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    WORLD HEALTH ORGANIZATION             FOOD AND AGRICULTURE
                                          ORGANIZATION
    ORGANISATION MONDIALE DE LA SANTE     ORGANISATION POUR L'ALIMENTATION
                                          ET L'AGRICULTURE
 
                                          VBC/DS/75.5 (Rev.1)
                                          ORIGINAL: ENGLISH


   DATA SHEETS ON PESTICIDES No.  5 Rev.1


   METHYL BROMIDE

  
    CLASSIFICATION:

    Primary use: Insecticidal fumigant
    Secondary use: Acaricide, fungicide,
                   nematocide, rodenticide
    Chemical group: Alkyl halide
    Data sheet No. 5 (Rev.1) August 1978


         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.


        
    1.    GENERAL INFORMATION

    1.1   COMMON NAME: No common name.  Methyl bromide is the chemical 
          name. 

    1.1.1 Identity: Methyl bromide
                    CH3Br

    1.1.2 Synonyms: Monobromomethane bromomethane

          Local synonyms:

            
    1.2   SYNOPSIS - A powerful fumigant gas which is one of the most toxic 
          of the common organichalides.  In massive dosage, it is narcotic 
          like a halogenated hydrocarbon solvent. It has a characteristic 
          delayed neurotoxic action. 

            
    1.3   SELECTED PROPERTIES

    1.3.1 Physical characteristics - A colourless gas at room temperature
          with a slightly sweet odour, b.p. 4.5°C.

    1.3.2 Solubility - Water, 3.4 g/l at 25°C.  Freely soluble in alcohol.  
          Soluble in most organic solvents. 

    1.3.3 Stability - Stable in air; non-inflammable and non-corrosive.  
          In cold water it forms a dense white precipitate of the hydrate. 

    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. 

    R 683 - 1185

    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.                                


    1.3.4 Vapour pressure (volatility) 2435 kla at 25°C.

            
    1.4 AGRICULTURE, HORTICULTURE AND FORESTRY

    1.4.1 Common formulations - Liquid, alone or with 2 g/l chloropicrin as 
          warning indicator.  Sometimes formulated as a mixture with 
          ethylene dibromide or carbon tetrachloride.  There is an FAO 
          specification for the technical product. 

    1.4.2 Susceptible pests - A very wide range of pests including most 
          insects and mites, nematodes, weeds, fungi and rodents. 

    1.4.3 Use pattern - Used for fumigation of all types of stored dry 
          foodstuffs, particularly produce in bags and packages, and of 
          clothing, furniture and timber.  Used for treatment of soil 
          before sowing, especially in glasshouses, to control nematodes, 
          insects, weeds, and fungi.  Used in plant quarantine on seeds and 
          plants, including fresh fruit and vegetables. 

    1.4.4 Unintended effects - Phytotoxic, particularly to growing plants, 
          but safe under normal conditions of use.  Its use on seed may 
          cause phytotoxicity if the recommended application rate is 
          exceeded. 

            
    1.5   PUBLIC HEALTH PROGRAMMES - None.


            
    1.6    HOUSEHOLD USE - Methyl bromide is too dangerous for household use 
          in the ordinary sense.  Specially trained and licensed pest 
          control operators may fumigate houses after they have been 
          vacated and sealed and after suitable warning signs have been 
          posed.  On rugs, furniture and clothing at 16-24 g/m3, 12-24 
          hours exposure at 16-21°C the following may be controlled: carpet
          beetles, clothes-moths, silverfish, fleas, roaches.  Furs,
          feathers, leather and rubber articles should not be fumigated
          with methyl bromide. 

            
    2.    TOXICOLOGY AND RISKS

    2.1   TOXICOLOGY - MAMMALS
            
    2.1.1 Absorption route - Absorbed in the lungs or if taken in solution 
          orally by the gastrointestinal tract.  The extent to which it 
          might be absorbed by the skin under severe conditions of exposure 
          is unclear.  However, under ordinary conditions of exposure, skin 
          exposure is insignificant, and a suitable respirator or mask is 
          protective. 

    2.1.2 Mode of action - A neurotoxic and narcotic agent with a 
          characteristic delayed action.  It acts by combining with the 
          sulfhydryl group of proteins and enzymes. 

