The CLEANUP: Containing the mess

Cleaning up a spill

worker in full gear cleaning up oil spill on land

Worker cleaning up oil after Hurricane Katrina. Source: Photobucket

The clean up and remediation of an oil spill is a difficult task. Those involved in the oil spill clean-up industry will admit that no two oil spills are alike. Variables such as type of oil, location of the spill, amount of oil spilled, weather conditions, and proximity to delicate areas are always different. Thus clean-up professionals must be prepared to face a variety of problems both known and unknown.

The volume of the spill can be estimated by observing the thickness of the coat of oil and its appearance and color on the surface of the water. Estimating the volume of a spill is important when deciding which strategies to use for clean up.

table showing how to estimate the volume of an oil spill

Information based on the surveillance process of oil on the surface of the water as described in
the Bonn Agreement Oil Appearance Code.

Cleanup Strategies & Methods: An Overview

cleaning an oiled beach by hand

Worker picking up tar balls at Elmer’s Island in Louisiana. Source: U.S. Coast Guard, Credit: Patrick Kelley

Determining the volume of a spill is only the beginning of trying to clean it up. If a cleanup crew can reach the site of the spill, containment and skimming technologies can efficiently begin the process. Large sponges called sorbentsmaterial used to absorb liquid or gas can also be used to absorb much of the oil. However if time, wind, and tides are working against the crew, the task becomes more formidable as the oil spreads.

Eventually the natural elements through time can cause the breakdown of oil through such process of evaporation, thus, many spills are left alone. Controlled burning is even used under the right conditions.

In some regions dispersantssubstance added to an oil spill to prevent clumping and setting and improve separation of particles are employed to speed up the natural process of the breakdown of oil. Unfortunately many dispersants are dangerous to wildlife. Frequently fertilizers rich in phosphates and nitrates are spread over an oil slick in hopes that these chemicals will cause microorganisms such as dinoflagellates to bloom and eat up the oil. Recently some researchers have genetically engineered bacteria to breakdown oil. No matter which method is employed, the processes of cleanup and remediation are nasty and costly.

an oil tanker surrounded by boom

Exxon Valdez in Prince William Sound. Source: National Oceanic & Atmospheric Administration

In 1989, the Exxon Valdez tanker ran aground, dumping 11 million gallons of oil on an Alaskian shoreline and awakening the world to the catastrophic impact of a major oil spill. Although spills affecting land and water had occurred since the oil industry began, the Exxon Valdez spill resulted in legislation that changed cleanup procedures in three significant ways: 1) Owners of the vessel or rig causing the spill became responsible for paying for cleanup; 2) The U.S. Coast Guard became responsible for overseeing cleanup; and 3) Companies leasing rigs had to file extensive plans for cleanup before they were issued permits to begin drilling.

Cleanup Methods: The Details

Several methods using various technologies have been developed through the years to cleanup oil spills. These methods include: letting the spill break down by natural means, using booms to channel and collect the oil, using dispersants to break up the oil, using biological agents to degrade the oil, burn off the oil, and recently using a bell to collect the oil.

graphic showing different responses occurring simultaneously

Diagram of different response efforts. Source: British Petroleum

Natural Breakdown

The oldest method that is still used today includes leaving the oil spill alone so that it will eventually break down by natural means. This method is primarily used if there is no possibility of the oil entering and polluting coastal regions interfering with fisheries or other marine industries. A combination of environmental conditions such as: wind, sun, current, and wave action will serve to disperse and evaporate many oils strictly by natural means. The natural method works better upon light oils because lighter oils will disperse more easily than heavier oils.

coast guard deploying boom

Unloading oil containment boom. Source: U.S. Coast Guard, Credit: Patrick Kelley

Using Booms & Skimmers

A common method employed in water and maritime oil spills is to contain the oil spill with booms and then collect the oil from the surface of the water by using skimmer equipment. Oil may float on the surface of the water and form an oil slick that is just a few millimeters in thickness. Booms can be used to either surround and isolate an oil slick, or to block the passage of an oil slick from certain locations. Boom types vary from inflatable neoprene tubes to solid, but buoyant material. Newer types contain absorbent sides.

