WHO/FOOD ADD./69.35



    Issued jointly by FAO and WHO

    The content of this document is the result of the deliberations of the
    Joint Meeting of the FAO Working Party of Experts and the WHO Expert
    Committee on Pesticide Residues, which met in Geneva, 9-16 December,



    Geneva, 1969


    This pesticide has been previously evaluated (FAO/WHO, 1965). However,
    no recommendations for acceptable daily intake or tolerances were
    made. Since that time additional studies have raised further problems
    which are outlined below. However, no further data have become
    available on ethylene oxide toxicity per se.

    Further information is now available on some of the reaction products
    resulting from ethylene oxide fumigation of foodstuffs. The number of
    known reaction products has increased considerably since 1965
    (Lindgren et al., 1968).

    Of these reaction products the ethylene oxide-amino acid adducts are
    reported to be non-toxic (Lehman, 1965). There is no toxicological
    information on the reaction products with carbohydrates, vitamins etc.

    Ethylene chlorohydrin has been shown to result from fumigation of
    foods with ethylene oxide due to interaction with natural chlorides
    present in the crop. In flour fumigated with ethylene oxide, a level
    of 260 ppm ethylene chlorohydrin has been detected. Fumigation of
    spices also produced ethylene chlorohydrin (Wesley et al., 1965). A
    consideration of the available toxicological data on ethylene
    chlorohydrin is therefore pertinent to the assessment of ethylene
    oxide (Anon., 1966a).


    Biochemical studies (on ethylene chlorohydrin)

    In the rat, orally-administered ethylene chlorohydrin rapidly depletes
    liver glutathione and forms S-carboxymethylglutathione.
    S-carboxymethylglutathione is degraded by kidney homogenates to
    glycine, glutamic acid and S-carboxymethyl-cysteine. In the formation
    of the S-carboxymethylglutathione, the intermediate metabolites
    probably include chloroacetaldehyde, which is thought to be
    responsible for the toxic properties of ethylene chlorohydrin
    (Johnson, 1967a).

    The formation of chloroacetic acid has been demonstrated in vivo.
    Oxidation of ethylene chlorohydrin is unaffected by the presence of
    the chlorine atom (Williams, 1959). A glucuronide is not formed in
    rabbits (el Masri and Williams, 1956).

    Acute toxicity (of ethylene chlorohydrin)

    Animal      Route    LD50 mg/kg   Reference

    Rat (M)     Oral         95       Smyth et al., 1941

    Acute toxicity (cont'd)

    Animal      Route    LD50 mg/kg   Reference
    Rat         Oral         72       Goldblatt and
                                      Chiesman, 1944

    Rat         i.p.         56       Goldblatt and
                                      Chiesman, 1944

    Guinea-pig  Oral        110       Smyth et al.,

    Short-term studies (on ethylene chlorohydrin)


    In a 220-day feeding experiment incorporating 0, 100, 200, 400, 800,
    1200, 1600, 2400, 3200, 6400 or 12 800 ppm of ethylene chlorohydrin in
    the diet of 11 groups each containing five male rats, mortality
    increased at and above the 6000 ppm level. At the 3200, 6400 and 
    12 800 ppm levels, 100 per cent mortality occurred in 49, 16 and seven
    days respectively. Food intake was reduced at 1600 ppm and above and
    the body weight gain was reduced at the 1200 ppm level and above. The
    tissues of the rats at all levels showed no histological changes
    (Ambrose, 1950).

    Other species

    Rodent diet containing up to 750 ppm of ethylene chlorohydrin
    following ethylene oxide fumigation, has been suggested as a cause of
    definite reduction in growth (Anon., 1966). Ninety-day feeding studies
    in the rat and dog permit an estimate of 45 mg/kg as the no-effect
    level for ethylene chlorohydrin. Results in monkeys were stated to be
    "somewhat less clear cut but consistent with the no-effect level
    determined for rats and dogs" (Anon., 1968a).

    Long-term studies (on ethylene chlorohydrin)


    Four groups of six female rats ingested 0, 4, 8 or 16 mg/kg of
    ethylene chlorohydrin daily in their drinking water for two years. No
    dose or compound related effects were noted on the mortality while the
    histopathological examination of all the animals revealed no unusual
    features (Johnson, 1967b).


    The main identified reaction product of ethylene oxide left as a
    residue on food is ethylene chlorohydrin. Some data on the probable
    biochemical reactions of this substance are available, but none on the
    rate of disappearance or on the amounts excreted following ingestion.
    Data on acute toxicity, some short-term tests and one long-term study
    on ethylene chlorohydrin have been reported. These data are
    insufficient to permit an estimation of an acceptable daily intake for
    either ethylene oxide or ethylene chlorohydrin or any other possible
    reaction products remaining as residues.


