Oil Spill Cleanups: Common Methods and Their Effectiveness (2024)

Oil spill cleanups vary depending on the size and location of the spill, the rate at which oil is released, the type of oil, and water temperature and chemistry. Each major spill in history offers lessons in how to improve cleanup—however, technologies are far from capable of preventing ecological damage.

Here, we review the methods of cleaning up oil spills and whether or not they really work.

Common Cleanup Methods

According to the National Oceanic and Atmospheric Administration, cleaning up oil spills at sea relies primarily on four techniques.

Booms and Skimmers

Floating booms are long, floating barriers typically made of plastic or metal that can contain and slow the spread of oil. Booms can be put in place to corral oil slicks and help prevent them from reaching coastal communities and sensitive ecological areas. Some of these sensitive areas include shellfish beds or seagrass meadows and beaches that serve as breeding grounds for turtles, birds, and marine mammals. Booms may have “skirts'' that extend below the surface to further contain oil.

Skimmers are boats or other equipment that skim oil from the surface. Often, the oil is contained by booms until a skimmer can collect it, sometimes by using a mesh material that allows water to pass through but traps the oil. However, effective use of skimmers relies on good conditions at sea; choppy seas, high surf, and strong winds reduce their ability to collect the oil.

Chemical Dispersants

Chemical dispersants are employed to break the oil into small droplets and help remove it from surface waters, where it’s more likely to migrate toward coastal ecosystems. These small droplets can be consumed by microbes, reducing overall volume. However, chemical dispersants are toxic to aquatic life, so they are typically used when other methods prove less effective.

Early chemical dispersants were not formulated for use in oil spill response. They contained degreasing agents that succeeded in dispersing oil, but at a considerable ecological cost.

During the 2010 BP oil spill, which released oil into the Gulf of Mexico for months, responders applied an unprecedented amount of dispersants, including deep underwater around the source of the leak. The ecological risks of doing so in deep ocean waters were unknown, but responders reasoned that applying dispersants at the source might break up oil long before it reached the surface, reducing the overall amount of dispersants needed. However, since this method was largely untested, concerns remain about the ecological impacts of adding toxic components deep underwater.

In Situ Burning

When an oil spill is recent and sea conditions are calm, response teams sometimes surround the slick with fireproof booms and set the oil on fire.

This method, like dispersants, has environmental drawbacks. Air pollutants are released by in situ burning, and the people most at risk are spill response personnel. In addition, burnt residues sink and may smother benthic organisms, according to NOAA. Research continues, but much remains unknown about the full range of ecological consequences.

In situ burning is relatively inexpensive compared to the use of booms, skimmers, and chemical dispersants, making it an attractive option for countries with limited oil spill response capacity. However, these same countries often lack resources for regulation and management of the process, which increases environmental risks.

Secondary Cleanup Methods

Secondary cleanup methods might be implemented after the more common approaches, or in place of them if other resources are not available.

Sorbents

A variety of materials have been used over time to absorb oil that collects on and near shore. But many of the sorbents employed to absorb oil from spills are made of synthetic materials that may be damaging or expensive. In recent years, researchers have sought to identify non-toxic, biodegradable, and natural materials that reduce environmental and economic impacts.

Peat moss, rice husk, wood fiber, fruit peels, cotton, wool, clay, ash, and various types of straw are among the materials that have been tested on different kinds of oil spills. Because these materials are biodegradable, they help reduce the overall cleanup waste.

Effectiveness varies, however. One concern is that many natural materials sink after absorbing oil, making them difficult to retrieve, which means the oil they absorb remains in the ecosystem. Scientists are researching ways to improve the effectiveness of organic materials.

Biological Agents

Microbes naturally biodegrade oil from spills over time and constitute an important part of spill cleanup. In addition, research continues into effective means of bioremediation, a technique in which specific microbes are used to help decompose oil, often in combination with fertilizing elements like nitrates, phosphates, and iron.

This technique was used extensively in the aftermath of the 1989 Exxon Valdez oil spill and during the 2010 BP oil spill, among others. Matching the ideal microbes to the type of oil and sea conditions in a given spill remains an area of investigation.

Manual Cleaning

When an oil spill affects a coastal region, the response usually involves an army of people descending on beaches, marshes, and other affected ecosystems to painstakingly remove the oil foot by foot. They may rake it, shovel it, scrub or use a high-pressure hose to spray it off of rocks, or simply walk along the coastline picking up clumps of oil and depositing it for collection and disposal. Heavy machinery may also be used, although these create other environmental impacts.

Natural Methods

Natural weather and water conditions also play a role in breaking up oil. Sunlight, wind and waves, and microorganisms already in the environment can all reduce impacts of spills, though these processes generally take much longer than human interventions. Still, there are situations in which the environmental impacts of intervening are greater than those of letting nature take its course.

Oil Disposal

Part of cleaning up an oil spill entails disposing of tons of waste in the least environmentally harmful manner possible. This is challenging. Whether processing oil skimmed from the water’s surface or dealing with tons of oily sand, gravel, and cleanup materials, any spill will generate tons of toxic waste that requires specific processing and disposal protocols.

In the United States, companies that contract with the government to provide these services must have the equipment and expertise necessary to do this. But in parts of the world that lack the infrastructure and resources, waste materials may be disposed of more haphazardly.

Wildlife Response

Cleaning up an oil spill often entails caring for wildlife suffering impaired mobility and health impacts related to ingesting oil or contaminated food and water sources, inhaling petroleum fumes, or getting coated in oil or tar. Much has been learned about how to care for oil-affected wildlife.

Today, in places with advanced systems to care for oil-affected wildlife, trained personnel transport affected wildlife to a medical facility where they are fed, hydrated, and warmed if necessary. Then, they are cleaned using appropriate methods. Birds are washed in soapy water, while furry marine mammals like otters have soap applied directly to their fur and scrubbed. They often undergo a rehabilitation period in which they are reintroduced to water and have time to groom and rest before release. It’s a time and labor-intensive process, and many rescued animals are simply too injured or stressed to survive.

Do Oil Spill Cleanups Really Work?

Following the Exxon Valdez spill, Congress passed the Oil Pollution Act, intended to prevent spills by creating response, liability, and compensation systems to manage oil pollution incidents caused by vessels and facilities in navigable waters. Despite advances over decades, oil spill cleanups still don't come close to recovering all the oil or fully restoring affected ecosystems. The majority of the oil—and damage—is left to nature to resolve, often with long-lasting consequences.

Cleanup crews recovered only about 25% of the oil in the BP spill, the largest in U.S. history. Another quarter dissolved or evaporated, and an equal portion was dispersed naturally or through the use of dispersants. Between 6 and 10 million gallons are estimated to be on the seafloor and continue to impact the marine food web as organisms ingest contaminated sediment.

It isn't possible with current technologies, methods, and resources to fully remediate a spill.The better and less expensive option is to avoid oil spills in the first place.