Spill update: From booms to dispersants

Choppy seas prevailed in the northern Gulf of Mexico on May 13, with even protected waters hosting rough 4 to 5 foot waves. But three-plus weeks into the explosion and ensuing spill from a BP exploratory well, measures to respond to the catastrophe continued ramping up.

To date, some 13,000 people and more than 525 boats have lent their assistance. Some have deployed booms — floating curtains that extend slightly above and below the water to corral oil and protect vulnerable isles and coastal sites. More than 450 kilometers (280 miles) of boom already have been placed in the water. It’s the largest quantity in history, and more is on its way.

At a May 12 briefing, BP Chief Operating Officer Doug Suttles noted that a major airlift is underway, hauling boom from every available source. “We’ve had 15 large aircraft — generally either 747s or C-17s — which have delivered over 200,000 feet of boom in the last three days alone” from places like Norway, Brazil, Mexico and Alaska. Twice that much awaits at staging locations, ready for deployment. And he says there’s “another 2.3 million feet of boom on order, and being delivered as we speak.”

That hasn’t prevented oil from reaching beaches, but so far the contamination has been manageable, he says. Tides have been depositing oil in a few spots. “It’s generally dime and quarter-size droplets of the oil,” which Suttles described as having the consistency “of something like mousse or a chocolate fudge.”

Wildlife impacts remain minimal, according to federal on-scene coordinator, Coast Guard Rear Admiral Mary Landry. “To date, seven oiled birds were rescued and are being treated;” two have already been released. Bodies of 18 birds, 87 sea turtles and six dolphins have been recovered. Cascasses surface all the time, so Landry cautioned that it’s “too early to say if these are spill related.” But experts are examining these animals “to determine whether these deaths are,” she added.

Keeping oil offshore
The good news if there can be any from this environmental tragedy is that most of the oil has been pooling on the surface of the Gulf near the accident site, more than 40 miles off the Louisiana coast — and not flooding the coastline. Yet. But Suttles confirmed that the oil continues to spew unchecked from a pipe at the seafloor.

There’s no way to actually gauge the flow rate, Suttles says. Experts must eyeball it from video and guess. His estimate remains in the “5,000 barrel a day range. But this is highly uncertain,” he acknowledges. With 42 gallons in a barrel, that’s still a 210,000-gallon torrent per day — or a probable release so far of at least 5 million gallons.

According to the Deepwater Horizon government-industry Unified Command, some 3.6 million gallons of oily water has been recovered. Indeed, that’s mostly water since the vast majority of the released oil remains asea.

Landry said that on May 12, “We prepositioned oil skimming and controlled burn resources on scene, just hoping that we might have a window of opportunity with the weather.” She added, however, that burns didn’t look likely for the near term, owing to the uncooperative winds. “But we will continue to stand ready offshore should the opportunity arise.”

I happened to observe the first major test of controlled burns at sea. In the North Atlantic in August 1993, 25 nautical miles east of Newfoundland, I and some 200 researchers watched as scientists ignited a boomed pool of oil. Flames during the three hour spectacle at times licked 300 feet into the air and roiling, sooty plumes billowed 10 times that high.

But the tests showed the technology definitely has its limitations. At one point, the fire burned through a supposedly fireproof boom. And booms really can’t contain oil — much less oil fires — when wave action is high. Still, fire can be one fairly appealing oil-removal option. Dirty black clouds will disperse much faster than a foot-thick and miles-long slick of goopy hydrocarbons. Such dirty cleanup tactics point to the tradeoffs that can become acceptable in the context of managing catastrophes.

Federal regulators are encountering this with another technology: oil dispersants. Such chemicals have been around for decades, generally used in fairly contained spills. But they’ve never been dispensed in the quantities now being peppered over the Gulf — or necessarily in the same way.

For instance, an experimental program is injecting dispersants into the underwater plume of oil. If it appears effective in limiting the subsea plume’s contribution to the spill, the Environmental Protection Agency will begin evaluating the impacts of this application of dispersants. Additional dispersant is being dropped onto the surface slick from the air. To date, an estimated 372,000 gallons of this product — a mix of 2-butoxyethanol, propylene glycol and a proprietary sulfonic-acid salt — have been used on the spill.

It’s a clear amber liquid that can irritate the skin, poison the GI tract and liver or kidneys if ingested, and harm red blood cells. What it would do to wildlife remains anyone’s guess as a safety data sheet on the chemical, known as Corexit R, points out that in terms of environmental effects “no toxicity studies have been conducted on this product.”

The purpose of dispersants is to break up oil, much as a dish detergent breaks salad oil into little microglobules. At sea, this dispersion can speed oil’s detoxification and microbial breakdown. It can also limiting surface pooling so that there’s less to wash ashore at one time as a huge tsunami of marsh-smothering gooey muck.

The Coast Guard had formally approved plans to use dispersants for spills in Alaska at the time of the Exxon Valdez accident, notes Seldon Graham, a former Exxon attorney who initially trained as a petroleum engineer. Indeed, he says, planes loaded with the chemicals — not the current formula — had been poised for takeoff, shortly after the tanker accident, when the Coast Guard told these craft to stand down.

While Graham told me that he believes shelving the dispersants during the Exxon Valdez emergency response was a blunder on the Coast Guard’s part, Jeff Short has his doubts.

A petroleum chemist who spent the better part of two decades as a federal scientist investigating the effects of Exxon Valdez oil on the environment, Short notes that the tanker’s crude had spilled in coastal waters, home to lots of anchored wildlife, such clams and mussels. These critters “are extraordinarily efficient at accumulating those [oil] microdroplets, which can lead to their tainting,” observes the Juneau-based Short, now a staff scientist with Oceana, an environmental group.

Breaking spilled oil into microdroplets also can prolong its residence time in the water column, Short says. So while conceptually he sees the use of dispersants at sea as a potentially good thing, he questions their protective value in near-shore waters.