NOAA's Response and Restoration Blog

An inside look at the science of cleaning up and fixing the mess of marine pollution


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From Natural Seeps to a Historic Legacy, What Sets Apart the Latest Santa Barbara Oil Spill

Cleanup worker and oiled boulders on Refugio State Beach where the oil from the pipeline entered the beach.

The pipeline release allowed an estimated 21,000 gallons of crude oil to reach the Pacific Ocean, shown here where the oil entered Refugio State Beach. (NOAA)

The response to the oil pipeline break on May 19, 2015 near Refugio State Beach in Santa Barbara County, California, is winding down. Out of two* area beaches closed due to the oil spill, all but one, Refugio State Beach, have reopened.

NOAA’s Office of Response and Restoration provided scientific support throughout the response, including aerial observations of the spill, information on fate and effects of the crude oil, oil detection and treatment, and potential environmental impacts both in the water and on the shore.

Now that the response to this oil spill is transitioning from cleanup to efforts to assess and quantify the environmental impacts, a look back shows that, while not a huge spill in terms of volume, the location and timing of the event make it stand out in several ways.

Seep or Spill: Where Did the Oil Come From?

This oil spill, which allowed an estimated 21,000 gallons of crude oil to reach the Pacific Ocean, occurred in an area known for its abundant natural oil seeps. The Coal Oil Point area is home to seeps that release an estimated 6,500-7,000 gallons of oil per day (Lorenson et al., 2011) and are among the most active in the world. Oil seeps are natural leaks of oil and gas from subterranean reservoirs through the ocean floor.

The pipeline spill released a much greater volume of oil than the daily output of the local seeps. Furthermore, because it was from a single source, the spill resulted in much heavier oiling along the coast than you would find from the seeps alone.

A primary challenge, for purposes of spill response and damage assessment, was to determine whether oil on the shoreline and nearby waters was from the seeps or the pipeline. Since the oil from the local natural seeps and the leaking pipeline both originated from the same geologic formation, their chemical makeup is similar.

However, chemists from Woods Hole Oceanographic Institution, the University of California at Santa Barbara, Louisiana State University, and the U.S. Coast Guard Marine Safety Lab were able to distinguish the difference by examining special chemical markers through a process known as “fingerprinting.”

Respecting Native American Coastal Culture

The affected shorelines include some of the most important cultural resource areas for California Native Americans. Members of the Chumash Tribe populated many coastal villages in what is now Santa Barbara County prior to 1800. Many local residents of the area trace their ancestry to these communities.

To ensure that impacts to cultural resources were minimized, Tribal Cultural Resource Monitors were actively engaged in many of the upland and shoreline cleanup activities and decisions throughout the spill response.

Bringing Researchers into the Response

The massive Deepwater Horizon oil spill in the Gulf of Mexico in 2010 highlighted the need for further research on issues surrounding oil transport and spill response. As a result, there was a great deal of interest in this spill among members of the academic community, which is not always the case for oil spills. In addition, the spill occurred not far from the University of California at Santa Barbara.

From the perspective of NOAA’s Office of Response and Restoration, this involvement with researchers was beneficial to the overall effort and will potentially serve to broaden our scientific resources and knowledge base for future spills.

The Legacy of 1969

Another unique aspect of the oil spill at Refugio State Beach was its proximity to the site of one of the most historically significant spills in U.S. history. Just over 46 years ago, off the coast of Santa Barbara, a well blowout occurred, spilling as much as 4.2 million gallons of oil into the ocean. The well was capped after 11 days.

The 1969 Santa Barbara oil spill, which was covered widely in the media, oiled miles of southern California beaches as well. It had such a devastating impact on wildlife and habitat that it is credited with being the catalyst that started the modern-day environmental movement. Naturally, the 2015 oil spill near the same location serves as a reminder of that terrible event and the damage that spilled oil can do in a short period of time.

Moving Toward Restoration

In order to assess the environmental impacts from the spill and cleanup, scientists have collected several hundred samples of sediment, oil, water, fish, mussels, sand crabs, and other living things. In addition, they have conducted surveys of the marine life before and after the oil spill.

The assessment, which is being led by the state of California, involves marine ecology experts from several California universities as well as federal and state agencies.

After a thorough assessment of the spill’s harm, the focus will shift toward restoring the injured natural and cultural resources and compensating the public for the impacts to those resources and the loss of use and enjoyment of them as a result of the spill. This process, known as a Natural Resource Damage Assessment, is undertaken by a group of trustees, made up of federal and state agencies, in cooperation with the owner of the pipeline, Plains All American Pipeline. This group of trustees will seek public input to help guide the development of a restoration plan.

*UPDATED 7/10/2015: This was corrected to reflect the fact that only two area beaches were closed due to the spill while 20 remained open in Santa Barbara.


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From Building B-17 Bombers to Building Habitat for Fish: The Reshaping of an Industrial Seattle River

Imagine living in as little as two percent of your home and trying to live a normal life. That might leave you with something the size of a half bathroom.

