Author: Hannah

NOAA’s Approach to Oil Sheen Risk Assessment is Incomplete

NOAA’s Approach to Oil Sheen Risk Assessment is Incomplete

Oil sheen contained in Talbert Channel near site of last year’s major O.C. pipeline spill. Photo by: Andrew Fowler

The environmental community must take a closer look at oil sheen.

Despite the media and political pressure to the contrary, that is exactly what the National Oceanic and Atmospheric Administration is doing. On March 25, NOAA released a two-page synopsis of their recent review of the potential risk of contamination by oil sheen. The synopsis explains:

The public is being asked to trust NOAA with its expertise and information in the event of an oil spill, and trust us that we have the knowledge and resources to mitigate potential risks …. The public should not be concerned about these statements, since NOAA’s scientific expertise has been assessed and it is clear that it will be able to respond to any oil spill.

To the extent that this is an accurate representation of NOAA’s intentions, NOAA has not engaged in the kind of science-based risk assessment that should be at the heart of an oil spill response.

Instead, NOAA has relied on a series of assumptions and models that are insufficient for addressing this new environment in the absence of more scientific data and expertise.

As you will see, NOAA’s approach is dangerously incomplete, and it is not at all clear that NOAA’s assessment that sheen poses no significant risk at the present time is anything but incomplete.

Oil sheen is a problem

First, let’s begin with the assumptions that the NOAA scientists have been making about how sheen behaves and can be dispersed. In a nutshell, the NOAA scientists believe that oil sheen can be dispersed in a number of ways, including dispersion in wind and ocean currents, dispersion through the water column and through the hydrocarbon emulsions, and dispersion of the oil in the sea floor.

The NOAA scientists have been combining these dispersion options — which are all different in their own ways — into one overarching approach, or “framework,” for developing sheen-risk assessments.

To be clear, we are not asking NOAA to conduct a sheen-risk assessment. We simply want to point out that they have been using different terms to describe different aspects of she

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