mechanical skimmers working inside boom permimeter

Mechanical skimmers working inside boom. Source: U.S. Coast Guard, Credit: Patrick Kelley

The majority of booms extend about a meter above the surface of the water. Unfortunately rough waters and high winds can cause the oil to spill over such a boom. Many times a mechanical skimmer is used in conjunction with a boom. Skimmers float across the top of the oil slick and serve to suck or siphon the oil into storage tanks on nearby vessels.

Chemical Dispersants

plane releasing dispersants

Airplane releasing oil dispersant. Source: U.S. Coast Guard, Credit: Stephen B. Lehmann

Another common method is to use dispersants to break up the oil and speed up the natural biodegradation processthe breakdown of chemicals by a microorganism . Dispersants are similar to emulsifying agents that act to reduce the surface tension of water that prevents oil and water from mixing. In turn, small droplets of oil are then formed, which can break down more rapidly. It is recommended that dispersants be used within an hour or two of the initial spill.

Dispersants are not appropriate for all oils and all locations. If the oil is dispersed through the water column it can affect marine organisms like corals and sea grass. It can also affect organisms that are important in the seafood industry.

Adding Biological Agents

Under certain conditions, biological agents can be introduced to a spill in order to the spill to hasten biodegradation. Many microorganisms can serve to break oil down into harmless substances such as fatty acids and carbon dioxide. This action is known as biodegradation. The natural process of biodegradation can be made speedier by the addition of fertilizing nutrients like nitrogen and phosphorous, which stimulate growth of the important microorganisms. In addition, research is being done that will employ genetically engineered bacteria to degrade oil. Many universities such as Louisiana State University is working on such “tiger bugs.”

navy performing a controlled burn

Controlled burn of oil on ocean surface. Source: U.S. Navy, Credit: Justin Stumberg

Controlled Burns

Although burning an oil slick is not visually appealing, research reveals that under certain conditions, burning of an oil slick may be acceptable. Controlled burning can efficiently and rapidly reduce the volume of a threatening oil slick. In addition, it eliminates the need for collecting and storing the oil. Concerns over atmospheric emissions and a lack of understanding about the combustibility of oil in water calls for more careful research.

Development Driller begins relief well after Deepwater Horizon explodes

Drilling a relief well. Source: U.S. Coast Guard, Credit: Patrick Kelley

Drilling Relief Wells

On land as well as in marine environments, upon several occasions, relief wells have been drilled to pump heavy fluids into the damaged well above the reservoir line. These fluids theoretically stop the oil from flowing, thereby stopping the leak. Learn exactly how a relief well works.

Relief wells are the only permanent solution to capping leaking wells where equipment, piplines, and or blowout preventers have failed. They intersect the pipelines of the failed well and then deliver concrete and fluids to seal the broken pipelines. Other containment methods will be used while drilling relief wells because drilling new wells takes at least 3 months, sometimes longer.

New Techniques Used in Deepwater Horizon

As the result of the Deepwater Horizon accident off the coast of Louisiana, several new ways of containing and stopping the spill—nearly 5,000 feet beneath the surface—were attempted. One method involved placing a large four-story containment box over the point of the leak in hopes that it would channel the oil to be collected. The box was successful in shallower water, but as the box was lowered deeper and deeper, cold water filled the box with ice crystals and the attempt failed.

The next attempt involved threading a pipe into part of the broken pipes still connected to the blowout preventer. Although the smaller pipe was threaded successfully into the larger pipe, only a small portion of the oil could be siphoned to the surface where a tanker captured it. Another method relied on shooting mud, golfballs, and pieces of tire into the blowout preventer, hoping to fill the holes. However, the force of the oil and natural gas spewing from the well was too strong, and this "junk shot" was abandoned.

