Oil Spill: BP Ordered to Use Less Toxic Dispersant

Dispersants are chemicals used to break up oil into small droplets so that they are more easily degraded by microorganisms in the water. The amount of dispersant used to date totals approximately 655,000 gallons.

The dispersant currently being used is Corexit, which just one of the 18 EPA-approved dispersants. Twelve are considered are more effective on southern Louisiana crude oil than Corexit, and some are up to 20 times less toxic, EPA data shows.

The EPA directive requires BP to identify a less toxic alternative to be used both on the surface and under the water at the source of the oil leak within 24 hours and to begin using the less toxic dispersant within 72 hours of submitting the alternative.

If BP is unable to identify available alternative dispersant products, the company must provide the Coast Guard and EPA with a detailed description of the alternative dispersants investigated, and the reason they believe those products did not meet the required standards.

Off Louisiana coast, an aircraft releases oil dispersant to break up the Deepwater Horizon oil spill, May 5, 2010. (Photo courtesy U.S. Coast Guard)

While the dispersant BP has been using is on the approved list, BP is using this chemical in unprecedented volumes and, last week, began using it underwater at the source of the leak.

On May 15, EPA and the U.S. Coast Guard authorized BP to use dispersants underwater at the source of the Deepwater Horizon leak. As the dispersant is used underwater, BP is required to do constant, scientifically rigorous monitoring so EPA scientists may determine the dispersant's effectiveness and impact on the environment, water and air quality, and human health.

The agency reserves the right to discontinue the use of this dispersant method if any negative impacts on the environment outweigh the benefits.

Today, the EPA said that the toxicity data collected to date does not indicate any significant affects on aquatic life. Moreover, decreased size of the oil droplets is a good indication that, so far, the dispersant is effective.

"We are closely watching the dissolved oxygen levels, which so far remain in the normal range. Dissolved oxygen levels initially appeared low when measured with a device called a LaMotte tool. In order to conduct a more thorough analysis, more sensitive equipment was then employed, called an Extech Probe. The subsequent dissolved oxygen readings from the Extech Probe indicate that dissolved oxygen levels are within the normal range," the EPA said in a statement.

Click here to see the EPA's posting of the information BP collects during dispersant monitoring.

On Wednesday, Louisiana Governor Bobby Jindal and local officials inspected Plaquemines Parish in the Pass a Loutre area where they observed thick, dark oil that has made its way into the state's fragile wetlands. At a press conference in Venice following the tour, Governor Jindal renewed his plea to the Army Corps of Engineers to issue an emergency permit so the dredging plan can begin quickly.

"We saw some heavy oil stranded in the wetlands. The oil is no longer just a projection or miles from our shore. The oil is here. It is on our shores and in our marsh," Governor Jindal said.

According to the National Oceanic and Atmospheric Administration, NOAA, the total amount of Louisiana shoreline with oil impact to date is 34.52 miles. The state Department of Environmental Quality confirms shoreline impacts on: the Chandeleur Islands, Whiskey Island, Raccoon Island, South Pass, East Fourchon/Elmers Island, Grand Isle, Trinity Island, Brush Island, and the Pass a Loutre area.

Oil spreading from the ruptured Deepwater Horizon well has reached the Gulf of Mexico's Loop Current, but predicting where the oil is going continues to be a challenge for scientists.

The fast-moving, warm waters of the Loop Current and the unprecedented nature of the spill require constant monitoring. The latest estimates from the University of South Florida's College of Marine Science's Ocean Circulation Group released today indicate a portion of the Loop Current moving clockwise could keep the oil away from the southern Gulf, allowing the oil to become more weathered.

Led by USF physical oceanographer Robert Weisberg, the scientists are using data gathered from five different models tracking the spilled oil. They expect that the oil will move rapidly through the warm water of the Loop Current. Two teams of USF scientists on separate research vessels will gather water samples and use sensors to collect more information.

The Loop Current is described as a "conveyor belt" about 100 miles off Florida's west coast that moves some 27 million cubic meters of water a second. Scientists believe the warm underwater stream is pulling oil from the spill southward where it has the potential to move toward the Florida Keys, the Straits of Florida and the Atlantic Coast.

Meanwhile, BP contines its subsea efforts to stop the flow of oil from the well through interventions via the blowout preventer, and to collect the flow of oil from the leak points.

The volume of oil and gas being collected by the riser insertion tube tool containment system at the end of the leaking riser is estimated to be about 3,000 barrels a day of oil and some 14 million standard cubic feet a day of gas. The oil is being stored and gas is being flared on the drillship Discoverer Enterprise, on the surface 5,000 feet above.

BP also continues to develop options to shut off the flow of oil from the well through interventions via the failed blowout preventer.

Plans continue to develop a so called "top kill" operation where heavy drilling fluids are injected into the well to stem the flow of oil and gas, followed by cement to seal the well. Most of the equipment is on site and preparations continue for this operation, with a view to deployment in the next few days.

Options have also been developed to potentially combine this with the injection under pressure of a variety of materials into the blowout preventer to seal off upward flow. Work on two relief wells continues.

NOAA's data shows that more than 1,040 vessels are responding to the spill, and more than 24,700 people are responding.

Nearly two million feet of boom have been deployed, including containment and sorbent boom. NOAA says more than 370,000 feet of containment boom and more than 1.28 million feet of sorbent boom are available.

But Governor Jindal says Louisiana is short of boom. "We continue to be concerned about the shortage of boom in parishes west of the river and we're pushing the Coast Guard and BP for more boom in these and other sensitive areas," he said Wednesday.

Jindal says the state is not waiting for boom to arrive but is employing National Guard engineers to backfill gaps in the barrier islands with earth and sandbags to hold the oil out of the marshy lowlands.

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