DCNA (Dicloran) Reregistration Eligibility
Decision (RED) Fact Sheet
EPA 738-F-06-013
July 2006
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 first
registered before November 1, 1984, 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 that describe the human health and environmental effects of each pesticide. To
implement provisions of the Food Quality Protection Act (FQPA) of 1996, EPA considers the special
sensitivity of infants and children to pesticides, as well as aggregate exposure of the public to
pesticide residues from all sources, and the cumulative effects of pesticides and other compounds with
common mechanisms of toxicity. The Agency develops any mitigation measures or regulatory controls
needed to effectively reduce each pesticide's risks. EPA then reregisters pesticides that meet current
human health and safety standards and can be used without posing unreasonable risks to human
health and the environment.
When a pesticide is eligible for reregistration, 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 the pesticide DCNA (Dicloran), case number 0113.
Uses
DCNA is a pre- and post-harvest fungicide formulated as a dust, wettable powder and liquid.
DCNA is registered for pre-harvest use on apricots, snap beans, carrots, celery, cherries,
cucumber, endive, fennel, garlic, grapes, lettuce, nectarines, onions, peaches, plums,
potatoes, prunes, rhubarb, shallots, sweet potatoes and tomatoes. DCNA is registered for
post-harvest use on apricots, carrots, nectarines, peaches, plums, sweet cherries, and sweet
potatoes. It is also registered for use on conifers, Christmas trees, and various ornamentals.
The major pre-harvest crop uses include celery and lettuce; the major post-harvest use is on
sweet potatoes.
Application rates range up to 4.5 pounds active ingredient per acre (Ib ai/acre), with the
highest single application rate being permitted on potatoes.
The maximum annual application rate is 4.0 Ib ai/acre/year for all crops except for potatoes
(for which a maximum annual application rate of 7.5 Ib ai/acre/year is allowed) and celery
and fennel (for which a maximum annual application rate of 5.0 Ib ai/acre/year is allowed).
DCNA is a general use pesticide with no residential uses.
Over 200,000 pounds of DCNA is used annually.
Health Effects
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DCNA has low acute toxicity, but is a potential skin sensitizer.
The target organs for DCNA include the kidney, liver, spleen and hematopoietic system,
particularly red blood cells.
No reproductive effects were observed in studies with DCNA.
DCNA appears to elicit neuropathology (vacuolation in the brain).
DCNA is classified as "Suggestive Evidence of Carcinogenic Potential," but EPA concluded that
no quantification of cancer risk is required.
Ecological Effects
DCNA has low volatility and is expected to be persistent and have low mobility in soil, although
mobility will be increased in coarser soils.
DCNA is classified as practically non-toxic to mammals on an acute oral basis. However,
developmental effects and maternal toxicity were noted in a two-generation reproduction
study.
DCNA is classified as slightly toxic to bobwhite quail and practically non-toxic to mallard ducks
in acute avian toxicity tests.
DCNA is highly toxic to freshwater fish and moderately toxic to freshwater invertebrates on an
acute basis.
Risks
Acute and chronic dietary risks from exposure to DCNA through food and drinking water are
below the Agency's level of concern (i.e., less than 100 percent of the population adjusted
dose (PAD)). At the 99.9th percentile of exposure, the estimated food and drinking water
exposure for females 13 to 49 years old accounted for 52% of the acute PAD. For chronic
exposures, the most highly exposed subgroup was children 1-2 years old, with exposures
accounting for 15% of the chronic PAD.
Risks to occupational handlers are below the Agency's level of concern with some level of
personal protective equipment (PPE) and/or engineering controls for all handler exposure
scenarios except for aerial application of dust products, and aerial and chemigation methods
of application for wettable powder products not packaged in water soluble bags.
Risks to workers entering fields recently treated with DCNA to perform tasks such as scouting
and irrigation are below EPA's level of concern with a 12-hour Restricted Entry Interval (REI)
for all crops except for grapes (assuming the new lower application rates for apricots,
grapes, peaches, nectarines, plums, prunes, snap beans, sweet cherries, conifers, and
Christmas trees, as discussed below).
EPA's screening level ecological risk assessment shows some exceedances of the acute and
chronic levels of concern for birds and the chronic level of concern for mammals.
No acute or chronic risks are predicted for fish, aquatic invertebrates, or aquatic plants.
Risk Mitigation
The following risk mitigation measures are required for DCNA to address risks of concern.
Occupational Handler Risk Mitigation
Aerial application of dust formulation is prohibited.
Aerial and chemigation methods of application are prohibited for wettable powder
products not packaged in water soluble bags.
PF-10 respirators are required for mixers and loaders using dust and wettable powder
(non-water soluble bag) formulations.
Closed cabs that provide both dermal and inhalation protection are required for
application of dust using ground equipment.
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Occupational Post-Application Risk Mitigation
The maximum application rates were reduced for the following crops: apricots, grapes,
peaches, nectarines, plums, prunes, snap beans, sweet cherries, conifers, and
Christmas trees, as shown in the table below.
Crops
Grapes
Apricots, peaches, nectarines, plums,
prunes, sweet cherries
Snap Beans
Conifers, Christmas Trees
Previous Max.
Rate
(Ib ai/acre)
3.5
New Max.
Rate
(Ib ai/acre)
1.5
4 1.5
3
2
2
1.5
For grapes, in addition to reducing the maximum application rate, the REI was
extended to 14 days. Furthermore, all DCNA products labeled for use on grapes must
prohibit cane turning and girdling for 30 days following the application of DCNA.
Regulatory Conclusion
EPA has determined that all supported uses of DCNA are eligible for reregistration, provided that
registrants implement risk mitigation measures described in the RED and make required 4 changes to
product labeling and provided that additional data identified in Chapter V of the RED confirm this
decision.
For More Information
Electronic copies of the DCNA RED and all supporting documents are available in Docket #EPA-HQ-
OPP-2005-0265 at http://www.regulations.gov.
For more information about EPA's pesticide reregistration program, the DCNA RED, or reregistration of
individual products containing DCNA, please contact the Special Review and Reregistration Division
(7508P), Office of Pesticide Programs, 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 Information Center (NPIC). Call
toll-free 1-800-858-7378, from 6:30 am to 4:30 am Pacific Time, or 9:30 am to 7:30 pm Eastern
Standard Time, seven days a week. The NPIC internet address is http://npic.orst.edu I EXIT Disclaimer)
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