United States Office of Pertlckfa and Toxic Sufaetancas
Environmental Protection Office of Pertiode Programs (TS-766C)
Agency Washington, DC 20460
v>EPA Pesticide
Fact Sheet
s
Name of Chemical: CLIPPER (PACLOBUTRAZOL)
Reason for Issuance:
Date Issued: Ia]gaat 14, 1985
Fact Sheet Number:
62
1. Description of chemical t
Cannon name: Paclobutrazol
Code name: PP333
Trade name: dipper 50 WP
EPA Shaughnessv code: 125601
Chemical abstracts service (CBS) nunher: 76738-62-0
Year of initial registration: 1<*85
Pesticide type: Plant Growth Regulator
U.S. and foreign producers: ICI Americas Inc.
2. Use patterns and formulations:
Application sites: Ornamental trees (deciduous and broadleaf evergreen)
Types of formulations: Wettable powder (50% a.i.)
Types and methods of application: Applied in a pressurized tree injection
system.
Application rates: Pates vary depending upon tree size: dosage for smallest
treatable tree is 0.006 oz. active ingredient per tree.
Usual carriers: water
3. Science findings:
Summary science statement: The data base for paclobutrazol (non-food uses)
is well developed. Results of acute inhalation (50% formulation) and
eye irritation studies indicate toxicity category II. The chemical is non-
mutagenic and is rapidly cleared from bcdv tissue (rat and dog studies).
Exceot for sandy soils, paclobutrazol does not exhibit a tendency to leach.
The chemical does not photodegrade and is not expected to hydrolyze.
Hazards to aquatic and terrestrial wildlife are not anticipated because of
low toxicity and low risk of exposure (tree iniection system).
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th nical tharacteristics:
Physical state: Solid
lor: W ,ite
Q or: Nzt significant
Melting point: 165—166°C
Density: l.22g/an 3
Vapor pressure: 1.5 x 10 Pa at 50°C
8 x 10 Pa at 30°C
1 x 106 Pa at 20°C (by extracolation)
Solubility: water 35 p n
Cyc].ohexanone 18%
Methanol 15%
Acetate 11%
Methylene dithoride 10%
Xy lene 6%
Propylene clycol 5%
Rexane < 1%
Octanol/water partition coefficient: Log P 3.2
unusual har*lling dtaracteristics: !bne
Toxicoloqy characteristics:
Acute toxicology results:
Tedtnica l
Acute oral toxicity (rat): 1.95 g/kg (male)
1.33 g/kg (f nale)
Toxicity category 111
Acute dermal toxicity (rat): greater than 2g/kg
Toxicity category III
PriiTlary skin irritation (rabbit): Paclobutrazol caused mild skin
irritation. Toxicity cateqory III
Primary eye irritation (rabbit): Paclobutrazol caused reversible
corneal opacities with irritation lasting 72 hours. Toxicity
category II
Dermal sensitization (guinea pig): Paclobutrazol is not a skin
sensitizer.
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Acute toxicology results:
50% Formulaticn
Acute inhalation toxicity (rat): greater than 766 i /m 3 (male)
359—766 /m 3 (female)
Toxicity category II
Chronic toxicology results:
21—day derinal (rabbit): NOEL is 10 IT /kg/day
LEL is 100 iig/kgfday
90-day feedir g (rat): NOEL is 250 ppm
LEL is 1,250 ptT
One year feeding (dog): NOEL is 15 xrgJkg/day
LEL is 75 ir€/kg/day
Teratology (rat): NCEL (maternal toxicity) is greater than 100 g/kg/day
(highest dose tested). NOEL (fetal effects) is 10 n /kgJday.
Teratology (rabbit): Within limitations of sthdy (low fertility),
NOEL (maternal toxicity) is 25 ir /1cg/day. JEL is 75 n /kg/da.y.
Mutagenicity: Paclobutrazol does not cause mut.agenic effects.
Metabolism: ults fr rat and dog studies indicate that paclobutrazol
and its metabolites are rapidly eliminated.
Major routes of exposure: Mixers, loaders arid applicators would receive
the most exposure via skin/eye contact and inhalation.
Physiological and bioc m1cal behavioral characteristics:
Mechanism of pesticidal action: Paclobutrazol acts as a plant growth
regulator and reduces regrowth in orr mental trees following
trinrni.ng.
Envira mental characteristics:
Adsorption and leaching in basic soil types: Paclobutrazol could leach
in sandy soils with low organic content. In other soil types, the
chemical does not have a high propensity to leach.
Loss fran photodegradatiC1 : Paclobutrazol does not photodegrade after
exposed to 10 days of simulated sunlight.
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Resultant average persistance: Paclobutrazol degrades aerobically in
soil with half-lives of about 1-7 n nths depending upon soil type.
Paclobitra 1 is not expected to hydrolyze in the enviroriT nt.
Ec loqical &aracteristicS:
Avian acute oral toxicity (Mallard): greater than 7,913 u /kg
Avian dietary toxicity ( b it ite quail): greater than 5,000 ppn
Avian dietary toxicity (Mallard): greater than 20,000 n
Fish acute toxicity (Bluegill): 23.6 m /l
Fish acute toxicity (Rainbow trout): 27.8 u /l
Aquatic invertebrate toxicity ( Da *inia magna) : 33.2 lTg/l
potential problens related to endangered species: Minimal hazard to
endangered soecies is exoected because of the low toxicity of
pac1obutra l and proposed use (tree injection).
4. Si.mvnaty of regulatory position and rationale :
Use classification: General
Use, formulation, manufacturing process or aeoqra iical restrictions:
Raclotxitra l is not to be injected: (1) into trees that do not
appear healthy, (2) into fruit or nut trees that will be harvested
within one year after application and (3) into suqar maple or any
other trees that are or could be tapped for suaar.
Unique label rning statei ents:
End-Use Product :
“ ar protective clothing, rubber gloves aid a mask or pesticide
respirator jointly approved by the Mining Enforc nent and Safety
Administration and the National Institute for C cupational Safety
and Realth.
5. Suninary of major data gaps : N ne
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6. Ccmtact pers at EPA :
bert 3. Taylor
product Manager (25), TS—767C
Err,iraInental Protectia ency
401 N Street, S.W.
Waththat , D.C. 20460
(703) 557—1800
DISCLAIMER: The informatia presented in this thenical Information Pact Sheet
is for informational purpDses only ar 3 may not be usei to fulfill data
requirements for pesticide reaistraticn and rereaistraticn.
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