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Protective measures that have been applied concerning the chemical
Annex 1 - further information on the substance
Annex 2 - details on reported control actions
Annex 3 - list of designated national authorities
Annex 4 - References

Published: June 97

Common Name





Insecticide, acaricide with systemic and contact action

Trade Names

Azodrin, Crotos, Bilobrin, Crisodrin, Glore Phos36, Monocil, Monocron, More-Phos, Plantdrin, Susvin, Monocrotophos 60 WSC, Harcros Nuvacron, Nuvacron 600 SCW, Red Star Monocrotophos, Monocron

Formulation Types

Water miscible, soluble concentrate; Ultra Low Volume Spray

Basic Manufacturers

Agrolinz, Inc. Bharat Pulverizing Mills Ltd. (India), Cia-Shen Co. Ltd. (China.), Comlets Chemical Industrial Co. Ltd. (R.O.C.), Cyanamid (Brasil), Hindustan Ciba Geigy ltd (India), Lupin (India), Nantong Pesticides Factory (China), Hui Kwang (China), National Organic Chemical Industries Ltd. (India), Quimica Estrella S.A.C.I.el (Argentina), Quingdao Pesticides Factory (China), Sudarshan (India), United Phosphorus (India), Sundat (S) Pte. Ltd. (Singapore)

Reasons for Inclusion in the PIC Procedure

Formulations of the substance which exceed 500 g a.i./l are included because of their acute hazard classification and concern as to their impact on human health under conditions of use in developing countries. (Fifth meeting of the Joint Expert Group).

Monocrotophos is included in the PIC procedure because of its high toxicity which could cause problems under conditions of use in developing countries.

Registrars need to carefully consider the formulations actually used in each country when determining the risks of continued use of this pesticide. The toxicity of the active ingredient is high, but many formulations will fall into a much lower category of hazard.

Hazard Classification by International Organisms



Technical product.: Ib (highly hazardous), classification based on oral toxicity

Classification of formulations

oral toxicity

dermal toxicity

LD50: 14 mg/kg bw (see Ann. 1)

LD50: 112 mg/kg bw (see Ann. 1)


a.i. (%)

hazard class

a.i. (%)

hazard class






















Category 1 (highly toxic)


T+ (very toxic), N (dangerous for the environment)


not classified

Protective measures that have been applied concerning the chemical

Measures to Reduce Exposures


WHO recommends that for the health and welfare of workers and the general population, the handling and application of monocrotophos should be entrusted only to competently supervised and well-trained applicators, who must follow adequate safety measures and use the chemical according to good application practices. Regularly exposed workers should receive appropriate monitoring and health evaluation. (IPCS, 1993)

In Germany, monocrotophos may not be handled by adolescents and pregnant and nursing women. Before its withdrawal in the United States, monocrotophos was a Restricted Use Pesticide (RUP) which could be used only by certified applicators.


Protective clothing as indicated in the FAO Guidelines for Personal Protection when Working with Pesticides in Tropical Climates (FAO, 1990) is required; a respirator should also be worn by mixers and when spraying tall crops. The use of flaggers should be avoided; if used, they need full protective clothing including a respirator. All equipment and protective clothing should be washed thoroughly after use; clothing should be laundered separately from family clothing.

Unprotected workers should be kept out of treated areas for 48 hours. (FAO, 1990)


The manufacture, formulation, agricultural use and disposal of monocrotophos should be carefully managed to minimize contamination of the environment. To minimize risks for all individuals, a 48-hour interval between spraying and re-entry into any sprayed area is recommended.

Pre-harvest intervals have been set in several countries and are generally in the order of 7-15 days for vegetables and potatoes, maize and citrus, and 28-30 days for other crops.

In view of the high toxicity of monocrotophos, this agent should not be considered in hand-applied ULV spraying practices. (IPCS, 1993)

Regulatory measures

Although the chemical has been included in the PIC procedure because it is a highly toxic pesticide that is likely to cause problems under conditions of storage, transportation and use in developing countries, some countries have reported control actions that may be of interest when considering its use as a pesticide (see below).

Control actions are reported by 3 countries (Annex 2). The only registered use in Malaysia is application by trunk injection. The two other reporting countries (USA and Sri Lanka) indicated no remaining uses, By a ministerial decree of June 1996, the use of monocrotophos in Indonesia was limited until June 1997.

