WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE
ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
ET L'AGRICULTURE
VBC/DS/80.46
ORIGINAL: ENGLISH
DATA SHEETS ON PESTICIDES No. 46
PHOSPHINE
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 résumé 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 Santé.
CLASSIFICATION:
Primary use: Insecticidal fumigant
Secondary use: Rodenticide
Chemical group: Phosphide
Date issued:
1. GENERAL INFORMATION
1.1 COMMON NAME:
Phosphide
1.1.1 Identity:
Hydrogen phosphide, PH3
1.1.2 Synonyms:
Phosphorus trihydride
Phosphoretted hydrogen
Local synonyms: Phosphine for use in pest control is usually
generated from phosphide salts. One synonym for this is
Phostoxin(R).
1.2 SYNOPSIS:
A gas of very high mammalian toxicity which affects the
gastrointestinal tract and central nervous system, without
cumulative effect. It is used for the fumigation of insect pests of
stored grains and is released by exposure of phosphide tablets to
moist atmosphere.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics
A colourless, inflammable gas with carbide or fish-like odour, B.p.
87.4°C, f.p. 132.5°C.
1.3.2 Solubility
Slightly soluble in water: 228 ml gaseous phosphine/l at 17°C.
1.3.3 Stability
Spontaneously flammable in air with a lower explosion limit of 26.15
to 27.06 g/m2.
1.3.4 Vapour pressure
Not applicable. Phosphine odour (decaying fish) is detectable at
1.5-3 ml/m3 of air.
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY:
No specific use except for the fumigation of stored products to
which the paragraphs below apply.
1.4.1 Common formulations
As aluminium phosphide or other salts in tablets, pellets, and
powder in bags. These are usually used in phosphine generators in
which the salts are exposed to moisture.
1.4.2 Susceptible pests
All insects and their developmental stages: mites and rodents.
1.4.3 Use pattern
For fumigation of stored food products in gas tight areas: sacked
goods 0.75-1.5 g/m3 of piles, grain in silos 1-3 g/tonne.
1.4.4 Unintended effects
No information.
1.5 PUBLIC HEALTH PROGRAMMES
No recommended use.
1.6 HOUSEHOLD USE
No recommended use.
2. TOXICOLOGY AND RISKS
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption route
Absorbed by inhalation of gas and from the gastrointestinal tract
after ingestion of a salt (as aluminium calcium or zinc phosphide).
It is not absorbed percutaneously.
2.1.2 Mode of action
Not clear: possibly phosphorylation of enzymes.
2.1.3 Excretion products
See also data sheet No. 24, zinc phosphide. Phosphine is easily
oxidized; it is excreted in urine either as a hypophosphite or as
dissolved phosphine. Other metabolites include phosphoric acid and
phosphate; it can also be exhaled from the lungs.
2.1.4 Toxicity, single dose
Oral: Not applicable in gaseous form: as zinc phosphide, rat:
41 mg/kg.
Inhalation of phosphine gas.
Rat: LC50 0.68 g/m3 - 65-75 minutes exposure.
1.47 g/m3 35-50 minutes exposure.
Cat: LC50 25 ppm - 2-4 hours daily during three days.
2.1.5 Toxicity; repeated doses:
Inhalation: Cats, guinea pigs and rats were exposed to 1.4 or
3.5 mg phosphine/m3 for more than 800 hours. No haemolysis or
formation of methemoglobin was observed in the erythrocytes or
haemoglobin. There was no evidence of cumulative poisoning. It has
been suggested that, at these levels, an equilibrium is attained
between the intake of phosphine and the detoxification and excretion
and cell repair. The threshold for behavioural changes and
alterations in blood parameters and liver function was 7 mg/m3 in
air.
Cumulation of compound: Phosphine is not cumulative in body
tissues.
Cumulation of effect: See 2.1.5.
2.1.6 Dietary studies
Short-term: Rats fed with grain which had been fumigated at
excessive dosages, showed no ill effects, even when the grain was
not cleaned before consumption.
Long-term: Rats were fed for two years a diet exposed to high
concentrations of phosphine released from aluminium phosphide
pellets. Behaviour, general appearance, survival, body weight, food
consumption, haematology, blood chemistry, urine analyses and bone
marrow data, as well as gross and microscopic findings and rate of
tumour development did nor reveal any toxic effects.
Supplementary studies of toxicity
Carcinogenicity: see 2.1.6.
Teratogenicity: No information.
2.1.8 Modification of toxicity.
No information.
