BLUE MASTER: USE OF COREXIT®9500 TO DISPERSE IFO 180 SPILL1

Abstract

ABSTRACT COREXIT®9500 was used to disperse 100 barrels (bbls) of Intermediate Fuel Oil (IFO) 180 30 nautical miles south of Galveston, Texas. The dispersant was highly effective in dispersing this heavy fuel oil. Efficacy was based on the fact that only 1.5 barrels of oil washed up on the beach in the form of tarballs a week later. No reports of oiled birds or wildlife related to the incident were received. The pre-authorization limits of the Regional Response Team (RRT) Region VI On-Scene Coordinator (OSC) Pre-Approved Dispersant Use Manual were outdated; COREXIT®9500 was placed on the National Contingency Plan (NCP) Product Schedule list of approved dispersants after the manual was written. COREXIT®9500 enables dispersal of heavier products than those originally considered by the RRT. The specific gravity of IFO 180 is 0.988 while the OSC Pre-Approved Dispersant Use Manual considered 0.953 an upper limit. The dispersant was applied outside the 6-hour time limit because an overflight showed little to no emulsification of the oil because of calm weather conditions. Although current conditions were calm, thunderstorms were expected to develop in the area that would provide the mixing action needed to enhance dispersal. The Unified Command considered this dispersant application a “cautious success.” The small amount of oil that reached the beach and the absence of oiled birds support a statement of success but, because of time limitations, Tier II SMART (Specialized Monitoring of Applied Response Technologies) data were not obtained to substantiate this conclusion. Following this case, RRT Region VI convened a committee to review the Pre-Approved Dispersant Use Manual, to evaluate whether the pre-approved protocols were still relevant, and to develop changes to the Pre-Approved Dispersant Use Manual if needed for consideration and approval by the RRT. At its January 2000 meeting, RRT Region VI approved several short-term changes to the manual and authorized continued work on several mid- and long-term revisions. These changes not only give the OSC more flexibility in choosing the right dispersant tools, but also give greater requirements to document dispersant operations.