Not all of the reports have been determined to be of control actions which conform with the FAO/UNEP definitions of banned or severely restricted for health or environmental reasons. However, all reports are provided here since the FAO/UNEP Joint Expert Group on Prior Informed Consent decided that the substance should be included in the PIC procedure due to its potential to cause problems under conditions of use in developing countries regardless of the number of qualifying actions.

For further information on the control actions provided in Annex 2, contact the Designated National Authorities (Annex 3) in the country reporting the control action.


The USA indicated bifenthrin, carbaryl, chlorpyrifos, cyfluthrin, pyrethrins, diazinon and permethrin as alternatives to specific uses of monocrotophos. Alternatives have been reported in literature. (Gips, 1990)

It is essential that before a country considers substituting any of the reported alternatives, it ensures that the use is relevant to its national needs. A first step may be to contact the DNA in the country where the alternative has been reported (see addresses of DNAs in Annex 3). It will then be necessary to determine the compatibility with national crop protection practices.

Packaging and Labelling

Follow FAO Revised Guidelines on Good Labelling Practice for Pesticides (FAO, 1995).

Monocrotophos must be labelled as a marine pollutant.

The United Nations Committee of Experts on the Transportation of Dangerous Goods (IPCS, 1993) classifies the chemical in:

Hazard Class 6.1

poisonous substance

Packing Group 2

serious risk of poisoning: 25-100 % monocrotophos

Packing Group 3

harmful substances: less than 25 % monocrotophos

Waste Disposal

All waste and contaminated material associated with this chemical should be considered hazardous waste. The material should be destroyed by incineration in a special high temperature chemical incinerator facility.

See FAO Guidelines on Prevention of Accumulation of Obsolete Pesticide Stocks and The Pesticide Storage and Stock Control Manual. (FAO, 1996)

It should be noted that the methods recommended in literature are often not suitable in a specific country. High temperature incinerators or secure landfills may not be available.

Exposure Limits

Type of limit



MRLs (Maximum residue limits in mg/kg) in specified products (FAO/WHO, 1996)


JMPR ADI (acceptable daily intake) in mg/kg (FAO/WHO, 1996)



USA (NIOSH) TLV-TWA (Threshold Limit Value, Time-weighted average in mg/m3) (Niosh, 1996)

0.25 mg/m3

First Aid

Early symptoms of poisoning may include excessive sweating, headache, weakness, giddiness, nausea, vomiting, hypersalivation, stomach pains, blurred vision and slurred speech. If these symptoms occur, the person should remove contaminated clothes, wash the affected skin with soap and water and flush with large quantities of water. If in the event of collapse artificial resuscitation is used; vomit may contain toxic amounts of the substance. In case of ingestion, the stomach should be emptied as soon as possible by careful gastric lavage. Do not induce vomiting if the formulation contained hydrocarbon solvents.

Persons who have been poisoned (accidentally or otherwise) must be transported immediately to a hospital and put under the surveillance of properly trained medical staff.

Antidotes are atropine sulphate and pralidoxime chloride.

General surveillance and cardiac monitoring must be maintained for at least 14 days. (IPCS, 1986)

Annex 1 - further information on the substance

1. Chemical and Physical Properties



Colourless, hygroscopic crystals (tech: dark brown semi-solid). Technical monocrotophos is at least 75% pure




Chemical Name

Dimethyl (E)-1-methyl-2-(methylcarbamoyl)vinyl phosphate (IUPAC)

Chemical Type




1 kg/I (20°C, water)


-0.22-0.5 (calculated)


Vapour Pressure

0.29 mPa (20°C)


Melting Point

54-55 °C



Decomposes above 38°C; unstable in short chain alcohols; half-life in aqueous solutions range from 96 days (pH 5) to 17 days (pH 9); monocrotophos is corrosive to black iron, drum steel and stainless steel

Further information in Tomlin, 1994 and IPCS, 1993

2. Toxicity

2.1 General


Mode of action

Monocrotophos affects the nervous system by inhibiting acetylcholinesterase, an enzyme essential for normal nerve impulse transmission.



Monocrotophos can be absorbed following ingestion, inhalation and skin contact



In mammals, the primary conversion products of monocrotophos are dimethylphosphate, O-desmethyl monocrotophos and N-desmethyl monocrotophos. N-desmethyl monocrotophos is more toxic than monocrotophos.

