PMEP Home Page --> Pesticide Active Ingredient Information --> Insecticides and Miticides --> Insecticides N to P --> Pyrethrins --> Pyrethrins - Chemical Profile 3/85

Pyrethrins - Chemical Profile 3/85


      CHEMICAL NAME:      Six related esters:  pyrethrins I and II, cinerins
                          I and II, and jasmolins I and II (56).  From flowers
                          of Pyrethrum cinerariaefolium (62).


      TRADE NAME(S):      Pyrenone, Pyrocide (56)

      FORMULATION(S):  Wettable powders, emulsifiable concentrates, dusts,
      aerosols, space sprays; livestock sprays.  Usually combined with a
      synergist such as piperonyl butoxide (1).
           Pyrethrum extract is available to formulators as a concentrate in
      oil, usually containing synergists; in impregnated and stabilized dust
      concentrates; and in dilute dusts made from ground flowers.  In recent
      years a low-color, 20% pyrethrin extract in oil has become the "standard"
      item of the industry, although less concentrated solutions in oil are
      still available (56).

      TYPE:               Botanical insecticide

      BASIC PRODUCER(S):  Fairfield American Corp.
                          An AOSI Co.
                          238 Wilson Ave.
                          Newark, NJ 07105

                          McLaughlin Gormley King Co.
                          8810 Tenth Ave. North
                          Mineapolis, MN 55427

                          Prentiss Drug and Chemical Co., Inc.
                          21 Vernon St.
                          CB 2000
                          Floral Park, NY 11001

      STATUS:             General use

      PRINCIPAL USES:  Mostly a contact insecticide for household insects,
      flies, mosquitoes and livestock.  Usually applied as aerosols or space
      sprays but some formulations can be applied to agricultural crops (1).
           Because of their safety, pyrethrum extracts are used extensively
      in stock sprays, pet sprays, household sprays, and aerosols, industrial
      sanitation sprays, and to protect stored food in warehouses, etc (56).

                                   I.  EFFICACY

           These esters rapidly paralyze the insect nervous system, making them
      famous for their quick "knockdown" effect (25).

      Important Pests Controlled:  Mosquitoes, flies, aphids, Mexican bean
      beetles, imported cabbage worms, mealybugs, beetles, thrips, fleabeetles,
      sod webworm, loopers, leafhoppers, lice, Colorado potato beetle and many
      others (8a).

                             II.  PHYSICAL PROPERTIES

      MOLECULAR FORMULA:  pyrethrin I, C21 H28 O3; pyrethrin II, C22 H28 O5;
                          cinerin I, C20 H28 O3; cinerin II, C21, H28 O5;
                          jasmolin I, C21 H30 O3; jasmolin II, C22 H30 O5

      MOLECULAR WEIGHT:   pyrethrin I, 328.4; pyrethrin II, 372.4; cinerin I,
                          316.4; cinerin II, 360.4; jasmolin I, 330.4;
                          jasmolin II, 374.4 (62).

      PHYSICAL STATE:     Most commercial extracts contain 20-25% pyrethrins
                          and are pale yellow, the plant waxes and pigments
                          having been removed.  The ratio of pyrethrin :
                          cinerin : jasmolin is generally 71 : 21 : 7 (62).

      VAPOR PRESSURE:     Essentially zero at 20 C (14)

                          III.  HEALTH HAZARD INFORMATION

      OSHA STANDARD:  5 mg/m3 averaged over an eight-hour work shift (14).

      NIOSH RECOMMENDED LIMIT:  None established

      ACGIH RECOMMENDED LIMIT:  TWA (Time Weighted Average) = 5 mg/m3;
                                STEL (Short Term Exposure Limit) = 10 mg/m3


           A.  ACUTE TOXICITY

               DERMAL:  LD50 = >1500 mg/kg (rat).  Constituents of the
                          flowers may cause dermatitis to sensitized
                          individuals (62).
                        LD50 = >1800 mg/kg (rat) (56)

               ORAL:    LD50 = 584-900 mg/kg (rat) (62)
                        LD50 = 1500 mg/kg (rat) (56)

               INHALATION:  Carpenter and co-workers (1950) exposed rats
                            at 6000 mg/m3 of pyrethrum in peanut oil for
                            30 minutes.  Moderate lung congestion resulted


           Rats and dogs inhaled a concentration of 16 mg/m3 for thirty
      minute periods during 31 calendar days with only slight lung irritation
           Lehman (1952) estimated that the fatal human dose might be 100 grams
      (1430 mg/kg) for a 70-kg man (15b).
           Ambrose and Robbins (1951) reported no effect in rats fed pyrethrins
      at a dietary level of 1000 ppm for two years, but tissue damage and gross
      signs appeared in some rats given 5000 ppm.
      Lehman (1952) confirmed these results.  The no-effect level corresponds
      to a rate of 3600 mg/man/day (15b).