2.2 TOXICOLOGY - MAN
2.2.1 Absorption
Inhalation of phosphine gas or ingestion of phosphide formulations
are main routes of absorption.
2.2.2 Dangerous doses
Single: 9.8 mg phosphine/m3 air gives rise to grave symptoms
after several hours. 14 1 280 mg/m3 are tolerated for 60 minutes.
560 mg/m3 is lethal in 60 minutes - 2.8 g phosphine/m3 is lethal
in a short time.
Repeated: A review of 59 poisonings suggests that the minimum
lethal concentration in air is 7-14 mg/m3 inhaled for two or four
hours for several days.
2.2.3 Observations of occupationally exposed workers
Although phosphine is highly toxic, cases of poisoning are rare and
generally due to careless handling.
2.2.4 Observations on exposure of the general population
With good practice in stored food fumigation the general population
will not be exposed to phosphine.
2.2.5 Observations of volunteers
None.
2.2.6 Reported-mishaps
One fatal and three non-fatal accidental cases of phosphine
poisoning are reported due to an unprofessionally performed
fumigation of stored grain on a tug boat using aluminium phosphide
tablets. Six hundred and seventy-five tablets (675 g of PH3) were
used for the fumigation of 500 t of oats.
Two families with four children who were moved before the fumigation
returned to the area 72 hours afterwards. The onset of the poisoning
signs occurred 24 hours afterwards and the next day one child aged
six, died while being transported to the hospital.
2.3 TOXICITY TO NON-MAMMALIAN SPECIES
2.3.1 Fish
No data available but solubility in water slight.
2.3.2 Birds
No data available.
2.3.3 Other species
Frog LC50: 0.56 mg/l for 30 minutes
0.84 mg/l for 15 minutes.
3. FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON REGULATION OF
COMPOUND
Phosphine is not used as such, but is generated by action of moist
air on aluminium phosphide and other salts.
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY
(For definition of categories, see introduction).
All formulations, Category 2
3.2 TRANSPORTATION AND STORAGE
All formulations - Should be transported and stored in clearly
labelled, hermetically sealed containers; away from sunlight,
oxidizing agents, acids; away from living quarters, under lock and
key, and secure from access by unauthorized persons and children.
They must not be stored in damp condition or allowed to become damp.
No food or drink should be stored in the same compartment.
3.3 HANDLING
All formulations - Full respirator protection should be used by
all those handling this compound. Adequate washing facilities should
be available at all times during handling and should be close to the
site of handling. Eating, drinking and smoking should be prohibited
during handling and before washing after handling. Keep well away
from naked lights.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINER
Containers must be either burned or crushed and buried below
topsoil. Decontamination of containers in order to use them for
other purposes should not be permitted.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
All formulations - Pre-employment and routine medical examination
of workers desirable. Workers suffering from active hepatic renal or
haematological disease should be excluded from contact. Special
account should be taken of workers' mental ability to comprehend and
follow instructions. Training of workers in respiratory protection
is essential.
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT
All formulations - Not applicable.
3.7 LABELLING
All formulations - Minimum cautionary statement - "POISON" (skull
and cross-bones insignia). Aluminium phosphide is a very toxic
substance. Do not inhale dust or fumes. Keep this material out of
reach of children and domestic animals and well away from
foodstuffs, animals feed and their containers. Keep dry; away from
sunlight and acids of all kinds. Open only in open air and keep away
from naked lights. No smoking allowed in vicinity.
3.8 RESIDUES IN FOOD
Preparations of aluminium phosphide which evolve hydrogen phosphide
by reaction with moisture in the surrounding atmosphere are used for
the post-harvest fumigation of a wide range of produce including
processed foods. The powder remaining after the use of the fumigant
preparation is mainly aluminium hyroxide, but may contain a small
amount (up to 5%) of the original content of aluminium phosphide.
The normal cleaning of cereals before milling is effective in
eliminating almost all of this powder. For other foods which cannot
be so cleaned before processing, good practice requires that the
fumigant preparation residues does not come into contact with the
food.
3.8.1 Maximum residue levels
Maximum residue levels have been recommended by the joint FAO/WHO.
Meeting on Pesticide Residues.
4. PREVENTION OF POISONING IN MAN AND EMERGENCY AID
4.1 PRECAUTIONS IN USE
4.1.1 General
Aluminium phosphide decomposes on exposure to humidity to liberate
phosphine gas which is highly hazardous. It is readily absorbed from
the gastrointestinal tract and dust may be absorbed by inhalation.
It is not readily absorbed through the intact skin.
