TECHNOLOGY UPDATE Building a better fire boom by adding water In spite of recent findings that deliberate burning can be a relatively environmentally benign tool for cleaning up oil spills, the approach has always been notoriously hard to use. However, a new water-cooled oil boom introduced this March at an oil-spill response conference provides an improved method for responding to the challenge of dealing with oil spill fires on the open water. Controlling an oil-spill burn on the open water is "very difficult," explained Jacqueline Michel, vice president of science and technology for Research Planning, Inc., of Columbia, S.C., a firm that provides expert oil-spill support to the National Oceanic and Atmospheric Administration (NOAA). "You've got to corral the oil, put a boom around it, and then light it." The boom has to contain the burning oil and allow die entire process to be repeated several times, Michel explained. Fire booms can be used to remove much more spilled oil man diat possible witii conventional mechanical recovery methods, stressed Alan Allen, the self-employed oilspill specialist who invented the new water-cooled oil boom. If spilled oil is properly restrained, upward of 95% of it can be removed from the water by burning it. There are, however, significant problems widi using conventional fire booms, which are generally made of metal or a burnresistant ceramic or fabric, explained Allen. Allen, who has spent more than 18 years researching the use of combustion for oil-spill cleanups, engineered the first in situ use of the method in helping to clean up the 1989 oil spill from the tanker, Exxon Valdez. In Allen's experience, metal fire booms, which are usually made of stainless steel, are extremely heavy and difficult to handle. Both Michel and Allen concurred that all of the © 1999 American Chemical Society
ceramic fire-resistant booms that their organizations used in the past performed poorly. They "weren't very good—they burned up," Michel said. Allen is one of a number of researchers trying to build a better boom, but his unconventional approach sets him apart. His efforts began more than eight years ago with the goal of finding a way to keep the boom fabric saturated with water so it could withstand the 1500-2000 °F temperatures of a typical oil fire. The patented result of his efforts is a new product called the Hydro Fire Boom being marketed by Elastec/American Marine of Carmi, 111. The boom is constructed of air-inflated bags covered with a layer of a "very unique" hydrophilic fabric that "grabs and soaks up any water that gets near it," according to Allen. Oil containment booms are always towed in a U-shaped configuration behind two boats, and pumps located on each boat constantly keep the Hydro Fire Boom wet by continually sending water throughout its entire length. According to Allen, his boom is easy to handle because of its light weight. It is also reusable, which is a significant feature because fire booms are very expensive. Allen estimates that his boom will cost between $170 and $180 per foot; most fire booms range between $150 and $200, he said, adding that conventional ceramic and fabric booms are not reusable. Burn tests show that Allen's boom can hold up much longer than traditional booms. It has emerged unscathed from all the fire tests conducted on it, he said. He predicts that it will likely withstand burning oil flames for "days, perhaps even weeks," situations that can occur when there is a continuous leak. Ceramic booms normally last no more man a few hours, he said. Allen's new fire-resistant boom and other less-advanced efforts to create a better fire boom are important because 73% of the nation's
The water-cooled Hydro Fire Boom has emerged unscathed from dozens of experimental burning tests. (Courtesy Elastec/ American Marine, Carmi, III.)
states with coastal waterways now have preapproval plans for using controlled burns in certain situations, said Ann Hayward Walker, president and founder of Scientific and Environmental Associates of Cape Charles, Va., an environmental firm specializing in oil spills that presented a paper on the topic at the recent oil spill conference. Obtaining preapproval requires states to earn official authorization from the Coast Guard, EPA, the Department of Interior, and the Department of Commerce; the number of states with these plans has jumped more than sixfold since 1994. In 1994, three coastal states had preapproval plans; now, there are 19, Walker said. The growing number of preapprovals increases the possibility that combustion will be used to clean up oil spills in die future, said Charlie Henry, scientific support coordinator for NOAA's District 8, which encompasses die Gulf of Mexico. There is a short narrow window—from a few hours to a few days, depending upon how rough the seas are—when it makes sense to use fire in response to an oil spill, Allen explained. With preapproval, states can make determinations about whether to use fire (or other spill control techniques) within a matter of hours. This allows fire to be considered during the time window when it makes sense, he said. —KELLYN S. BETTS
MAY 1, 1999 /ENVIRONMENTAL SCIENCES TECHNOLOGY/ NEWS • 2 1 3 A