                        IV.  ENVIRONMENTAL  CONSIDERATIONS

           Little or no hazard to birds, fish and beneficial insects.
      Relatively nonhazardous to honey bees.  No biological magnification.
      Nonphytotoxic when used as directed (1).

           Highly toxic to fish (62).

      Approximate Residual Period:  1-3 days on plant and unexposed surfaces;
      short residue in soil and water (1).


           The chemical information provided below has been condensed
      from original source documents, primarily from "Recognition and
      Management of Pesticide Poisonings", 3rd ed. by Donald P.  Morgan,
      which have been footnoted.  This information has been provided in
      this form for your convenience and general guidance only.  In
      specific cases, further consultation and reference may be required
      and is recommended.  This information is not intended as a sub-
      stitute for a more exhaustive review of the literature nor for the
      judgement of a physician or other trained professional.

           If poisoning is suspected, do not wait for symptoms to develop.
      Contact a physician, the nearest hospital, or the nearest Poison
      Control Center.



           A STUFFY, RUNNY NOSE and scratchy throat from inhalation of partly
      purified pyrethrum extract is the most common adverse effect of these
      agents.  Asthmatic WHEEZING may be precipitated by exposure of
      predisposed individuals.  Sudden bronchospasm, swelling of oral and
      laryngeal mucous membranes, and shock (anaphylaxis) have been reported
      after pyrethrum inhalation.  Delayed appearance of dyspnea, cough and
      fever, with patchy lung infiltrates on x-ray, suggest hypersensitivity
      pneumonitis.  Nervous irritability, tremors, and ataxia have occurred
      rarely in persons who have had massive inhalation exposure to
      pyrethrins.  Halocarbon propellents in bug-bomb products present a risk
      of CARDIAC ARRHYTHMIA and possibly fibrillation if inhaled to excess.
      Hydrocarbons used as solvents in spray products are likely to result in
      COUGH, FEVER, and CHEST PAIN (hydrocarbon pneumonitis) if these liquids
      are inadvertently aspirated (25).

           SKIN CONTACT:  Wash contaminated pesticide from the eye with
      copious amounts of water (25).

           INGESTION:  When pyrethrum or liquids containing pyrethrum have
      been swallowed and the person is conscious, give the person large
      quantities of water immediately.  After the water has been swallowed,
      try to get the person to vomit by having him touch the back of his
      throat with his finger.  Do not make an unconscious person vomit.  Get
      medical attention immediately (14).

           INHALATION:  If a person breathes in large amounts of pyrethrum,
      move the exposed person to fresh air at once.  If breathing has
      stopped, perform artificial respiration.  Keep the affected person warm
      and at rest.  Get medical attention as soon as possible (14).

           EYE CONTACT:  Wash contaminating pesticide from the eye with
      copious amounts of water (25).


      If victim is not fully alert, empty stomach immediately by intubation,
      aspiration, and lavage, using isotonic saline or 5% sodium bicarbonate.
      Because many pesticides are dissolved in petroleum distillates, emesis
      and intubation of the stomach involve a risk that solvent will be
      aspirated, leading to chemical pneumonitis.  Do not administer or
      instill milk, cream, or other substances containing vegetable or animal
      fats, which enhance absorption of lipophilic substances, such as
      pyrethrins and pyrethroids.

      Diazepam (Valium) 5-10 mg in adults, 0.1 mg/kg in children, given
      orally or slowly IV, should control nervousness and tremors in rare
      cases having these symptoms after extraordinary exposure to pyrethrins
      and pyrethroids (25).

                        VI.  FIRE AND EXPLOSION INFORMATION

      GENERAL:  Flash point:  82-88 C (180-190 F) (open cup) (14).

