United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-97-003
March 1997
R.E.D. FACTS
Pesticide
Reregistration
Use Profile
3-lodo-2-propynyl
butylcarbamate (IPBC)
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 Reregi strati on Eligibility Decision (RED) document. This
fact sheet summarizes the information in the RED document for reregistration
case 2725, 3-Iodo-2-propynyl butylcarbamate (IPBC).
IPBC is a fungicide/antimicrobial used as a preservative in paint,
adhesives, emulsions, metal cutting fluids, oil recovery drilling mud/packer
fluids, plastics, textiles, inks, paper coatings, and wood products. It is also
used in residential settings as a wood preservative stain to combat wood
rot/decay, and as a preservative in paints. IPBC is also applied to heating,
ventilation, and air conditioning (HVAC) ducts and equipment to control
mold and fungi.
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Regulatory
History
Human Health
Assessment
IPBC was first registered in the United States in 1975 for use as a
disinfectant, fungicide and algicide. A September 1993 reregi strati on data
call-in (DCI) was sent to the pesticide manufacturer requesting technical
product chemistry, ecological effects, and environmental fate studies.
There are currently 53 registered pesticide products containing IPBC.
Toxicity
In studies using laboratory animals, IPBC has been shown to be
practically non-toxic for dermal irritation, and has been placed in Category IV
(the lowest of four categories) for this effect. It is slightly toxic for acute oral,
dermal, and inhalation exposure, and has been placed in Toxicity Category III
for these effects. IPBC is highly toxic for eye irritation and has been
classified as Category I for this effect.
IPBC is not considered a developmental toxicant or a mutagen. The
Agency has classified IPBC as "not likely" to be a carcinogen using the
Agency's revised Guidelines for Carcinogen Risk Assessment. In the
context of the revised guidelines this classification was based on: a) the
lack of a carcinogenic response for combined adenoma/carcinoma of the
liver in male mice as a result of the re-evaluation of the tumor incidence in
the mouse carcinogenicity study; b) the lack of carcinogenic response in
female mice and in male or female rats; c) the absence of mutagenic
activity; and d) the absence of data suggesting formation of a reactive
metabolite of IPBC which might be responsible for initiation of the tumors
observed.
Dietary Exposure
Since IPBC is not currently approved for use on food or feed crops, no
dietary exposure to IPBC residues is expected.
Occupational and Residential Exposure
Based on current use patterns, handlers (mixers, loaders, and
applicators) and other people may be exposed to IPBC formulations during
and after application. The Agency has identified two levels of exposure, to
primary handlers — persons directly handling IPBC pesticide products; and to
secondary handlers — persons handling manufactured products, such as paints
and adhesives, to which IPBC has been added as a preservative.
Human Risk Assessment
IPBC generally is of low acute toxicity. Using the revised Guideline for
Carcinogen Risk Assessment, the Agency has classified IPBC as "not likely"
to be carcinogenic. Dietary exposure to IPBC residues in foods is not
expected to occur since there are no currently registered uses for IPBC on food
or feed products.
The Agency assessed the risk resulting from short-term and
intermediate-term IPBC exposures associated with occupational and
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homeowner handlers (primary and secondary). The Agency also assessed the
risk resulting from chronic IPBC exposures to certain occupational handlers
(primary and secondary). The NOEL for short and intermediate-term
exposure is 200 mg/kg/day (from the subchronic dermal rat study) and the
NOEL for chronic exposures is 20 mg/kg/day (from the chronic rat study).
EPA assessed risks to handlers using margins of exposure (MOEs).
The MOE is a ratio of the NOEL to the daily dose. EPA generally is not
concerned with MOEs greater than or equal to 100. The MOEs for all IPBC
occupational and homeowner scenarios for which data are available are
acceptable, except for occupational painters using airless or compressed air
sprayers; their exposure becomes acceptable when PPE (long-sleeve shirt,
long pants, shoes, socks, and chemical resistant gloves) is used. EPA's
regulatory authority does not encompass requiring label statements for paints.
However, EPA believes that occupational painters would likely wear
appropriate PPE. Furthermore, painters are not likely to use only paints
containing IPBC, nor are they likely to use only airless or compressed air
sprayers.
Due to the lack of exposure data for IPBC, the potential risks related to
several exposure scenarios cannot be assessed at this time. These include:
• exposure to workers during industrial treatments to milled forest products,
including post application exposure to workers handling or processing treated
wood products;
• exposure to workers applying IPBC products to heating, ventilation, and air
conditioning (HVAC) ducts or equipment, and post application exposure to
occupants of areas where HVAC systems have been treated;
• post application exposure to persons handling and using textiles, such as
carpets, drapes, shower curtains, and canvas, to which IPBC has been applied;
and
• exposure to non-industrial, occupational workers and homeowners
applying IPBC products to wood by dipping, using a pad, or any method other
than a brush, roller, and airless or compressed air sprayer.
The Agency is therefore requiring additional data to characterize the risk
associated with these exposure scenarios before a reregistration eligibility
decision can be made. For all other uses, exposure and risk to workers will be
adequately mitigated by the use of additional PPE as required by this RED.
Additional confirmatory data are also being required to satisfy the following
guidelines: 81-8 (Acute Rat Neurotoxicity with cholinesterase) and 82-7 (90-
day Rat Neurotoxicity with cholinesterase).
Other Considerations
Because IPBC currently has no food uses and no tolerances have been
established, the specific determinations outlined in the Food Quality
Protection Act of 1996 are not required for this chemical. Nevertheless, EPA
has considered available data relating to the special sensitivity of infants and
children, the potential for aggregate exposures to IPBC, and the potential for
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Environmental
Assessment
cumulative effects from IPBC and other chemicals with a common mode/
mechanism of toxicity because children and other individuals could be
exposed to this compound in non-occupational settings.