    2.1.3 Excretion products - Appears to be broken down and excreted as 
          inorganic bromide in the urine.  It is also excreted via the 
          lungs.  After exposure to methyl bromide, volatile bromide, 
          presumably unchanged methyl bromide, is stored in the tissues, 
          particularly those tissues which are rich in lipoidal material. 

    2.1.4 Toxicity, single dose

          Oral: LD50 rat: <100 mg/kg

          Inhalation: LC50 (15 minutes): rat 21 000 mg/m3
                                                                            
          Most susceptible species: Not known

     
    2.1.5 Toxicity, repeated doses:

          Oral: No information.

          Inhalation: Guinea-pigs tolerated six hour exposures to 780 
          mg/m3 or 10 hours exposure to 390 mg/m3.  Rats, monkeys and 
          guinea-pigs tolerated seven to eight hour daily exposures to 130 
          mg/m3 for many months without overt effects.  Rabbits showed 
          lung irritation at this level but were unaffected by 65 mg/m3. 

          Cumulation of compound: The compound is cumulative upon 
          repeated exposure.  After absorption bromine is widely 
          distributed in body tissues and is stored in lipoidal tissue. 

    2.1.6 Dietary studies

          Short-term: No information.

          Long-term: No information.

    2.1.7 Supplementary studies of toxicity: No information.

    2.1.8 Modification of toxicity: There are a considerable number of 
          studies on the toxicity of foodstuffs which have been fumigated 
          with methyl bromide.  Since, in these foodstuffs, the amount of 
          unchanged methyl bromide is very low the studies are of no use in 
          assessing the toxicity of methyl bromide per se. 

            
    2.2   TOXICOLOGY - MAN

    2.2.1 Absorption - See 2.1.1. Inhalation is the important route of
          absorption, with this compound.

    2.2.2 Dangerous doses

          Oral: No information.

          Inhalation: Concentrations of about 400 mg/m3 are definitely 
          toxic and fatalities have occurred from exposures to 1200 mg/m3 
          and above.  Information is lacking on the duration of exposure in 
          these cases.  An exposure level of 31 000 mg/m3 for "a few
          hours" proved fatal. 

    2.2.3 Observations of occupationally exposed workers - Among 90 human 
          subjects industrially exposed to concentrations up to 140 
          mg/m3, 33 showed mild intoxication, 22 showed skin lesions. 
          There is no information on the duration of exposure. 

    2.2.4 Observations on exposure of the general population - Because of
          the rapid breakdown to inorganic bromide after food is fumigated
          with methyl bromide it is unlikely that the general population 
          will be exposed to methyl bromide. 

    2.2.5 Observations of volunteers - None.

    2.2.6 Reported mishaps - In one location in the Americas the absolute 
          mortality to persons exposed to methyl bromide is reported to be 
          greater than that associated with any other agricultural 
          chemical. 

          Another report states that there are 56 isolated reports of 
          fatalities due to methyl bromide up to 1964.  The majority 
          resulted from inhalation of leaking fire extinguishers or during 
          fumigation.  There are also 179 reports of non-fatal methyl 
          bromide poisoning and it has been stated that the actual figure 
          is probably much higher. 
          
          In one mishap there were 34 cases of methyl bromide poisoning at 
          a date packing plant.  The majority had neurological disturbances 
          involving vision, speech, tremors and numbness of the 
          extremities.  There was a high incidence of mild mental confusion 
          and some hallucinosis.  Depressive states lasted as long as five 
          months.  Two cases, one of apathy and one neurosis were cited as 
          possibly permanent.  No fatalities were reported. The 
          concentrations in the air were 400-2000 mg/m3.  Numerous 
          similar cases are reported. 

            
    2.3   TOXICITY TO NON-MAMMALIAN SPECIES

    2.3.1 Fish  ) 
                ) Toxic to fish and birds but the conditions of use make it 
    2.3.2 Birds ) non-hazardous.

    2.3.3 Other species - Toxic but generally no hazard owing to the
          conditions of use.  Pre-planting treatment of soil will kill
          beneficial as well as harmful soil organisms. 

