Unknown Unknowns

The most common story written about the 1989 Exxon Valdez oil spill begins with a sentence like this one, used in National Geographic in January 1990: “When the supertanker Exxon Valdez ran aground [on] March 24, spewing 11 million gallons of crude oil into Prince William Sound, some feared that the pristine waters would never recover.”   Yet even such a simple introductory fact—used to orient the reader to the spill’s detrimental effects—does not represent the full truth. 

For example, although most estimates place the volume of the spill at 11 million gallons, the State of Alaska estimates more than 30 million gallons were spilled.  Another local newspaper reported the spill volume at 38 million gallons.  The variance in estimates of the amount of oil spilled is only one of the many instances where the answer to even simple questions about the spill remain unsettled and inconclusive.  When the Exxon Valdez ran aground on Bligh Reef, it spread more than viscous oil into the waters and communities of Prince William Sound.  Uncertainty in damage assessment also clouded the aftermath of the spill.

Uncertainties common to all oil spills—such as how much oil was spilled and how many animals were killed—dominated discussions and analyses after the Exxon Valdez oil spill.  Other uncertainties remained entirely undiscussed.  Such uncertainties included the effects of the spill on subsistence economies of indigenous communities.  These were generally not covered in dominant news stories, although one local Native Alaskan newspaper, the Tundra Times, did discuss them.  Various Native Alaskan communities were later shown to have increased rates of drinking and drug abuse, medical conditions, and post-traumatic stress disorder following the spill.  But it was not until long after the spill, and the subsequent court settlement, that detailed studies focused on indigenous subsistence livelihoods.

Many long-term effects on some species residing in Prince William Sound were also not taken into account, either because premature termination of the studies made data unobservable or because those studies may not have seemed useful for the settlement initially, since a settlement number ultimately depended on conversion of data into clear monetary units.  Some species, such as harlequin ducks, showed latent effects that became apparent after studies were prematurely terminated.  This knowledge was only observed over long timescales, preventing injured parties from assigning liability to Exxon at the time it could have impacted settlement amounts.

To account for effects unobserved in initial data assessments, the $1.025 billion settlement in 1991 between the federal and state governments and Exxon contained a “Reopener Claim,” which permitted federal and state governments to seek up to $100 million from Exxon if additional restoration projects became necessary.  In practice, however, the “reopener agreement” has not worked; the $92 million requested in 2006 has yet to be paid by what is now ExxonMobil.  The claim, which seeks funds to clean up lingering oil, ignores other unanticipated injuries caused by the spill, such as mental health and subsistence-related effects.  The reopener claim, as Marine Conservation Professor Rick Steiner puts it, “is so poorly conceived that Exxon may never have to pay it.”

Similarly, the 1994 Restoration Plan created a Restoration Reserve to provide long-term observation of injured resources, but long-term damage assessments were not necessarily tied to settlement awards or the reopener agreement.  Exxon could not be held accountable for effects that were unobserved, either partially or fully, at the time of the spill.  Mechanisms to account for these formerly unrealized effects were either not used for their designed purposes (i.e. the reopener agreement) or were implemented too late to be useful (i.e. long-term ecosystem damage assessment).

The Exxon Valdez tanker ran aground on Bligh Reef twenty-five years ago.  Recent disasters, however, have not incorporated lessons learned about uncertainty after the Exxon Valdez spill.  Following the 2010 BP oil spill, a $7.8 billion initial settlement similarly left out unanticipated effects.  The settlement, for example, provides a health outreach program for twenty-one years of health monitoring.  If unanticipated ailments occur, the patient must sue BP and prove causality to receive compensation.  If one accepts an initial $5,000 payment, however, one must relinquish the right to sue BP for damages later on.  The BP settlement, like the Exxon settlement, created a mechanism to retroactively assign responsibility for delayed observations, but undermined its effectiveness by making later health claims nearly impossible to prove.  The long-term monitoring program tracks formerly unobserved effects, but makes compensation of those claims nearly impossible.

In the aftermath of environmental disasters, uncertainty manifests itself both in what we observe and what we do not initially see.  In the recent Elk River chemical spill in West Virginia this year, questions focused around the enigmatic spilled chemical, 4-Methylcyclohexanemethanol.  In order to account for the unobserved uncertainties, however, those assessing damage will also need to create practical mechanisms to account for long-term effects on health and on the ecosystem of Elk River.

Following future environmental disasters, what we do not know may be as important as what we do know.  Only by incorporating the observed and the unobserved can one assess damage in a way that can hold responsible parties accountable.  Twenty-five years after the Exxon Valdez spill, one thing is certain: the spill continues to offer valuable lessons on how to approach uncertainty after environmental disasters today.





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