Spilled oil being burned on open water, EPA monitoring

Oil spill response officials are using controlled burns to eliminate some of the crude oil spilled off Louisiana. They say burning crude oil offshore has been effective elsewhere in the past.

Meanwhile, federal officials are monitoring air quality and testing water samples. Officials say it will take some time to measure the effectiveness of the controlled burns in the Gulf of Mexico.

US Coast Guard Rear Adm. Mary Landry said a controlled burn off the coast of Newfoundland in 1993 proved very effective at eliminating oil trapped in special containment booms and set on fire.

The majority of the spill on the gulf’s surface is an oil-water mixture called a rainbow sheen with some areas of emulsified oil. The spill is moving closer to the shore and to Louisiana’s wetlands.

The controlled burn eliminates the emulsified oil, leaving a waxy substance that can be picked up by skimming vessels.

“If we don’t secure this well, this could be one of the most significant oil spills in US history,” Landry said during an Apr. 27 news conference. An estimated 5,000 b/d is leaking from a BP PLC well drilled by Transocean Ltd’s Deepwater Horizon.

An Apr. 20 explosion and fire on the semisubmersible left 11 crew members missing and presumed dead. The semi sank on Mississippi Canyon Block 252 on Apr. 22. Efforts continue to stop the leaking oil.

The controlled burn practice does involve tradeoffs in that it creates air pollution, said Charlie Henry, a scientific support coordinator with the National Oceanic and Atmospheric Administration.

Meanwhile, other scientists say warm water temperatures, strong sunshine, and microbial action will help the oil degrade and evaporate. The spill involves light, sweet crude so it will degrade faster than did the heavy oil spilled from the Exxon Valdez tanker. An API spokewoman says a controlled burn was used on the Valdez spill and was effective.