WORLD HEALTH ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE
FOOD AND AGRICULTURE ORGANIZATION
OF THE UNITED NATIONS
ORGANISATION DES NATIONS UNIES POUR
L'ALIMENTATION ET L'AGRICULTURE
Date of issue: February 1994
WHO/FAO DATA SHEET ON PESTICIDES
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
The issue of this document does not constitute formal
publication. It should not be reviewed, abstracted or quoted
without the agreement of the Food and Agriculture Organization
of the United Nations or of the World Health Organization.
Ce document ne constitue pas une publication. Il ne doit faire
l'objet d'aucun compte rendu ou résumé ni d'aucune citation
sans l'autorisation de l'Organisation des Nations Unies pour
l'Alimentation et l'Agriculture ou de l'Organisation Mondiale
de la Santé.
Primary use: Insecticide
Secondary use: Acaricide
Chemical group: Organophosphorus compound
1.0 GENERAL INFORMATION
1.1 COMMON NAME: bromophos (ISO)
IUPAC chemical name: O-4-bromo-2,5-dichlorophenyl
CAS chemical name: O-(4-bromo-2,5-dichlorophenyl) O,O-
CAS registry number: 2104-96-3
RTECS number: TE7175000
Molecular formula: C8H8BrCl2O3PS
Relative molecular mass: 366.0
Synonyms and tradenames : Bromofos; BrofeneR; BropheneR;
CELA-1942; ENT-27162; NexionR; Omexan; OMS-658; S-1942;
1.2 SYNOPSIS: Bromophos is a broad spectrum,
non-cumulative non-systemic organophosphorus insecticide. It is
a cholinesterase inhibitor with contact and stomach action,
having slight toxicity to mammals, fish and bees. Bromophos is
listed in the WHO Recommended Classification of Pesticides by
Hazard under class III, "Slightly hazardous".
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics: Bromophos consists of
yellowish crystals with a melting point of 53 °C. It has a
boiling point of 140-142 °C. The technical product is 95% pure.
1.3.2 Solubility: In water, solubility is 40 mg/L
at 27 °C and it is soluble in most organic solvents.
1.3.3 Stability: Bromophos is stable in aqueous
suspension up to pH 9 but it hydrolyses in a stronger alkaline
1.3.4 Vapour pressure: 17 mPa (20 °C).
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY
1.4.1 Common formulations: These include emulsifiable
concentrates of 250 and 400 g a.i./L; wettable powder, 250 g/kg;
dusts, 20-50 g/kg; granules, 50-100 g/kg; atomising concentrate,
400 g/L; dip 200 g/L; and coarse powder, 30 g/kg.
1.4.2 Susceptible pests: Active against Hemiptera ,
Diptera , certain Lepidoptera , Coleoptera and other insects.
1.4.3 Use pattern: Used at a concentration of
250-1500 g a.i./ha on field, vegetable and fruit crops as well as
ornamentals and grain storage. Also used as a sheep dip.
1.4.4 Unintended effects: Bromophos is not
recommended for use on cotton or grapes. Injury has been
reported on varieties of cabbage, pears and ornamentals.
1.5 PUBLIC HEALTH USE:
1.5.1 Common formulation: See section 1.4.1.
1.5.2 Pests controlled: See section 1.4.2.
1.5.3 Use pattern: Used in the control of flies and
mosquitos at 0.5 g/m2.
1.5.4 Unintended effects: None reported.
1.6 HOUSEHOLD USE: No recommended usage
2.0 TOXICOLOGY AND RISKS
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption: Bromophos may be absorbed through
intact skin as well as by the respiratory and gastrointestinal
2.1.2 Mode of action: Bromophos is an indirect
inhibitor of cholinesterase through phosphorylation of the
esteratic site of the enzyme. Accumulation of acetylcholine at
nerve synapses and myoneural junctions causes the toxic effects.
2.1.3 Excretion products: Bromophos is excreted
rapidly via the urine, the major metabolites found are
dichloro-bromophenol and monodesmethyl bromophos. Extremely low
levels of bromoxon may also occur in blood. Approximately 63% of
a 10 mg/kg oral dose of bromophos was excreted in urine and 16%
in faeces over a 24 hour period.
