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    Primary use:   Insecticide
    Secondary use:
    Chemical group:   Pyrethroid

         It must be noted that the issue of a Data Sheet for a
    particular pesticide does not imply endorsement of the pesticide by
    WHO or FAO for any particular use, or exclude its use for other
    purposes not stated. While the information provided is believed to
    be accurate according to data available at the time when the sheet
    was compiled, neither WHO nor FAO are responsible for any errors or
    omissions, or any consequences therefrom.

    The issue of this document does    Ce document ne constitue pas une
    not constitute formal              publication. Il ne doit faire
    publication. It should not be      l'objet d'aucun compte rendu ou
    reviewed, abstracted or quoted     rsum ni d'aucune citation sans
    without the agreement of the       l'autorisation de l'Organisation
    Food and Agriculture               des Nations Unies pour
    Organization of the United         l'Alimentation et l'Agriculture
    Nations or of the World Health     ou de l'Organisation Mondiale de
    Organization.                      la Sant.


    1.1  COMMON NAME: Permethrin (ISO, BSI, ANSI)

    1.1.1 Identity:

          IUPAC: 3-phenoxybenzyl (1RS)-cis,trans-3-(2,2-dichlorovinyl)-

          CAS No. 1: (3-phenoxyphenyl)methyl (1RS)-cis,trans-3-(2,2-

          CAS Reg. No.: 52645-53-1

          Molecular formula: C12H20O3

          Molecular weight: 391.29

          Structural formula:

    Chemical Structure

    1.1.2 Synonyms: Acion(R); AI3-;29158; Ambush(R); AMbushfog(R); BW-21-7; 
          CO-Opex(R); Ectiban(R); Eskmin(R); FMC 33297; Indothrin(R); 
          Kafil(R); Matadon(R); NIA 33297; NRDC 143; Outflank; OMS-1821; 
          Perthrine(R); Picket(R); Picket G(R); Pounce(R); Perigen(R); 
          Pramex(R); PP557; Qamlin(R); R86557; Stockade(R);   Stomoxin(R);   
          S-3151; SBP-1513; Talcord(R); WL43479.

    1.2  SYNOPSIS: Permethrin is a composite synthetic pyrethroid; a broad 
         spectrum, non-cumulative pesticide; and, a fast acting neurotoxin 
         with good contact, limited stomach and no fumigant action.  It is 
         moderately stable in the environment and has good residual action 
         on inert surfaces.  Permethrin is nonsystemic in plants; of low 
         mammalian toxicity,, and is readily metabolized with immediate 
         loss of toxicity. 


    1.3.1 Physical characteristics - The pure isomers are colourless 
          crystals at ambient temperatures changing to a clear, pale 
          yellow, viscous liquid above the melting points of 63-65C for 
          the cis isomers and 44-47C for trans isomers.  The boiling point 
          is 200C/0.01 mmHg.  The technical product is a viscous, brown 
          liquid which may partially crystallize at ambient temperatures 
          and is completely liquid above 60C.  The technical products boil 
          at 210-220C/0.05 mmHg.  The specific gravity is 1.190-1.272 at 

    1.3.2 Solubility - at 20C, less than 0.1 mg/l water

                       at 30C,           0.2 mg/l water

                                        +450.0 g/l acetone

                                        +450.0 g/l cyclohexanone

                                        +450.0 g/l ethanol

                                        +450.0 g/l xylene

                                        +450.0 g/l chloroform

          it is soluble in or mixable with most organic solvents except 
          ethylene glycol. 

    1.3.3 Stability - Permethrin has good stability on plant surfaces  

          under severe conditions of temperature, humidity and solar 
          radiation but it is relatively unstable in most soils. 
          In solution it is stable under neutral and acidic pHs but 
          relatively unstable in alkaline conditions. 

    1.3.4  Vapour pressure - at 20C, cis isomer 2 x 10-9 kPa

                                      trans isomer 1 x l0-9 kPa


    1.4.1 Common formulations -

          Agronomic  uses:  Emulsifiable concentrates (100-500 g  
          a.i./l);  fogging solutions (50 g/l) ; ULV concentrates 
          (50- 470 g/l) . 

