Acute chemical incidents surveillance—Hazardous Substances Emergency Events Surveillance, nine states, 1999-2008.

Problem/condition: Although they are infrequent, acute chemical incidents (i.e., uncontrolled or illegal release or threatened release of hazardous substances lasting <72 hours) with mass casualties or extraordinary levels of damage or disruption severely affecting the population, infrastructure, environment, and economy occur, and thousands of less damaging chemical incidents occur annually. Surveillance data enable public health and safety professionals to better understand the patterns and causes of these incidents, which can improve prevention efforts and preparation for future incidents.

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 provides a historical overview of HSEES and summarizes incidents 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: During 1999-2008, a total of 57,975 chemical incidents occurred: 41,993 (72%) occurred at fixed facilities, and 15,981 (28%) were transportation related. Chemical manufacturing (NAICS 325) (23%) was the industry with the most incidents; however, the number of chemical incidents in chemical manufacturing decreased substantially over time (R² = 0.78), whereas the educational services category (R² = 0.65) and crop production category (R² = 0.61) had a consistently increasing trend. The most common contributing factors for an incident were equipment failure (n = 22,535, 48% of incidents) and human error (n = 16,534, 36%). The most frequently released chemical was ammonia 3,366 (6%). Almost 60% of all incidents occurred in two states, Texas and New York. A decreasing trend occurred in the number of incidents in Texas, Wisconsin, and Colorado, and an increasing trend occurred in Minnesota.

Interpretation: Although chemical manufacturing accounted for the largest percentage of incidents in HSEES, the number of chemical incidents over time decreased substantially for this industry while heightened awareness and prevention measures were being implemented. However, incidents in educational services and crop production settings increased. Trends in incidents and number of incidents varied by state. Only a certain few chemicals, sectors, and areas were found to be related to the majority of incidents and injured persons. Equipment failure and human error, both common casual factors, are preventable. PUBLIC HEALTH IMPLICATIONS: The findings in this collection of surveillance summaries underscore the need for educational institutions and the general public to receive more focused outreach. In addition, the select few chemicals and industries that result in numerous incidents can be the focus of prevention activities. The data in these surveillance summaries show that equipment maintenance, as well as training to prevent human error, could alleviate many of the incidents; NTSIP has begun work in these areas. State surveillance allows a state to identify its problem areas and industries and chemicals for prevention and preparedness. Beginning in 2010, ATSDR replaced HSEES with the National Toxic Substance Incidents Program (NTSIP) to expand on the work of HSEES. NTSIP helps states to collect surveillance data and to promote cost-effective, proactive measures such as converting to an inherently safer design, developing geographic mapping of chemically vulnerable areas, and adopting the principles of green chemistry (design of chemical products and processes that reduce or eliminate the generation of hazardous substances). Because the more populous states such as New York and Texas had the most incidents, areas with high population density should be carefully assessed for preparedness and prevention measures. NTSIP develops estimated incident numbers for states that do not collect data to help with state and national planning. NTSIP also collects more detailed data on chemical incidents with mass casualties. HSEES and NTSIP data can be used by public and environmental health and safety practitioners, worker representatives, emergency planners, preparedness coordinators, industries, emergency responders, and others to prepare for and prevent chemical incidents and injuries.