Case study

Storm surge from Hurricane Katrina placed an oil tank facility and surrounding neighborhoods in St. Bernard Parish, Louisiana under water for several days. When the water receded, it was discovered that the hurricane had dislodged a 250,000 barrel above-ground storage tank containing about 65,000 barrels of mixed crude oil (Agency for Toxic Substances and Disease Registry, 2005b). Approximately 25,110 barrels (slightly over a million gallons) of oil spilled from the ruptured tank.

The initial response was delayed because of high water, debris, barricades by the National Guard or local police, downed telephone lines, and lack of satellite phones. When the area was accessible, the United States Environmental Protection Agency on-scene commander directed the facility to secure the tank, identify the extent of the release, and begin recovery operations. The facility immediately began pumping out the containment canals and recovered approximately 72% of the oil.

In October 2005, long-term remediation was initiated with oversight by the United States Environmental Protection Agency and the Louisiana Department of Environmental Quality, including clean up on land, residential areas, and non-commercial waterways. Approximately 1,800 affected properties in an area of about one square mile were identified through a house-to-house visual survey conducted from the street. The Environmental Protection Agency classified contamination on 114 properties as heavy (more than 50% of the yard, sidewalks, and home were covered with oil), 286 properties as medium (about 50% of the yard and sidewalks were covered in oil), and the balance as light to oil line only (small percent of oil was visible on horizontal surfaces or a "bathtub ring" of visible product band approximately 3 to 6 inches wide was seen on the residence, with no visible oil on the yard, sidewalks, and home (Agency for Toxic Substances and Disease Registry, 2005c). However, some affected properties may have been missed because properties that were not visible from the street or public sidewalk were not surveyed due to legal access requirements. The more heavily affected areas were immediately to the west of the facility. The 25 month long clean-up of the contaminated properties within the impacted area began with the facility removing oil-stained sediment and soil. After removal, the remaining soil was analyzed to ensure that the Louisiana Department of Environmental Quality risk evaluation/corrective action program residential soil standards for High Public Use Areas were met. If the standards were not met, additional soil was removed and the process was repeated.

Residential clean-up was complex and involved two phases. In Phase 1, property owners requested clean-up from the facility and granted them access to the property, and the facility obtained wipe and sediment samples (10% of the samples were split with the Environmental Protection Agency) and washed home exteriors. In Phase 2, the homeowner was responsible for gutting the house to the studs, and the facility removed the oiled part of the debris and transported it to an industrial landfill. The homeowner then requested an interior cleaning from the facility and granted them a second access to the property which involved the facility power washing the home's interior and exterior and replacing the yard. Reoccupation of the property was determined by the parish based on results of a final air sample (U.S. Environmental Protection Agency Region 6, 2006).

Several factors impeded residential clean-up, including class actions lawsuits filed against the facility that restricted homeowner contact with the facility and therefore barred remediation by the facility; temporary or permanent relocation of many residents after the spill; and lack of funds to complete the clean-up because the facility was only responsible for the oil-damaged part of the cleanup. This resulted in a less efficient clean-up and an "island effect" where oiled homes were next to cleaned homes because crews could not clean up whole contiguous blocks of neighborhoods (U.S. Environmental Protection Agency Region 6, 2006). The Environmental Protection Agency shared the results of more than 800 sediment/soil samples collected from properties between September 19 and November 8, 2005 with the Agency for Toxic Substances and Disease Registry and requested an assessment of potential health hazards posed by the contamination. In December 2005, the Agency for Toxic Substances and Disease Registry released a health consult for the site which concluded that for the properties sampled, there were no short or long term risks from oil-related chemicals in sediment and soil for most properties. Recommendations were made that properties should be evaluated and remediated if necessary for other potential health hazards, such as indoor mold and structural damage, prior to re-occupancy. The recommendation was also made that properties which exceeded recommended soil standards should be remediated to be protective of public health for re-occupancy. Additionally, the health consult recommended that residents avoid bare skin contact with sediment, soil, and indoor surfaces with visible oil contamination and that homes with visible indoor oil contamination or noticeable petroleum odors be tested to determine if concentrations of chemicals in indoor air were of health concern prior to re-occupancy (Agency for Toxic Substances and Disease Registry, 2005b).

Oil companies were not required to plan to withstand storm surges that resulted from Hurricane Katrina. However, in 2007, a buyout program to create a buffer around the facility was approved to minimize the threat of future spills. In August 2009, the Louisiana Department of Environmental Quality determined that the area's shallow groundwater was unaffected by the spill and concluded that the area impacted by the spill had been remediated to acceptable levels.

Recovery and response related to this spill were complicated by competing priorities (local, state, and federal) and high background levels of contamination in that area of Louisiana which interfered with the sampling. Communication issues were also a major barrier and included delays in the public receiving information about contaminant levels which was often on a website that was not accessible to the affected population; difficulties in interpreting data and comparing it with general drinking water or ambient air quality standards which were not appropriate for an acute exposure event; and adequately conveying re-occupancy policies because federal agencies had a different opinion than the parish who ultimately made the decision (Manuel, 2006; Johnson, et al. 2005).

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