Emergency and Continuous Exposure Limits for Selected Airborne Contaminants Volume 2 (1984) / Chapter Skim
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Phosgene
Phosgene
Pages 69-86
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From page 69... ...
; soluble in carbon tetrachioride, chloroform, acetic acid, and toluene Easily liquified, colorless, nonflammable gas; odor, sweet at low concentrations and pungent at higher concentrations 1 ppm = 4 mg/m3 1 mg/m3 = 0.25 ppm Phoagene was first prepared in 1812 by the photochemlcal reaction of carbon monoxide and chlorine; it is now commercially prepared by passing chlorine and exces'; carbon monoxide over activated carbon. Depending on the quantity required and the availability of the raw material, numerous variations of the basic synthetic process are used.
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From page 70... ...
· The resulting mixture slurry is digested in one to three stages for several hours at progressively increasing temperatures up to 200°C; digestion is accompanied by the injection of additional phoagene. · The final solution of reaction products is fractionated to recover hydrogen chloride, unreacted phosgene, and solvent for recycling, isocyanate product, and distillation residue.
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From page 71... ...
The atmospheric sinks of phoagene have not been fully delineated. Simulated tropospheric irradiation in the presence of water vapor suggests negligible tropospheric loss through photolysis and gas-phase hydrolysis.
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From page 72... ...
Splashes of liquid phoagene into the eye may produce severe irritation, and skin contact may cause severe burns (Hygienic Guide Series, 1968~. Fatal exposure to phosgene has resulted in extensive degenerative changes in the epithelium of the trachea, bronchi, and bronchioli and hemorrhagic edematous focal pneumonia (Gerritsen and BuschmaDn, 1960~.
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From page 73... ...
The lunge appear to be the principal target organ for phoagene, and the characteristic pathologic feature is the development of pulmonary edema of unknown pathogenesis. Survivors of an acute episode exhibit various degrees of bronchopneumonia, benign pneumonia, bronchial plugging, lung collapse, pulmonary consolidation, pneumonia, and emphysema; animals that die after exposure show severe pulmonary edema.
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From page 74... ...
Much of the current information on the metabolism of phosgene has been gained indirectly through recent studies of the in vitro metabolism of chloroform (Cress eil _ al., 1979; Mansuy et al., 1977; Pohl et al., 1977) and_ _ _ carbon tetrachloride (Shah et a1., 1979~; that shows the intermediary formatio" of phoagene from both chlorinated hydrocarbons.
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From page 75... ...
In 1980, ACGIH recommended a TLV of 0.1 ppm, on the basis of its irritating effects on the respiratory tract at slightly above 0.1 ppm, to which tolerance develops (ACGIH, 1980~. Table 10 lists additional maximal allowable concentrations (MACs)
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From page 76... ...
It was further noted that, although high doses of phoagene can cause chronic lung disease in man and animate, it is not certain whether low doses can aggravate pre-existing conditions or cause lung disease (Cucinell, 1974~. Because the lowest experimental values available for long-term exposure suggest that 0.2 ppm for 5 hid for 5 d may cause slight changes in the lung (Cameron et al., 1942b)
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From page 77... ...
. The present Committee's recommended EELs and CEL for phoagene and the limits proposed in 1966 are shown below.
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From page 78... ...
b,C 3.5 h Pulmonary edema, Spolyar et al., death 1951 Unknownb 4.5 h Acute bronchitis Glass et al 1971 2 Unknown Brief Bronchial irri- Delephine, 1923 Unknown Brief tation, death 1 Unknownb Brief Pulmonary edema Seidelin, 1961 7 Unknown Brief Acute bronchitis, Steel, 1942 delirium, pul monary edema a Data from NIOSH, 1976. b Simultaneous exposure to chlorinated hydrocarbons.
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From page 79... ...
b 0 = no chroTlic pneumonitis; + = slight chror~c plleumorlitis; = moderate chronic pneumonitis; l t I = severe chronic pneumonitis; P = acute pneumonia; and F = fibrinous pneumonia.
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From page 80... ...
TABLE 9 Phoagene Inahalation Exposures and Effects in Animalsa Duration of Duration of Species Concentration, ppm Exposure Effects Reference , Rat 55-100 10 min Reduction in Box and death rate from Cu~lumbine, 74% to 33% by 1947 previous challenge Rabbit 50-200 14-25 min Decrease in sym- Ivanhoe and pathetic tone Meyers, 1964 Rabbit 67 30 min Pulmonary edema Boyd and Perry, 1960 Dog 44-120 30 min Pulmonary edema, Underhill, pneumonia, 1920 emphysema, death Dog 72 30 min Pulmonary conso- Durlacher lidation, death and Bunting, 1947 Dog 24-40 30 min. 1 or Acute bronchio- Clay and 2 exposures, litis Rossing, 1964 1-3/week Dog 24-40 30 min.
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From page 81... ...
Lab. Off ., 1970 Baited Arab Republic NG 4 Inter.
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From page 82... ...
1941. Effects of low concentrations of phoagene repeated for 5 hours on 5 consecutive days in groups of different animals.
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From page 83... ...
1947. Pulmoaury changes following exposure to phoagene.
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From page 84... ...
1960. Phosgene poisoning caused by the use of chemical paint removers containing methylene chloride in ill-ventilated rooms heated by kerosene stoves.
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From page 85... ...
Vol. 1 Chemical Warfare Agents, and Related Chemical Problems.
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From page 86... ...
Nature 264:428-429. Societa Italiani di Medicina de Lavoro, Associazione Italiana degli Igienisti Industriali, Valori Limite Ponderati degli Inquinanti Chimici e Particolati degli Ambienti di Laoro per il.
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