    Residues resulting from supervised trials

    Heuser and Scudamore (1968) experimentally treated flour at 25C with
    375 g ethylene oxide per 28.31 m3 and found from 13 to 23 ppm
    ethylene chlorohydrin, depending on the moisture content of the flour.
    At 570 g per m3 residues ranged from 33 to 57 ppm. A clear
    relationship between concentration-time product and resulting ethylene
    chlorohydrin residue level was established; there were no significant
    differences between untreated and chlorine-dioxide-treated flour (the
    latter with and without bromate). Pfeilsticker and Rasmussen (1967)
    have shown that, depending on the moisture content, 20-50 per cent of
    the ethylene oxide is decomposed in the course of wheat fumigation.
    The outer membranes of the grain take up more ethylene oxide than the
    endosperm, as is to be expected. These results were confirmed in a
    later paper using fully labelled 14-C ethylene oxide (1968).

    Evidence of residues in food moving in commerce

    The Netherlands Government has consolidated residue information for
    the period 1964-1966 for shipments of imported cereal produce (Anon.,
    1968b) using an indicator tube method with a limit of detectability
    for ethylene oxide of 0.1 ppm. Only two of 374 samples examined
    (including 280 cereal samples) from world-wide sources showed
    detectable residues: these were a consignment of rice from North Korea
    (30 ppm) and one of peas from Leningrad (50 ppm).

    Wesley et al. (1965) have shown that ethylene oxide will combine with
    chlorine (derived from the small amounts of inorganic chloride present
    naturally in the produce) to form ethylene chlorohydrin in various
    products under fumigating conditions. Commercially fumigated ground
    rice mixtures were found to contain 490 - 1030 ppm ethylene
    chlorohydrin (average of 34 samples, 805 ppm) and little of this was
    lost in autoclaving at 246F for 70 min in subsequent soup production.
    Other results for commercial fumigation for five hours at 750 ml
    ethylene oxide per m3 were:

                                          ppm ethylene chloroydrin

              Flour                                   280
              Desiccated coconut                      42
              Albumen (spray-dried)                   310
              French beans (deep frozen)              8
              Currants                                4
              Green peas (air dried)                  1
              Green peas (ground)                     36

    These observations were generally substantiated by Ragelis et al.
    (1966) for flour and pepper using gas chromatography supported by
    infra-red and nuclear magnetic resonance spectroscopy: commercially
    treated ground pepper contained 110 ppm. The following ethylene
    chlorohydrin residues were found by Ragelis et al. (1968) in fumigated
    foods in a later paper:

                                          ppm ethylene chlorohydrin

              Celery seed                            83
              Paprika                                45
              Turmeric                               53
              Pepper                                 110
              Gum tragacanth                     less than 5

    Heuser and Scudamore (1968) found 5 to 60 ppm ethylene chlorohydrin in
    flour treated commercially at the rate of 2820 g ethylene oxide per
    m3 plus 200 g ethylene oxide per metric ton of flour.

    Hall (1968) has reported collaborative tests on fumigated spices by
    six commercial firms. Of 37 products fumigated, 15 were found to
    contain residues of ethylene chlorohydrin. Levels averaged more than
    1000 ppm, ranging from 2760 ppm (cloves) to less than 23 ppm (mustard
    flour), black pepper (1550 ppm) being regarded as the most significant
    potential dietary source.

    Fate of residues

    As indicated above, free ethylene oxide can combine with chlorine in
    foods (present as naturally occurring inorganic chloride) to give
    residues of ethylene chlorohydrin (2-chloroethanol). This is contrary
    to the conclusions of earlier workers, e.g. el Khishen (1950). At high
    sterilization dose rates, ethylene oxide also reacts with moisture to
    form ethylene glycol and, in the presence of sugars, glycol
    derivatives (Vojnovich et al., 1967).

    Evidence of residues in food in commerce or at consumption

    No information available.