2.2 Known Effects on Human Health


Acute Toxicity

Symptoms of poisoning

The organophosphate insecticides are cholinesterase-inhibitors. They are highly toxic by all routes of exposure. When inhaled, the first effects are usually respiratory and may include bloody or runny nose, coughing, chest discomfort, difficult or short breath and wheezing due to constriction or excess fluid in the bronchial tubes. Skin contact with organophosphates may cause localized sweating and involuntary muscle contractions. Eye contact will cause pain, bleeding, tears, pupil constriction and blurred vision. Following exposure by any route, other systemic effects may begin within a few minutes or be delayed for up to 12 hours. These may include pallor, nausea, vomiting, diarrhoea, abdominal cramps, headache, dizziness, eye pain, blurred vision, constriction or dilation of the pupils, tears, salivation, sweating and confusion. Severe poisoning will affect the central nervous system, producing incoordination, slurred speech, loss of reflexes, weakness, fatigue, involuntary muscle contractions, twitching, tremors of the tongue or eyelids, and eventually paralysis of the body extremities and the respiratory muscles. In severe cases there may also be involuntary defecation or urination, psychosis, irregular heart beat, unconsciousness, convulsions and coma. Respiratory failure or cardiac arrest may cause death.

The ingestion of 120 mg monocrotophos can be fatal.

(IPCS, 1993, Occupational Health Services, 1991; Hayes, W.J. and E.R. Laws, 1991)


Short and long term exposure

Repeated daily high level exposure may gradually lead to poisoning.

Several studies on occupationally exposed workers have been conducted in countries with a hot climate where workers usually did not wear protective clothing. In most cases plasma cholinesterase was inhibited. It was extrapolated that absorption of 20 mg of monocrotophos caused inhibition of Plasma AchE. (JMPR, 1993).

Some organophosphates may cause delayed symptoms beginning 1 to 4 weeks after an acute exposure that may or may not have produced immediate symptoms. In such cases, numbness, tingling, weakness and cramping may appear in the lower limbs and progress to incoordination and paralysis. Improvement may occur over months or years, but some residual impairment will remain.

2.3 Toxicity studies with laboratory animals and in vitro systems


Acute Toxicity


LD50 (a.i; mg/kg bw): 14 - 20 in different test species. (Tomlin, 1994)


LD50 (a.i.; mg/kg bw): 112 - 250 in different test species. (IPCS, 1993)


LC50 (a.i.; mg/m3 air-exposure 4 hrs) 80. (JMPR, 1993)


Technical monocrotophos is not irritant to skin or eyes. Formulations may be irritant due to the content of organic solvent. (Skripsky and Loosli, 1994)


Short-term exposure

Doses of 10 and 100 mg/kg bw (dermal) given for 4 weeks caused toxic signs and significant inhibition of cholinesterase activities. The dose of 1 mg/kg bw was a NOAEL (no observed adverse effect level). In rats, behavioural tolerance to monocrotophos was observed within 16 days of repeated oral dosing with up to 6 mg/kg bw per day. (Skripsky and Loosli, 1994).


Long term exposure

In a two years study on rats with dietary concentrations from 0.01-10 ppm the NOAEL (no observed adverse effect level) was equivalent to 0.005 mg/kg bw per day.(JMPR, 1991)


Effects on reproduction

The existing data about teratogenic effects are not conclusive. In a teratogenicity study in rabbits, monocrotophos was not teratogenic at doses up to 6 mg/kg bw/day, which was lethal to the mothers. (JMPR, 1993).



Weak mutagenicity in vitro. In vivo assays were mostly negative or rarely equivocal. (JMPR, 1993)



Carcinogenicity studies in mice and rats were negative. (JMPR, 1993)

3. Exposure



Monocrotophos is not usually detected as a residue in food in total diet studies.



In a study conducted by US-EPA regarding acute worker exposure risk assessment under conditions of use in Indonesia for chemicals of concern, a MOE-value (MOEL = NOEL/anticipated exposure level) of 5 was estimated for monocrotophos. EPA generally considers an MOE of lower than 100 to present an unacceptable risk. (FAO Jakarta, 1996)

In a study conducted in the Philippines, it was demonstrated that in the course of a normal spraying operation, farmers are exposed to contamination of their clothing and potential dermal absorption.

