Conundrum of Dispersant Use in the Gulf of Mexico

We prefer that no dispersants should be used to fight the oil spill in the Gulf. Of course, it is easy to make this decision when you are not directly in charge and will be held responsible for the consequences. So we understand the conundrum the EPA faces in recommending as little use of least toxic dispersaant as possible. Either you contain the oil out in the ocean in smaller droplets, thus dooming any life coming into contact with it, or allow oil slicks along the coasts and in the marshes of five states. And this with the knowledge that you will get some of both anyway. EPA Administrator Lisa P. Jackson is a chemist and understands the situation perfectly.

However, we have two main concerns about use of dispersant in the Gulf:

1) the effect of dispersed oil particles and

2) the effect of the chemical dispersants themselves.

A federally convened group of scientists is set to recommend that BP and the government continue spraying chemicals into the Gulf of Mexico to help prevent leaking oil from washing ashore. It is unclear how sea life will be affected when exposed to dispersed oil over long periods of time. Dispersants have not ever been used in the quantities and for long periods of time included in the BP incident. At the end of the day, and considering the economic, political, and scientific considerations, keeping it out in the water column is probably better than letting it into the coastal areas. This is just a really tough decision and a decision has to be made.

Shortly after approving use of the Corexit 9500 dispersant, EPA shifted its position and ordered BP to find a less-toxic alternative or explain why it couldn't find one. Nalco Comapany, Corexit's maker, informed BP that the dispersant was safe and BP told the EPA that it could find no less-toxic dispersant in the quantities necessary to fight this spill. EPA had no choice but to accept this finding. The agency asked BP to reduce the amount of Corexit 9500 the company is using.

The EPA doesn't regulate dispersants' toxicity. It requires dispersant manufacturers to test the amount of dispersant necessary to kill a given quantity of one type of fish and one type of shrimp in lab tests. But it doesn't impose any maximum toxicity level that dispersants must stay below.

The EPA does require dispersant manufacturers to show that their chemicals break apart and sink a given amount of oil in a given time in a lab test. The dispersants that have that documentation are placed on a list maintained by the EPA, along with the dispersants' toxicity levels. (WSJ, 6/1/2010)