4.1.2 Manufacture and formulation
T.L.V.: 0.3 mg/m3 (USSR) 0.1 mg/m3 (ACGIH). Closed systems and
forced ventilation are required to reduce as much as possible the
exposure of workers to the chemical.
4.1.3 Applicators
Particularly when opening the container, boots, clean overalls,
gloves and respirator must be worn. All protective clothing should
be washed immediately after use and respirator filtres must be
regularly renewed. Before eating, drinking or smoking, hands and
other exposed skin should be washed.
4.1.4 Other associated workers including flagmen in aerial
operations)
Not applicable.
4.1.5 Other populations likely to be affected
With good practice, the general population will not be exposed to
phosphine after the use of the fumigant preparation.
4.2 ENTRY OF PERSONS INTO TREATED AREAS
After adequate ventilation after use, treated areas should be
checked for residual gas concentrations before any unprotected
persons enter these areas.
4.3 DECONTAMINATION OF SPILLAGE AND CONTAINERS
Residues in containers should be buried in a deep well away from any
habitation and taking care to avoid contamination of ground waters.
Decontamination of containers in order to use them for other
purposes should not be permitted. Spillage shot d be removed as much
as possible into a deep dry pit as above and the remainder washed
away with large quantities of water. It should be borne in mind that
during these operations and in the presence of water, phosphine gas
will be liberated and therefore a respirator must be worn, and the
whole area of spillage thoroughly aerated until checked for zero gas
concentration.
4.4 EMERGENCY AID
4.4.1 Early symptoms of poisoning
Earliest symptoms are usually nausea, abdominal pain, vomiting and
diarrhoea, dyspnoea, chilliness, thirst, headache which may be
followed by convulsions or coma.
4.4.2 Treatment before person is seen by a physician if these
symptoms appear following exposure
The person should stop work and move away from the area of treatment
into fresh air. If swallowed, vomiting should be induced if the
person is conscious. The person should be kept at complete rest
until the physician arrives.
5. FOR MEDICAL AND LABORATORY PERSONNEL
5.1 MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF
POISONING
5.1.1 General information
Upon exposure to moisture, aluminium phosphide liberates phosphine,
a gas of very high toxicity which affects the gastrointestinal tract
and central nervous system. It is readily absorbed by inhalation and
from the gastrointestinal tract, but not through the skin.
5.1.2 Symptoms and signs
Earliest symptoms are usually restlessness and fatigue, disturbances
of speech, vision and gait, nausea, abdominal pain, vomiting and
diarrhoea, headache, thirst, chilliness. Respiratory symptoms
include dyspnoea, tightness of the chest and pulmonary oedema. These
may be followed by convulsions and coma. Death may occur from heart
failure within four days or be delayed one to two weeks. Chronic
inhalation of subtoxic doses has been said to lead to toothache,
swollen jaw and mandibular necrosis. Other symptoms are anorexia and
weight loss, anaemia and a tendency to spontaneous bone fracture.
The patient's breath may smell of phosphine (fish-like odour) and
there may be coughing with green, fluorescent sputum.
5.1.3 Laboratory
No specific test is known to confirm exposure.
5.1.4 Treatment
Treatment is mainly symptomatic. If ingested, vomiting should be
induced immediately followed by gastric lavage with two to four
litres of water. Acute pulmonary oedema should be treated by oxygen
inhalation and prophylactic penicillin. The patient should be kept
at rest.
5.1.5 Prognosis
If the patient survives for four days the prognosis is good.
However, recovery is slow and there may be irreversible lesions of
the kidneys and liver.
5.1.6 References of previously reported cases
Cases of poisoning are documented in: Harper, R. N. & Spolyar, L. W.
(1958) Archs. Industr. Hlth, 18, 497. Sovljanski, R. et al. (1969)
Arhiv. Big. Rada Toksi. 20 (2), 209. Van Oettingen, E. W. The
toxicity and potential dangers of zinc phosphide and of hydrogen
phosphide, Public Health Report, 203.1, 1947.
5.2 SURVEILLANCE TESTS
There are no readily available surveillance procedures to determine
the degree of absorption prior to the appearance of symptoms.
5.3 LABORATORY METHODS
References only are given.
5.3.1 Detection and assay of compound
For the estimation of phosphine in air, aspirate through mercurous
chloride solution and note the change of pH: Taylor (1968). Very low
concentrations of phosphine in air can also be detected by gas
chromatography: see Dumas (1969) and Berck (1970).
5.3.2 Other tests in cases of poisoning
Estimation of methaemoglobin.
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