          Veterinary uses:  Emulsifiable  concentrates  (25-200 g  
          a.i./l) and dusts (2.5-10 g a.i./kg).  For plant use the 
          cis:trans isomer ratio is 40:60 or higher, a lower ratio of 
          25:75 is available for use on animals and on animal shelter 

    1.4.2 Susceptible pests - Permethrin is effective, at low doses, as 
          an ovicide, larvicide and adulticide; and, as a repellent and 
          a feeding suppressor against a wide variety of insect 
          ectoparasites of plants and animals. It is particularly 
          effective against members of the Lepidoptera, Coleoptera,  
          Diptera and Heteroptera orders.  However, as a lipophilic 
          substance lacking fumigant action it is not usually effective 
          against aphids, systemic parasites and soil pests except by  
          direct contact application.  Mites, cockroaches, locusts 
          and grasshoppers are well controlled at high dose levels.         
          In addition to biting insects, other arthropod ectoparasites  
          such as ticks are well controlled on animals. 

    1.4.3 Use pattern - Permethrin is used in the protection of a wide 
          variety of field crops (cotton, tobacco, hops, fruits and 
          vegetables), in greenhouses, market gardens and vineyards.  
          Successful use in large-scale silviculture programmes is under 
          review.  Permethrin may be applied from ground or from air 
          dispensers to field crops. It may be sprayed on plants in 
          enclosed areas and on inert surfaces for quick knockdown or 
          repellent effect or used as a dip or spray for animals. Some 
          biting insects are well controlled for several weeks by simply 
          applying the formulation to one or two dominant members of a 
          small herd (10-30 animals). 

    1.4.4 Unintended effects - Permethrin is not phytotoxic when used as 
          recommended, rapid degradation in soils, aquatic environment and 

          low mobility limit adverse effects on non-target organisms.  It 
          is very toxic to bees. 


    1.5.1 Common formulations - See 1.4.1, also available in hand held 
          aerosol and fogging formulations; as a transparent emulsion; and, 
          in a variety of formulations in combination with several other 
          active ingredients including, bioallethrin, copper sulfate, 
          dichlorvos, pirimicarb, pirimiphos-methyl, tetramethrin and 

    1.5.2 Susceptible pests - Pemethrin is effective in the control of 
          several insect vectors of disease, ticks, ants, mosquitos, lice, 
          fleas, blackflies, tsetse fly, domestic flies and other pests 
          which contaminate food and water sources. 

    1.5.3 Use pattern - Most commonly permethrin is used as a spray or 
          fogging treatment of surfaces, buildings, plants, confined spaces 
          or larval habitats.  Permethrin is very effective as a direct 
          contact poison or as a residual substance.  It has been 
          experimentally absorbed onto fabric with good effect retained 
          after the fabric was washed.  Permethrin has also been effective 
          when used as a low concentration dusting powder directly on 
          humans against body lice in experimental trials. 


    1.6.1 Common formulations - See 1.4.1; also available in hand held 
          aerosol sprays or fogging devices; as a transparent emulsion; 
          and, in a variety of formulations in combination with several 
          other active ingredients including bioallethrin, copper sulfate, 
          dichlorvos, pirimicarb, pirimiphos-methyl, tetramethrin and 

    1.6.2 Susceptible pests - See 1.5.2; Permethrin is also effective 
          against termites and woodboring beetles, silverfish, bed-bugs, 
          cockroaches, crickets and other undesirable arthropods. 

    1.6.3 Use pattern - Permethrin may be used as a space or surface spray; 
          as a residual film on inert surfaces, in fabrics and on exposed
          wood.  It is used for its knockdown and kill properties and as 
          a repellent. 



    2.1.1 Absorption route - Permethrin is readily absorbed from the 
          gastrointestinal tract; minimally through the intact skin, in 

          non-polar solvents more rapidly than in aqueous solutions; and, 
          by inhalation of dust and fine spray mist. 

    2.1.2 Mode of action - Permethrin is a neurotoxin which acts directly 
          on neuron membranes.  It prolongs sodium ion permeability during 
          the excitatory phase of the action potential thus effecting 
          repetitive activity in the sensory and motor pathways. The parent 
          compound is the neurotoxic agent. 

