in treated buildings.
None of the companies, including Bayer, the basic producer of propoxur,
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Human Health
Assessment
committed to support all of the uses registered at that time. In 1987,
propoxur was registered for outdoor use as a premise spray, use on turf,
and for adult mosquito control. These uses were not supported and were
deleted from labels.
In 1988, the Agency issued a preliminary notification (Grassley-Allen)
letter to Bayer indicating its decision to consider propoxur for Special
Review because of the potential carcinogenic risks to pest control operators
and the general public during indoor and outdoor applications and risks to
occupants of buildings treated with propoxur products.
In 1989, a DCI was issued to end-use producers after Bayer decided
not to support the outdoor uses. None of the end-use producers elected to
support the outdoor uses.
In 1990, a Notice of Intent To Suspend (NOITS) was issued for
certain propoxur registrations for which Bayer failed to provide acceptable
data. This was after they committed to provide exposure data for all uses
except the fogger, which they declined to support. These exposure data
were eventually provided and the suspensions lifted.
In January, 1995, the Agency issued a notice (60 FR 3210) proposing
not to initiate a Special Review of the insecticide propoxur. The Agency
had received and evaluated new exposure and carcinogenicity data on
propoxur and determined that the uses which posed the greatest concern had
been eliminated through voluntary cancellation or label amendment.
Therefore, the Agency believed that the estimated risks did not warrant
initiation of a Special Review. The Agency issued a final decision not to
initiate a Special Review in February, 1996 (61 FR 7508). Currently, 173
propoxur products are registered.
Toxicity
In studies using laboratory animals, propoxur generally has been
shown to be of moderate acute toxicity. It has been placed in Toxicity
Category II (the second highest of four categories) for effects via the oral
route of exposure, and Toxicity Category III for the dermal and inhalation
routes. Propoxur has been classified as a Group B2, probable human
carcinogen, with a Qx* of 3.7 x 103. Propoxur shows little if any genotoxic
activity. The Agency has calculated a reference dose (RfD), the amount of
pesticide believed not to cause adverse effects if consumed daily over a 70-
year lifetime, of 0.005 mg/kg/day, based on a human study with a LOEL of
0.15 mg/kg, the lowest dose tested. An uncertainty factor of 10 was applied
to account for intra-species variability and an additional factor of 3 was
applied to compensate for the lack of a NOEL.
Dietary Exposure
People may be exposed to residues of propoxur through the diet.
However, exposure is likely to be limited because the only use of propoxur
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that could result in residues in food, is for crack and crevice treatments in
food handling establishments and food processing plants. Sufficient data are
available to support the proposed tolerance of 0.2 ppm in/on all foods. The
anticipated residue contribution (ARC) for the overall US population is
1.84% of the RfD. For the most highly exposed sub-group, non-nursing
infants < 1 year old, the ARC is 7.23 % of the RfD. These low fractions
of the allowable RfD (100%) are well within the range of acceptable dietary
risk.
The cancer dietary risk estimate for incidental residues of propoxur on
food in food handling establishments for the overall US population is 3.4 x
10 7. EPA considers dietary cancer risks less than 1 x 106 to be minimal.
Because of very limited outdoor use of propoxur, no residues are
anticipated in drinking water.
Occupational and Residential Exposure
Professional pest control operators (PCOs) as well as residents and
residential applicators (RAs) can be exposed to propoxur during and after
applications in and around the home, and in commercial and industrial
settings. Combined application and post-application cancer risks to resident
applicators range from 2.3 x 108 for pet flea and tick collars to 4.5 x 10 7
for crack and crevice applications. EPA considers residential cancer risks
of less than 1 x 106 not to be of concern.
Propoxur has an estimated cancer risk to workers of 7.7 x 106. The
Agency's policy for worker risk is that risk should be as close to negligible
(i.e., 1 x 106) as possible. EPA is requiring personal protective clothing,
including long-sleeved shirt, long pants, chemical resistant gloves, and shoes
plus sox, for professional applicators applying propoxur to cracks and
crevices. The Agency believes that there are no other reasonable measures
that could be imposed to further reduce risk.