An epidemiological study conducted from 1972 to 1984 in a rural district of central Luzon (Philippines) resulted an increase in mortality of 27 % only in the age and sex classes occupationally (rice growing) exposed. These years were a period of high pesticide use. Among the 4 most commonly used pesticides was monocrotophos. (Loevinsohn, 1987; Forget, 1990)



The general population is not generally exposed to monocrotophos from the air or water. (IPCS, 1993)


Accidental Poisoning

There have been several reports of accidental poisoning with monocrotophos due to occupational use or suicide attempts. (Hayes, 1990; IPCS, 1993)

In Parana State (Brazil) pesticides causing more than 10 incidents were analysed in 1990; monocrotophos caused 107 of the 412 reported incidents. (Dinham, 1993)

4. Effects on the Environment

4.1 Fate



Monocrotophos has a low environmental persistence. It does not accumulate in soil because it is biodegradable. Its half-life is less than 7 days in soil exposed to natural sunlight. (Tomlin, 1994; IPCS, 1993; US-EPA, 1985)



Monocrotophos and its metabolites are not expected to bioaccumulate. (Farm Chemicals Handbook, 1994)

4.2 Ecotoxicity




Monocrotophos is moderately toxic to fish

LC50 48 hrs (Rainbow trout) 7 mg/l and bluegill sunfish (23 mg/l)

(Tomlin, 1994; Farm Chemicals Handbook, 1994)


Aquatic invertebrates

EC50 48 hrs (Daphnia) 0.023 mg/l (103)



Acute oral LD50s range from 0.9-6.7 mg/kg bw. Monocrotophos is extremely toxic to birds and is used as an avian poison. Monocrotophos may also kill birds which eat insects poisoned with monocrotophos.

Due to the use of monocrotophos, an estimated 15,000 to 20,000 were killed in Argentina 1995

(Woodbridge, 1996)




Hazardous to bees (LD50 28-33 m g/bee)

(Tomlin, 1994)

Annex 2 - details on reported control actions



Control Action:

Severely restricted.

Uses still allowed:

Used on plants, only up to the flowering stage.




Control Action:

Registration for use only on coconut and oil palm by means of trunk injection.

Uses still allowed:


Highly toxic and hazardous for use under local conditions.



Control Action:

Severely restricted. Import has been prohibited since July 1995.

Uses still allowed:


High toxicity.




Control Action:

The substance was voluntarily withdrawn by the registrant, effective July 30, 1989. This represented the deadline for the manufacture, sale and distribution of the product by the registrant. No remaining uses allowed.

Uses still allowed:


EPA's concerns with respect to monocrotophos primarily involved effects of exposure to non-target species, notably birds. Monocrotophos is very highly toxic to birds exposed on an acute oral and sub-acute dietary basis. Monocrotophos was determined to be the cause of mortality or was strongly implicated in a large number of bird kill incidents affecting a wide variety of avian species. Monocrotophos posed serious risks to birds even when application was performed in a manner consistent with label directions. Monocrotophos is also highly toxic to freshwater invertebrates. The chemical is an organophosphate and is determined to be a potent cholinesterase inhibitor. Therefore, applicators and workers are potentially at risk for acutely toxic effects. In laboratory studies on rats and rabbits, monocrotophos was found to induce maternal toxicity and developmentally toxic effects (runting), but no major teratological abnormalities, at low doses.

Annex 3 - list of designated national authorities




(965) 2427161

Public Authority for Agriculture Affairs & Fish Resources Plant Wealth Department




13075 Kuwait P. 0. Box 21422




(965) 2452790; 2456835/36

The Secretary General


(965) 2421993

Environment Protection Council


46408 EP CNCL KT



13104 Kuwait P.O. Box 24395




603 2938955

The Director-General



Ministry of Science, Technology and Environment Department of Environment



12th and 13th floor, Wisma Sime Darby Jalan Raja Laut


50662 Kuala Lumpur



60 3 2983077

The Secretary


60 3 2983646

Pesticide Board Department of Agriculture


Jalan Gallagher


50480 Kuala Lumpur




94 (08) 88135

Registrar of Pesticides


94 (08) 88206

Pesticides Registration Office,




Peradeniya P. 0. BOX 49



94 (1) 549455

The Director-General


Central Environmental Authority ,


22775 NHDA

Maligawatte New Town

10 Colombo





1 202 260 2902

The Assistant Administrator


1 2022601847

Environmental Protection Agency Prevention, Pesticides and Toxic Substances,


892758 EPA WSH

401 M Str. S.W.

20460 Washington, D.C.



Industrial and consumer product chemicals




Pesticides, industrial and consumer product chemicals

Annex 4 - References

The information on monocrotophos given in this DGD is mainly based on documents published by WHO, FAO and the International Programme on Chemical Safety (IPCS). If important information from other sources has been used, these references are noted in the text. The following list also includes other publications containing useful information.