    2.1.3 Excretion - The metabolism of permethrin has been extensively 
          studied in rats and mice and in lactating cows and goats.  The 
          two sets of cis and trans isomers are metabolized by liver 
          microsomal esterases and oxidases; however, the sequence of 
          enzyme activity and the relative contribution of each enzyme are 
          quite variable among the isomers and within animal species for 
          individual isomers.  A concise and thorough review has been 
          published by D. R. Hutson (Prog. Drug. Metab., 3; Chap. 4, p. 
          215, 1979).  The trans isomer metabolism is dominated by 
          hydrolysis whereas the cis isomers are less easily hydrolised and 
          more toxic. Oxidase activity in both isomers involves 
          stereospecific oxidation of the acid moiety, 
          cyclopropanecarboxylic acid; oxidation of the alcohol moiety, 3-
          phenoxybenzyl alcohol (3-PB alc) to 3-phenoxybenzoic acid 
          (3-PBA); and hydroxylation of the alcohol moiety at positions 
          4', 6 and to a limited extent at position 2. Trans isomers are
          excreted more rapidly than the cis isomers and excretion of the
          acid radioisotope label is more rapid than that of the alcohol.  
          Hydrolysis resistance is associated with low urinary (45-55%) 
          and high faecal excretion of the cis isomers whereas trans 
          isomers are primarily eliminated in urine (81-90%). The major 
          excretion products of the alcohol moiety in both isomers are 4'-
          HO-3-PBA sulfate in rats; 4'-HO-3-PBA (trans) and 6-HO-3-PBA 
          cis) sulfates in mice; and, N-(3-phenoxybenzoyl) glutamate in 
          cows.  These, along with the cyclopropanecarboxylic acid 
          glucuronides and 3-PBA glucuronides are the primary excretion 
          products in most of the species studied.  In rats the metabolism 
          of racemic permethrin is very rapid, some 42 metabolites have 
          been identified none of which have known toxic effects. 
          Elimination is rapid, following a single oral dose of a racemic 
          mixture over 50% of the radioactive lable was excreted within 48 
          hours. It is completely eliminated within 8 to 12 days of 

    2.1.4 Toxicity, sinple dose - The toxicity of the racemic mixture 
          varies with the cis/trans ratio and the characteristics of the 
          vehicle uged. In general the cis isomers are the most toxic and 
          non-polar carriers increase the toxicity of both isomers. 

          Oral LD50:

          Rat  (M)          430 mg/kg b.w.;  racemic permethrin in corn oil
          Rat  (F)          470 mg/kg b.w.;  racemic permethrin in corn oil
          Mouse (M, F)    3 150 mg/kg b.w.;  1R, trans-permethrin
          Mouse (M, F)       96 mg/kg b.w.;  1R, cis-permethrin
          Mouse (M, F)   +5 000 mg/kg b.w.;  1S, cis/trans-permethrin
          Mouse (M)         310 mg/kg b.w.;  racemic cis/trans = 75/25
          Mouse (M)         470 mg/kg b.w.;  racemic cis/trans = 50/50
          Mouse (M)       1 620 mg/kg b.w.;  racemic cis/trans = 25/75
          Mouse (M)         490 mg/kg b.w.;  racemic permethrin in corn oil
          Mouse (M)      +4 000 mg/kg b.w.;  racemic permethrin in water
          Rabbit (F)     +4 000 mg/kg b.w.;  racemic permethrin in water
          Guinea-pig (M) +4 000 mg/kg b.w.;  racemic permethrin in water

          Dermal LD50:

          Mouse (M, F)   +2 500 mg/kg b.w.;  racemic permethrin no solvent
          Rat   (M, F)   +2 500 mg/kg b.w.;  racemic permethrin no solvent
          Rat   (M, F)      750 mg/kg b.w.;  racemic permethrin in xylene
          Rabbit (F)     +4 000 mg/kg b.w.;  racemic permethrin no solvent

          Subcutaneous LD5O:

          Mouse (M, F)  +10 000 mg/kg b.w.;  racemic permethrin in corn oil
          Rat   (M, F)    6 500 mg/kg b.w.;  racemic permethrin in corn oil

          Intraperitoneal LD50:

          Rat   (M, F)   +3 500 mg/kg b.w.;  racemic permethrin in water
          Mouse (M, F)      540 mg/kg b.w.;  racemic permethrin no solvent

          Inhalation LC50:

          Mouse (M, F)     +685 mg/m3;  racemic permethrin in kerosine
          Rat (M, F)       +685 mg/m3;  racemic permethrin in kerosine

          In general pyrethroid poisoning is characterized by hyperactivity
          and hypersensitivity (somatosensory).  Permethrin is included 
          among those pyrethroids which produce the T-syndrome in rats,
          consisting of hypersensitivity to external stimuli and fine whole
          body tremors progressing to gross tremors and prostration. 