Risk assessments for chronic (non-cancer) and short-term, dermal and
inhalation exposure to propoxur have not been conducted because no
adverse effects were seen at the highest dose tested of 1000 mg/kg/day in a
dermal study and the vapor pressure of propoxur is low.
FQPA Considerations
EPA conducted additional risk analyses using available data in
response to the new FQPA requirements. The Agency found that the
propoxur data base for pre- and post-natal effects is complete based on
current requirements. Because these reliable data indicate no special
sensitivity of young organisms to propoxur, the Agency has concluded that
an additional uncertainty factor need not be applied to the NOELs used in
the propoxur risk assessments.
EPA has considered the potential for aggregate exposure from various
sources of propoxur to residents including children. Dietary exposure is
possible from incidental residues of propoxur used as a crack and crevice
treatment in food handling establishments and food processing plants.
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Exposure to homeowners is also anticipated during applications of propoxur
in and around the home and to both homeowners and children after such
applications. Becasue of the limited outdoor use of propoxur for structural
perimeter applications and spot treatments to wasp nests and ant hills, little
or no post application exposure is anticipated to residents or children and no
residues are expected in drinking water. When dietary and residential risks
are combined, the aggregate cancer risk from propoxur ranges from 3.6 x
10 7 to 7.9 x 10 7, well within acceptable limits.
The Agency has not made a determination whether propoxur and any
other pesticide have a common mechanism of toxicity for either cancer or
non-cancer effects and require cumulative risk assessment. For the purposes
of this RED, EPA has considered only the risks from propoxur. If
required, cumulative risks will be assessed when methodologies for
determining common mechanism of toxicity and for performing cumulative
risk assessments are finalized.
Environmental
Assessment
Environmental Fate
For the currently registered uses of propoxur, the Agency typically
requires an abbreviated set of environmental fate data on hydrolysis,
metabolism, and mobility. Only supplemental data are available for
propoxur. While shortcomings in the studies preclude a comprehensive
assessment of the environmental fate of propoxur, a general assessment can
be made.
Based on supplemental data, propoxur is likely to be moderately
persistent (the metabolic half-life is on the order of several months), mobile,
and may potentially leach to groundwater. It is apparently hydrolytically
stable at acid to neutral pHs (3 to 7) but degrades rapidly at alkaline pH
values. The parent chemical appears susceptible to photolysis in water but
not on soil. However, the intensity of light in the studies did not reflect that
of natural sunlight. Aerobic and anaerobic soil metabolism half-lives are on
the order of several months. Degradate characterization was incomplete in
these studies. Laboratory mobility studies indicate that propoxur is very
mobile (Kd values less than 1). Propoxur exhibits fate and transport
characteristics similar to chemicals that are known to leach to groundwater.
Well-designed, scientifically-valid studies could result in changes in
the overall assessment, particularly in relation to persistence. For instance,
photolysis may play a role in degradation of propoxur applied outdoors.
However, considering the nature of the current outdoor uses, additional
studies are not required at this time. The limited data available only support
the uses discussed in this document. Any additional uses will require data to
support them.
Ecological Effects/Risk
Although calculated acute avian risks exceed the LOCs, the Agency
believes risks to birds from the limited outdoor bait applications are not
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Risk Mitigation
excessive. There are no reported bird poisoning incidents from propoxur
according to Agency records. Potential exposure to birds has been greatly
reduced since the 1992 deletion of broadcast uses on lawns/turf.
Outdoor applications are limited to exteriors of buildings, on and
immediately around patios, sidewalks and building foundations, and boat
mooring lines, water lines and utility supply lines. Exposure of propoxur to
avian and mammalian wildlife species with the current outdoor uses results
in slight exposures, if any.
Minimal aquatic exposure from runoff or drift is expected from
propoxur outdoor bait products. Although the toxicity is high, the aquatic
risk does not exceed the Agency's LOCs. Based on the limited outdoor bait
applications of propoxur, minimal to no risk is expected to aquatic
organisms.
