Controversy and publicity surrounding the Exxon Valdez spill notwithstanding, there were fewer major oil tanker spills in U.S. waters last year than the average during 1978 89.
That can be seen in a recent study by Golob's Oil Pollution Bulletin, Cambridge, Mass.
Golob's study found the number of major tanker incidents involving the loss of 10,000 gal of oil or more-off the U.S. averaged six or seven/year in 1978-89.
In 1989, there were only five tanker spills in U.S. waters involving more than 10,000 gal of oil, Golob figures show. Oil & Gas Journal incorrectly reported the Golob study involved U.S. oil spills, not just tanker oil spills in U.S. waters (OGJ, Mar. 26, p. 1).
The Exxon Valdez tanker spill in Alaska's Prince William Sound on Mar. 24, 1989, was the biggest in North American waters.
STUDY DETAILS
During the study period, there were 78 major oil spills in U.S. waters involving 79 tankers, one involving a collision of two tankers. In all, those spills accounted for more than 41 million gal of oil lost.
"Although massive spills can cause extensive environmental and economic damage, they remain low probability events," the Golob bulletin said.
There were only seven tanker spills in U.S. waters involving a loss of 1 million gal of oil or more during 1978 89, according to the study.
Tankers caused 30 spills of 10,000-49,999 gal, 11 spills of 50,000-99,999 gal, and 28 spills of 100,000-999,999 gal.
The annual volumes of oil spilled-including volumes recovered-ranged from 92,000 gal in 1983 to 11.7 million gal in 1989, the study found.
SINGLE SPILLS' ROLE
In several of the years in the study period, a single spill accounted for the vast majority of the total volume of spillage.
The Exxon Valdez accounted for more than 90% of the total spilled in major tanker accidents in 1989.
In 1979, the Burmah Agate tanker lost more than 10 million gal of oil, about 85% of the total volume lost that year. In 1981, the Olympic Glory tanker collision spilled 1 million gal, about 66% of the year's volume of crude oil lost.
In 1982, only two major tanker spills were reported, with the loss of 1.47 million gal from the Arkas tanker representing 98% of the oil lost that year.
Smaller tankers tended to account for most of the spills. More than half the spills involved tankers of 30,000 99,999 dwt. Of that number, vessels of 30,000-49,999 dwt accounted for almost half.
The third worst year in total volume lost covered by the study was 1984, which saw two major tanker spills of more than 1 million gal each: the 2.8 million gal Alvenus tanker crude spill and the more than 2 million gal Puerto Rican tanker bunker fuel/lube oil spill.
During 1978-89, two vessels repeated accidents. The Amazon Venture tanker had two spills involving valve failure in 1986, and the Stuyvesant tanker had hull damage twice in 1987-each time spilling a volume of about 600,000 gal.
The Gulf Coast was the region with most of the spills in the study, with Texas and Louisiana accounting for 30 of the region's 34 major tanker spills. Alaska had six major tanker spills, California had three.
RISING IMPORTS LINK?
Golob's study did not attempt to establish a link between tanker oil spills in the U.S. and the levels of tanker traffic in U.S. waters.
There are too many variables to easily establish that link, said Richard Golob, president of World Information Systems, Cambridge, and publisher of the oil spill newsletter.
However, the peak year for the number of tanker oil spills in U.S. waters covered by the study period, 1979, also was the peak year for total U.S. crude and products imports. In addition, the biggest total volume of oil lost-not just spilled-from tankers in U.S. waters occurred in 1979.
Total U.S. oil imports averaged 8.456 million b/d in 1979, compared with 7.979 million b/d in 1989, according to Energy Information Administration data.
Conversely, the years with the fewest tanker oil spills in Golob's study period-1982, 1983, and 1985-also had the lowest levels of U.S. oil imports in the study period and the lowest since 1972.
Whether the below-average number of oil spills in 1989 weakens the presumption that there is a link between increased imports and increased number of tanker spills remains to be seen. The decline in 1989 spills could be the result of tighter safeguards in the aftermath of the Exxon Valdez, luck, or both.
In the first 2 months of 1990, U.S. oil imports jumped to an average of 8.584 million b/d, compared with 7.978 million b/d in the first 2 months of 1989.
Oil & Gas Journal forecast a 5.4% increase to about 8 million b/d in average U.S. oil imports for 1990 (OGJ, Jan. 29, p. 49).
Copyright 1990 Oil & Gas Journal. All Rights Reserved.