    2.1.5 Toxicity, repeated doses -

          Oral: Beagle dogs were given permethrin in gelatin capsules for 
          three months at dosage levels of 5, 100 or 500 (mg/kg b.w.)/day 
          in one study and 10, 100 or 5000 (mg/kg b.w.)/day in a second 
          study.  Transient clinical signs of toxicity were observed at 500 
          and 5000 mg/kg b.w. and liver to body weight ratios were 
          increased at 5000 mg/kg b.w./day. 

          Dermal: Rabbits administered up to 1.0 (g/kg b.w.)/day on intact 
          and abraded skin for 21 days showed no clinical signs of toxicity 
          other than moderate skin irritation and no other ill-effects.  In 
          a 21 day wear-test, cotton cloth impregnated with permethrin 
          (0.125or 1.25 mg/cm2) applied to shaved, intact rabbit skin 
          produced no observed ill-effects. 

          Inhalation: Sprague Dawley rats subjected to permethrin at 0, 
          125, 250 or 500 mg/m3 for six hours a day, five days a week for 
          13 weeks in a metabolism and excretion study exhibited no 
          observed toxicological effects. 

          Cumulation of compound: Permethrin does not accumulate in body 
          tissues due to rapid metabolism and excretion. 

          Cumulation of effects: No evidence of adverse effects were 
          presented in the reports of subacute studies. 

    2.1.6 Dietary studies -

          Short-term: Technical permethrin dissolved in corn oil was fed to 
          mice at dietary levels of 200 to 4000 mg/kg and to an additional 
          group, 80 mg/kg for two weeks increased to 10 000 mg/kg for the 
          remainder of the 28-day study; to rats in several studies of 
          different durations (from 4-26 weeks) and several ranges of 
          dietary levels up to 3000 mg/kg for 26 weeks, 4000 mg/kg for 13 
          weeks and 10 000 mg/kg for four weeks; and, to lactating cows at 
          dietary levels of 0.2 to 50 mg/kg for 28 days.  Acetone solutions 
          of permethrin were given to rats at dietary levels up to 13 000 
          mg/kg for 90 days and 17 280 mg/kg for 14 days.  There were no 
          observed compound related changes in growth. Mortality was not an 
          observed effect of permethrin administration except in rats fed 
          very high dose levels which were usually associated with reduced 
          food consumption.  Corn oil solutions appear to be more toxic 
          than acetone solutions.  In Sprague Dawley rats the observed 
          minimum lethal level for corn oil solutions was 5000 mg/kg (diet) 
          compared to 8640 mg/kg (diet) for acetone solutions.        
          Transient, early clinical signs of toxicity were observed in rats 
          at high sublethal doses only.  Consistently in mice and rats, 
          liver weight and liver-to-body weight ratios were elevated by 
          permethrin administration and were accompanied by slight 
          hypertrophy and fatty changes; these changes were not permanent.  
          Compound-induced changes in histo-pathology suggestive of 
          tumorigenicity were not observed.  In lactating cows permethrin 
          residues, originating from the cis isomer primarily, were found 
          to plateau at low levels in milk and body tissues within a few 
          days of initial administration.  These residues were quickly 
          eliminated after cessation of exposure. 

          The observed no-effect level in rats was 2000 mg/kg diet in a 90-
          day study, equivalent to 175 (mg/kg b w.)/day and 1500 mg/kg 
          (diet) in a 26-week study, equivalent to 93 (mg/kg b.w.)/day.