Several weeks later, engineers used robots to cut off part of the broken blowout preventer and then affixed a second blowout preventer as a cap. Over several days, they began closing vents on the second blowout preventer, monitoring the pressure to ensure the well's integrity. This temporary "cap" sealed off the oil until the crews could finish drilling the relief well, which was the permanent way to seal off the spewing well. Even after permanently sealing the well, though, cleanup would continue for many months.

workers cleaning up Port Fourchon in Louisiana

Cleaning up Port Fourchon, Louisiana, Source: U.S. Coast Guard, Credit: Patrick Kelley

how many?

According to the U.S. Energy Information Administration (EIA), the world consumes more than 85.5 million barrels of oil each day. Each barrel holds about 42 gallons of oil.

So the world is consuming 3.6 billion gallons of oil every day.

The U.S. consumes 19.5 million barrels each day, which is 819 million gallons of oil every day. Fueling our cars (32%) and light trucks (28%) uses the majority of this oil. In fact, 819 million gallons of oil fills the tanks of 68 million cars.

legal issues

What laws come into play after an oil spill? The Oil Pollution Act was signed into law in 1990 following the Exxon Valdez spill. It required that governments and oil companies develop contingency plans, and it increased the role of government in monitoring oil companies.

The Clean Water Act of 1977 and the Federal Water Pollution Act of 1972 put the federal government in charge of water quality and enforcement.

Maritime law also comes into play with oil spills in the ocean. The Limitation of Liability Act of 1851 was intended to help U.S. shipping businesses by encouraging investors to "buy into" ships. If the ship sank, the investor could get back some if not all of his money.

cleanup inc.

Did you know there's a yellow pages of those who cleanup oil spills? It's called the International Directory of Oil Spill Cleanup Contractors.

Their website also provides news about cleanups, equipment links, descriptions of technological advances, photos, and a list of training classes.

cover of cleanup oil directory

Cover of the Directory

helping animals

oiled pelican

Oiled pelican. Source: Audubon Magazine, Credit: Kim Hubbard

Cleaning oiled wildlife requires special training and equipment. Learn more about each step and see pictures of the process at the Oiled Wildlife Center in Fort Jackson, Louisiana.

cleaning an oiled pelican

Cleaning a pelican. Source: U.S. Navy, Credit: Justin Stumberg

oiled turtle

Rescuing an oiled turtle. Source: Louisiana Dept of Wildlife & Fisheries

After a spill occurs, Fish & Wildlife Departments survey the area to find animals who need cleaning.

Learn more about how aquariums and researchers provide additional support.

response time

logo for Deepwater Horizon response team

The 2010 Deepwater Horizon incident shows how complicated a spill can become.

deepwater horizon explosion

Deepwater Horizon explosion. Source: U.S. Coast Guard

4/20 Deepwater Horizon explodes killing 11 workers.

4/24 Oil leak is detected and estimated at 1,000 barrels/day.

4/29 Leak amount is revised to 5,000 barrels/day. Louisiana declares state emergency as oil is 16 miles from coast.

cleaning up beach in Louisiana

Cleanup on a beach in South Pass, LA. Source: Deepwater Horizon Response

4/30 Oil begins staining Louisiana's shoreline.

5/28 Leak amount is revised to 10,000-12,000 barrels/day.

6/3 BP cuts off the broken pipeline and inserts a new riser that collects some oil.

7/15 BP stops the flow of oil by closing valves on the new capping stack.

8/3 BP begins pumping mud and cement through the "static kill" that essentially seals off the flow of oil

cement and mud around well from static kill

Cement and mud seal the well. Source: BP Video Feed

Aug-Sept BP works to permanently seal the well by drilling the relief well.

For detailed timelines and interactive maps, visit the Times Picayune, PBS, and The New York Times.