Now imagine it’s a dirty half bathroom that hasn’t been cleaned in years.

Gross, right? As Muckleshoot tribal member Louie Ungaro recently pointed out, that has been roughly the situation for young Chinook salmon and Steelhead trout for several decades as they pass through the Lower Duwamish River in south Seattle, Washington.

Salmon and Steelhead trout, born in freshwater streams and creeks in Washington forests, have to make their way to the Puget Sound and then the ocean through the Duwamish River. However, this section of river has been heavily industrialized and lacks the clean waters, fallen trees, huge boulders, and meandering side channels that would represent a spacious, healthy home for young fish.

Chair of his tribe’s fish commission, Ungaro sent a reminder that the health of this river and his tribe, which has a long history of fishing on the Duwamish and nearby rivers, are closely tied. “We’re no different than this river,” he implored. Yet he was encouraged by the Boeing Company’s recent cleanup and restoration of fish habitat along this Superfund site, a move that he hopes is “just a start.”

The Pace—and Price—of Industry

Starting as far back as the 1870s and stretching well into the twentieth century, the Lower Duwamish River was transformed by people as the burgeoning city of Seattle grew. The river was straightened and dredged, its banks cleared and hardened. Factories and other development lined its banks, while industrial pollution—particularly PCBs—poured into its waters.

More than 40 organizations are potentially responsible for this long-ago pollution that still haunts the river and the fish, birds, and wildlife that call it home. Yet most of those organizations have dragged their feet in cleaning it up and restoring the impacted lands and waters. However, the Boeing Company, a longtime resident of the Lower Duwamish River, has stepped up to collaborate in remaking the river.

Newly restored marsh and riverbank vegetation with protective ropes and fencing on the Duwamish River.

The former site of Boeing’s Plant 2 is now home to five acres of marsh and riverbank habitat, creating a much friendlier shoreline for fish and other wildlife. Protective fencing and ropes attempt to exclude geese from eating the young plants. (NOAA)

Boeing’s history there began in 1936 when it set up shop along 28 acres of the Duwamish. Here, the airplane manufacturer constructed a sprawling building known as Plant 2 where it—with the help of the women nicknamed “Rosie the Riveters”—would eventually assemble 7,000 B-17 bombers for the U.S. government during World War II. The Army Corps of Engineers even took pains to hide this factory from foreign spies by camouflaging its roof “to resemble a hillside neighborhood dotted with homes and trees,” according to Boeing.

But like many of its neighbors along the Duwamish, Boeing’s history left a mark on the river. At the end of 2011, Boeing tore down the aging Plant 2 to prepare for cleanup and restoration along the Duwamish. Working with the City of Seattle, Port of Seattle, and King County, Boeing has already removed the equivalent of thousands of railcars of contaminated sediment from the river bottom and is replacing it with clean sand.

From Rosie the Riveter to Rosie the Restorer

By 2013, a hundred years after the Army Corps of Engineers reshaped this section of the Duwamish from a nine mile estuary into a five mile industrial channel, Boeing had finished its latest transformation of the shoreline. It planted more than 170,000 native wetland plants and grasses here, which are interspersed with large piles of wood anchored to the shore.

Five acres of marsh and riverbank vegetation now line its shores, providing food, shelter, and calmer side channels for young fish to rest and grow as they transition from freshwater to the salty ocean.

Canada geese on an unrestored portion of the Duwamish River shoreline.

Protecting the newly restored shoreline, out of sight to the left, from Canada geese is a challenge to getting the young wetland plants established. Behind the geese, the artificial, rocky shoreline is a stark difference from the adjacent restored portion. (NOAA)

Now the challenge is to keep the Canada geese from eating all of the tender young plants before they have the chance to establish themselves. That is why protective ropes and fencing surround the restoration sites.

Already, biologists are beginning to see a change in the composition of the birds frequenting this portion of the river. Rather than the crows, starlings, and gulls typically associated with areas colonized by humans, birds such as herons and mergansers, a fish-eating duck, are showing up at the restoration sites. Those birds like to eat fish, which offers hope that fish such as salmon and trout are starting to make a comeback as well.

Of course, these efforts are only the beginning. Through the Natural Resource Damage Assessment process, NOAA looks forward to working with other responsible organizations along the Duwamish River to continue restoring its health, both for people and nature now and in the future.


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How Do Oil Spills out at Sea Typically Get Cleaned Up?

This is a post by Kate Clark, Acting Chief of Staff with NOAA’s Office of Response and Restoration.

Close up of skimming device on side of a boat with oil and boom.

Skimmers come in various designs but all basically work by removing the oil layer from the surface of the water. (U.S. Coast Guard)

Whether for hanging a picture on the wall or fixing a leaky faucet, most people keep a common set of tools in their home. While some tools get more use than others, it’s good to have an array on hand to handle most repair jobs. The same is true for responding to oil spills.