2.1.4 Toxicity, single dose:
Rat (M,F) 3750 - 6100 mg/kg b.w.
Rat (M,F) 1600-1730 mg/kg b.w.
Mouse 2829-5850 mg/kg b.w.
Guinea pig 1500 mg/kg b.w.
Rabbit 720 mg/kg b.w.
Rat (M,F) 5000 mg/kg b.w.
Rabbit 2181 mg/kg b.w. (scarified skin)
Rat 1625-3125 mg/kg b.w.
Mouse 1040 mg/kg b.w.
2.1.5 Toxicity, repeated dose: Rats given bromophos
by gavage at doses from 188 to 1250 mg/kg b.w. for 100 days
displayed signs of poisoning for approximately one hour after
each administration. Observed compound related adverse effects
were: depression of body weights, depressed food consumption at
the high dose level and depression of brain, liver and plasma
esterase at all doses.
2.1.6 Dietary studies:
Short term: Rats were fed bromophos at 0, 1500, 6000 and 10000
mg/kg/diet for a period of 100 days. Animals at the 2 higher
doses showed a marked decrease in weight gain. Some minor
pathological changes were observed in liver and kidney at the
Groups of male and female beagle dogs were fed bromophos at
levels of 0, 20, 80, 320 and 1280 mg/kg/diet for one year.
Reduced body weight and food consumption occurred at 1280
mg/kg/diet and females in this group had less frequent oestrus.
Plasma cholinesterase inhibition occurred at 80, 320, 1280
mg/kg/diet, erythrocyte cholinesterase inhibition occurred at 320
and 1280 mg/kg/diet and brain cholinesterase inhibition occurred
at 1280 mg/kg/diet.
Long term: Male and female dogs were given bromophos at 11, 44
and 87.5 and 175 mg/kg/b.w./day, by gavage for two years. One
dog at 87.5 mg/kg b.w. and three at 175 mg/kg b.w. died after
developing respiratory difficulties, hoarseness, salivation,
tremors followed by ataxia and then paresis of the hind limbs.
Two other dogs at 175 mg/kg b.w. developed the same signs but
recovered. Plasma, erythrocytes, liver and brain cholinesterases
were depressed at all doses.
2.1.7 Supplementary studies of toxicity:
Carcinogenicity: Male and female rats were administered 87.5,
175 and 350 mg/kg b.w. of bromophos by gavage for two years.
Cholinesterase was inhibited in plasma, erythrocytes, brain and
liver at all dose levels. No tumours were reported to have
occurred at any dose level.
Albino mice fed bromophos at 0, 85, 350 and 1400 mg/kg/diet for
18 months did not reveal any carcinogenic potential. Erythrocyte
and brain cholinesterase inhibition occurred at 350 and 1400
Mutagenicity: No mutagenic activity was seen using Drosophila
melanogaster as a test organism.
Neurotoxicity: In early studies in hens administered bromophos,
either as a single oral dose of 10 g/kg b.w./day, or as 1
g/kg/day for periods of 12-56 days, incoordination and ataxia
associated with demyelination were observed. These studies were
In later studies hens were given 5.5 g/kg b.w. over a period of 7
weeks, or 2 oral doses of 2 g/kg b.w. 3 weeks apart. No
neuropathological changes were observed in the CNS or peripheral
In order to reinvestigate the paralysis described in dogs in the
2 year feeding study described under Section 2.1.6. Long term
dietary studies, dogs were administered 87.5 and 175 mg/kg
b.w./day orally for 270 days. An extensive neuropathological
examination of the central nervous system, spinal ganglia and
peripheral nerves failed to reveal any pathological changes.
Teratogenicity: Female rabbits were administered 25, 50, 100,
200 or 400 mg/kg b.w. of bromophos from day 6 to 18 of pregnancy.
In no group did the type or number of malformations observed
differ from that of the controls.
Reproduction: No effect was seen in a three generation study at
5 and 20 mg/kg of bromophos. At 80 mg/kg, reduced weanling
weight and increased stillbirths were seen in F1a generation. In
this study the cholinesterase activity of liver and plasma was
significantly depressed in animals receiving five mg/kg/day. The
threshold dose for erythrocyte enzyme inhibition was between 5
and 30 mg/kg/day and for brain enzyme between 5 - 30 mg/kg/day
for males and 20-80 mg/kg/day for females.
