May 2010 – Updates on BP spill in Gulf of Mexico: Cleanup approaches

While crude oil is still released at the bottom of the ocean in Gulf of Mexico, clean-up efforts continue along with environmental monitoring by U.S. EPA (Environmental Protection Agency or EPA). The massive spill was caused by an explosion which occurred on April 20, 2010 on a BP offshore drilling rig in the Gulf of Mexico (Deepwater Horizon oil exploration rig). As a result of the explosion, the pipe leading from the wellhead up to the platform ruptured and crude oil started being released from the bottom of the ocean. As of May 24, 2010, the spilled oil had made contact with the shore and seems to have caused the death of some fishes (e.g., dead dolphin was reported on a shore), in spite of various cleanup efforts recorded to date. Below we provide a brief update of the clean-up.

The cleanup of the oil spill takes advantage of the various methods available. Several cleanup methods are used in a concentrated effort to reduce the environmental, ecological and human-health potential impacts of the spill. The cleanup methods used to date include several proved "traditional" techniques/cleanup tools:

• Use of skimmers to adsorb spilled oil accumulated on the ocean surface - these are polyethylene mop-like pads which were placed on ocean's surface;
• In-Situ burns of spilled oil(slicks) on the ocean surface - this was done in controlled delineated areas by fire-resistant booms. The method is quite effective to burn up to 90% of spilled oil from targeted areas; however it may only be applied in calm waters and very soon after the spill before the oil gets more mixed with water. This technique has several caveats including:
  • affecting air quality through the smoke and residuals
  • some heavy crude oil compounds are left behind (they do not burn well) such as sticky asphaltenes from which road tars are made
• Spray of dispersants:
  • from planes into the oil slicks on top of the ocean water - in order to break down the oil into small droplets which are more susceptible to natural degradation by marine microorganisms. The dispersants consist in mixtures of surfactants and solvents, cleaning the oil spills in similar manner soaps clean grease when washing. The application of dispersants on the ocean surface is the "traditional" application method.
  • Under water - this method has been tested by BP engineers in order to prevent the spilled oil to reach ocean surface. Since April 25, 2010, 3 tests have been performed by BP using operated underwater vehicles. The scattered oil was observed with underwater cameras. These results were considered encouraging.

It has to be mentioned that applying of dispersants has caveats, too. The main one relates to their possible toxic effects on coral reefs and other marine life - raised by some environmental groups such as Natural Resources Defense Council. EPA has also raised concerns related to the dispersants used by BP.

May 20, 2010, EPA issued a directive requiring the identification and use (by BP) of a less toxic dispersant. The dispersant of choice should be from the EPA list of authorized dispersants. Under this directive, BP is required to identify less toxic dispersant within 24 hours and begin to use it within 72 hours of submitting of the identified dispersant alternative. BP also had the alternative to provide explanation if not complying.