Persons Injured During Acute Chemical Incidents - Hazardous Substances Emergency Events Surveillance, Nine States, 1999-2008
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| MMWR Surveillance Summaries Vol. 64, No. SS-2 April 10, 2015 |
Persons Injured During Acute Chemical Incidents — Hazardous Substances Emergency Events Surveillance, Nine States, 1999–2008
Surveillance Summaries
April 10, 2015 / 64(SS02);18-24
Corresponding author: Mary Anne Duncan, Division of Toxicology and Human Health Sciences, Agency for Toxic Substances and Disease Registry, CDC. Telephone: 770-488-3668; E-mail: maduncan@cdc.gov.
Abstract
Problem/Condition: Persons exposed to chemicals during acute chemical incidents (i.e., uncontrolled or illegal release or threatened release of hazardous substances lasting <72 hours) can experience both acute and chronic health effects. Surveillance of toxic substance incidents provides data that can be used to prevent future incidents and improve the emergency response to those that occur, leading to a decrease in morbidity and mortality from chemical releases.
Reporting Period: 1999–2008
Description of System: The Hazardous Substances Emergency Events Surveillance (HSEES) system was operated by the Agency for Toxic Substances and Disease Registry (ATSDR) during January 1991-September 2009 to describe the public health consequences of chemical releases and to develop activities aimed at reducing the harm. This report summarizes the data collected on injured persons from the nine states (Colorado, Iowa, Minnesota, New York, North Carolina, Oregon, Texas, Washington, and Wisconsin) that participated in HSEES during its last 10 full years of data collection (1999–2008).
Results: A total of 57,975 chemical incidents were reported by these states during the 10-year surveillance period. In 4,621 (8%) of these incidents, 15,506 persons were injured. Among them, 354 deaths occurred. The most commonly reported category of injured persons included employees of the responsible party (7,616 [49%]), members of the general public (4,737 [31%]), students exposed at school (1,730 [11%]), and responders to the incident (1,398 [9%]). Deaths occurred among members of the general public (190 [54%]), employees (154 [44%]), and responders (10 [3%]). The most frequent health effects experienced as a result of these incidents included respiratory irritation (7,443), dizziness or central nervous system problems (3,186), and headache (3,167). The three chemicals associated with the largest number of persons injured were carbon monoxide (2,364), ammonia (1,153), and chlorine (763).
Interpretation: Company employees, followed by members of the general public, are frequently injured in acute chemical incidents. The chemicals most often associated with these injuries are carbon monoxide, ammonia, and chlorine, all of which are hazardous gases that can be found in various locations including schools and homes. Respiratory irritation is the most common health effect.
Public Health Implications: By understanding the types of persons injured in chemical release incidents, as well as how they are injured and the injuries sustained, prevention outreach activities can be focused to protect the health of these groups in the future. Improved awareness among and training for not just employees but also the public is needed, particularly regarding carbon monoxide, ammonia, and chlorine. Appropriate measures to provide protection from respiratory effects of chemical incidents could prevent injuries.
Introduction
Chemicals that can cause adverse health effects are used in many settings, including manufacturing industries, water treatment facilities, food processing plants, schools, and homes. Because of this, chemicals are involved in tens of thousands of emergency incidents each year and lead to thousands of personal injuries and hundreds of deaths. In addition to physical injuries, persons exposed to chemical releases can experience long-lasting mental health effects (1–3), and communities where incidents occur can be strained (4).
The Hazardous Substances Emergency Events Surveillance (HSEES) database provides information on the characteristics and spatial and temporal dimensions of hazardous chemical releases within the states that participated in the surveillance system (5). This report summarizes the data collected on injured persons in selected states during 1999-2008 and is a part of a comprehensive collection of surveillance summaries (6). Public and environmental health and safety practitioners, worker representatives, emergency planners, preparedness coordinators, industry employees, emergency responders, and others who prepare for or respond to chemical incidents can use the findings in this report to prepare for and prevent chemical incidents and injuries.