2.1.8 Modification of toxicity: Potentiation of the
acute toxicity of bromophos occurred with, bromophos-ethyl,
diazinon, dichlorvos, dimethoate, malathion, mevinphos, naled,
parathion and carbaryl.
2.2 TOXICOLOGY - MAN
2.2.1 Absorption route: Bromophos is absorbed through the
intact skin as well as by the respiratory and gastrointestinal
2.2.2 Dangerous doses:
Single: Not known.
Repeated: Not known.
2.2.3 Observations on occupationally exposed
workers: A group of workers applied bromophos to house
interiors for malaria control, for 4 hours on one day and for 2.5
hours on the following day. No clinical effects were seen in
spraymen or villagers. Spraymen plasma cholinesterase activities
the day after spraying were 94.9% of the pre-exposure levels.
One week after spraying villagers had plasma cholinesterase
activities 92% of pre-exposure value rising to 94.4% four weeks
2.2.4 Observations on exposure of the general population:
See section 2.2.3.
2.2.5 Observations on volunteers: The no effect
level for bromophos was found to be 0.4 mg/kg b.w./day after a 28
day period of administration. At 0.8 mg/kg/b.w./day, plasma
cholinesterase was inhibited.
2.2.6 Reported mishaps: No information available.
2.3 TOXICITY TO NON-MAMMALIAN SPECIES
Oral LD50 Chickens 9700 mg/kg
Mosquito fish, at 0.5 - 1.0 mg/L, no mortality.
LC50 Guppies 0.5 mg/L
2.3.3 Other species: Slightly toxic to honey bees.
3.0 FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON
REGULATION OF COMPOUND
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY
[For definition of categories see the 'Introduction to Data
All available liquid formulations, Category 4.
All available solid formulations, Category 5.
3.2 TRANSPORT AND STORAGE
Formulations in category 4: Should be transported in clearly
labelled, rigid and leakproof containers out of reach of
children, away from food and drink. Storage should be under lock
and key and secure from access by children and other unauthorized
persons. Avoid contact with metals other than aluminium and tin.
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.
Formulations in category 4: Full protective clothing should be
used by all handling the compound. Adequate washing facilities
should be available at all times during handling and they should
be close to the site of handling. Eating, drinking and smoking
should be prohibited during handling and before washing hands and
Formulations in category 5: No facilities other than those needed
for the handling of any chemical are required.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINERS
All formulations: Containers must 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 crushed and buried below
topsoil (at least 0.5 m). Care must be taken to avoid subsequent
contamination of water sources.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
Formulations in category 4: Pre-employment medical examination for
workers desirable. Special account should be taken of the
workers' ability to comprehend and follow instructions.
Formulations in category 5: Warning of workers to minimize contact
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT
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 4 - minimum cautionary statement:
WARNING - POISON
(Skull and cross bones insignia)
Bromophos is an organophosphorous compound which inhibits
cholinesterase. It is of slight toxicity. Contact with the skin,
inhalation of dust or spray, or swallowing may be hazardous.
Wear protective gloves, clean protective clothing. Bathe
immediately after work. Ensure that containers are stored under
lock and key. Empty containers must be disposed of in such a way
as to prevent all possibility of accidental contact with them.
Keep the material out of reach of children and well away from
foodstuffs, animal feed and their containers.
In case of contact, immediately remove contaminated clothing and
wash the skin thoroughly with soap and water; for eyes, flush
with water for 15 minutes.
If poisoning occurs, call a physician. Atropine sulphate is a
pharmacological antidote. Repeated doses may be necessary.
Artificial respiration may also be needed.
Formulations in category 5 - minimum cautionary statement: This
formulation contains bromophos, it is poisonous if swallowed.
Keep the material out of reach of children and well away from
food stuffs, animal feed and food containers.
3.8 RESIDUES IN FOOD
Maximum Residue Limits (MRLs) have been recommended by the Joint
FAO/WHO Meeting on Pesticide Residues. In 1977 an Acceptable
Daily Intake (ADI) for bromophos was set at 0.04 mg/kg b.w.