     3.    FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON REGULATION OF
          COMPOUND

    3.1   RECOMMENDED RESTRICTIONS ON AVAILABILITY

          (for-definition of categories see introduction)

          All formulations, Category 3

        
    3.2   TRANSPORTATION AND STORAGE

          United Nations classification 2.0 and 6.1.

          Should be transported and stored in conventional gas cylinders in 
          a cool and dry place protected against excessive heat.  The 
          cylinders should be moved carefully and when not in use they 
          should be safeguarded by adequate holding Devices.  They should 
          be inspected periodically for leaks by means of a halide detector 
          lamp.  They should be stored under lock and key secure from 
          access by unauthorized persons and children.  No food or drink 
          should be transported or stored in the same compartment. 


        
    3.3   HANDLING - Full protective clothing (see part 4) should be 
          provided for all handling of the 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.  In discharging the gas, the connecting lines to 
          the equipment should be strong enough to withstand the maximum 
          operating pressure and the valves should be opened slowly and 
          closed promptly after use.  Areas in which methyl bromide is 
          handled routinely should be equipped with adequate exhaust 
          ventilation.  Methyl bromide should not be used to fumigate a 
          house or part of a house unless the entire structure can be 
          vacated and marked with suitable warning signs. 

        
    3.4   DISPOSAL AND/OR DECONTAMINATION OF CONTAINERS - Not applicable - 
          empty containers should be re-used with methyl bromide.

        
    3.5   SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS - Pre-
          employment medical examination of workers recommended.  Persons 
          suffering from pulmonary diseases, afflictions of the central 
          nervous system and from cardiovascular disturbances should be 
          excluded from operations where this material is handled.  Special 
          account should be taken of the workers I mental ability to 
          comprehend and follow instructions.  Training of workers in 
          techniques to avoid contact essential. 
                
        
    3.6   ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT - 
          Not applicable. 

        
    3.7   LABELLING

          Minimum cautionary statement


                                      "POISON"

                          (Skull and crossbones insignia)

          "This cylinder contains methyl bromide gas under pressure.  The 
          gas is poisonous if inhaled and may be absorbed through the skin.  
          Wear protective gloves, clean protective clothing, goggles and a 
          respirator of the organic vapour type when handling this 
          material.  Avoid any exposure to fumes.  Wash hands and exposed 
          skin after handling and before eating and bathe immediately after 
          work. 

          Ensure that the cylinder is tightly sealed and stored and 
          disposed of in such a way as to prevent accidental contact with 
          the vapour.  Keep the cylinder 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." 

            
    3.8   RESIDUES IN FOOD

    3.8.1 Maximum residue levels - The Joint FAO/WHO meeting on Pesticide 
          Residues has recommended maxim= acceptable limits for unchanged 
          methyl bromide in some stored products at specific periods after 
          treatment.  The Meeting has also recommended levels of inorganic 
          bromide, arising from the use of bromine-containing fumigants 
          such as methyl bromide or ethylene dibromide. 

          The Codex Alimentarius Commission has recommended international 
          tolerances for inorganic bromide designed to control the use of 
          bromine-containing fumigants such as methyl bromide and ethylene 
          dibromide. 

            
    4.    PREVENTION OF POISONING IN MEN AND EMERGENCY AID

    4.1   PRECAUTIONS IN USE

    4.1.1 General - Methyl bromide is a powerful fumigant gas and is one of
          the most toxic of the common organic halides.  In massive dosage,
          it is narcotic like a halogenated hydrocarbon solvent.  It has a 
          characteristic delayed neurotoxic action. It should only be 
          handled by trained personnel wearing protective clothing. 

    4.1.2 Manufacture and formulation

          T.L.V.: ACGIH 60 mg/m3: USSR 1 mg/m3.  Closed systems and 
          forced ventilation are required to reduce as much as possible the 
          exposure of workers to the chemical.  It is recommended that a 
          small amount of chloropicrin be added to the gas in order to 
          enable persons to detect leaks and to prevent careless over-
          exposure. 

    4.1.3 Applicators - When discharging the gas, workers should wear high 
          top safety shoes, woollen outer clothing, suitable gas-tight 
          goggles and a respirator.  Leather or rubber gloves should not be 
          worn since they are permeable to methyl bromide and will enhance 
          injury of the skin because they interfere with evaporation and 
          thus prolong the contact. Particular care is needed when the 
          equipment is being washed after use.  All protective clothing 
          should be washed immediately after use, and placed outdoors. 