Methods
This report is based on data reported to HSEES by health departments in nine states (Colorado, Iowa, Minnesota, New York, North Carolina, Oregon, Texas, Washington, and Wisconsin) that participated in HSEES during its last 10 complete calendar years of data collection, 1999–2008. Data from 2009 were not included because several states ended data collection mid-year. A detailed description of the HSEES data used in this analysis is found elsewhere (6). Case definitions, exclusion criteria, and 2006 changes in reporting guidelines used for this analysis are described (Box).
Chemical incidents that result in injuries were characterized and the injured persons were described by analyzing collected data that included location, industry, substances released, contributing factors, injured persons, injuries experienced, and shelter-in-place or evacuation orders. These data were entered into an Agency for Toxic Substances and Disease Registry (ATSDR) online data collection system. Data analysis using statistical software was performed and included descriptive statistics and odds ratios (ORs) with 95% confidence intervals (CIs) for injury given different protective actions, including evacuation, shelter in place, and decontamination. Chi square for linear trend in proportions also was calculated. P values of <0.05 were considered significant. In this analysis, members of a company response team were categorized as responders and not considered to be employees of their company.
HSEES defined an injured person as a person who experienced at least one documented acute (i.e., occurring in <24 hours) adverse health effect or who died as a consequence of the incident; injured persons must have at least one injury type or symptom, and up to seven could be listed (5).
Results
A total of 57,975 chemical incidents were reported by the nine states to HSEES during 1999-2008. In 4,621 (8%) of these incidents, 15,506 persons were injured (Table 1). The number of incidents with injuries during this period varied among states because of differences in population and industry composition, from 157 in Colorado to 1,260 in New York. The proportion of incidents in which injuries occurred varied from 2% in Texas to 27% in Washington. In both Oregon and Washington, the proportion of incidents resulting in injury decreased over the 10-year period (p<0.05). The number of persons injured in each incident ranged from one to 259 (mean: three to four, median: one) (Table 2). A total of 4,041 incidents occurred in which a single chemical was released, resulting in 13,198 persons being injured; 9,230 (70%), of these incidents involved volatilization or aerosolization of the chemical (Table 3).
The sex of 12,611 injured persons was known; 8,096 (64%) were male and 4,515 (36%) were female. The majority of responders (91%) and employees (70%) of the responsible party were male. More members of the general public who were injured in chemical incidents were male (54%), whereas more students injured at school were female (58%). The mean age was similar for employees (37 years), responders (36 years), and the general public (34 years). Students exposed at school were an average age of 13 years.
Employees of the company responsible for the chemical release were the persons most frequently injured in these incidents (7,616) (Table 4). The next most commonly injured groups were members of the general public (4,737) and students exposed at school (1,730). Emergency responders, primarily firefighters and police officers, also were commonly injured in incidents involving chemical releases (1,398). Of the 543 incidents in which responders were injured, the most common locations involved private households (33 [6%]), merchant wholesalers (13 [2%]), utilities (11 [2%]), chemical manufacturing (10 [2%]), and food manufacturing (10 [2%]). Methamphetamine laboratories often are in private households. Two hundred thirty-one (17%) of the 1,398 responders were injured when responding to incidents in illegal methamphetamine laboratories. Throughout the 10-year period, the proportion of injured persons that were members of the general public has shown an increasing trend (p<0.05).
Medical care received as a result of the incident is known for 15,369 persons (Table 5). The majority of persons received care at a hospital, including those observed without treatment (414 [3%]), treated in the emergency department and released (8,414 [55%]), or admitted for hospital care (1,189 [8%]). Almost one fourth (3,431 [22%]) of injured persons were treated with first aid at the scene of the incident. Some injured persons (683 [4%]) sought care with their primary care physician within 24 hours of the incident. Of those admitted to a hospital, 663 (56%) were employees of the responsible party, 418 (35%) were members of the public, 83 (7%) were responders, and 25 (2%) were students exposed during an incident at a school. A total of 354 deaths occurred as a result of these incidents. Among deaths for which location was known, 257 (87%) occurred at the scene or were declared when the person arrived at the hospital. Thirty-seven (13%) deaths occurred after the injured person arrived at the hospital. The location of death for 60 persons was not collected. A total of 190 (54%) of the deaths occurred among members of the general public, 154 (44%) among employees of the responsible party, and 10 (3%) among responders.