Like a home repair job, each oil spill has unique aspects that call for careful consideration when deciding which tool to use. Responders keep an array of response methods in their toolkit for dealing with oil in offshore waters: skimming and booming, in situ burning, and applying dispersants.

Let’s get to know a few of those tools and the situations when they might be the most appropriate method for dealing with oil spills out at sea.

Skimming: Take a Little off the Top

Skimming is a process that removes oil from the sea surface before it reaches sensitive areas along a coastline. Sometimes, two boats will tow a collection boom, allowing oil to concentrate within the boom, where it is then picked up by a “skimmer.” From whirring disks to floating drums, skimmers come in various designs but all basically work by removing the oil layer from the surface of the water. These devices attract oil to their surfaces before transferring it to a collection tank, often on a boat. Ideal conditions for skimming are during the day when the oil slick is thick and the ocean surface is fairly calm.

The success of a skimming operation is dependent on something known as the “encounter rate.” Much like a vacuum picks up dirt from your carpet, a skimmer has to come in direct contact with the oil in order to remove it from the surface and, even then, it will still pick up some water. That’s why responders will often refer to the volume of oil removed via skimming as gallons of an oil-water mixture.

In Situ Burning: Burn After Oiling

Plumes of smoke from two fires burning oil on the ocean surface.

Burning oil “in place” (in situ) on the water’s surface requires gathering a layor of oil thick enough to sustain the burn. (NOAA)

In situ burning is the process of burning spilled oil where it is on the ocean (known as “in situ,” which is Latin for “on site”). Similar to skimming, two boats will often tow a fire-retardant collection boom to concentrate enough oil to burn. Burning is sometimes also used in treating oiled marshes.

Ideal conditions for in situ burning are daylight with mild or offshore winds and flat seas. The success of burning oil is dependent on corralling a layer of oil thick enough to maintain a sustained burn. Any burn operation includes careful air monitoring to ensure smoke or residue resulting from the burn do not adversely impact people or wildlife.

Chemical Dispersants: Break It Up

Releasing chemical dispersants, usually from a small plane or a response vessel, on an oil slick breaks down the oil into smaller droplets, allowing them to mix more easily into the water column. Smaller droplets of oil become more readily available to microbes that will eat them and break them down into less harmful compounds.

However, using dispersants has its drawbacks, shifting potential impacts to the marine life living in the water column and on the seafloor. Because of this, the decision to chemically disperse oil into the water column is never made lightly. This decision is often made so that much less oil stays at the surface, where it could affect birds and wildlife at the ocean surface and drift onto vulnerable coastal habitat like beaches, wetlands, and tidal flats.

Ideal conditions for chemical dispersion are daylight with mild winds and moderate seas. Chemical dispersion is never done close to the shore, in shallow waters, near coastal communities, or when there is a potential for winds to carry the chemical spray away from its intended target.

Natural dispersion can and does occur when waves at the ocean surface have enough turbulent energy to allow surface oil to mix into the water column. Applying chemical dispersants can expedite this process when there is an imminent threat associated with allowing the oil to stay on the surface.

Graphic showing methods for responding to oil spills at sea. Plane applying chemical dispersants: Chemical dispersion is achieved by applying chemicals to remove oil from the water surface by breaking  the oil into small droplets. Burning oil surrounded by boom: Also referred to as in situ burning, this   is the method of setting fire to freshly spilled oil, usually while still   floating on the water surface. Booms: Booms are long floating barriers used to   contain or prevent the spread of spilled oil. A boat skimming oil: Skimming is achieved with  boats equipped with a floating skimmer designed to remove thin layers of oil from   the surface, often with the help of booms.One Size Does Not Fit All

You may have noticed that each of these tools has one common factor limiting its effectiveness: daylight, or more precisely, visibility. Being able to see the spilled oil, often over large areas of the ocean, is critical to being able to clean it up. That means these tools become ineffective at night, during certain seasons, or in regions where prolonged darkness, fog, or clouds are the norm.

Table showing the conditions which may affect the use of different oil spill response methods at sea (skimming, burning, dispersing). Conditions are sunlight, wind, rough seas, cold, and nearshore.

Conditions which may affect the use of different oil spill response methods at sea.

Rough seas can be prohibitive for skimming and burning since these methods rely on calm conditions and collection booms to gather (and keep) oil in one place. High winds can often rule out burning and aerial dispersion as an option.

While these techniques perform best under certain, ideal conditions, responders often have to make do with the variety of conditions going on during an oil spill and can and do use these tools under less-than-ideal conditions. Their effectiveness also depends on factors such as the type or state of the spilled oil or the environment it was spilled in (e.g., sea ice).

Just like your home repairs, the job sometimes calls for a non-traditional tool or creative fix. The continued development of alternative response methods and technologies for cleaning up oil is critical for addressing oil spills in geographic areas or conditions that the traditional toolbox is not equipped to fix.

