Maritime Security: Opportunities Exist to Further Clarify the Consequences of a Liquefied Natural Gas Tanker Spill, Statement of Mark Gaffagan, Acting Director of Natural Resources and Environment, Testimony before the Subcommittee on Coast Guard and Maritime Transportation, Committee on Transportation and Infrastructure, House of Representatives [open pdf - 707KB]
"The six studies GAO reviewed examining the potential effect of a fire resulting from an LNG spill produced varying results; some studies also examined other potential hazards of a large LNG spill and reached consistent conclusions on explosions. Specifically, the studies' conclusions about the distance at which 30 seconds of exposure to the heat (heat hazard) could burn people ranged from less than 1/3 of a mile to about 1-1/4 miles. Sandia National Laboratories (Sandia) conducted one of the studies and concluded, based on its analysis of multiple attack scenarios, that a good estimate of the heat hazard distance would be about 1 mile. Federal agencies use this conclusion to assess proposals for new LNG import terminals. The variations among the studies occurred because, with no data on large spills from actual events, researchers had to make numerous modeling assumptions to scale up the existing experimental data for large LNG spills. Three studies considered LNG vapor explosions and concluded that such explosions are unlikely unless the vapors were in a confined space. Only the Sandia study examined the potential for the sequential failure of multiple tanks on the LNG vessel (cascading failure) and concluded that only three of the five tanks in a typical tanker would potentially be affected, and that such failure would increase the duration of the LNG fire."