America's 10 Worst Man-Made Environmental Disasters

Leaf at the center of two images showing two vastly different landscapes
Photo: By Piyaset/Shutterstock

As millions of gallons of oil leaked into the Gulf of Mexico in 2010 — killing wildlife, contaminating waters and threatening the fragile ecosystem — it was hard to determine the worst part of the disaster. But perhaps it was the fact that it was preventable.

Most environmental disasters — earthquakes, hurricanes, floods and wildfires — lie outside human control, but some of the world's most devastating catastrophes have been caused by people. As mankind continues to pursue fuel, food and building materials, we're polluting ecosystems and destroying the planet we depend on for survival. Here's a look at some of the worst man-made environmental disasters in U.S. history. When it comes to environmental destruction, the blood is often on our hands.

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Gulf dead zone


An area in the Gulf of Mexico — beginning at the Mississippi River Delta and extending to Texas — is a wildlife dead zone for many months of the year. During the summer, this area, which is more than 7,000 miles wide, is devoid of wildlife except for the bodies of shrimp, crabs and other marine life that die because of oxygen depletion in polluted water.

This underwater wasteland is the world’s second largest dead zone and is caused by drainage from the Mississippi River, which deposits massive amounts of pesticides, fertilizers and animal waste from the central United States. Nitrogen in the chemicals and animal waste spur the growth of algae, which is eaten by zooplankton. Those microscopic creatures then excrete pellets that decay on the ocean floor, a process that depletes oxygen.

Although the dead zone fades in winter, not all the organic matter decays, which means the zone will get larger even if the same amount of nitrogen is released next year. The zone has grown steadily over the past few decades, and scientists are concerned the Gulf oil spill could have widened the massive dead zone.

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Three Mile Island meltdown

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The most significant accident in the history of American nuclear power took place on March 28, 1979, at Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania. The accident was a partial core meltdown caused by a failure in the non-nuclear secondary system that was followed by a stuck valve that released radioactive gases.

Experts concluded that the amount of radiation released into the atmosphere was too small to result in health problems, and public record states that no one died as a result of the Three Mile Island accident. However, the Nuclear Regulatory Commission later told Congress it didn't know exactly how much radiation had been released.

More than 2,400 residents have filed class-action lawsuits demanding compensation for death and disease, but no open judicial hearing has been allowed. However, the owners of Three Mile Island paid millions in damages to area residents whose children were born with birth defects. The federal government didn't track the health histories of the region’s residents, and some have accused the state of Pennsylvania of hiding the health impacts of the Three Mile Island accident.

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Dust Bowl


Extensive farming combined with severe drought caused the Dust Bowl in the 1930s. Deep plowing on the Great Plains killed the natural grasses that kept soil in place, and the topsoil turned to dust and blew away. Tons of soil were blown off barren fields and carried in storm clouds for hundreds of miles, creating one of the most disastrous ecological events in U.S. history.

Between 1930 and 1940, severe dust storms, or “black blizzards,” reached heights of 10,000 feet, blowing cars off the road and blocking out sunlight. At times, the clouds blackened the sky all the way to New York City, and much of the topsoil was deposited in the Atlantic Ocean. An estimated 2.5 million people were displaced and millions of acres of farmland became useless, intensifying the economic impact of the Great Depression.

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Love Canal


Love Canal is a neighborhood in Niagara Falls, N.Y., that gained environmental notoriety when it was discovered that 21,000 tons of toxic waste had been buried beneath it. The area became a dumping ground in the 1920s after William T. Love abandoned his attempt to dig a canal, and in the 1940s, Hooker Chemical began dumping industrial waste in the canal and covering it with dirt.

In 1953, the company sold the land to the local school board for $1, and the 99th Street School was built. Two years later a 25-foot area crumbled, exposing toxic chemical drums that filled with rainwater and created puddles that children played in. The situation worsened when the city began constructing sewers for low-income housing — the construction broke canal walls and released more toxic waste.

Love Canal residents reported exploding rocks, strange odors and blue goo that bubbled up into basements, but it was the high rates of asthma, miscarriages, mental disabilities and other health problems that brought Love Canal into national headlines in 1978. More than 80 toxins had seeped from the canal, and a survey found that 56 percent of the children born from 1974-1978 had birth defects. The federal government relocated area families and declared Love Canal the first federal disaster area due to man-made causes. The event started the EPA’s Superfund program.

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Pacific garbage patch

The Great Pacific Ocean Garbage Patch is a swirling vortex of plastic bags, bottles and other trash that stretches hundreds of miles across the north Pacific Ocean. Some experts estimate it is as large as a continent, and in 2008 the Algalita Marine Research Foundation found that plastic outnumbers plankton in some areas of the patch by 48 to one.

The patch, which may contain more than 100 million tons of debris, formed gradually as pollution gathered in ocean currents and collected in the North Pacific Subtropical Convergence Zone. About 80 percent of the debris in the Great Pacific Ocean Garbage Patch comes from land, and it may take several years for the trash to reach the area.

This churning sea of trash can entangle marine life, especially sea turtles, and end up in the digestive systems of fish, birds and other animals. Plus, sunlight can break down the plastic in the garbage patch, leaking toxins into the ocean and entering the food chain.

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Libby asbestos contamination


The W.R. Grace plant in Libby, Mont., spewed asbestos over the small town for decades, sickening more than 1,000 people and killing more than 200. Smoke from the factory coated the town in tremolite asbestos, a particularly toxic form linked to numerous diseases including mesothelioma.