Kate Clark is the Acting Chief of Staff for NOAA’s Office of Response and Restoration. For nearly 12 years she has responded to and conducted damage assessment for numerous environmental pollution events for NOAA’s Office of Response and Restoration. She has also managed NOAA’s Arctic policy portfolio and served as a senior analyst to the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling.


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On the Front Lines of an Oil Spill in My Own Backyard: A Report from Santa Barbara, California

This is a post by Gabrielle Dorr, NOAA/Montrose Settlements Restoration Program Outreach Coordinator.

Oiled boulders on a California beach with cleanup workers in the distance.

NOAA has been involved with the May 19, 2015 oil spill resulting from a pipeline break at Refugio State Beach, near Santa Barbara, California, which released an estimated 100,000 gallons of crude oil, with a reported 21,000 gallons reaching the ocean. (Bill Stanley/U.S. Fish and Wildlife Service)

When I first heard about the pipeline oil spill at Refugio State Beach near Santa Barbara, California, a couple weeks ago, I felt concerned about the fact that it was only a few hours up the coast from where I currently live and work. I couldn’t stop thinking about what the long-term impacts would be to the beautiful beaches we have here in southern California.

As a NOAA communications specialist who had cut her teeth in providing communications support for the 2010 Deepwater Horizon oil spill, I thought I knew roughly what to expect when I was called in to help in Santa Barbara.

When I was asked to provide support for that oil spill in July 2010, oil had been gushing into the ocean for several months and was washing up on beaches bordering five states far from my home in California. I was able to get out into the field in Louisiana to see firsthand what an oiled marsh looks like, but that was months after the spill began. In addition, the massive scale of the response and damage assessment efforts made it tough to grasp the full picture of the spill.

Still, it was important for me to see the impacts for myself, so that I could better tell the story about what happened and what NOAA and our partners were going to do to make it right.

From the Gulf of Mexico to Southern California

Fish being measured on a table.

After an oil spill, scientists collect lots of data on the potential impacts of the oil and response efforts to fish, birds, and wildlife. (NOAA)

This time, at Refugio State Beach, was different. I was stationed at a command center for those working to assess the environmental impacts of the spill only three days after a pipeline released up to 105,000 gallons of oil, with at least 21,000 gallons reaching the Pacific Ocean north of Santa Barbara.

From the start of this oil spill, I was able to see the inner workings of the Natural Resource Damage Assessment process and how complex and challenging this process can be for the scientists involved. Biologists, armed with notebooks and cameras, were diligently filling out paperwork and going over every painstaking detail of their data. Collecting good data is extremely important at this early stage because it will be used as evidence showing the oil spill’s potential impacts to wildlife and natural areas.

The next day I was asked to follow a team into the field to take photos of them collecting fish samples from one of the oil spill’s “hot zones.” At the stretch of Refugio State Beach where the majority of the oil cleanup activities were taking place, it was easy to be overwhelmed by the scene. There were a huge number of trucks, cars, buses, people in hard hats, reporters, and even an eating area with eight large tables set up under tents.

That day I was part of a team of nine people who would be sampling fish for oil contamination, with representatives from NOAA, the National Park Service, California Department of Fish and Wildlife, and an environmental consulting firm representing Plains All American Pipeline, the company responsible for the leaking pipeline. When we checked in with the on-site safety officer, he told us that we would need to wear Tyvek suits, booties taped around our calves, gloves, and hard hats.

Oil and Fish Don’t Mix

Out on the beach it was hard not to step in oil since it covered most of the cobble rocks lining the beach in a thick band. I watched as the team baited their hooks and cast their lines in the water. The fishing team spread out along the beach, making the job of running buckets of samples between those catching and processing the fish even more challenging.

Once I had finished taking photos, I began shuttling buckets of fish from the edge of the contaminated zone to a picnic table several yards away. There, two women were working hard to process the samples of fish that will later be analyzed for oil contaminants in a lab.

The team caught 18 barred surfperch in total, giving us a robust sample of the local population which might have been affected by the oil spill. It was a successful day of sampling, but at the same time, I found it difficult not to think about how all of that oil was going to be cleaned off of those rocks.

Working at the front line of the oil spill at Refugio State Beach was a unique experience for me, but it also feels a little too close to home. When I was responding to the Deepwater Horizon oil spill in the Gulf of Mexico, I was stationed two hours away from the nearest coast and lived almost 2,000 miles away in California.

I found having an oil spill in your own backyard is much more personal and reminds me of how important it is to plan, train, and prepare for oil spills long before any oil hits the water.

For more information on the response to this oil spill, visit the Refugio Response Joint Information Center website.

Gabrielle Dorr

Gabrielle Dorr.

Gabrielle Dorr is the Outreach Coordinator for the Montrose Settlements Restoration Program as part of NOAA’s Restoration Center. She lives and works in Long Beach, California, where she is always interacting with the local community through outreach events, public meetings, and fishing education programs.