    Methods of residue analysis

    Various gas chromatographic systems have been described in the
    literature for the separation, detection and measurement of residues
    of ethylene oxide, ethylene chlorohydrin, ethylene glycol and
    diethylene glycol in extracts of treated produce. The methods of
    Wesley et al. (1965) and Ragelis et al. (1966) have been mentioned
    above. Ben-Yehoshua and Krinsky (1968) describe a system suitable for
    dates and a more recent and comprehensive system has been described by
    Ragelis et al. (1968) for ethylene chlorohydrin in treated pepper,
    celery seed, turmeric and gum tragacanth (together with propylene
    chlorohydrin, 1-chloro-2-propanol, residues derived from the use of
    propylene oxide on cocoa, walnut meats, tapioca starch, flour, glazed
    cherries and glazed citron). Pagington (1968) has described a simple
    gas chromatographic method for the determination of ethylene
    chlorohydrin residues. Adler (1965) obtained a sensitivity of 0.1 ppm
    ethylene oxide using a thermal conductivity detector: he also
    describes a chromatropic acid method for total ethylene oxide plus
    ethylene glycol (lower limit of sensitivity about 2 ppm) in sterilized

    Heuser and Scudamore (1967, 1968) discuss the problem of extracting
    ethylene chlorohydrin and of avoiding breakdown of ethylene oxide to
    ethylene chlorohydrin in extraction procedures during analysis and
    describe an improved method of extraction using aqueous acetone and
    giving 98 per cent recovery of ethylene chlorohydrin. A gas
    chromatographic method using a flame-ionization detector sensitive to
    as little as 1 ng of ethylene chlorohydrin is also described.

    National tolerances

           Country                   Crop           Tolerance (ppm)

      United States of           Spices, whole
           America               Walnut meats             50

    Note: The British Industrial Biological Research Association has
    suggested a limit of 300 ppm ethylene oxide in spices (Anon., 1966a,
    1966b). There are no tolerances for ethylene chlorohydrin.



    There is evidence that food treated with ethylene oxide, either as a
    bacterial sterilent or to a lesser extent as an insecticidal fumigant,

    may contain residues of unchanged ethylene oxide unless there is an
    adequate subsequent holding period or aeration treatment to allow this
    residue to volatilize. There is also evidence of the formation,
    derived from inorganic chloride present naturally in food, of residues
    of ethylene chlorohydrin; and limited evidence that this does not
    disappear from the treated produce in storage so readily as do
    residues of unchanged ethylene oxide.

    In a general review of residues from post-harvest treatments, Lindgren
    et al. (1958) summarize the earlier work of Oser and Hall (1956),
    Bakerman et al. (1956) and Mickelsen (1957) on the vitamin losses in
    ethylene oxide treatment.


    In the absence of an acceptable daily intake no recommendations can be
    made at this time.

    Further work or information

    Required (before acceptable daily intakes or tolerances can be

    1. Additional data on the required rates and frequencies of
       application, pre-harvest intervals, and the resultant residues.

    2. Data on the disappearance of residues during storage and processing
       following bactericidal or insecticidal treatment.

    3. Data on the disappearance of residues resulting from commercial
       fumigation treatments.

    4. Identification of reaction products with food, evaluation of the
       effects on nutritional value, and toxicological studies on the

    5. Determination of levels of ethylene chlorohydrin in fumigated

    6. Long-term studies on ethylene chlorohydrin in experimental animals.


    Data on the rate of disappearance of ethylene chlorohydrin or on the
    amounts excreted.


    Adler, N. (1965) Residual ethylene oxide and ethylene glycol in
    ethylene oxide sterilized pharmaceuticals. J. Pharm. Sci., 54:

    Ambrose, A. M. (1950) Toxicological studies of compounds investigated
    for use as inhibitors of biological processes. II - Toxicity of
    ethylene chlorohydrin. J. Industr. Hyg. occup. Med., 2: 591-597

    Anon. (1966a) Possible hazards from ethylene oxide and propylene oxide
    sterilization. Food cosmet. Toxicol., 4: 607-609. (Brit. industr.
    biol. Res. Assoc., Info. Bull., 5 (4): 223-225)

    Anon. (1966b) Proposed acceptable residue level of ethylene
    chlorohydrin in spices. Brit. industr. biol. Res. Assoc., Info. Bull.,
    5 (10): 644-645

    Anon. (1968a) Safety of ethylene oxide spice fumigation reported.  
    Food Chemical News, 10 (26): 19-20

    Anon. (1968b) Residues of insecticides in cereals and related products
    imported into the Netherlands. Codex Alimentarius Commission document
    CCPR. 68/2

    Bakerman, H., Romine, M., Schricker, J. A., Takahashi, S. M, and
    Mickelson, O. (1956) Stability of certain B vitamins exposed to
    ethylene oxide in the presence of choline chloride. J. Agric. Food
    Chem., 4: 956-959

    Ben-Yehoshua, J. and Krimsky, P. (1968) Gas chromatography of ethylene 
    oxide and its toxic residues. J. Gas Chromatog., 6: 350-351

    el Khishen, S. A. (1950) Determination of ethylene oxide and methods
    of its recovery from fumigated substances. J. Sci. Food Agric., 1:

    el Masri, A. M. and Williams, R. T. (1959) Unpublished data cited by 
    Williams, R. T., 1959, q.v.

