What Are the Methods for Cleaning Up an Oil Spill?

Between Friday, Oct. 1, and Saturday, Oct. 2, 2021, an estimated 126,000 gallons (572,807 liters) of heavy crude oil spilled into the Pacific Ocean near Huntington Beach, California. Boaters noticed an oily film on the water's surface and reported it to authorities, who subsequently notified the operators of three nearby offshore platforms and pipelines. All three, owned by Amplify Energy Corp., were deactivated by Sunday.

"This oil spill is one of the most catastrophic events our community has faced in decades," stated Huntington Beach Mayor Kim Carr during a Sunday press conference. The ocean and beachfront are temporarily closed from Seapoint to Santa Ana until further notice.

The cleanup effort is being managed by the U.S. Coast Guard and Huntington Beach officials, covering approximately 6 miles (9.6 kilometers) of beaches and wetlands, as stated in a press release from the Huntington Beach Police Department. But what does this process entail? How does one tackle the challenge of cleaning up such a large-scale oil spill?

First, let's delve into some background on crude oil. In 2021, global oil consumption has averaged around 97.4 million barrels per day [source: U.S. Energy Information Administration]. To put this into context, each barrel contains about 42 gallons (159 liters). In the U.S., 90 percent of this oil is transported via pipelines, though it also moves by rail, tanker trucks, and large ships. Wherever pipelines and oil tankers operate, the risk of leaks and spills exists.

Thanks to stricter regulations and improved technology, the frequency of oil spills has declined since the 1960s oil shipping boom. However, since the 1969 Santa Barbara oil well blowout, the U.S. has experienced at least 44 oil spills exceeding 10,000 barrels (420,000 gallons) each. The most significant was the 2010 Deepwater Horizon disaster in the Gulf of Mexico, which claimed 11 lives and lasted over 87 days. The spill released 4 million barrels (134 million gallons) of oil, resulting in $8.8 billion in environmental damages.

The 1989 Exxon Valdez disaster remains unforgettable, highlighting the dangers of oil tanker spills. The Valdez struck a reef in Alaska's Prince William Sound, spilling 11 million gallons of crude oil. The incident left Americans horrified as they witnessed countless oil-covered birds and marine animals struggling to survive.

These harrowing images of oil-drenched wildlife raised the question: how do you address the monumental task of cleaning up millions of gallons of oil? Agencies like the Coast Guard, National Oceanic and Atmospheric Administration (NOAA), and the Environmental Protection Agency employ innovative and straightforward methods to tackle such spills.

When an oil spill happens, the oil creates a thin layer, about a millimeter thick, that floats on the water's surface. Over time, the oil spreads out, becoming thinner and forming a wide sheen. The speed at which a cleanup team responds, along with factors like wave action, currents, and weather conditions, influences the method chosen to address the spill.

If a response team can arrive within an hour or two, containment and skimming may be used to manage the spill. Floating booms with underwater skirts help contain the oil, preventing it from spreading further. This containment makes it easier to remove the oil using specialized boats that collect it from the surface and transfer it to storage tanks.

Teams may also deploy sorbents—large absorbent materials that soak up the oil from the water.

An oil spill that is addressed quickly and occurs far from populated areas is the simplest to manage using standard cleanup techniques. However, such ideal scenarios are rare. Oil spills are typically chaotic, dangerous, and pose significant environmental risks. They often spread to coastlines, affect ecosystems, and harm wildlife, necessitating more complex cleanup strategies.

Other Oil Clean Up Methods

Natural factors like the sun, wave action, and weather conditions help break down oil in water over time. Eventually, the oil evaporates. For this reason, experts sometimes leave certain spills untreated. If the spill does not endanger wildlife, businesses, or communities, cleanup agencies may opt to let nature take its course.

Oil typically floats on saltwater and often on freshwater, though the densest crude oil may sink in freshwater. As oil degrades, it can mix with water and particles like sand, forming tar balls. These balls harden on the outside while remaining soft inside. Since they are dispersed, tar balls and other degraded oil forms in the ocean pose less environmental risk compared to concentrated oil slicks.

In tropical regions, oil spills are often treated with dispersants—chemicals that accelerate the breakdown of oil. Dispersants were used during the Deepwater Horizon disaster, but subsequent studies raised concerns about their effectiveness and impact on marine ecosystems.

According to NOAA, mechanical recovery methods like skimmers and booms are preferred, as they physically remove oil from the environment. However, these methods are not entirely efficient; even under optimal conditions, they can recover only about 40 percent of spilled oil. During the Deepwater Horizon incident, skimmers managed to collect just 3 percent of the spilled oil.

When an oil slick threatens coastal areas—or worse, when a spill occurs near a coastline like the one in Huntington Beach—the situation becomes critical. Cleanup efforts become more challenging, requiring more precise and delicate methods to address the spill.

Shoreline spills are particularly harmful to wildlife habitats. The extent of damage to wildlife from the recent California spill remains uncertain. "We're hoping for minimal impact, but preparing for the worst," said Christian Corbo, a lieutenant with the California Department of Fish and Wildlife, in an interview with The Washington Post.

The impact of an oil spill on aquatic wildlife depends on its severity and how close it is to animal habitats. Birds like waterfowl and marine mammals such as seals and otters can get coated in oil, which destroys the water-repellent nature of feathers and the insulating properties of fur. Animals may also ingest oil while trying to clean themselves, leading to poisoning [source: NOAA].

Cleanup teams deploy floating decoys and balloons to deter wildlife from entering spill zones, but this doesn't fully protect animals. Specialists have methods to reduce fatalities among oil-affected animals, though rescuing birds and marine mammals like walruses and otters remains difficult. If oil reaches and lingers on beaches, other species, including snails and clams, can also be harmed.