          Long-term: At the time of preparation of this data sheet, only 
          four of several long-term studies were available in published 
          form.  In two mouse chronic studies the dietary levels were 250, 
          1000 and 2500 mg/kg in one and, 20, 100 and 500 mg/kg in the 
          other.  In the second study, after 2-3 weeks of administration, 
          the two highest dose levels were increased to 4000 and 5000 mg/kg 
          respectively, the latter increase was reversed after two weeks 
          however.  In two chronic rat studies, dietary levels of 20, 100 
          and 500 mg/kg and 500, 1000 and 2500 mg/kg were administered.  
          There were no consistent compound-related changes in growth or 
          food consumption in either species.  In general, mortality was 
          not an observed effect of permethrin administration although in 
          mice, at 4000 mg/kg, the incidence of mortality in the later 
          stage of the study was increased significantly.  Permethrin 
          caused a dose-dependent increase in liver weights and liver-to-
          body weight ratios in both species.  In mice, and to a lesser 
          extent in rats, hepatocellular hypertrophy, pleomorphism and 
          hepatic degeneration were highest in the treatment groups and 
          were possibly dose dependent in mice.  There was no oncogenic 
          effect due to permethrin in these studies.  The rat chronic study 
          no effect level was observed to be 100 mg/kg (diet) equivalent 
          to 5.0 (mg/kg b.w.)/day. 

    2.1.7 Supplementary studies of toxicity -

          Carcinogenicity: Administration of high doses of permethrin to 
          mice in long-term dietary studies was associated with significant 
          increases in very frequently occurring benign lung adenomas.  
          This apparent induction activity was restricted to only one sex 
          in any given study and to only one species.  The lesion was not 
          seen in comparable rat studies.  In mice, the increased incidence 
          was not associated with increased mortality, decreased latency or 
          increased malignancy.  Furthermore, extensive mutagenicity 
          testing including point mutation, chromosomal aberration, 
          dominant lethal, Ames, DNA repair and mammalian cell 
          transformations (in vivo and in vitro studies) produced no 
          evidence of permethrin-induced genetic activity. Although 
          tumorigenic activity has been demonstrated in mice, collectively 
          these findings do provide any evidence of carcinogenic potential 
          for permethrin. 

          Teratogenicity: Permethrin was neither embryotoxic nor 
          teratogenic in a mouse study at dosage levels of 5-150 mg/kg b.w. 
          administered from days 7 through 12 of gestation nor in two rat 
          studies, one at 22.5 to 225 mg/kg b.w. from days 6 through 15 and 
          another study at 4-83 mg/kg b.w. (in corn oil) from days 6 

          through 16.  It also did not adversely affect weaning efficiency 
          following normal deliveries in the mouse study nor in a third rat 
          study at dosage levels of 10-50 mg/kg b.w. administered from day 
          9 through 14 of gestation. In the latter rat study, the only 
          observed effect was a slightly increased incidence of 
          non-ossified sternebrae in the Caesarean delivered pups at
          50 mg/kg b.w.

          Mutagenicity: See carcinogenicity section above.

          Reproduction: In a standard rat three-generation study, 
          permethrin at dosage levels of 20 and 100 mg/kg (diet) produced 
          no adverse reproductive effect (including indices of fertility, 
          gestation, viability and lactation).  In a second rat study also, 
          permethrin at dosage levels of 500, 1000 and 2500 mg/kg (diet) 
          produced no adverse changes in standard indices of reproductive 
          success.  In the F3 b-litters females displayed transient 
          clinical signs of acute toxicity, and dose-dependent increased 
          incidences of hepatic centrilobular hypertrophy and cytoplasmic 
          eosinophilia were observed in both sekes. (No teratogenic effects 
          were observed in a third set of litters of the F3 generations at 
          21 days of gestation.) 

          Neurotoxicity: In rats, high doses of pemethrin (6.0 g/kg of 
          diet for 14 days), caused some neuropathy, including minimal 
          demyelination and myelin ovoids on the sciatic nerve.  Clinical 
          signs of neurotoxicity were observed at doses of 5.0 g/kg diet 
          and above. 

          Hens given 1.0 g/kg b.w. doses of permethrin in DMSO (p.o.) 
          showed no evidence of delayed neuropathy or other adverse effects 
          during three weeks of post-treatment observation.  Changes in EEG 
          spike and slow wave patterns were observed in rabbits, cats and 
          guinea-pigs given 100 mg/kg b.w. in a single dose, no EEG changes 
          were observed at 30 mg/kg b.w.