    FAO/WHO (1965) Evaluation of the hazards to consumers resulting from
    the use of fumigants in the protection of food. (FAO, PL: 1965/10/2;
    WHO/Food Add./28.65)

    Goldblatt, M. W. and Chiesman, W. E. (1944) Toxic effects of ethylene
    chlorohydrin. Part II, Experimental. Brit. J. industr. Med., 1:

    Hall, R. L. (1968) American Chemical Society Meeting at Atlantic City,
    N.J. (September 1968). Reported in Brit. industr. biol. Res. Assoc.,
    Info. Bull., 7: 370-371

    Heuser, S. G. and Scudamore, K. A. (1967) Determination of ethylene 
    chlorohydrin, ethylene dibromide and other volatile fumigant residues
    in flour and whole wheat. Chem. and Ind., 1557-1559

    Heuser, S. G. and Scudamore, K. A. (1968) Pest Infestation Research
    1967 (Pest Infestation Laboratory, Slough, Bucks). (In press)

    Johnson, M. K. (1967a) Metabolism of chloroethanol in the rat.
    Biochem. Pharmacol., 16: 185-199

    Johnson, M. K. (1967b) Detoxication of ethylene chlorohydrin. Food 
    cosmet. Toxicol., 5: 449

    Lehman, A. J. (1965) Summaries of Pesticide Toxicity, p. 115, Part 
    VIII. Fumigants, ethylene oxide. Ass. of Food and Drug Officials of
    the United States, Topeka, Ka.

    Lindgren, D. L., Sinclair, W. B. and Vincent, L. E. (1968) Residues in 
    raw and processed foods resulting from post-harvest insecticide
    treatments (g) ethylene oxide and propylene oxide. Residue Reviews,
    21: 93-95

    Mickelsen, O. (1957) Is toxicity enough for a food protection
    programme? J. Amer. Dietet. Assoc., 33: 341

    Oser, B. L. and Hall, L. A. (1956) The effect of ethylene oxide 
    treatment on the nutritive value of certain foods. Food Technol.,
    10: 175

    Pagington, J. S. (1968) A simple method for the determination of 
    chlorohydrin. J. Chromatog., 36: 528

    Pfeilsticker, K. and Rasmussen, H. (1967) Z. Lebensm. Unters. Forsch., 
    637: 79-89

    Pfeilsticker, K. and Rasmussen, H. (1968) Fumigation of wheat with
    radiolabelled ethylene oxide. Z. Lebensm. Unters. Forsch. (In press)

    Ragelis, E. P., Fisher, B. S. and Klimeck, B. A. (1966) Note on the 
    determination of chlorohydrin in foods fumigated with ethylene oxide
    and propylene oxide. J. Assoc. Offic. AgriC. Chem., 49: 963-965

    Ragelis, E. P., Fisher, B. S. and Klimeck, B. A. (1968) Isolation and 
    determination of chlorohydrin in foods fumigated with ethylene oxide
    or with propylene oxide. J. Assoc. Offic. Anal. Chem., 51: 709-715

    Smyth, H. F., jr, Seaton, J. and Fisher, L. (1941) The single dose 
    toxicity of some glycols and derivatives. J. industr. Hyg., 23:

    Vojnovich, C. and Pfeifer, V. F. (1967) Reducing the microbial 
    population of flour during milling. Cereal Sci. Today, 12: 54

    Wesley, F., Rourke, B. and Darbishire, O. (1965) The formation of
    persistent toxic chlorohydrins in foodstuffs by fumigation with
    ethylene oxide and with propylene oxide. J. Food Sci., 30: 1037-1042

    Williams, R. T. (1959) Detoxification Mechanisms, 2nd ed., p. 54.
    Substituted ethanols. Chloroethanol. Chapman and Hall, London

    See Also:
       Toxicological Abbreviations
       Ethylene oxide (EHC 55, 1985)
       Ethylene oxide (HSG 16, 1988)
       Ethylene oxide (ICSC)
       ETHYLENE OXIDE (JECFA Evaluation)
       Ethylene oxide (FAO Meeting Report PL/1965/10/2)
       Ethylene oxide (WHO Pesticide Residues Series 1)
       Ethylene oxide (CICADS 54, 2003)
       Ethylene Oxide (IARC Summary & Evaluation, Volume 60, 1994)