There is no such thing as a good oil spill. Nevertheless, some spills are much worse than others, though that bit of perspective would not be particularly welcome in my former home state of California, just now. Anyone following the coverage of the Cosco Busan spill, for with legislators are now seeking a federal investigation of the response, might naturally conclude that it ranks among the larger spills in recent years. Seeing the volume cited in gallons--58,000 of them--certainly reinforces that impression. While the environmental damage to the shoreline and marine life of San Francisco Bay saddens me, this spill from a container vessel was relatively modest, as such things go, and until we can replace oil's 150 quadrillion BTU annual contribution to global energy consumption, an attitude of zero tolerance to spills is bound to be disappointed.
Contrary to widely-held perceptions, the number of large oil spills--defined as exceeding 700 metric tons--around the world has declined in each decade since the 1970s, even though oil shipments and seaborne cargo trade have both grown significantly since then. More importantly, the volume of oil spilled in such incidents has also fallen dramatically, particularly over the last dozen years. In 2006, there were 14 spills between 7 and 700 tons and only 4 spills over 700. Statistics from the US Coast Guard reflect similar trends to those of the International Tanker Owners Pollution Federation (ITOPF). For comparison purposes, the Busan spill tallies at about 212 tonnes, a far cry from the Exxon Valdez at 37,000 tonnes, or a monster like the Amoco Cadiz at 223,000 tonnes (69 million gallons.)
That doesn't mean that, since this wasn't a giant spill, we should make light of it, or overlook negligence on the part of anyone involved. It doesn't take very much oil to foul beaches and harm wildlife. But what stands out here is the diminishing tolerance for spills, in spite of the evidence that their frequency and severity are declining. In the post-Katrina US, it is not hard to imagine the outcry that would accompany a truly major oil spill in our coastal waters or a harbor. That has implications for offshore drilling, pipelines, barge and tanker operations, and cargo lines. The number of places from which oil could spill is increasing, and the industry's success at bringing down its spill statistics, while reflecting a lot of hard work, won't win accolades in a world that regards any spill as one too many.