      EXTINGUISHER TYPE:  Carbon dioxide, foam, dry chemical (14).

                                VII.  COMPATIBILITY

           Incompatible with lime and ordinary soaps (1).  Contact with
      strong oxidizers may cause fires and explosions (14).

                            VIII.  PROTECTIVE MEASURES

      STORAGE AND HANDLING:  Avoid contact with skin.  Keep out of any body
      of water.  Do not contaminate water by cleaning of equipment or
      disposal of waste.  Do not reuse empty container.  Destroy it by
      perforating or crushing.  Bury or discard in a safe place away from
      water supplies (56).

      PROTECTIVE CLOTHING:  Employees should be provided with and required to
      use impervious clothing, gloves, face shields (eight-inch minimum), and
      other appropriate protective clothing necessary to prevent contact with
      pyrethrum or liquids containing pyrethrum where skin contact may occur
      (14).  Employees should be provided with and required to use dust- and
      splash-proof safety goggles where pyrethrum or liquids containing
      pyrethrum may contact the eyes (14).
           None for household level sprays or aerosols (56).

      PROTECTIVE EQUIPMENT:  Respirators may be used when engineering and
      work practice controls are not technically feasible, when such controls
      are in the process of being installed, or when they fail and need to be
      supplemented.  Respirators may also be used in emergency situations.
      If the use of respirators is necessary, the only respirators permitted
      are those that have been approved by the Mine Safety and Health
      Administration or by the National Institute for Occupational Safety and
      Health (14).

                       IX.  PROCEDURES FOR SPILLS AND LEAKS

                                  (800) 424-9300

      Persons not wearing protective equipment and clothing should be
      restricted from areas of spills until cleanup has been completed.

      If Pyrethrum is spilled, the following steps should be taken:

      1.   Ventilate area of spill.
      2.   For small quantities, sweep onto paper or other suitable material,
           place in an appropriate container and burn in a safe place (such
           as a fume hood).  Large quantities may be reclaimed; however, if
           this is not practical, dissolve in a flammable solvent (such as
           alcohol) and atomize in a suitable combustion chamber.

      Waste disposal methods:

      Pyrethrum may be disposed of:

      1.   By making packages of pyrethrum in paper or other flammable
           material and burning in a suitable combustion chamber.
      2.   By dissolving pyrethrum in a flammable solvent (such as alcohol)
           and atomizing in a suitable combustion chamber (14).

                               X.  LITERATURE CITED

       1.  Harding, W.C.  1979.  Pesticide profiles, part one: insecticides
               and miticides.  Univ. Maryland, Coop. Ext. Serv. Bull. 267.
               30 pp.

       8a. Thomson, W. T.  1976.  Agricultural chemicals - book 1:
               insecticides, acaricides, and ovicides.  Revised ed.  Thomson
               Publ., Indianapolis, IN.  232 pp.

      14.  U. S. Department of Health and Human Services, National Institute
               for Occuptational Safety and Health.  1981.  Occupational
               health guidelines for chemical hazards.  F. W. Mackinson, R.
               S. Stricoff, L. J. Partridge, Jr., and A. D. Little, Inc.,
               eds.  DHHS (NIOSH) Publ. No. 81-123.  Washington, DC.

      15b. American Conference of Governmental Industrial Hygienists.  1971.
               Documentation of the threshold limit values for substances in
               workroom air with supplements for those substances added or
               changed since 1971, 3rd ed., 4th printing (1977).  Cincinnati,
               OH.  484 pp.

      15c. American Conference of Governmental Industrial Hygienists.  1984.
               TLVs:  threshold limit values for chemical substances and
               physical agents in the work environment and biological exposure
               indices with intended changes for 1984-85.  Cincinnati, OH.
               116 pp.

      25.  Morgan, D.P.  1982.  Recognition and management of pesticide
               poisonings, 3rd ed.  U.S. Environmental Protection Agency,
               Washington, DC.  120 pp.

      56.  Farm Chemicals Handbook, 70th ed.  1984.  R. T. Meister, G. L.
               Berg, C. Sine, S. Meister, and J. Poplyk, eds.  Meister
               Publishing Co., Willoughby, OH.

      62.  The Pesticide Manual:  A World Compendium, 7th ed.  1983.  C.R.
               Worthing, ed.  The British Crop Protection Council, Croydon,
               England.  695 pp.