Grand Rounds: Outbreak of Hematologic Abnormalities in a Community of People Exposed to Leakage of Fire Extinguisher Gas

Abstract

ContextAlthough there are ample data on the respiratory effects of exposure to fire extinguisher gas, the potential hematologic effects have not been fully documented. We conducted this study to determine the possible etiologic agent(s) for a decrease in red blood cells among community residents in Taipei, Taiwan, after they were exposed to leakage of mixed fire extinguishants containing bromotrifluoromethane (CF3Br, Halon 1301), bromochlorodifluoromethane (CF2BrCl, Halon 1211), and dichlorodifluoromethane (CCl2F2, CFC-12).Case presentationWe studied 117 exposed residents who came into one hospital for physical examinations. We also selected age- and sex-matched referents for comparison from residents who came to the same hospital for health examinations. Nine months after the exposure to mixed fire extinguishants, 91 of the exposed residents came back for a second physical examination. In the first examination of the exposed residents, we found a significant reduction in red blood cell count and hemoglobin and a relationship between dose and response.DiscussionAfter excluding iron-deficiency anemia, thalassemia, and other possible agents, we suspected that the hematologic effects might have resulted from pyrolytic products of CFC-12 and Halon 1211, which may contain phosgene, among other products.Relevance to clinical practiceThe acute transient hematologic effects observed in the exposed residents were associated with the incident of leakage of mixed fire-extinguisher gases and were most likely caused by a small amount of pyrolytic products, probably phosgene. Nine months after the exposure, we found a significant improvement in the abnormalities without any specific treatment.

Challenges of exposure assessment for health studies in the aftermath of chemical incidents and disasters

“…The small scale of the incident and the geographically uncomplicated area may have contributed to its success. The estimated concentrations of extinguisher gas from the model corresponded with the data collected from a door-to-door interview and observed symptoms (Lo et al, 2006).…”

“…The absence of timely available funding made it impossible to collect biological samples within a relevant time frame after the hydrofluoric acid (HF) spill in Texas City (TX, USA) (Dayal et al, 1992). No data on exposure to fire extinguisher gas were collected after a fire was extinguished in Taipei (Taiwan), because the extinguisher gas leaked to a residential area by accident and people were caught by surprise (Lo et al, 2006).…”

“…Cone et al, 1994;Koo et al, 1995) (Dayal et al, 1992(Dayal et al, ,1994a). The mathematical model created after the fire extinguisher gas leak in Taipei was more successful even though there were no measured concentrations of gas to validate the model (Lo et al, 2006). The small scale of the incident and the geographically uncomplicated area may have contributed to its success.…”

“…Blood samples were collected 1 week after the incident and gave impartial results on health effects. A questionnaire focused on health effects caused by the gas exposure included symptoms unrelated to fire extinguisher gas exposure and indicated a 6% potential report bias (Lo et al, 2006). In conclusion, no data are actively collected during the early phase of a type 1 scenario, which leads to a limited amount of exposure data to study the relation between exposure and subsequent health effects.…”

“…In a type 1 scenario, this is often the only data that may be collected. This type of information was sufficient to create adequate exposure zones after the Taipei gas leak (Lo et al, 2006), but the same type of information was not enough to create reliable exposure measures after the incidents at Bhopal and Texas City (Dayal et al, 1992). Areas that have been evacuated or decontaminated may also function as crude exposure measures.…”