To lessen the occupational and residential risks posed by propoxur,
EPA is requiring the following risk mitigation measures:
oPersonal protective equipment (PPE) including long-sleeved shirt, long
pants, chemical-resistant gloves and shoes plus socks for PCOs applying
propoxur as a crack and crevice treatment
oAreas treated are not to be entered until the sprays have dried and the dusts
have settled.
Additional Data
ReQUired
Product Labeling
Changes Required
EPA is requiring product-specific data including product chemistry
acute toxicity studies, revised Confidential Statements of Formula
(CSFs), and revised labeling for reregistration.
All propoxur end-use products must comply with EPA's current
pesticide product labeling requirements and with additional reentry
specifications to their labels. The following labeling changes are required.
For products intended for occupational and homeowner use:
• For liquid applications to surfaces other than on pets: "Do
not allow people or pets to enter the treated area until
sprays have dried."
For products which have applications to surfaces other than on pets:
• "Do not apply this product in a way that will contact any person
or pet, either directly or indirectly. Keep people and pets out of
the area during application."
User Safety Recommendations
• "Users should wash hands before eating, drinking, chewing
gum, using tobacco, or using the toilet."
• "Users should remove clothing immediately if pesticide gets
inside. Then wash thoroughly and put on clean clothing."
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• "Users should remove protective clothing and equipment
immediately after handling this product. Wash the outside of
gloves before removing. Keep and wash protective clothing and
equipment separately from other laundry."
For products with residential outdoor uses:
• This product is toxic to wildlife and aquatic invertebrates. Birds
and small mammals feeding on treated bait may be killed. Do
not apply directly to water. Do not contaminate water by
cleaning of equipment or disposal of wastes.
• "Birds and small mammals feeding on treated bait may be
killed"
• "Do not apply as a landscape treatment (to lawns, shrubs or
trees, garden plants)"
For a comprehensive list of labeling requirements, please see the propoxur
RED document.
Regulatory
Conclusion
For More
Information
EPA has determined that the proposed tolerance for propoxur meets
the safety standard under the FQPA, and that there is a reasonable certainty
that no harm will result to infants and children or to the general population
from aggregate exposure to propoxur residues. The use of currently
registered products containing propoxur in accordance with approved
labeling will not pose unreasonable risks of adverse effects to humans or the
environment. Therefore, all uses of these products are eligible for
reregistration.
Propoxur products will be reregistered once the required product-
specific data, revised Confidential Statements of Formula, and revised
labeling are received and accepted by EPA. These products will be
reregistered once any required confirmatory generic data, product specific
data, CSFs, and revised labeling are received and accepted by EPA.
Products which contain active ingredients in addition to propoxur will be
reregistered when all of their other active ingredients also are eligible for
reregistration.
EPA is requesting public comments on the Reregistration Eligibility
Decision (RED) document for propoxur 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 document or to submit written comments, please
contact the Pesticide Docket, Public Response and Program Resources
Branch, Field and External Affairs Division (7506C), Office of Pesticide
Programs (OPP), US EPA, Washington, DC 20460, telephone
703-305-5805.
Electronic copies of the RED and this fact sheet can be downloaded
from the Pesticide Special Review and Reregistration Information System at
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703-308-7224. They also are available on the Internet by using ftp on
FTP.EPA.GOV, or using WWW (World Wide Web) on WWW.EPA.GOV.
Printed copies of the RED and fact sheet can be obtained from EPA's
National Center for Environmental Publications and Information
(EPA/NCEPI), PO Box 42419, Cincinnati, OH 45242-0419, telephone
513-489-8190, fax 513-489-8695.
Following the comment period, the propoxur RED document also 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 EPA's pesticide reregistration program,
the propoxur RED, or reregistration of individual products containing
propoxur, 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 9:30 am and 7:30 pm Eastern Standard
Time, Monday through Friday.
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