Asian Development Bank, 1987. Handbook on the use of pesticides in the Asia-Pacific region. ADB, Manila.

Codex Alimentarius Commission 1987. Codex Alimentarius. Guide to Codex recommendations concerning pesticide residues, part 2. Maximum limits for pesticide residues, 3rd prelim, issue, Rome.

FAO - Regional Office for Asia and the Pacific (RAPA), 1989. Pesticide Use by Vegetable Farmers: Case Study in a Multiple Cropping System in Sri Lanka. Quarterly Newsletters, Asia and Pacific Plant Protection

FAO Jakarta, 1996. Acute Worker Exposure Risk Assessment under Conditions of Use in Indonesia for Chemicals of Concern. Letter to AGPP.

FAO, 1996. Technical guidelines on disposal of bulk quantities of obsolete pesticides in developing countries. Food and Agriculture Organization, Rome.

FAO, 1995. Revised guidelines on good labelling practices for pesticides. Food and Agriculture Organization, Rome.

FAO, 1990. Guidelines for personal protection when working with pesticides in tropical countries. Food and Agriculture Organization, Rome.

FAO, 1996. Pesticide storage and stock control manual. Food and Agriculture Organization, Rome.

FAO/WHO, 1993. Pesticide Residues in Food -1993 - Evaluations. Joint Meeting on Pesticide Residues (JMPR).

FAO, Rome. Plant Prod. Paper Monocrotophos.

FAO/WHO, 1991. Pesticide Residues in Food -1991; Evaluations. Part II - Toxicology. Joint Meeting on Pesticide Residues (JMPR);

Farm Chemicals Handbook 1994. Meister Publishing, Willoughby, Ohio, USA.

Ferioli et.a., 1993. Literature Review Monocrotophos and Health Hazard for Humans. International Center for Pesticide Safety.

Forget, G., Goodman, T. and A. de Villiers, 1990. Impact of Pesticide Use on Health in Developing Countries. International Developing Research Center.

Hayes, W.J. and E.R. Laws (ed.), 1990. Handbook of Pesticide Toxicology, Vol. 3, Classes of Pesticides. Academic Press, Inc., NY.

Hayes, W.J. and E.R. Laws (ed.), 1991. Handbook of Pesticide Toxicology. Academic Press, Inc., New York,

IPCS, 1986. Environmental health criteria No. 63: Organophosphorous insecticides: a general introduction. International Programme on Chemical Safety, IPCS/ World Health Organization, Geneva.

IPCS, 1993. Health and Safety Guide No. 80: Monocrotophos. International Programme on Chemical Safety, IPCS/ World Health Organization, Geneva.

Michael E. Loevinsohn, 1987. Insecticide use and increased mortality in rural central Luzon, Philippines. The Lancet, June 13.

NIOSH, 1996. Database. Database SKC Inc, 863 Valley View Road, Eighty Four, PA 15330, USA.

Occupational Health Services, 1991. Inc. 1991 (Feb. 25). MSDS for methyl parathion. OHS Inc., Secaucus, NJ, USA.

Pesticide Trust, 1989. The FAO Code: missing ingredients. Pesticides Trust, London N1 2UN, United Kingdom

Schulze-Rosario and Loosli, R., 1994. Reviews of Environmental Contamination and Toxicology. Vol. 139.

Smith G.J., 1993. Toxicology & Pesticide Use in Relation to Wildlife: Organophosphorus & Carbamate Compounds. CK Smoley. Boca Raton, FL.

Tomlin, Clive 1994. The Pesticide Manual: A World Compendium. (10th ed.), British Crop Protection Council, Surrey, (United Kingdom)

US-EPA, 1985. Guidance for the reregistration of manufacturing use and certain end use pesticide products containing monocrotophos. US Environmental Protection Agency. EPA, Washington, D.C. (Sept. 1985).

US-EPA, 1985. Pesticide fact sheet No 72: monocrotophos. US Environmental Protection Agency. USEPA, Washington, DC, USA.

WHO, 1996, Recommended classification of pesticides by hazard and guidelines to classification 1996-1997. WHO/PCS/96.3. World Health Organization, IPCS, Geneva.

Woodbridge, Brian, 1996. USDA Forest Service, Information Note on Swainsons Hawk Mortalities in Argentina. Briefing Note February.

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