Based on reliable data for pre- and post-natal effects indicating no
special sensitivity of young organisms to IPBC, the Agency has concluded
that an additional uncertainty factor need not be applied to the short- and
intermediate-term NOELs used in the IPBC risk assessments.
Because it degrades rapidly, IPBC is not likely to be found in drinking
water and no dietary exposure is expected. EPA assumes that handling and
applying paint would be the reasonable worst case exposure scenario for
homeowners (non-occupational exposure). Because MOEs for this worst case
exposure are high, EPA believes that aggregate exposures to other sources of
IPBC in the home are not likely to be of concern.
The Agency has not yet determined whether it is appropriate to consider
exposure from other carbamates with IPBC in order to address potential
cumulative effects. However, based on the high MOEs for homeowner
applicators, the lack of food uses, unlikely residues in drinking water, and the
high NOEL for dermal exposure (the most likely route), the Agency believes
that it is reasonable to assume that the contribution of IPBC exposure to the
risks from other carbamate pesticides is likely to be minimal considering
currently registered IPBC uses.
The Agency has adequate data to assess the toxicity of IPBC to
nontarget organisms.
Environmental Fate
A qualitative environmental fate assessment has been completed for
IPBC. Submitted environmental fate and transport data suggest that IPBC is
non-persistent and mobile in soil and aquatic environments. Because it
degrades rapidly, IPBC should not pose a contamination threat to surface and
ground water.
Ecological Effects
IPBC is slightly toxic to practically nontoxic to avian species on an
acute oral and subacute dietary basis. IPBC is slightly toxic to small
mammals on an acute oral basis. Because repeated or continuous avian
exposure through persistence, bioaccumulation, or multiple applications, is not
expected to occur for IPBC, avian and mammalian reproduction testing is not
required. Also because applications of IPBC are not likely to result in
exposure to honey bees, non-target insect toxicity data are not required.
The results of the acute toxicity studies indicate that IPBC is very highly
toxic to cold-water fish and highly toxic to warm-water fish. IPBC is highly
toxic to aquatic invertebrates. Also, IPBC is highly toxic to estuarine/marine
fish and highly to very highly toxic to estuarine/marine invertebrates.
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Additional Data
Required
Product Labeling
Changes
Required
Ecological Effects Risk Assessment
Assessment of submitted studies by the Agency indicates that IPBC
should not pose a threat to surface water and ground water because it degrades
rapidly.
The submitted data indicate that IPBC is slightly toxic to practically
nontoxic to birds and very highly toxic to highly toxic to freshwater fish and
aquatic invertebrates. While the hazard to aquatic organisms from IPBC has
been characterized, a quantitative risk assessment has not been conducted.
The risks to aquatic environments from the microbicide use of this chemical
are regulated under the NPDES permitting program of EPA's Office of Water.
All IPBC labeled products must require that discharges to aquatic
environments comply with an NPDES permit. Because the outdoor use of
IPBC is limited to industrial treatment of forest products, exposure to wildlife
is not expected to be significant.
EPA is requiring the following additional generic studies for IPBC:
guidelines 81-8 and 82-7 to further characterize the potential for IPBC to
cause neurological effects; and guidelines 133-3, 133-4, 231, 232, 233, and
234 to characterize exposure to IPBC during wood protection treatment to
milled forest products and subsequent handling of treated lumber; exposure to
applicators and occupants during and after HVAC treatments; exposure to
handlers and consumers of textiles after IPBC treatments, and exposure to
non-industrial applicators from IPBC wood treatments by any methods other
than brush, roller, and airless or compressed air sprayer. EPA is developing a
generic exposure DCI for antimicrobial chemicals.
The Agency also is requiring IPBC product-specific data including
product chemistry and acute toxicity studies, revised Confidential Statements
of Formula (CSFs), and revised labeling for reregi strati on.
All IPBC end-use products must comply with EPA's current pesticide
product labeling requirements. For a comprehensive list of labeling
requirements, please see the IPBC RED document.
Although the Agency is not establishing minimum (baseline)
engineering controls for occupational uses of IPBC end-use products, the
Agency is establishing minimum (baseline) personal protective equipment for
occupational uses of IPBC end-use products. Applicators and other handlers
must wear:
—long-sleeve shirt and long pants,
—chemical-resistant gloves,
—shoes plus socks.
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Regulatory
Conclusion
For More
Information
EPA has determined that products containing IPBC are eligible for
reregi strati on except products labeled for industrial wood protection treatment
of milled forest products, HVAC uses, textile uses, and non-industrial wood
treatments by methods other than brush, roller, and airless or compressed air
sprayer. Additional exposure data are being required so that the Agency can
assess the risk to workers and handlers from the above-mentioned uses. The
Agency cannot make eligibility decisions for these uses at this time.
The use of eligible IPBC products in accordance with labeling specified
in this RED will not pose unreasonable adverse effects to humans or the
environment. These products will be reregistered once the 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 IPBC will be reregistered when all of their other active
ingredients also are eligible for reregi strati on.
EPA is requesting public comments on the Reregi strati on Eligibility
Decision (RED) document for IPBC 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 Operations 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 Reregi strati on Information System at
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 1-800-
490-9198, fax 513-489-8695.
Following the comment period, the IPBC 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 reregi strati on program, the
IPBC RED, or reregi strati on of individual products containing IPBC, please
contact the Special Review and Reregi strati on 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 Pesticide 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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