4.0 PREVENTION OF POISONING IN MAN AND EMERGENCY AID
4.1 PRECAUTIONS IN USE
4.1.1 General: Bromophos is an organophosphorus pesticide
of slight mammalian toxicity. It is readily absorbed through the
intact skin, from the gastrointestinal tract, and by inhalation
of dust or spray mist. Repeated exposure may have a cumulative
effect on acetylcholinesterase activity.
4.1.2 Manufacture and formulation - TLV: 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 the
container and when mixing, protective impermeable boots, clean
overalls, gloves and a suitable respirator should be worn.
Mixing, if not mechanical, should always be carried out with a
paddle of appropriate length. When spraying tall crops or during
aerial application, a face mask should be worn, as well as an
impermeable hood, clothing, boots, and gloves. The applicator
should avoid working in spray mist and avoid contact with the
mouth. Particular care is needed when equipment is being washed
after use. All protective clothing should be washed separately
from other laundry immediately after use, including the insides
of gloves. Splashes must be washed immediately from the skin, or
eyes with large quantities of water. Before eating, drinking, or
smoking, hands and other exposed skin should be washed.
4.1.4 Other associated workers: Persons exposed to
bromophos and associated with its application should wear
protective clothing and observe the precautions described above
in 4.1.3. under "Mixers and Applicators".
4.1.5 Other populations likely to be affected:
With good application practice subject to 4.2 below, other
persons are not likely to be exposed to hazardous amounts of
4.2 ENTRY OF PERSONS INTO TREATED AREAS
Unprotected persons should be kept out of tall crops for four
days and out of other crops for 24 hours.
4.3 DECONTAMINATION OF SPILLAGE AND CONTAINERS
Residues in containers should be emptied in a diluted form into a
deep dry pit (depth >0.5 m) taking care to avoid contamination
of ground waters. The empty container may be decontaminated by
rinsing two or three times with water and scrubbing the sides.
An additional rinse should be carried out with 5% sodium
hydroxide solution which should remain in the container
overnight. Impermeable gauntlets should be worn during this work,
and a soakage pit should be provided for the rinsings.
Decontaminated containers should not be used for food, feed or
water storage. Spillage of bromophos and its formulations should
be removed by washing with 5% sodium hydroxide solution and then
rinsing with large quantities of water.
4.4 EMERGENCY AID
4.4.1 Early symptoms of poisoning: Early symptoms of
poisoning may include excessive sweating, headache, weakness,
giddiness, nausea, vomiting, inceased salivation, stomach pains,
blurred vision, diarrhoea, slurred speech and muscle twitching.
Later there may be shortness of breath, convulsions and coma.
4.4.2 Treatment before person is seen by physician, if
these symptoms appear following exposure:
The person should stop work immediately, remove contaminated
clothing and wash contaminated skin with soap and water and flush
the area with large quantities of water. If swallowed, and if
the person is conscious, vomiting should be induced. In the
event of collapse, artificial respiration should be given bearing
in mind that if mouth-to-mouth resuscitation is used, vomit may
contain toxic amounts of bromophos.
5.0 FOR MEDICAL AND LABORATORY PERSONNEL
5.1 MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING
5.1.1 General information: Bromophos is an
organophosphorus pesticide of slight mammalian toxicity which is
active against a variety of agricultural and public health pests.
It is readily absorbed from the gastrointestinal tract, through
the intact skin, and by inhalation of dust or spray mist. It is
converted in vivo to the oxygen analogue of bromophos which
inhibits acetylcholinesterase. It does not accumulate in body
5.1.2 Symptoms and signs: Symptoms of poisoning are
due to excessive stimulation by acetylcholine of all cholinergic
innervation. Thus initial symptoms and signs of poisoning may
include excessive sweating and salivation, headache, weakness,
miosis, dyspnoea, nausea, and diarrhoea, blurred vision and
muscle fasciculations. More severe poisoning leads to
respiratory failure due to a combination of bronchorrhea,
bronchoconstriction (muscarinic effects), paralysis of
respiratory muscles (nicotinic effects) and respiratory centre
paralysis (central effects). Central nervous system effects
include, in severe cases, coma and convulsions.
5.1.3 Laboratory: Diagnosis is confirmed by finding
inhibition of erythrocyte or whole blood acetylcholinesterase.
