PATTERNS AND TRENDS IN REPORTED SMALL OIL SPILLS

Abstract

ABSTRACT Many recent analyses of oil spill data have focused on the occurrence of large spills. For example, a 1981 study compared the incidence of spills of more than 10,000 gallons in four U.S. coastal regions. A 1983 U.S. Department of the Interior study of spills of 1,000 barrels or more from outer continental shelf platforms found a statistically significant decrease in spill occurrence rates after 1974. Data from the U.S. Coast Guard's Pollution Incident Reporting System (PIRS) show a drop in the number of all reported oil spills from more than 12,000 in 1977 to fewer than 7,000 in 1982. Such reductions in reported spills have been attributed in part to stricter government regulation and enforcement, to changes in technology, or to a decline in oil transportation. The significance of small oil spills is discussed, and data on the occurrence of reported small oil spills are analyzed using information from the PIRS database. The trend over time in the number of spills of fewer than 10 gallons was found to be upward for some sources, water bodies, and regions, but downward for others. Although this paper does not examine causal relationships, increased awareness of the requirement to report oil discharges may have resulted in increased reporting of spills in some cases and increased efforts toward prevention of spills in other cases.