Arctic Science Journeys
Radio Script
1996

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Oil Spill Sleuths
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"Petroleum is a mixture of many different chemical substances. Those things arise deep in the earth in processes in which oil is formed and they vary for every oil."

Shaw uses a sophisticated technique called gas chromatography to separate and identify the thousands of complex chemical compounds found in oil. The result is called a trace, and it looks very much like a grocery store barcode.

"When you've got these traces that have all the different peaks, all the individual compounds from the oil, they serve very much like a fingerprint, and it's possible to compare two different oils and see whether they are the same or different."

The Coast Guard's National Oil Identification Lab in Groton, Connecticut, uses gas chromatography traces to identify oil polluters. They take samples of oil from the spill and then look for a match in the fuel taken from suspected ships.

Recently, the Coast Guard used the technique in Alaska's Bering Sea. There, a unknown ship spilled several hundred gallons of dark, gooey, asphalt-like bunker fuel. The oil killed hundreds of seabirds and tainted the shores of the Pribilof Islands. Although the culprit ship was long gone, the oil it left behind was all investigators needed. Coast Guard Lt. Christie Plourde is a chemist at the oil identification lab.

"What we do in this laboratory is basically use up to four different instruments to analyze that oil. We'll analyze the spill and suspected sources and we'll see if they match or they don't match. It's extremely accurate."

Plourde tested fuel samples taken from 30 ships in the area during the time of the spill. An exact match was found in samples taken from the tanks of the Japanese container ship, the Citris. Coast Guard investigator Lt. Guy Thereaux.

"We have two positive matches now, in the number one port fuel tank and the number 3 center fuel tank."

It took just 13 days to identify the Citris, but it could have taken much longer. Thereaux says investigators were fortunate the spill was a heavy grade bunker fuel and not diesel fuel.

"By getting the feathers right in the beginning, sending them off to the central oil identification lab, they told us it was a heavy fuel oil. It really narrowed our focus, because there are so many vessels out there that operate on a heavy fuel oil. If it came back diesel, there literally would have been hundreds of vessels in the Bering Sea that operate on diesel. It would have made our job a lot more difficult."

But not impossible. The owner and captain of the Citris have been charged with violating federal oil pollution laws. Meanwhile, the Citris and its crew have headed back to Japan, after posting a $25,000 bond. For Arctic Science Journeys, this is Debra Damron.