However, treatment must start immediately and cannot be delayed
until confirmation from the laboratory. This test cannot be used
to control the effectiveness of the treatment nor is it of help
5.1.4 Treatment: Patients with respiratory failure
must be given artificial ventilation, then diazepam (10 mg
intravenously) to control convulsions. When vital functions are
controlled, atropine sulfate is given (initial dose is usually 2
mg intravenously) followed by pralidoxime (1000 mg) or toxogonin
(250 mg) by slow intravenous infusion.
If the pesticide has been ingested, gastric lavage might be
needed or vomiting induced. Protection of airways (intubation)
is required if inducing vomiting in unconscious patients.
For skin contact, the skin should be washed with soap and large
amounts of water. Precautions should be taken by medical
personnel during these decontamination procedures to prevent
their own overexposure. If the compound has entered the eyes,
they should be washed with large quantities of saline or water.
Atropine treatment might be required for several days after
poisoning. Only clinical assessment determines atropine dose,
i.e. evident signs of atropinization (dry mouth, tachycardia,
vasodilation, mydriasis) should be maintained. Total amounts of
atropine given to these patients might be extremely high because
they are tolerant to the effects of atropine.
Caution should be taken when doses of atropine are reduced because
reappearance of symptoms might occur, due to redistribution
processes in the body. Cholinesterase reactivators such as
pralidoxime and toxogonin are usually only effective during the
first few days of poisoning, unless the slow disposal of the
chemical within the body suggests that some acetylcholinesterase
is newly inhibited. Indications for the continuing use of
reactivators might derive from measurements of erythrocyte
cholinesterase before and after treatment with such reactivators.
Unless brain hypoxia has occurred, full recovery is expected.
5.1.6 References to previously reported cases:
No information available.
5.2 SURVEILLANCE TESTS
Any fall of erythrocyte cholinesterase activity to 70% of pre-
exposure values requires an investigation of working methods and
hygiene and more frequent cholinesterase tests. Symptoms of
poisoning may appear when the erythrocyte cholinesterase activity
is less than 35% of normal. If erythrocyte cholinesterase
activity is less than 50% of normal, the worker must be suspended
from all contact with organophosphorus or carbamate pesticides
until the level rises above 70% of normal. Pseudocholinesterase
activity in the plasma can fall to very low levels without
evidence of symptoms. This only indicates undesirable exposure.
5.3 LABORATORY METHODS
5.3.1 Detection and assay of compound:
Thin-layer chromatography and gas liquid chromatography methods
have been used to analyze bromophos in technical products and in
its formulations. Analysis of residues in plant and animal
tissues is by gas chromatography and flame photometry methods.
Weeren RD & Eichler D (1978), Anal Methods Pestic Plant Growth
Regul 10: 31-40.
5.3.2 Other tests in case of poisoning: Activity of
cholinesterase in the blood provide the most useful diagnosis of
Ellman GL et al (1969) Biochem pharmacol 7: 88-95.
Wilhelm K & Reiner E (1973), Bull Wld Health Org, 48: 235-238.
Measurement of urine metabolites such as dialkylthiophosphates
may also be determined in order to give an indication of exposure
for methods. See section 5.3.1, Detection and Assay.
1. The Pesticide Manual, A World Compendium (9th edition 1991),
Worthing, C.R. and Hance, eds., British Crop Protection Council,
20 Bridport Road, Thornton Heath, CR4 7QG, United Kingdom.
2. WHO (1975), 1974 Evaluations of Some Pesticide Residues in Food.
WHO Pesticide Residue Series No. 4, 295-333, Geneva, World Health
3. WHO (1994) The WHO Recommended Classification of Pesticides by
Hazard and Guidelines to Classification 1994-1995, Geneva, World
Health Organization mimeographed document (WHO/PCS/94.2).
4. FAO/WHO (1988) Pesticide Residues in Food - 1987 Evaluations,
Part II - Toxicology, FAO Plant Production and Protection Paper
86/2, Rome, Food and Agriculture Organization of the United
5. WHO (1986). Environmental Health Criteria No. 63,
Organophosphorus Insecticides: A General Introduction.
= = =
Bromophos (PIM 742)