          Splashes of the liquefied gas should 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.  Until a treated area has been ventilated and found 
          satisfactory by means of a suitable detector, it must not be 
          entered, except by trained persons wearing appropriate 
          respirators or masks. 

    4.1.4 Other associated workers (including flagmen in aerial operations)
          - Not applicable.

    4.1.5 Other populations likely to be affected - With good agricultural
          and manufacturing practices subject to 4.2 below, other 
          populations should not be exposed to hazardous levels of 
          unchanged methyl bromide. 

            
    4.2   ENTRY OF PERSON INTO TREATED AREAS - With adequate ventilation 
          after use unprotected persons should be able to safely enter 
          treated areas after three days. 

            
    4.3   SAFE DISPOSAL OF CONTAINERS AND SPILLAGE - Containers which are 
          gas cylinders should be emptied during use and returned to the 
          manufacturer to be refilled with methyl bromide.  They should not 
          be used for any other purpose. 

          Spills of methyl bromide should be mopped up promptly with an 
          alkaline solution and the rags used for the purpose should be 
          placed outdoors. 

            
    4.4   EMERGENCY AID

    4.4.1 Early symptoms of poisoning - Onset of symptoms is delayed with a 
          latent period of one half to 48 hours after acute exposure.  
          Early symptoms are malaise, headache, nausea, vomiting, visual 
          disturbances and sometimes pulmonary oedema. Later there may be 
          tremors giving way to violent convulsions. 

    4.4.2 Treatment before person is seen by a physician, if these symptoms
          appear following exposure - The person should stop work and 
          should move or be moved away from the gas into fresh air.  All 
          soiled garments should be removed at once and placed outdoors.  
          The skin should be washed with soap and water and if necessary 
          the eyes should be irrigated with lukewarm water.  The person 
          should be kept at rest until the physician arrives.  If the 
          person stops breathing artificial respiration should be applied. 

    5.    FOR MEDICAL AND LABORATORY PERSONNEL

    5.1   MEDICAL DIAGNOSIS AND TREATMENT OF CASES OF POISONING

    5.1.1 General information - A powerful fumigant gas which is one of the 
          most toxic of the common organic halides.  In massive dosage, it 
          is narcotic like a halogenated hydrocarbon solvent.  It has a 
          characteristic delayed neurotoxic effect. It acts by combining 
          with the sulfhydryl groups of proteins and enzymes.  It appears 
          to be broken down and excreted as inorganic bromine in the urine.  
          It is also excreted via the lungs.  After exposure to methyl 
          bromide, bromine-containing compounds are stored in the tissues 
          particularly those tissues which are rich in lipoidal material. 

    5.1.2 Symptoms and signs - Onset of symptoms is delayed with a latent 
          period of one half to 48 hours after acute exposure. Early 
          symptoms are malaise, headache, nausea, vomiting, visual 
          disturbances and sometimes pulmonary oedema.  Late after initial 
          symptoms tremors occur giving way to violent convulsions 
          continuing until death which occurs primarily from respiratory 
          failure because of poor oxygenation of blood due to lung oedema 
          plus failure of the respiratory centres of the central nervous 
          system.  Chronic intoxication involves visual, speech, gait and 
          mental process disturbances; complex neurological abnormalities 
          and syndromes may occur, the abnormalities being persistent and 
          sometimes permanently incapacitating.  Skin lesions may also 
          appear upon exposure to high concentrations. 
                
    5.1.3 Laboratory - Blood levels of bromide following poisoning from 
          methyl bromide are much lower than that found from poisoning from 
          inorganic bromide, see 5.2 Surveillance methods. 