          Primary irritation and sensitization: In rabbits, technical 
          permethrin produced mild primary skin irritation following 24-
          hour application of 0.5 ml to intact and abraded skin and mild 
          primary eye irritation (conjunctivitis) following ocular 
          instillation of 0.1 ml without rinsing. 

          Technical pemethrin did not produce sensitization reactions in 
          guinea-pigs in a standard Draize test nor acneform dermatitis in 
          rabbits following 30 daily applications of 0.1 ml to the ears.  
          It also did not cause dermal photochemical reactions in rabbits 
          under test conditions. 

          Special pharmacological effects: In rabbits, 4 mg/kg b.w. 
          produced hypotension, reduced respiration and an increased heart 

          rate with no attendant changes in ECG wave pattern.  In mice, 
          dosage levels up to 2000 mg/kg b.w. did not change hexobarbital 
          induced sleeping time. 

    2.1.8 Modifications of toxicity - Esterase and oxidase enzyme systems 
          are important in the detoxification process, inhibitors of these 
          enzymes will increase the toxicity to permethrin in both mammals 
          and target organisms. 


    2.2.1 Absorption route - Permethrin may be readily absorbed from the 
          gastrointestinal tract; minimally through the intact skin, 
          especially in non-polar solvents; and by inhalation of dust and 
          fine spray mist. 

    2.2.2 Dangerous doses - No information available.

    2.2.3 Observations of occupationally exposed workers - In Sweden 33% of 
          workers polled reported skin and eye irritation following 
          occupational exposure. 

    2.2.4 Observations on exposure of the general public - No information 

    2.2.5 Observations of volunteers - In WHO trials in Nigeria, following 
          indoor use at doses of 0.5 g/m3, volunteers to exposure made no 
          complaint about adverse effects nor were any observed. 

    2.2.6 Reported mishaps - No information available.


    2.3.1 Fish - Permethrin is highly toxic to fish, however the risk is of 
          short duration due to rapid loss from water by adsorption and 
          degradation.  There have been no reports of problems of fish 
          toxicity during commercial use (including aerial application). 

          LC50 (96 h):          Technical material

          Rainbow trout               0.1-0.5  g/l
          Channel catfish                 1.10 g/l
          Large-mouth bass (fingerlings)  8.50 g/l
          Mosquito fish                  15.0  g/l
          Salmon                         12.0  g/l

          LC50 (24 h):

          Rainbow   trout                25.0  g/l (cis)
                                         14.0  g/l (trans)

                                         18.0  g/l (technical grade)
          LD50 (I.P.):

          Rainbow trout                  22.0  mg/kg b.w. (cis)
                                          7.0  mg/kg b.w. (trans)
                                         14.0  mg/kg b.w. (technical grade)

    2.3.2 Birds - Permethrin is of very low toxicity to birds.  Hens 
          treated with coarse spray mist (3.77-11.94 mg/bird) showed no 
          adverse effects and no significant accumulation in body tissues 
          or eggs. 

          Oral LD50 acute:     Technical material

          Starlings                 +32 000 mg/kg b.w.
          Mallard duck              +11 275 mg/kg b.w.

          Oral LD50 subacute:
          Pheasants                 +23 000 mg/kg b.w.
          Japanese quail            +23 000 mg/kg b.w.
          Starlings                 +23 000 mg/kg b.w.

    2.3.3 Beneficial insects - In laboratory studies permethrin is found to 
          be toxic to bees; however, hazard in the field is limited by 
          repellancy, low rates of application and lack of toxic effect 
          once the spray has dried. 

    2.3.4 Others - Permethrin is toxic to some groups of aquatic 
          invertebrates, amphibian larval forms, insects and crustaceans.
          However, due to the short persistence of permethrin, most 
          populations soon recover.


         categories see introduction) 

         All current formulations: Category 5


         Formulations in category 5 - Should be transported and stored in 
         clearly labelled, leakproof containers out of reach of children, 
         away from food and drink.  Avoid contact with metals other than 
         aluminium and tin.