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On the Chesapeake Bay, Turning Artillery Sites and Landfills into Places for Wildlife

Excavator removes metal debris from the shore of a coastal landfill.

Used from 1972 to 1974, this landfill at Naval Support Facility Indian Head’s site 36 saw more than 57,000 pounds of metal and other materials hauled away as part of its cleanup and restoration. (U.S. Navy)

Roughly 25 miles downstream of Washington, DC, on the Potomac River is a military base known as Naval Support Facility Indian Head. Established in 1890, it is the U.S. Navy’s oldest continuously running ordnance station (ordnance includes artillery and ammunition). In the course of its history, this sprawling 2,500 acre naval installation has served as a research facility, a testing site for artillery, and a manufacturing site for some of the explosive chemical powders used in weapons.

However, as is the case for many other military facilities scattered along the shores of Chesapeake Bay, the land and waters of the Indian Head base became so polluted by the range of military activities—at one point, the Navy used it to test large naval guns by firing projectiles into the Potomac River—that it was designated a Superfund site and slated for cleanup under CERCLA.

Aerial view of Naval Support Facility Indian Head surrounded by water.

Like many other military facilities along the Chesapeake Bay, the land and waters of the Indian Head base became so polluted by the range of military activities that it was designated a Superfund site and slated for cleanup. (U.S. Navy)

But tackling environmental cleanup and restoration in a place with such a long history of explosives makes for unusual challenges.

For example, when the cleanup team needed to take soil or water samples, they often had to call in ordnance clearance specialists to help deal with the dangerous chemicals, guns, rockets, missiles, ordnance, and explosives potentially littering the area.

Juxtaposed against this scene at the base is Mattawoman Creek, a beautiful freshwater tidal creek with abundant wetlands and wildlife adjacent to the military site. Migratory fish such as yellow perch, herring, and shad follow the creek as they travel further inland to reproduce. In addition, many fish use the wetlands as a nursery and source of food. Large, hungry birds such as bald eagles, herons, and egrets flock to the area, as well as recreational fishers eager to cast their lines to the plentiful fish.

Fortunately, a detailed investigation indicated that this natural area has not suffered widespread impacts from pollution at the nearby base. Instead, the investigation directed the base’s cleanup strategy to focus on key sections serving as major pollution sources.

Laying Waste

The Caffee Road Landfill at the base’s Site 11 was such a mix of soil, waste, and debris that it actually extended the shoreline up to 150 feet into Mattawoman Creek. In addition to serving as a landfill for Indian Head, the military used the site to burn waste, and munitions and explosives potentially lay buried in pockets along the shoreline.

Getting this landfill—an ongoing source of pollution—under control needed to accomplish three goals: block contact with the contaminated soil, prevent shoreline erosion, and avoid exposing potential ordnance.

The design for remediating this site included placing a protective soil cover over the landfill and stabilizing the shoreline. Historically, shoreline stabilization has been achieved by positioning large rocks and riprap on the edge of the water, which “hardens” the shoreline and would move the wave energy from the protected area to adjacent areas.

Instead, NOAA and the trustee agencies responsible for the area’s natural resources proposed what is called a “living shoreline.” These hybrid shorelines are constructed habitats designed to mimic the functions of natural shoreline habitats and which incorporate both natural habitat and built infrastructure. They aim to provide the same benefits as nature, such as shoreline stabilization, improved water quality, and wildlife habitat. The project was rounded out by planting marsh shrubs and trees along the shoreline and by seeding and mulching the soil cover on top of the landfill.

All the while during these construction operations, the cleanup team had a trained professional clearing the munitions and explosives to provide safe working conditions as they transformed this dump into a safe place for fish, birds, and wildlife.

The close partnership among several federal and state agencies, including the Navy, U.S. Environmental Protection Agency, Maryland Department of the Environment, and the trustees, was instrumental in successfully and efficiently converting this former landfill into vibrant habitat, resulting in savings of more than $700,000.

Recycling for Wildlife

A similar transformation has occurred at a landfill on the base’s Site 36. This landfill, most likely originally part of Chickamuxen Creek and a nearby wetland, was used from 1972 to 1974 and has been inactive since that time. The fill material dumped into the creek was believed to contain metal casings from mines, bombs, and torpedoes—not exactly normal working conditions.

Cleanup focused on removing scrap metal and potential munitions items from the surface of the landfill and the shoreline. The multi-agency team hauled away more than 57,000 pounds of metal and other materials from the site, with much of it recycled rather than left under the existing soil cover. By taking a common-sense approach to removing this debris, the project managed risk and minimized environmental impacts by maintaining natural habitats, including forests and wetlands, whenever possible, while also ensuring the landfill’s soil cover would control pollution.