Injured persons must have had at least one injury listed (and could have up to seven). The most frequently reported injuries included respiratory irritation (7,443 [30%]), dizziness or central nervous system problems (3,186 [13%]), and headache (3,167 [13%]) (Table 6). Trauma, which is common in motor vehicle accidents, could be unrelated to the chemicals involved in the incident or could be the result of the chemical. Likewise, burns could either be thermal or related to the chemical. Persons injured in chemical incidents often have more than one symptom, such as respiratory irritation and eye irritation. In addition, heat stress might be a result of wearing personal protective equipment (PPE) during responses with a high ambient air temperatures rather than be caused by the chemical incident. However, most persons injured during acute chemical incidents were not wearing any PPE (12,354 [82%]) (Table 7).
Sheltering in place and evacuations are used to protect the local population from becoming exposed during a chemical incident. Although HSEES summary data do not have sufficient detail to determine at which point during an incident the injuries occurred, ORs were calculated for shelter-in-place orders and evacuations, using injury during the incident as the outcome measure. Among the 4,621 incidents in which persons were injured, a shelter-in-place order was issued for 156 incidents, and an evacuation was ordered for 1,439 incidents. The odds of a shelter-in-place or evacuation order being given in incidents with injuries were higher than the odds of this order being given among incidents without injuries (OR: 5.4; CI: 4.4−6.5, OR: 8.5; CI: 7.9− 9.2, respectively).
Decontamination is used to remove chemicals from contaminated persons to prevent future exposure to the chemicals and prevent additional contamination and secondary exposures. Decontamination was performed in 1,152 of the 4,621 incidents in which persons were injured. The odds of decontamination being performed were greater in incidents with injuries than in incidents without injuries (OR: 17.1; CI: 15.6-18.7).
Discussion
Acute chemical releases are common in the United States, and injuries and deaths caused by these incidents remain a problem. Data obtained by surveillance of chemical release incidents can be used to develop prevention activities to decrease the number of incidents and the resulting morbidity and mortality.
Four distinct groups were injured during chemical incidents: employees of the responsible party, the general public, students exposed at school, and responders to the incident. The reasons various groups are exposed during these incidents and the methods needed to protect them are different.
Employees of the entity responsible for the chemical release are the most commonly injured persons and represent the highest proportion of those hospitalized. The Occupational Safety and Health Administration, whose mission is to ensure safe and healthful working conditions, recommends a hierarchy of control to protect the health of employees who work with chemicals (7). The most effective way to protect those who work with toxic chemicals is to completely eliminate use of a known hazardous chemical or substitute it with a less toxic one. The next most effective method is to establish an engineering control that creates barriers or prevents workers from performing actions that could result in a chemical exposure or release. Administrative controls, which require a worker to perform a specific action, or use of PPE are less effective workplace protective measures. Employees have a right to a safe workplace, and employers have responsibilities under occupational safety and health laws to ensure that these rights are protected (8). Injury and illness prevention programs are fundamental for protecting workers and transforming workplace culture, leading to reductions in injuries, illnesses, and deaths. These programs also decrease workers' compensation and other costs, improve morale and communication, enhance image and reputation, and improve processes, products and services. Important characteristics of effective programs include management commitment and leadership, effective employee participation, integration of health and safety with business planning, and continuous program evaluation (9). Over the 10-year surveillance period, the number of injured employees decreased slightly (10), which might be attributable to advances in worker safety and training.
Members of the general public are the second most commonly injured group and have the largest number of deaths. The percentage of all injured persons in the general public has increased as the percentage of injured workers decreased. The public might be affected by various types of incidents, including an explosion at a nearby factory, a transportation incident such as a truck rollover or train derailment, or illegal activities such as methamphetamine production in the home. Avoiding the transport of hazardous substances through densely populated areas or through small secondary roads, where responding to an emergency would be difficult, could help decrease injuries and deaths among members of the general public. In addition, local industries can provide a list of the chemicals they use to their local emergency planning committees so that the committees can plan for possible related emergencies. Use of the best available data by all relevant persons and facilities, including first responders, hospitals, and industries, increases understanding of potential chemical incidents, which helps ensure efficient coordination and response during an incident.