    3.3  HANDLING

         Formulations in Category 5 - No facilities other than those 
         needed for the handling of any chemical are required. 


         All formulations - Containers may be decontaminated (for 
         method see paragraph 4.3 of Part 4). Decontaminated 
         containers should not be used for food and drink.         
         Containers that are not decontaminated should be burned or 
         should be crushed and buried below topsoil.  Care must be 
         taken to avoid subsequent contamination of water sources. 


         Formulations in Category 5 - Warning of workers to minimize 
         contact is essential.  Persons under medication with 
         neuroactive drugs should avoid contact. 


         All formulations - Pilots and loaders should have special 
         training in application methods and recognition of early 
         warning symptoms of poisoning and, they must wear a suitable 
         respirator.  Flagmen should wear overalls and a broad brimmed 
         hat and be well away from the dropping zone. 


        Formulations in Category 5 - Minimum cautionary statement - 
        "CAUTION" - This formulation contains permethrin, it may be 
        poisonous if swallowed.  Keep the material out of reach of 
        children and well away from foodstuffs, animal feed and food 


        Maximum residue limits for permethrin have been recommended 
        by the joint FAO/WHO Meeting on Pesticide Residues. 



    4.1.1 General - Permethrin is a synthetic pyrethroid and a neurotoxic 
          agent of low toxicity to mammals.  It may be readily absorbed 
          from the gastrointestinal tract; by inhalation of dust and spray 
          mist; and, minimally through the intact skin.  The health hazard 
          is considerably diminished by the low concentrations of the 

          active ingredient in all formulations. 

    4.1.2 Manufacture and formulation - T.L.V. - No information.  Closed 
          systems and forced ventilation may be required to reduce, as much 
          as possible, the exposure of workers to the chemical. 

    4.1.3 Mixers and applicators - When opening a container and when 
          mixing, protective impermeable boots, clean overalls, impermeable 
          gloves, eye protection and a respirator should be worn.  Mixing, 
          if not mechanical, should always be carried out with a paddle of 
          appropriate length.  Avoid contact with mouth and eyes.  Before 
          eating, drinking or smoking, hands and other exposed skin should 
          be thoroughly washed with alkaline soap. 

    4.1.4 Other associated workers (including flagmen in aerial operations)
          - Persons exposed to permethrin and associated with its 
          application should observe the precautions described above in 

    4.1.5 Other populations likely to be affected - With good agricultural 
          practice, subject to 4.2 below, other populations are not likely 
          to be exposed to hazardous amounts of permethrin. 

    4.2  ENTRY OF PERSONS INTO TREATED AREAS - Though permethrin is 
         relatively persistent, low application rates ensure low 
         residue levels.  Unprotected persons may enter treated areas 
         almost immediately after spraying without being exposed to 
         hazardous amounts of permethrin. 

         containers should be emptied in a diluted form into a deep 
         pit taking care to avoid ground waters.  The empty container 
         may be decontaminated by rinsing two or three times with 
         water and detergent and scrubbing the sides.  The hands 
         should be protected during this work.  Decontaminated 
         containers should not be used for food and drink. 


    4.4.1 Early symptoms of poisoning - These may include nausea and 
          vomiting; shortness of breath and laboured breathing; fine or 
          coarse tremors, hypersensitivity to external stimuli and general 
          weakness, and prostration.  A burning and itching sensation often 
          follow contact. 

    4.4.2 Treatment before person is seen by a physician, if these symptoms 
          appear following exposure- The person should stop work 
          immediately, remove contaminated clothing and clean the affected 
          skin area.  First, soak-up any liquid remaining on the skin with 
          readily disposable material (e.g., talcum powder or absorbant 

          cloth or paper), wash the affected area with warm water and 
          alkaline soap.  For eye contamination, wash with copious amounts 
          of 4% sodium bicarbonate or water.  Avoid exposing affected skin 
          or eyes to bright light. If the material was swallowed and signs 
          of toxicity are severe, induce vomiting if the person is 
          conscious and aspiration of vomit can be avoided. In the event of 
          collapse, apply artificial respiration.  Keep in mind that if 
          mouth to mouth respiration is used, vomit may contain toxic 
          amounts of permethrin. Keep the person calm and comfortable and, 
          obtain medical help as soon as possible. 