While there is still work to be done, progress abounds elsewhere on the naval facility. For example, the multi-agency cleanup team removed creek sediments contaminated with mercury and surrounding floodplain soils to protect and enhance restoration of habitat along a tributary to Mattawoman Creek. The tributary has been blocked off from the main channel to prevent mercury from getting to Mattawoman Creek, but with the mercury gone, there is now potential for opening up the tributary and reconnecting it with the creek.

Naval Support Facility Indian Head occupies a unique place in military history, and thanks to efficient collaboration among federal and state agencies working to clean it up, this locale again provides valuable and healthy habitat for fish, birds, and wildlife along the Chesapeake Bay.


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Five Key Questions NOAA Scientists Ask During Oil Spills

Responders in a small boat pressure-wash rocky shore at the site of an oil spill.

Responders pressure wash the Texas shoreline after the tank ship Eagle Otome oil spill in January of 2010. (NOAA)

During an emergency situation such as an oil spill or ship grounding, scientists in NOAA’s Office of Response and Restoration are guided by five central questions as they develop scientifically based recommendations for the U.S. Coast Guard.

These recommendations help the Coast Guard respond to the incident while minimizing environmental impacts resulting from the spill and response.

Identified in the late 1980s by NOAA, these questions provide a sequential framework for identifying key information at each step that will then inform answers to subsequent questions raised during an oil spill. For example, in order to predict “where could it go?” (question two), you first need to know “what spilled?” (question one), and so on.

Questions guiding NOAA's oil spill response science, with a ship leaking oil, surrounded by boom, with flying birds and a benzene molecule.

Naturally, during a spill response, it may become necessary to revisit earlier questions or assumptions as conditions change and more—or better—information becomes available.

The Scene of the Spill

Establishing what happened is the first step. What is the scenario for this incident and where is it occurring? Gathering this information means figuring out facts such as:

  • the type of incident (e.g., pipeline rupture versus oil tanker collision).
  • the volume and types of oil involved.
  • the incident environment (e.g., stormy, calm).
  • the incident location (e.g., open ocean, near shore, water temperature).

Forecast: Cloudy with a Chance of Oil

Dr. Amy MacFadyen is a NOAA physical oceanographer who frequently works on the next step, which is predicting where the oil is going to go. In most of the spills we respond to, the oil is spilled at or near the water surface and is less dense than water. Initially, the oil will float and form a slick. Dr. MacFadyen looks at what is going on in the environment with wind and waves, which can break up the slick, causing some of the oil to mix into the water column in the form of small droplets.

An important point is that responders can potentially clean up what is on top of the water but recovering oil droplets from the water column is practically impossible. This is why it is so important to spill responders to receive accurate predictions of the movement of the surface slicks so they can quickly implement cleanup or prevention strategies.

In order to make predictions about oil movement, Dr. MacFadyen uses a computer model which includes ocean current and wind forecasts to generate an oil trajectory forecast map. Trajectory forecast models may be updated frequently, as conditions at the site of the spill change. Although the trajectory map shows the position of the oil, there is an element of uncertainty as the forecasts are based on other predictions, such as weather forecasts, which are not always perfect and are themselves subject to change.

To reduce uncertainty, trajectory forecasts incorporate information from trained observers flying over the slick who can confirm the actual location of the oil over the course of the spill response. MacFadyen can then incorporate that updated information as she runs the trajectory forecast model again.

A Sense of Sensitivity

In order to answer what the oil might affect, NOAA developed Environmental Sensitivity Index maps to identify what might be harmed by a spill in different habitat types. It is necessary for responders and decision makers to know what shoreline types exist in the path of the oil, as well as vulnerable species and habitats so that they can plan for the appropriate protection (such as booming) or cleanup method (such as skimming). Cleaning up oil off a sandy beach is very different than a salt marsh, mudflat, or rocky shore.

Animals, plants, and habitats at risk can include those on the water (e.g., seabirds), below the surface (e.g., fish), and on the bottom (e.g., mussels), as well as on the shoreline (e.g., marsh grasses).

Jill Petersen, manager of the Office of Response and Restoration Environmental Sensitivity Index map program, works to ensure that these maps of each U.S. coastal region are up-to-date so that this information is readily available should a spill occur.

Raise the Alarm for Harm

The next step is to look at what harm the oil could cause. When oil is released into the water, it can cause harm to marine animals and the environment. Oil contains thousands of chemical compounds. Polycyclic aromatic hydrocarbons [PDF], or PAHs as they are commonly known, are a class of oil compounds that have been associated with toxic effects in exposed organisms. Because of this, scientists frequently study PAHs in spilled oil to gauge the oil’s potential environmental impact.

However, the complexity of each oil’s chemistry and the changes that occur once it is in the environment make the assessment of risk a challenging task. In order to do so, response biologists consider the type of oil, the sensitivity of potentially exposed organisms, and how the oil is expected to behave in the environment.

Oil spills can involve releases of large volumes of oil that overwhelm whatever natural capacity there might be to absorb impacts, which leads to the photographs we see of heavy oil covering plants and animals. But recent research studies have shown that even minute amounts of petroleum can harm marine eggs and larvae—which means the decisions we make during a response are even more critical to the long-term health of the affected habitats.

