United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-96-025
September 1996
R.E.D. FACTS
Chlorhexidine
diacetate
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 which
were first registered years ago be reregistered to ensure that they meet
today's more stringent standards.
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 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 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 3038, chlorhexidine diacetate.
Chlorhexidine diacetate is a disinfectant used to control bacteria on
agricultural premises, egg handling and packing equipment, and meat and
poultry processing plants, and certain viruses in veterinary settings.
End-use products contain 2% of the active ingredient and are
formulated as soluble concentrates or liquids.
Chlorhexidine diacetate is applied by open-pour loading of liquid
formulations, hand-wiping surfaces, dipping tools/implements into diluted
disinfectant solution, mopping of surfaces, using hand-held high- and low-
pressure spray equipment, and with fogging devices. Use practice
limitations prevent exposure to food items.
Regulatory Products formulated with chlorhexidine diacetate as an active
History ingredient were first registered in the U.S. as early as 1955 for use as a farm
premise disinfectant/virucide.
Currently, two products (each containing 2% chlorhexidine diacetate)
are registered for use as hard surface-treatment disinfectants/virucides.
Use Profile
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Human Health
Assessment
Toxicity
In acute toxicity studies using laboratory animals, the Agency
concluded that chlorhexidine diacetate is mildly to moderately toxic when
administered by inhalation, oral and dermal routes. However, in repeat
primary eye irritation studies, the chemical is severely toxic.
In a subchronic dermal rabbit toxicity study systemic effects included
degenerative changes in the livers of females. In a developmental toxicity
study in rats, no observable malformations nor signs of developmental
toxicity were found at any dose level tested. A battery of mutagenicity
studies were negative for mutagenic effects.
Dietary Exposure
Chlorhexidine diacetate is registered for use on processing surfaces in
federally inspected meat, poultry, egg, and rabbit processing plants as a
disinfectant. The labeling for these products directs the user to remove or
carefully cover the food products prior to application, and to use a potable
water rinse after treatment. The U.S. Department of Agriculture and the
EPA have determined that disinfectants, when applied to federally
inspected meat, poultry, egg, and rabbit processing plants as described
above, do not present dietary exposure risks (USDA, FSIS publication
#1419, "List of Proprietary Substances and Nonfood Compounds").
Occupational and Residential Exposure
Based on current use patterns, handlers (mixers, loaders, and
applicators) may be exposed to chlorhexidine diacetate during and after
normal use of products containing this active ingredient. An exposure
assessment is appropriate because of the toxicological endpoint from the
subchronic dermal study.
Several exposure scenarios are possible, including open pouring,
wiping, dipping of implements, mopping, spraying, and fogging. Data are
not available to calculate exposures for the fogging scenario. For the
remaining scenarios, EPA's exposure assessment, which considered
combined dermal and inhalation exposures, suggests that short- and
intermediate-term exposures are greatest for the open pouring scenario
while chronic exposures are greatest from wiping activities. However, the
calculated margins of exposure (MOEs) for these uses were greater than
100. MOEs of greater than 100 are considered acceptable.
Because the exposure data used to calculate these risks were
generated for workers wearing personal protective equipment (PPE), these
PPE are required as described in the product labeling section of this fact
sheet.
The potential for exposures to chlorhexidine diacetate exists following
application. However, the Agency believes that exposures from post-
application are significantly lower than exposures during application,
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Environmental
Assessment
provided entry into treated areas is restricted immediately following
application. The Agency is concerned for workers exposed to
chlorhexidine diacetate from their entry into the fogged area. To protect
these workers, PPE, including gloves and a respirator, is required.
Human Risk Assessment
Chlorhexidine diacetate generally is of low to moderate acute toxicity,
but is highly acutely toxic when applied to the eye. It causes liver effects in
animal studies.
The Agency is concerned for risks posed to chlorhexidine diacetate
handlers and workers reentering areas recently treated with the pesticide.
To mitigate these risks, PPE is established for both handlers and workers
in early-entry situations.
For chlorhexidine diacetate, like other pesticides whose uses are
limited to indoor sites, the Agency required a limited set of ecotoxicology
and environmental fate studies. The Agency does not routinely conduct full
environmental assessments on such pesticides since minimal to no
environmental exposure is expected from the indoor use patterns. Only a
limited set of studies are necessary to characterize the pesticide's hazard
potential in the case of unanticipated environmental exposures caused by
transportation accidents, spills, or improper disposal or use.
Ecological Effects
Chlorhexidine diacetate is slightly toxic to avian species on an acute
and subacute oral dietary basis, moderately to highly toxic to fish, and very
highly toxic to aquatic invertebrates. Current uses of chlorhexidine
diacetate are expected to result in minimal exposure or risk to the
environment. Therefore, no environmental risk mitigation measures are
imposed at this time.
Additional Data The Agency is requiring product-specific data including product
Required chemistry and acute toxicity studies, revised Confidential Statements of
Formula (CSFs), and revised labeling for reregi strati on.
Product Labeling All chlorhexidine diacetate end-use products must comply with EPA's
Changes current pesticide product labeling requirements and with the following.
Required Minimum (Baseline) PPE Requirements
The minimum (baseline) PPE for persons applying
chlorhexidine diacetate by mopping and hand wiping is:
"Applicators and other handlers must wear:
- Long sleeve shirt and long pants
- Socks plus shoes."
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Regulatory
Conclusion
For More
Information
The minimum (baseline) PPE for occupational uses of
chlorhexidine diacetate end-use products with the exception of the
wet-mist fogging is:
"Applicators and other handlers must wear:
- Long-sleeve shirt and long pants
- Chemical-resistant gloves
- Socks plus shoes."
For the wet-mist fogging, the following PPE is required:
"Applicators and other handlers exposed to the fog during wet-
mist fogging applications and until the fog has dissipated and
the enclosed area has been thoroughly ventilated must wear:
- Long-sleeve shirt and long pants
- Chemical-resistant gloves
- Socks plus shoes."
The use of currently registered products containing
chlorhexidine diacetate in accordance with approved labeling and as
specified in the RED will not pose unreasonable risks or adverse effects to
humans or the environment. Therefore, all uses of these products are
eligible for reregi strati on.
Chlorhexidine diacetate products will be reregistered once the
required product-specific data, revised Confidential Statements of Formula,
and revised labeling are received and accepted by EPA.
EPA is requesting public comments on the Reregi strati on Eligibility
Decision (RED) document for [name] 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 on EPA's gopher
server, GOPHER.EPA.GOV, or 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.
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Following the comment period, the [name] 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 [name] RED, or reregi strati on of individual products containing [name],
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 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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