The U.S. Fish & Wildlife Service Fire Management Program is responsible for protecting and restoring lands in all 50 states, Puerto Rico, the Virgin Islands, Guam, American Samoa and Pacific Islands territories.
Oil Spill burns Protect Wildlife
While staff on 36 national wildlife refuges and several national park lands work to recover and clean-up oiled wildlife along the Gulf Coast shoreline, teams from BP and U.S. Coast Guard (USCG) conduct in-situ controlled burns 40 miles from land to remove oil that could otherwise wash onshore.
Since April 23, Day 4 of the Deepwater Horizon oil spill in the Gulf of Mexico, through June 20, 250 burns have occurred 7 to 12 miles from the well. To assist, local mariners were hired and trained in oil spill response tactics. An estimated 6.32 million gallons of oil have been burned.
As with prescribed burns on land, burn plans are developed and regular team safety briefings are held. Appropriate weather windows are needed, in this case calm waters with waves less than 3-5 feet and winds less than 15 nautical miles per hour. The latitude and longitude of the sites are reported to the EPA for air quality monitoring. Smoke is not visible from land. No burns are conducted at night.
Since the start of the incident, burn operations have grown to involve 120-130 people; two spotter planes; and 23 vessels, including a command ship, support boats, ignition vessels, and 16 commercial shrimp boats. These resources form eight controlled burn teams and two taskforces.
In order for the oil to burn, it must be concentrated to at least 2mm thickness. To ensure this, a pair of shrimp boats drag 300-foot cables attached to 500-foot fire booms, designed to withstand heat up to 2,000 degrees Fahrenheit. With observers overhead and on the water, the boats are vectored into the thickest oil.
As the fire booms are dragged into a U-shaped formation, overhead aircraft spotters lead the boats into the more concentrated oil streams or patches. An accelerant-filled container is hand-deployed by Nomex-clad team members. Road flares are attached to the floating container to ignite a fire. By monitoring burn duration and area, a burn rate is established. Two calculations are then used to establish the range of oil volume burned.
“The first, when oil is pretty fresh and dark, only 10 percent emulsified, we use a figure of .07 gallons/min/sq ft,” noted BP Integrity Management Engineer, Nere Mabile. “For oil further from the source, that is 50 percent or more emulsified, we use a figure of .05 gallons/min/sq ft. So far, between 100,000 – 140,000 barrels of oil have been burned.”
“Every gallon of oil we burn is one less gallon available to impact the environment,” said Mabile, who is serving as a technical advisor for the burn teams, along with veteran oil spill consultant Alan Allen, a private contractor who Mabile says is critical to the response. Allen was heavily involved in the response to the Exxon-Valdez incident in 1989, the first oil spill response that involved controlled burns on the open water. Deepwater Horizon marks the first incident where the method has been applied at such a large scale on a “continuous spill”. Exxon Valdez was a “batch spill” from the ship with 700 gallons of oil burned, according to Mabile.
|Shrimp boats pull fire boom during in-situ burning of oil. Photo: Nere Mabile, BP|
back to headlines
Back to News Archives