Acute health effects after exposure to chlorine gas released after a train derailment.

In January 2005, a train derailment on the premises of a textile mill in South Carolina released 42 to 60 tons of chlorine gas in the middle of a small town. Medical records and autopsy reports were reviewed to describe the clinical presentation, hospital course, and pathology observed in persons hospitalized or deceased as a result of chlorine gas exposure. Eight persons died before reaching medical care; of the 71 persons hospitalized for acute health effects as a result of chlorine exposure, 1 died in the hospital. The mean age of the hospitalized persons was 40 years (range, 4 months-76 years); 87% were male. The median duration of hospitalization was 4 days (range, 1-29 days). Twenty-five (35%) persons were admitted to the intensive care unit; the median length of stay was 3 days. Many surviving victims developed significant pulmonary signs and severe airway inflammation; 41 (58%) hospitalized persons met PO2/FiO2 criteria for acute respiratory distress syndrome or acute lung injury. During their hospitalization, 40 (57%) developed abnormal x-ray findings, 74% of those within the first day. Hypoxia on room air and PO2/FiO2 ratio predicted severity of outcome as assessed by the duration of hospitalization and the need for intensive care support. This community release of chlorine gas caused widespread exposure and resulted in significant acute health effects and substantial health care requirements. Pulse oximetry and arterial blood gas analysis provided early indications of outcome severity.

Rapid assessment of exposure to chlorine released from a train derailment and resulting health impact.

OBJECTIVES: After a train derailment released approximately 60 tons of chlorine from a ruptured tanker car, a multiagency team performed a rapid assessment of the health impact to determine morbidity caused by the chlorine and evaluate the effect of this mass-casualty event on health-care facilities. METHODS: A case was defined as death or illness related to chlorine exposure. Investigators gathered information on exposure, treatment received, and outcome through patient questionnaires and medical record review. An exposure severity rating was assigned to each patient based on description of exposure, distance from derailment, and duration of exposure. A case involving death or hospitalization > or = 3 nights was classified as a severe medical outcome. Logistic regression was used to examine factors associated with severe medical outcomes. RESULTS: Nine people died, 72 were hospitalized in nine hospitals, and 525 were examined as outpatients. Fifty-one people (8%) had a severe medical outcome. Of 263 emergency department visits within 24 hours of the incident, 146 (56%) were in Augusta, Georgia; at least 95 patients arrived at facilities in privately owned vehicles. Patients with moderate-to-extreme exposure were more likely to experience a severe medical outcome (relative risk: 15.2; 95% confidence interval 4.8, 47.8) than those with a lower rating. CONCLUSIONS: The rapid investigation revealed significant morbidity and mortality associated with an accidental release of chlorine gas. Key findings that should be addressed during facility, community, state, and regional mass-casualty planning include self-transport of symptomatic people for medical care and impact on health-care facilities over a wide geographic area.

Panel classification of self-reported exposure histories: a useful exposure index after a mass-casualty event.

OBJECTIVE: Although rapid epidemiologic investigations of toxic exposures require estimates of individual exposure levels, objective measures of exposure are often unavailable. We investigated whether self-reported exposure histories, when reviewed and classified by a panel of raters, provided a useful exposure metric. METHODS: A panel reviewed exposure histories as reported by people who experienced a chlorine release. The panelists received no information about health-care requirements or specific health effects. To each exposure case, each panelist assigned one of five possible exposure severity ratings. When assigned ratings were not in initial agreement, the panelists discussed the case and assigned a consensus rating. Percent agreement and kappa statistics assessed agreement among panelists, Kendall's W measured agreement among panelists in their overall ordering of the exposure histories, and Spearman's rho compared the resultant rankings with individual health outcome. RESULTS: In 48% of the cases, the panelists' initial ratings agreed completely. Overall, initial ratings for a given case matched the consensus rating 69% to 89% of the time. Pair-wise comparisons revealed 85% to 95% agreement among panelists, with weighted kappa statistics between 0.69 and 0.83. In their overall ranking of the exposure histories, the panelists reached significant agreement (W = 0.90, p < 0.0001). Disagreement arose most frequently regarding probable chlorine concentration and duration of exposure. This disagreement was most common when panelists differentiated between adjacent categories of intermediate exposure. Panel-assigned exposure ratings significantly correlated with health outcome (Spearman's rho = 0.56; p < 0.0001). CONCLUSION: Epidemiologists and public health practitioners can elicit and review self-reported exposure histories and assign exposure severity ratings that predict medical outcome. When objective markers of exposure are unavailable, panel-assigned exposure ratings may be useful for rapid epidemiologic investigations.

Smokeless tobacco use accelerates age-related loss of bone mineral density among older women in a multi-ethnic rural community.

Cigarette smoking is a recognized risk factor for low bone mineral density (BMD) and osteoporosis. Despite the prevalence of smokeless tobacco (ST) use by women in some areas of the United States, minority groups in the United Kingdom, and populations in South Asia and Africa, no data exist to evaluate its effect on bone health. The objective of the study is to identify risk factors for low BMD among older women in a multi-ethnic population, with particular attention to smoking and ST use. Data were collected in Robeson County, North Carolina. ST use from childhood is common among women in this community. Two hundred-forty women aged 60 years and older (approximately equal numbers of African Americans, Native Americans and whites) were recruited at a variety of community events to obtain a cross-section of the demographic composition of the county. The main outcome was BMD measured in the heel using a portable dual energy x-ray absorptiometry. Twenty-nine percent of women were current or former smokers, and 26% current or former ST users. Increased BMD was predicted by greater body mass index, estrogen use in the past year, and African American and Native American ethnicity. There was a significant interaction between ST use and age, and between smoking and nutritional supplement use. BMD declined with age; the decline with age was greater for women who were current or former ST users than for those who never used ST. Women who formerly smoked and did not use supplements had a decreased BMD. ST should be considered as an additional risk factor for osteoporosis in populations where its use is prevalent.