    5.1.4 Treatment - The person should discontinue exposure and be 
          transferred to fresh air.  All soiled garments should be removed 
          and the skin cleaned with soap and water.  Barbiturates 
          (preferably phenobarbitone or pentobarbitone) should be given 
          I.M. or I.V. in sufficient dosage to control restlessness or 
          convulsions.  Respiratory assistance with oxygen may be required.  
          When signs and symptoms of pulmonary oedema develop the oxygen 
          should be given against a pressure of 3-4 cm of water by 
          immersing the exhalation tube into water to this extent.  In 
          cases of frank pulmonary oedema venesection may be indicated.  If 
          the liver is enlarged or the patient complains of epigastric pain 
          glucose solution may be administered intravenously but only if 
          there is no danger of pulmonary oedema.  Epinephrine may also be 
          used subcutaneously for bronchospasm.  If methyl bromide in 
          liquid form or in high concentrations comes into contact with the 
          eyes these should be irrigated with lukewarm water for 15 
          minutes.  Skin lesions should be bathed in sodium bicarbonate 
          solutions and blisters should be treated as second degree thermal 
          burns. 

    5.1.5 Prognosis - Even moderate poisoning may lead to prolonged illness
          and if more severe, possibly to permanent injury.  In one case 
          neurological abnormalities persisted after one year. 

    5.1.6 References of previously reported cases - Cases of poisoning and 
          methods of treatment are documented in: Von Oettingen, W. F. "The 
          Halogenated Hydrocarbons of Industrial and Toxicological 
          Importance".  Elsevier Monographs on Toxic Agents, Browning, E., 
          ed., Chapter 3, Methyl Bromide, pp. 25-55.  Elsevier, Amsterdam, 
          London, New York 1964.  Rathus, E. M. & Landy, P. J. (1961) 
          Brit. J. Industr. Med., 18, 53-57. Hine, C. H. (1969) J.
          Occup. Med., 11, 1-10. 

            
    5.2   SURVEILLANCE METHODS - There are no readily available techniques 
          to determine the degree of absorption prior to the appearance of 
          symptoms.  Blood levels of bromide ion are indicative of 
          absorption but there appears to be no definite relationship 
          between the bromide level in the blood and the seriousness of the 
          poisoning.  It has been suggested that values of bromide ion in 
          blood of 50 mg/l and above are indicative of potentially 
          hazardous exposure.  However the presence of bromide ion is non-
          specific as to its source and the opportunity for methyl bromide 
          inhalation must be unquestionable. 

            
    5.3   LABORATORY METHODS - References only are given.
          
    5.3.1 Detection and analysis - For levels in air of 200 mg,/m3 or 
          higher the halide lamp may be used.  See Dudley, H. C., Miller, 
          J. W., Neal, P. A. & Sayers, R. R. (1940) Publ. Hlth Rep., 
          55, 2251.  For lower levels see Kaye, K., Braid, P. E. &
          Doherty, T. H. (1949) Industr. Hyg. Rev., 1, 3, and Berck,
          B. (1965) J. Agr. Fd. Chem., 13, 373-377. 

          Residues of methyl bromide in foodstuffs can be determined by the 
          gas-chromatographic method of Heuser & Scudamore (1969).  A later 
          modification (Heuser & Scudamore, 1970) allows the determination 
          of methyl bromide and inorganic bromide separately in the same 
          sample. 

          Bromide ion in biological samples can be determined by the method 
          of Castro (1964), based on that of Mapes & Schrader (1957). 

    5.3.2 Other tests in cases of poisoning - None.
          

                                     REFERENCES

    Heuser, S. G. & Scudamore, K. A. (1969) Determination of fumigant
          residues in cereals and other foodstuffs: a multi-detection 
          scheme for gas chromatography of solvent extracts, J. Sci. Fd 
          Agric., 20, 566 

    Heuser, S. G. & Scudamore, K. A. (1970) Selective determination of 
          ionised bromide and organic bromides in foodstuffs by gas-liquid 
          chromatography with special reference to fumigant residues, 
          Pestic.  Sci., 1, 244 

    Castro, C. E. (1964) In: Zweig, G., ed., Analytical methods for 
          pesticides, plant growth regulators and food additives, New
          York
          and London, Academic Press, vol.  III, p. 161 

    Mapes, D. A. & Schrader, S. A. (1957) Determination of total and 
          inorganic bromide residues in fumigated products, J. Assoc. Off. 
          Agr. Chem., 40, 189 



See Also:
        Methyl bromide (CHEMINFO)
        Methyl bromide (EHC 166, 1995)
        Methyl bromide (IARC Summary & Evaluation, Volume 71, 1999)
        Methyl bromide (PIM 340)