Occupational Phosgene Poisoning: a Case Report and Review

Home , Chemical weapon

J Accid Emerg Med: first published as 10.1136/emj.12.3.212 on 1 September 1995. Downloaded from Journal ofAccident CASE REPORT and Emergency Medicine 1995 Occupational phosgene poisoning: a case report and 12,212-213 review

J. P. WYATT & C. A. ALLISTER

Department of Accident and Emergency, Royal Alexandra Hospital, Paisley, Strathclyde, UK

(respiratory rate 24 min-') and tachycardic (pulse SUMMARY 100 min-1) and noted to have pharyngeal erythema. Phosgene is a highly toxic gas to which some The remainder of his examination and workers may be occupationally exposed. This case investigations (including ECG, chest radiograph report demonstrates the possibility of refrigeration and arterial blood gases) were normal. After workers suffering phosgene poisoning after consultation to determine the effect of heating heating certain chlorinated fluorocarbons ('freons'). chlorodifluoromethane, a diagnosis of phosgene The need to suspect phosgene exposure and gas exposure was made. The patient was admitted observe such patients is emphasized, especially for observation for 24 h. Following discharge he in view of the delay in clinical deterioration made a slow recovery, complaining of lethargy and observed in some patients who subsequently exertional dyspnoea, which prevented him from develop adult respiratory distress syndrome. returning to work for the next 2 weeks. Keywords: occupational health, phosgene DISCUSSION INTRODUCTION This patient's symptoms were typical of those seen Phosgene (carbonyl chloride; chemical formula after exposure to phosgene at a concentration COC12) has been widely used as a chemical weapon exceeding 3 parts per million.4 Phosgene is produced when extreme heat is applied to in the past, particularly in World War 1.1,2 Although http://emj.bmj.com/ use in this capacity appears to be currently less chlorinated fluorocarbons. The possibility of widespread, phosgene continues to be used in occupational exposure of refrigeration workers to various industrial processes.3 Occupational phosgene has been suggested previously, but has exposure after an accident in an industrial plant not been reported in the UK.5 Adequate purging of known to contain phosgene is unlikely to present refrigeration pipes before welding would help to

problems of recognition, but phosgene exposure reduce this risk significantly. on September 25, 2021 by guest. Protected copyright. can also occur in other seemingly innocuous Phosgene is a highly toxic gas, and exposure situations, as is illustrated by the following case may have a fatal outcome.6 Respiratory symptoms report. may be delayed by a latent period of several hours before adult respiratory distress syndrome of CASE REPORT becomes apparent.4' Diagnosis phosgene exposure may be straightforward in workers A 43-year-old man was involved in the demolition presenting from certain industrial plants where Correspondence: of a refrigeration plant. Whilst using a hot welding there is a recognized risk. Such workers should Jonathan Wyatt, torch to cut through a refrigeration pipe which be encouraged to wear phosgene indicator Senior Registrar, contained the freon chlorodifluoromethane, he was badges, which act as dose-dependent Department of exposed to a peculiar 'musty smelling gas'. He colorimeters, allowing an estimation of the degree Accident and initially experienced lacrimation, nausea, and a of exposure.7 In other situations, in the absence of Emergency, The cough with burning sensation in his mouth and or Royal Infirmary, any specific reliable diagnostic test, a high index Lauriston Place, throat and he subsequently experienced dyspnoea of suspicion is required. Suspicion should be Edinburgh EH3 9YW, and chest pain. On arrival at the accident and aroused in particular by the characteristic history UK emergency (A&E) department he was dyspnoeic of a peculiar musty smelling gas. Doctors need to © 1995 Blackwell Science Ltd J Accid Emerg Med: first published as 10.1136/emj.12.3.212 on 1 September 1995. Downloaded from Occupational be aware of the risk of phosgene exposure when exposure.'," Follow-up after hospital discharge is Phosgene heat is applied to certain chlorinated fluorocarbons therefore recommended. Poisoning commonly used in a variety of industries (including refrigeration and metal 'degreasing' plants). ACKNOWLEDGEMENT Any patient with a history and symptoms that The authors thank Dr l.S. Symington, Consultant suggest the possibility of phosgene exposure in Occupational Health, for his assistance. should be given oxygen and admitted for observation for at least 24h. Despite several studies, no parameters in the latent period allow REFERENCES either a definite diagnosis or an accurate 1. Sandall G. (1922) The late effects of gas poisoning. assessment of the degree of exposure.8 Instead, Lancet ii, 857- 859. whilst waiting for the development of potential 2. Vedder E.B. (1923) Medical Aspects of Chemical complications, reliance has to be placed on the Warfare. Williams and Wilkins, Baltimore. combination of the history of severity of symptoms 3. Sidell F.R. (1990) What to do in an unthinkable and the likely duration of exposure.8 chemical warfare attack or accident. Postgraduate The pathogenesis of phosgene poisoning is not Medicine 88, 70-84. clearly understood. The old theory that phosgene 4. DillerW.F. (1985) Pathogenesis of phosgene poisoning. produces lung injury entirely by hydrolysis, Toxicology and Industrial Health 1(2), 7-15. 5. Rinzema L.C. and Silverstein L.G. (1972) Hazards liberating hydrochloric acid (COCI2 + H20 + CO2 + hydrocarbon decomposition during 2HCI), has been abandoned.4 The miniscule from chlorinated welding. American Industrial Hygiene Association amounts of phosgene involved in clinical poisoning Journal 33, 35 - 40. release similarly tiny amounts of hydrochloric acid, 6. Regan R.A. (1985) Review of clinical experience in which would cause little damage. Phosgene is 800 handling phosgene exposure cases. Toxicology and times more toxic than the hydrochloric acid it Industrial Health 1(2), 69-72. produces, so other mechanisms must be involved. 7. Matherne R.N., Lubs P.L. & Kerfoot E.J. (1981) The Acylation reactions producing additional toxic development of a passive dosimeter for immediate chemicals may be important.4 assessment of phosgene exposures. American Various first-aid measures for phosgene Industrial Hygiene Association Journal 42, 631. exposure have been recommended. In its Medical 8. Diller W.F. (1985) Early diagnosis of phosgene Manual of Defence against Chemical Agents the overexposure. Toxicology and Industrial Health 1(2), Ministry of Defence recommends the use of a 73-80. 9. Ministry of Defence, (1987) Medical Manual of http://emj.bmj.com/ steroid inhaler, warmth, rest, oxygen and codeine Defence Against Chemical Agents, sixth edition. (to control coughing).9 There is no known antidote H.M.S.O., London. for phosgene, but severe cases benefit from close 10. Diller W.F. (1985) Therapeutic strategy in phosgene monitoring and positive pressure ventilation.10 The poisoning. Toxicology and Industrial Health 1(2), 93- role of steroids remains controversial.10 Complete 99. recovery after phosgene exposure may take a long 11. Diller W.F. (1985) Late sequelae after phosgene on September 25, 2021 by guest. Protected copyright. time, and most patients continue to complain of poisoning. Toxicology and Industrial Health 1(2), exertional dyspnoea for several months after 129-1 33.

213