Children are inherently more susceptible to environmental hazards because their bodies are still developing and because of certain age-associated behaviors (11). Although students in primary and secondary schools comprise the group that is the third most commonly exposed to chemical incidents, this proportion does not adequately describe the number or severity of injuries experienced during incidents at schools. In addition to students being exposed, teachers and other staff members are often also exposed or are the only persons exposed. However, although numerous student injuries occurred, few were severe enough to result in hospitalization, and none resulted in death. Triage and treatment of minor symptoms at the scene of a school incident could decrease unnecessary transport of students to hospitals. Campaigns to replace toxic cleaning substances with safer chemicals will help decrease exposure of children to toxic chemicals. In addition, a combination of educational campaigns such as Don't Mess with Mercury (12) and strict enforcement of bans on items such as homemade chemical bombs (e.g., bottle bombs) and pepper spray also can help minimize the number of school-related chemical incidents.
Firefighters and police officers who respond to chemical releases or incidents in which chemicals are present are the fourth most commonly affected group. Like employees of the responsible party, responders are employees who should receive appropriate training and be issued the PPE needed to prevent exposure to toxic chemicals. Responders who are injured during a chemical release often are unable assist and rescue others during a response. Responders who might encounter circumstances necessitating use of a respirator should be medically screened for respirator use, be properly equipped, and receive respirator use training that includes recognizing hazards (13,14). This training should be renewed frequently. All responders should receive training on how to recognize and handle a situation involving chemicals that could be hazardous. In addition, responders should be able to determine which incidents require decontamination, not only to prevent additional exposure among contaminated persons but also to prevent contamination among those providing medical care, in ambulances, and in hospitals.
A higher proportion of injuries occurred during incidents in which a shelter-in-place or evacuation order was issued or in which decontamination was performed than during incidents with no such orders or decontamination. Surveillance data such as those from HSEES do not indicate whether the injuries occurred before or after the public health action was implemented. Only a small percentage of chemical release incidents have a shelter-in-place order, evacuation, or decontamination during the response; these incidents generally involve the largest releases and the most toxic substances.
Limitations
The findings in this report are subject to at least seven limitations. First, despite the attempts to make the case definition the same among states, results are not comparable between states because reporting to HSEES was voluntary and data sources varied by state. Second, results are not generalizable because circumstances in specific states might not be representative of the entire United States. Third, inconsistencies within and across states likely exist because reporting capacity (e.g., staffing or participating units) or local requirements varied. Specifically, certain states and localities had more stringent reporting regulations than the federal regulations or had more resources to conduct surveillance, possibly resulting in more reported incidents. These factors might have influenced the quality and number of reports or level of detail provided about the incidents. These factors might influence the quality and number of reports or level of detail provided about the incidents. Fourth, states with access to data on sources of injury, such as occupational injury or hospital discharge data, might identify more injuries than other states even though they did not actually have more incidents with injuries. For example, Washington was the only state to have access to the occupational injury database of its state department of labor, which might have led to their high number of reported injuries. Fifth, states with stricter reporting requirements might have more small-scale incidents and thereby a lower proportion of incidents with injuries. Sixth, incidents that occurred in the transportation and warehousing industries often were related to motor vehicle crashes, and the associated injuries might have been related to the trauma of the crash rather than to the chemical release. Finally, because the timing of the injury cannot be determined (e.g., before or after protective actions were implemented), the effectiveness of public health interventions such as shelter-in-place orders, evacuation orders, or decontamination cannot be assessed. A separate analysis discusses this point in greater detail (15).
Conclusion
Chemical releases continue to cause injuries and deaths, not only among persons who work with chemicals but also among members of the public. Because new trends in incidents can emerge, ATSDR is continuing surveillance on chemical releases to develop interventions. In 2010, the HSEES program merged with the National Toxic Substance Incidents Program (NTSIP) (16). NTSIP has a new component called incident investigations, or the Assessment of Chemical Exposures (ACE) program (17). Through these investigations, a thorough evaluation of large-scale chemical releases can supplement what is known about acute health effects caused by chemical releases. In addition, effectiveness of communication and public health actions such as shelter-in-place or evacuation orders can be evaluated. ACE was designed to provide data to state and local health partners and responders to decrease morbidity and mortality caused by acute chemical releases.
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