We welcomed, along with the rest of the country, encouraging news about the installation of the latest containment cap on the Macondo well. This development may represent an important step in controlling the Gulf oil spill. Currently, pressure readings are being gathered to demonstrate the structural integrity of the well and crude reservoir, which would allow the cap to remain sealed. Alternatively, the dome is equipped to vent up to 80,000 barrels per day to surface ships, which would eliminate most if not all of oil discharges into the Gulf.
Efforts to contain the Macondo well fostered a constructive debate on the concepts of hazard and risk, and on the phenomenon of comparative risk. As millions of barrels of crude flowed into the Gulf during the Spring and early Summer, response authorities were faced with an emotionally-charged decision about the use of chemical dispersants to mitigate the ecological impacts. Dispersants are typically mixtures of solvents and other compounds designed to separate oil into smaller globules, which are more likely to be diluted to safer levels by currents and broken down by bacteria. The public and the media directed a great deal of focus on the chemical properties and toxicity of the dispersants, and whether they were making an environmental tragedy worse. An estimated 800,000 gallons of dispersants had been employed by June, both on the surface and around the leaking wellhead and riser pipe.
The principal dispersant used in the Gulf has been several versions of Corexit ®, a product of Nalco Holding Company. These reportedly contain 2-butoxyethanol and a proprietary organic sulfonate, along with low levels of propylene glycol. On May 19, EPA directed BP to deploy less toxic alternatives, or to justify its choice of Corexit over those products. BP cited an inadequate supply of most alternatives, and noted toxicological concerns about a more widely available dispersant. That chemical, marketed by Alabaster Corporation as Sea Brat 4 was itself less toxic than Corexit, but BP noted the risk that it could degrade into nonylphenol, which is environmentally persistent and toxic to some marine life.
Based on this information, on May 26 EPA approved the continued use of Corexit, but directed responders to significantly decrease the overall volume used and to cease use of dispersant on the surface whenever mechanical controls such as booms and skimmers could be relied upon. EPA also began its own testing of eight dispersants on native shrimp and fish species. Initial peer reviewed results announced in July indicated that neither Corexit nor the alternative products studied displayed biologically significant endocrine disruption.
The Agency’s approach to dispersants, the assessment of their hazard, and the risk-benefit analysis of their continued use demonstrate the value of sound, risk-based decision-making. Unfortunately, this thoughtful and deliberative process was overshadowed by an ineffective communications plan which failed to reassure the media and public as to the need for dispersants. In general, the inherent toxicity of these chemicals is far outstripped by crude oil. And yet the Agency, in their most recent press briefing, devoted more time and effort explaining the toxicity testing performed on the dispersants and less on the known toxicity of oil and the ecological devastation which its unfettered spread would visit on the region’s estuaries and beaches.
In our experience, risk management is never as effective as when it is coupled with a sound communications plan. Going forward, one would hope that the Agency improve their ability to articulate the risks and benefits associated with their decision-making so that concern over the response to a problem does not hinder action against the primary threat.
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