NOAA marine biologist Dr. Alan Mearns is an expert on how pollution from oil harms the environment. Each year, he reviews and summarizes recent research in this field to ensure oil spill response recommendations and decisions are based on the most current science that exists.

Sending Help

A skimmer picks up oil off the surface of the Delaware River.

A skimmer picks up oil off the surface of the Delaware River after the tanker Athos spilled oil in 2004. (NOAA)

Answering the previous questions allows us to determining what can be done to help. Doug Helton, the Office of Response and Restoration’s Incident Operations Coordinator, describes possible solutions as usually falling under three categories: containing the source, cleaning up, and protecting the shore.

To contain the source means to limit the further release of pollution by plugging the leak in the pipeline or containing the spill, for example, by keeping the ship from sinking and losing its entire cargo of oil.

Cleanup on the water could be conducted by mechanical means, such as booming and skimming, or through alternative technologies, such as burning the oil in open water or using chemicals to disperse the oil.

Cleanup along the shoreline can be done manually or mechanically using methods such as pressure washing. When considering cleanup options, sometimes monitoring the situation is the best option when a response method could actually cause more harm to the environment. One example is in an oiled marsh because these habitats are especially vulnerable to oil but also to being damaged by people walking through them trying to remove oil.

In addition to providing scientific support to the U.S. Coast Guard, NOAA’s Office of Response and Restoration develops oil spill response software and mapping tools. For responders, NOAA has published a series of job aids and manuals that provide established techniques and guidelines for observing oil, assessing shoreline impact, and evaluating accepted cleanup technologies for a variety of oil spill situations.


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What Have We Learned About Using Dispersants During the Next Big Oil Spill?

The Deepwater Horizon Oil Spill: Five Years Later

This is the eighth in a series of stories over the coming weeks looking at various topics related to the response, the Natural Resource Damage Assessment science, restoration efforts, and the future of the Gulf of Mexico.

A U.S. Air Force plane drops an oil-dispersing chemical onto an oil slick on the Gulf of Mexico

A U.S. Air Force plane drops an oil-dispersing chemical onto an oil slick on the Gulf of Mexico May 5, 2010, as part of the Deepwater Horizon response effort. (NOAA)

Five years ago, in the middle of the response to the Deepwater Horizon oil spill, I was thrown into a scientific debate about the role of chemical dispersants in response to the spill. Dispersants are one of those things that are talked about a lot in the context of oil spills, but in reality used pretty rarely. Over my more than 20 years in spill response, I’ve only been involved with a handful of oil spills that used dispersants.

But the unprecedented use of chemical dispersants on and below the ocean’s surface during the Deepwater Horizon oil spill raised all sorts of scientific, public, and political questions. Questions about both their effectiveness in minimizing impacts from oil as well as their potential consequences for marine life in the Gulf of Mexico.

Did we understand how the ingredients and components of the dispersants behave? How toxic are they? What are the potential risks of dispersants and do they outweigh the benefits?

We knew the flood of questions wouldn’t end when the gushing oil well was capped; they would only intensify the next time there was a significant oil spill in U.S. waters. NOAA, as the primary scientific adviser to the U.S. Coast Guard, would need to keep abreast of the surge of new information and be prepared to answer those questions. Five years later, we know a lot more, but many of the scientific, public, and policy questions remain open to debate.

What Are Dispersants?

Dispersants are a class of chemicals specifically designed to remove oil from the water surface. One commonly used brand name is Corexit, but there are dozens of different dispersant mixtures (see this list of all the products available for use during an oil spill).

They work by breaking up oil slicks into lots of small droplets, similar to how dish detergent breaks up the greasy mess on a lasagna pan. These tiny droplets have a high surface area-to-volume ratio, making them easier for oil-eating microbes to break them down (through the process of biodegradation). Their small size also makes the oil droplets less buoyant, allowing them to scatter throughout the water column more easily.

Why Does Getting Oil off the Ocean Surface Matter?

Oil slicks on the water surface are particularly dangerous to seabirds, sea turtles, marine mammals, sensitive early life stages of fish (e.g., fish eggs and embryos), and intertidal resources (such as marshes and beaches and all of the plants and animals that live in those habitats). Oil, in addition to being toxic when inhaled or ingested, interferes with birds’ and mammals’ ability to stay waterproof and maintain a normal body temperature, often resulting in death from hypothermia. Floating oil can drift long distances and then strand on shorelines, creating a bigger cleanup challenge.

However, applying dispersants to an oil slick instead shifts the possibility of oil exposure to animals living in the water column beneath the ocean surface and on the sea floor. We talk about making a choice between either protecting shorelines and surface-dwelling animals or protecting organisms in the water column.

