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).
DEC INGRED. CODE:
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.
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).
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
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
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
B. SUBACUTE AND CHRONIC TOXICITY:
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).
V. EMERGENCY AND FIRST AID PROCEDURES
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
FREQUENT SYMPTOMS AND SIGNS OF UNDUE EXPOSURE TO PYRETHRUM, PYRETHRINS,
PYRETHROIDS, AND PIPERONYL BUTOXIDE
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).
NOTES TO PHYSICIAN:
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).
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
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
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.
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.
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.