Unintentional Carbon Monoxide Poisoning Following a Winter Storm -- Washington, January 1993

Carbon monoxide (CO) poisoning was a major health consequence of a severe storm that struck the Puget Sound region of western Washington state the morning of January 20, 1993. Wind gusts up to 94 miles per hour interrupted electrical power for an estimated 776,000 residents, and during the 4 nights following the storm, temperatures fell to near freezing. Because of the use of alternative sources of energy for indoor cooking and home heating, the risk of exposure to CO increased for many persons. This report summarizes cases of storm-related CO poisoning among persons who were initially evaluated at Seattle's Harborview Medical Center (HMC) or who were referred to the Virginia Mason Medical Center (VMMC) for hyperbaric oxygen therapy.

All patient data were extracted from medical records. A case of CO poisoning was defined as an arterial carboxyhemoglobin (HbCO) level of greater than or equal to 2% (for nonsmokers) or greater than or equal to 9% (for smokers) in a person who sought medical care during January 20-25 and had not been involved in a fire or intentional CO exposure.

The 44 patients who met the case definition and were evaluated or treated at HMC or VMMC represented 17 separate incidents of CO exposure (median: two patients per incident; range: one-nine patients). Eight hospitals referred 35 of the patients to VMMC for hyperbaric oxygen therapy; these 35 included five of 14 patients initially evaluated at HMC. Nine (20%) patients had lost consciousness. The median arterial HbCO level on initial evaluation was 17% (range: 5%-46%).

The median age of patients was 29 years (range: 2-87 years); 26 (59%) were female. Eighteen (41%) patients were Asian, 14 (32%) were non-Hispanic white, nine (20%) were Hispanic, two (5%) were of Middle Eastern ancestry and unknown ethnicity, and one (2%) was black. Fifty percent of the patients did not speak English, including 11 (61%) who were Asian and all nine who were Hispanic.

Within 9 hours of the onset of the storm, case-patients began seeking care in emergency rooms; 38 (86%) patients sought care between 6 p.m. and 6 a.m. on one of the three nights following the storm (Figure 1). The source of CO was burning charcoal briquettes in 11 (65%) incidents (all involving racial/ethnic minorities), gasoline-powered generators in four (24%), a generator and a propane-powered space heater in one, and an automobile in one.

During the night of January 21, radio stations first broadcast reports of CO poisoning and the danger of using charcoal briquettes, gasoline-powered generators, and propane-powered heaters in poorly ventilated areas; newspaper and television reports appeared during January 22-23. On January 22, one fire department distributed more than 2000 written warnings door-to-door. All reports and warnings were in English only.

Reported by: NB Hampson, MD, CC Kramer, Hyperbaric Dept, Virginia Mason Medical Center; MK Copass, MD, Emergency Trauma Center, Harborview Medical Center, Seattle. Radiation Studies Br, Div of Environmental Hazards and Health Effects, National Center for Environmental Health, CDC.

Editorial Note

Editorial Note: The findings in this report differ from previous descriptions of CO poisoning following winter storms in the northern United States because of the large number of cases involved, especially among non-English-speaking persons (1-3). Because VMMC is the only hyperbaric referral facility in the region, and the indications for hyperbaric therapy (e.g., arterial HbCO level greater than or equal to 25%, any neurologic impairment regardless of HbCO level on initial evaluation, or ischemic changes on electrocardiogram {4}) have been publicized among emergency physicians in the area, the 35 patients referred for hyperbaric oxygen therapy probably represent most of the cases of severe poisoning resulting from this storm. Efforts to identify additional, less severe cases are in progress.

In Washington, burning charcoal briquettes were a common source of CO, especially for persons who were members of racial/ethnic minorities. Nonstorm-related CO poisoning resulting from indoor cooking with charcoal briquettes has been reported as a problem in Korea (5) and for non-English-speaking residents of the United States (6,7). A previous health advisory about the danger of CO poisoning was targeted at Asian immigrants because of their traditional use of briquettes for cooking (7).

The impact of media reports and other warnings to prevent CO poisoning following the storm in Washington cannot be determined. On January 23 -- when most reports had been publicized -- more than 160,000 persons remained without electrical power, but no cases occurred after 4 a.m. that day. However, the non-English-speaking members of the population would probably not have understood these warnings, even if they had had the electrical power to receive them.

The relation of culture and language to the risk of CO poisoning following this storm is under investigation. However, when such storms occur, public health and safety agencies and other organizations should attempt to provide public health warnings that are prepared in both English and the languages of groups that might be at increased risk because of cultural or linguistic factors.

References

1. Geehr EC, Salluzzo R, Bosco S, Braaten J, Wahl T, Wallenkampf V. Emergency health impact of a severe storm. Am J Emerg Med 1989;7:598-604.

2. Glass RI, O'Hare P, Conrad JL. Health consequences of the snow disaster in Massachusetts, February 6, 1978. Am J Public Health 1979;69:1047-9.

3. Faich G, Rose R. Blizzard morbidity and mortality: Rhode Island, 1978. Am J Public Health 1979;69:1050-2.

4. Piantadosi CA. Carbon monoxide intoxication. In: Vincent JL, ed. Update in intensive care and emergency medicine. New York: Springer-Verlag, 1990;10:460-71.

5. Kim YS. Seasonal variation in carbon monoxide poisoning in urban Korea. J Epidemiol Community Health 1985;39:79-81.

6. Gasman JD, Varon J, Gardner JP. Revenge of the barbecue grill: carbon monoxide poisoning. West J Med 1990;153:656-7.

7. Shusterman D, Liu K-S, Kizer KW. Carbon monoxide poisoning {Letter}. West J Med 1991;154:737-8.

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