But during a large spill like the Deepwater Horizon, this is a false choice. No response technology is 100 percent effective, so it’s not either this or that; it’s how much of each? If responders do use dispersants, some oil will still remain on the surface (or reach the surface in the case of subsurface dispersants), and if they don’t use dispersants, some oil will still naturally mix into or remain in the water column.

Why Don’t We Just Clean up Oil with Booms and Skimmers?

Cleaning up oil with mechanical response methods like skimmers is preferable because these vessels actually remove the mess from the environment by skimming and collecting oil off the water surface. And in most spills, that is all we use. There are thousands of small and medium-sized spills annually, and mechanical cleanup is the norm for these incidents.

But these methods, known as “mechanical recovery,” can only remove some of the oil. Under ideal (rather than normal) circumstances, skimmers can recover—at best—only around 40 percent of an oil spill. During the Deepwater Horizon oil spill response, skimmers only managed to recover approximately 3 percent of the oil released.

Dispersants generally are only considered when mechanical cleanup would be swamped or is considered infeasible. During a big spill, mechanical recovery may only account for a small percentage of the oil. Booms (long floating barriers used to contain or soak up oil) and skimmers don’t work well in rough seas and take more time to deploy. Booms also require constant maintenance or they can become moved around by wind and waves away from their targeted areas. If they get washed onto shore, booms can cause significant damage, particularly in sensitive areas such as marshes and wetlands.

Aircraft spraying dispersant are able to treat huge areas of water quickly while a skimmer moves very slowly, only one to two miles per hour. In the open ocean spilled oil can spread as fast, or faster, than the equipment trying to corral it.

Isn’t There Something Better?

Chemical product label for Corexit dispersant.

Dispersants, such as Corexit, are a class of chemicals specifically designed to remove oil from the water surface by breaking up oil slicks into lots of small droplets. (NOAA)

Well, researchers are trying to develop more effective response tools, including safer dispersants. And the questions surrounding the potential benefits and risks of using dispersants in the Gulf of Mexico have led to substantial research in the Gulf and other waters at risk from spills, including the Arctic. That research is ongoing, and answering one question usually leads to several more.

Unfortunately, however, once an oil spill occurs, we don’t have the luxury of waiting for more research to address lingering scientific and technical concerns. A decision will have to be made quickly and with incomplete information, applied to the situation at the moment. And if, during a large spill, mechanical methods become overwhelmed, the question may be: Is doing nothing else better than using dispersants?

That summer of 2010, in between trips to the Gulf and to hearings in DC, we began to evaluate the observations and science conducted during the spill to build a foundation for planning and decision making in future spills. In 2011, NOAA and our partners held a national workshop of federal, state, industry, and academic scientists to discuss what was known about dispersants and considerations for their use in future spills. You can read the reports and background materials from that workshop.

That was not the only symposium focused on dispersant science and knowledge. Almost every major marine science conference over the past five years has devoted time to the issue. I’ve been involved in workshops and conferences from Florida to Alaska, all wrestling with this issue.

What Have We Learned?

Freshly spilled crude oil in the Ohmsett saltwater test tank starts turning brown after dispersants applied.

The Deepwater Horizon oil spill spawned a larger interest in researching dispersants. Here, you can see freshly spilled crude oil in the Ohmsett saltwater test tank in New Jersey, where the oil starts changing a few minutes after dispersants were applied. Note that some of the oil is still black, but some is turning brown. (NOAA)

Now, five years later, many questions remain and more research is coming out almost daily, including possible impacts from these chemicals on humans—both those active in the response as well as residents near the sites of oiling. Keeping up with this research is a major challenge, but we are working closely with our state and federal partners, including the U.S. Environmental Protection Agency and Coast Guard, as well as those in the academic community to digest the flow of information.

The biggest lesson learned is one we already knew. Once oil is spilled there are no good outcomes and every response technology involves trade-offs.

Dispersants don’t remove oil from the environment, but they do help reduce the concentration of the oil by spreading it out in the water (which ocean currents and other processes do naturally), while also increasing degradation rates of oil. They reduce the amount of floating oil, which reduces the risk for some organisms and environments, but increases the risk for others. We also know that some marine species are even more sensitive to oil than we previously thought, especially for some developmental stages of offshore fish including tuna and mahi mahi.

But we also know, from the Exxon Valdez and other spills, that oil on the shore can persist for decades and create a chronic source of oil exposure for birds, mammals, fish, and shellfish that live near shore. We don’t want oil in the water column, and we don’t want oil in our bays and shorelines. Basically, we don’t want oil spills at all. That sounds like something everyone can agree with.

But until we stop using, storing and transporting oil, we have the risk of spills. The decision to use dispersants or not use dispersants will never be clear cut. Nor will it be done without a lot of discussion of the trade-offs. The many real and heart-felt concerns about potential consequences aren’t dismissed lightly by the responders who have to make tough choices during a spill.

I am reminded of President Harry Truman who reportedly said he wanted a one-handed economist, since his economic advisers would always say, “on the one hand…on the other.”