Dust from the plant became part of the residents’ lives in 1919, and for years it covered lawns, dusted cars and drifted through the air. Tailings from the plant were used as fill for driveways, gardens, playgrounds and even the Libby junior high and high school tracks. Family members of mine workers were also exposed to asbestos that employees brought home on their work clothing.

The mine closed in 1990, and the company is now bankrupt after facing more than 270,000 asbestos-related lawsuits, but asbestos remains in Libby. No one knows exactly how many people have been affected, but a local health clinic that specializes in asbestos-related diseases says it has 1,400 patients and sees about 20 new patients each month.

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Tennessee coal ash spill

Wade Payne/AP.

A few hours before dawn on Dec. 22, 2008, the walls of a dam holding 1.1 billion gallons of coal ash crumbled, spilling the toxic concoction into the town of Kingston, Tenn., and creating the largest industrial spill in U.S. history. The wave of ash, leftovers from burning coal mixed with water, wiped out roads, crumpled docks and destroyed homes.

The ash had been stored at the nearby Tennessee Valley Authority coal power plant and contained a decade’s worth of arsenic, selenium, lead and radioactive materials. These metals can cause cancer, liver damage, neurological disorders and other health problems, but the EPA doesn’t classify coal ash as a hazardous material. As workers in Hazmat suits picked through the sludge, Kingston residents were told the ash didn’t present a serious health risk.

A Duke University study revealed that toxic elements in the coal ash could be suspended in the air, posing a serious health risk. The study also said that the coal ash contaminated waters and that accumulation of toxins in river sediment could poison fish. Residents have reported numerous health problems — headaches, respiratory problems and seizures, among others — and scientists have found high levels of toxins in the tissues of fish in the Tennessee, Clinch and Emory rivers.

The long-term effects of coal ash on humans and wildlife remain largely unknown, and experts say the impact of the Tennessee coal ash spill may take decades to sort out.

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Exxon Valdez oil spill

John Gaps III/AP.

Perhaps the most notorious man-made environmental disaster in American history until recently, the 1989 Exxon Valdez oil spill devastated the Alaskan coast. When the Exxon Valdez supertanker hit a reef in Prince William Sound, 11 of its cargo tanks ruptured, dumping 10.8 million gallons of crude that eventually covered 11,000 miles of ocean.

Cleanup began immediately, but despite thousands of personnel helping over the next two years, the spill still hasn’t been fully cleaned up 20 years later. In 2001, a survey found oil at 58 percent of the 91 sites assessed, and oil remains a few inches below the surface on many of Alaska’s beaches.

Responders found carcasses of more than 35,000 birds and 1,000 sea otters. These discoveries were considered to be a fraction of the animal death toll because carcasses typically sink to the seabed. It’s estimated that 250,000 seabirds, 2,800 sea otters, 300 harbor seals, 250 bald eagles and up to 22 killer whales died along with billions of salmon and herring eggs. A 2006 study found that exposure to Exxon Valdez oil still impacts many shore-dwelling animals — otters have yet to reinhabit Herring Bay, and their overall numbers have declined.

The repaired Exxon Valdez was renamed the SeaRiver Mediterranean, and, although it is banned from Alaskan waters, the tanker still carries oil around the world.

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Picher lead contamination

Brandi Simons/Getty Images.

Picher, Okla., is a modern ghost town, and the EPA calls it the most toxic place in America. At one time, Picher was one of the most productive lead and zinc mining areas in the world, but today, the once-bustling town is full of abandoned homes, empty storefronts and enormous piles of lead-laced mine waste.

In 1967 mining ceased — contaminated water from the mines had turned the local creek red, and sinkholes were opening up in the mountains of mining waste. Picher’s giant chat piles — often used for climbing, sledding and picnicking — were found to be laced with lead. High levels of lead were found in blood and tissue of residents, cancer levels skyrocketed, and three quarters of the Picher’s elementary students were reading below grade level.

The area was declared the Tar Creek Superfund site in 1981, but most of the residents didn’t leave until 2006 when studies found that most of the town was in imminent danger of collapsing into the mines. The town — home to 14,000 abandoned mine shafts, 70 million tons of mine tailings and 36 million tons of mill sand and sludge — was deemed too toxic to clean up, and a federal buyout program paid people to leave. The city’s post office closed in July 2009, and the city ceased operations as a municipality on Sept. 1, 2009.

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Gulf oil spill

Jae C. Hong/AP.

The Gulf oil spill began April 22, 2010, and leaked an estimated 206 million gallons into the Gulf of Mexico, making it the worst oil spill in U.S. history and the largest accidental oil spill in the world. Oil washed ashore in all of the Gulf states, creating health threats for both humans and animals.

The spill began when an oil well a mile below the surface of the Gulf blew out, causing an explosion on BP’s Deepwater Horizon rig that killed 11 people. Oil flowed into Gulf for 87 days before the well was finally capped on July 16, 2010.

About 40 percent of the U.S. coastal wetlands are in southern Louisiana, and these areas are home to a variety of species, including the brown pelican, which was removed from the endangered species list in November. Miles of this delicate habitat were coated in oil, and the lives of more than 400 species were severely threatened.

The BP Deepwater Horizon spill also created vast plumes of oil behaving unlike any other spill in history. As these plumes moved through the sea, they suffocated everything in their path. Many of the long-term effects of these plumes and the chemical dispersants used to break up the oil on the ocean’s surface are unknown, but experts say they could devastate the Gulf Coast for years to come.