    5.1.1 General information - Permethrin is a synthetic pyrethroid 
          pesticide of low toxicity to mammals.  It is readily absorbed 
          from the gastrointestinal tract; by inhalation of dust and spray 
          mist; and, through the intact skin to a limited extent.  The 
          hydrolysis and oxidation products of metabolism are rapidly 
          excreted in the urine and faeces.  Permethrin is a neurotoxic 
          agent most probably acting on the central nervous system to cause 
          repetitive nerve activity. 

    5.1.2 Signs and symptoms - Little information is available on the acute 
          toxic effects of permethrin in humans.  Based upon animal 
          studies, high doses may cause repetitive activity in sensory and 
          motor nerves.  Early signs of poisoning may include nausea and 
          vomiting; dyspnoea and hyperpnoea; fine or coarse tremors, 
          hypersensitivity to stimuli and a feeling of general weakness and 
          prostration.  A burning and itching sensation often follow 

    5.1.3 Laboratory - There are no established, practical methods for 
          determining permethrin in body fluids.  Urinary levels of 3-
          phenoxybenzyl degradation products may be a useful index of 
          exposure.  In addition, electrophysiological monitoring of 
          sensory nerve potentials and, central nervous and cardiac 
          activities (EEG and ECG) may be useful in diagnosis and in 
          assessment of therapy. 

    5.1.4 Treatment - There are no specific antidotes, treatment must be 
          symptomatic.  Keep the patient warm and calm. In cases of severe 
          intoxication, therapy should include a sedative and 
          anticonvulsant (e.g. barbiturates, diazepam, paraldehyde, etc.). 
          The use of antispasmodic drugs is of limited value, mephenesin 
          and atropine have been found to effectively alleviate the 
          symptoms of pyrethroid poisoning in laboratory animals.  If a 
          large quantity of permethrin has been swallowed, unless the 
          patient is unconscious or vomiting, gastric lavage should be 

          perfomed using a 5% sodium bicarbonate solution, follow with 
          powdered activated charcoal.  For skin contact, soak up any 
          liquid remaining on skin with readily disposable absorbent 
          material, then wash the affected area with warm water and 
          alkaline soap.  If skin irritation occurs treat with a soothing 
          skin cream and avoid exposure to direct light.  For eye 
          contamination, wash the eye with 4% sodium bicarbonate or any 
          other non-irritating, alkaline aqueous solution. 

    5.1.5 Prognosis - There have been no reports of overt symptoms 
          resulting from poisoning of man by permethrin; the prognosis 
          therefore is not known.  However, by analogy with laboratory 
          animals it may be assumed that if the acute toxic effect is 
          survived the chances of complete recovery are good. 

    5.1.6 References to previously reported cases - No information.


    5.3  LABORATORY METHODS - References only are given,

    5.3.1 Detection and assay of compound and residues -

          Chapman, R. A. & Harris, C. R. (1978) Journal of Chromatography, 
          166(2), 513-516 

          Chiba, M. (1978) J. Environ. Sci. Health, B13(3), 261-268 

          Fujie, G. H. & Fullmar, D. H. (1978) J. Agric. Food Chem., 
          26(2), 395-398 

          Horiba, M., Akira, K. & Murano., A. (1977) Agric. Biol. Chem.,
          41(3), 581-586 

          Kikta, E. J. & Shierling, J. P. (1978) Journal of Chromatography,
          150, 229-232 

          Lam, S. & Grushka, E. (1978) Journal of Chromatography, 154,

          Oshler, D. D. (1979) J. Assoc. Off. Anal. Chem., 62(6), 

          Papadopoulou-Mourikidou, E., Iwata, Y. & Gunther, F. A. (1980)
          J. Agric. Food Chem., 28(6), 1043-1049 

          Siegel, M. W., Hildebrand, B. E. & Hall, D. R. (1980) Intern.  
          J. Environs Anal. Chem., 8, 107-126 

    5.3.2 Other tests in case of poisoning - No information.


See Also:
        Permethrin (EHC 94, 1990)
        Permethrin (IARC Summary & Evaluation, Volume 53, 1991)
        Permethrin (ICSC)
        Permethrin (UK PID)