Katrina storm surge led to over 200 onshore releases of petroleum and hazardous materials, rivaling Exxon Valdez oil spill

According to comprehensive research using government incident databases, about 8 million gallons of petroleum releases were reported as a result of Katrina hitting the U.S. Gulf coast in 2005, nearly 75 percent of the total volume of the 1989 Exxon Valdez oil spill in Alaska. The releases were largely due to storage tank failure and the shut down and restart of production processes. Storm surge floods were the primary cause, but some incidents occurred as a result of hurricane and tropical storm strength winds where no surge was present, according to the authors.

The study appears in the April issue of the journal Risk Analysis.

The authors include consultant Nicholas Santella, Laura Steinberg of Syracuse University, and Hatice Sengul of the Turkish Scientific and Technological Research Council. Ten onshore releases of petroleum products were greater than 10,000 gallons each, primarily made up of crude oil that leaked from storage tanks. Fewer and smaller releases were reported from chemical and manufacturing industries handling hazardous materials. Of the releases from onshore facilities and storage tanks, 76 percent were petroleum, 18 percent were chemicals and six percent were natural gas. Many refineries and other facilities shut down in anticipation of large storms to minimize damage and prevent process upsets and are required to do so for safety purposes. However, shutdowns and restarts have the disadvantage of leading to potentially large emissions of volatile organic compounds, particulate matter, and other chemicals.

"More attention should be given to planning for shutdowns, including coordination with government entities responsible for evacuation, and to plant startup after an emergency shutdown in order to minimize burning off excess gas by flaring and other releases," according to the authors. For example, storage tanks can be filled with water and other steps can be taken to mitigate damage during severe storms and floods.

"Where large releases do occur, in-depth analysis by each plant of mechanism of failure and contributing factors should be required," the authors add. Significant factors slowing response to the Katrina damage included indirect disruptions, such as displacement of workers, loss of electricity and communication systems, and difficulty acquiring supplies and contractors for operations and reconstruction. Of industrial facilities responding to a survey in the study, 55 percent experienced indirect disruptions, far more than had environmental releases of hazardous materials, indicating improved risk-based facility design and improved prevention and response planning may be warranted.

"Chemical accident prevention and emergency response regulations in the US and elsewhere generally do not address the threat of natural hazards directly. While many companies are proactive in taking steps to mitigate natural hazard risk, others may make only the minimum effort require by statute," the authors conclude. The study is the first to comprehensively analyze the incidence and causes of releases from all types of onshore industrial facilities as a result of Hurricane Katrina. The analysis relies on the key incident reporting databases of the National Response Center (NRC) Incident Reporting Information System (IRIS) administered by the U.S. Coast Guard. In addition, interviews and data were obtained from federal and Gulf state environmental agencies, energy and chemical associations, public accounts of particular incidents, and a small industry survey.