Scaling impacts from oil spills: lessons learned from Ixtoc I, Exxon Valdez, and BP/Deepwater Horizon J. Christopher Haney, Ph.D. Chief Scientist, Defenders of Wildlife Core science reviewer, Exxon Valdez Oil Spill Trustee Council, Principal Investigator, NRDA Bird Study #6, Deepwater Horizon Response Impacts of the Oil and Gas Industry to Natural Resources and Communities Congressional Meeting Room South U.S. Capitol Visitor Center, Washington, DC April 6, 2011

Major lessons learned: 1) previous spills show us that preparations for trans- boundary impacts from oil spills can never be fully anticipated – we plan for the last (not the next) spill. 2) locations, times, and other attributes peculiar to each spill confound our ability to respond to oil spills with regulation alone. Damages, both to our social and natural environments, are inevitable.

Generalized fate and transport of oil spilled in open ocean environments

Depending on weathering and other environmental factors, spilled oil takes on different consistencies Heavy pooled oil Tar balls Oil sheen Oil mousse

Exxon Valdez (U.S.) Ixtoc 1 (Mexico) BP/Deepwater Horizon (U.S.) Year 1989 – pre OPA 1979 – pre OPA 2010 – post OPA Spill type acute; surface chronic; subsurface (160) chronic; subsurface (5,000) Incident type ship grounding drilling accident Equipmenttanker well and rig Spill volume 10.8 million gallons 140 million gallons million gallons Multi-state domestic? NoYesYes Multi-national?No Yes, 2 Yes, ~4 Oil toxicity HighMediumMedium Contexts for three major oil spills in North America

The Exxon Valdez spill was notable for occurring with a relatively heavy, toxic type of crude oil, in cold water where biodegradation was slow, and for impacting steep, mostly rocky shorelines.

Ixtoc I was an exploratory oil well being drilled in the Bay of Campeche, Mexico, in Gulf of Mexico waters 50 m (160 ft) deep. On 3 June 1979, the well suffered a blowout,resulting in what was then this hemispheres largest accidental oil spill of ~140 million gallons.

The BP/Deepwater Horizon spill was the largest accidental oil spill in human history. Total estimates exceed 200 million gallons spilled.

Exxon Valdez (U.S.) Ixtoc 1 (Mexico) Deepwater Horizon (U.S.) Estimated cost in 2010 dollars $14.8 billion $3.2 billion $ billion Cost per gallon spilled $768$22.3 $768 (est.) Long-term impacts to deep sea floor UnlikelyUnknown Highly likely Impacts to near- shore sea floor and margin Yes, cobble beach and intertidal Yes, sand beach and estuaries Damages to fish and fishing industry Yes, both real and perceived Not yet quantified Lasting harm to top marine predators Yes, several to many species Probable, but largely unknown Likely, but still largely not quantified Social and environmental costs of spills vary unpredictably

Some environmental impacts of spills are obvious, like tar balls on tourist beaches, or oily coating on these young brown pelicans in coastal Louisiana. Yet other impacts are less obvious, especially certain changes to wildlife behavior, reproductive success, long-term population trends, and genetic integrity. Such damages can be detected only after years or decades of study using sophisticated research techniques.