Reviewing case studies is an important part of your preparation for the AP Environmental Science exam.
Case studies can give you perspectives on real-world concepts such as laws and treaties, which can help you learn about environmental concerns.
You may be given a set of events and asked to match them with a case study on the multiple choice section of the exam.
On the free-response section of the exam, you will be asked to write about a particular case and then give additional examples.
Several case studies that are common in the AP Environmental Science course are described in this section of the book.
The loss of salamanders is an important sign of the decline of the entire ecology.
Frogs, toads, and salamanders are indicators of environmental damage because of their sensitivity to pollution and environmental change.
Up to 200 species of salamanders have gone extinct in the past 20 years.
In addition to signaling the health of the environment, the salamanders act as a food source for many other species, and provide products for antibiotics and painkillers.
Amphibians are exposed to a lot of environmental risks when they spend a lot of their lives in the water.
Major threats include the loss of habitat due to fragmentation of land, filling in of wetlands, and development of land.
Pollution, disease, overhunting, and the introduction of competitors are all harmful to the salamander.
Climate change can cause the temperatures of regions to change, which can lead to a dry spell.
The loss of watering pools affects the survival of a population and a species since they are important for the laying of eggs.
Amphibians need wet skin.
The organisms can be weakened by events such as long-term drought or increased pollution, which can make them more susceptible to diseases.
There is no definitive answer to the cause of the global decline in amphibian species, but it is likely due to some combination of the listed factors working in unison.
Climate change increases the growth of some fungi, such as the chytrid.
In warm temperatures, this fungus can be lethal.
The golden toad in Costa Rica is at risk of extinction due to the chytrid fungus, which has grown in many areas due to the warmer climate.
The increasing loss of amphibians on a global scale is a warning to humans that the environment is changing quickly.
There has been an increase in the number of nonnative species introduced throughout the world.
Major economic issues can be caused by the impact from the introduced species.
The zebra mussel has caused a lot of damage in the United States.
The Great Lakes and their connected rivers, tributaries, and lakes were invaded by zebra mussels in 1988 after they arrived in North America attached to the hull and in the ballast water of ships from Europe.
Their ability to drift far in flowing water allowed them to spread quickly.
Since zebra mussels were not native to the United States and Canada, they were able to grow without being checked.
The impact of the spread of the mussels was far-reaching.
The zebra mussels can damage boats, fishing gear, and docks, as well as damage engines and pipes, due to their small size.
Native mollusks can be killed if the mussels attach to their shells because they consume large amounts of zooplankton.
Because of the large amount of food consumed by the zebra mussels, they deposit high quantities of nutrients on the bottom, which feeds the benthic population.
Eutrophication of the water can be caused by too much of this.
Large expanses of the Great Lakes that once teemed with life are nearly barren because of zebra mussels.
There are high costs associated with repair of physical damage caused by zebra mussels and the eradication of this species.
At one time, passenger pigeons were the most abundant birds in North America and they flew in huge flocks.
The passenger pigeon is extinct due to habitat loss and overhunting.
People used pigeons for other purposes, including using feathers for pillows and bones for fertilization.
Commercial hunters can kill many birds in a single hunting session because of the large flocks.
Pigeons were seen as disposable.
Pigeon populations declined from their historic billions to a few thousand over the course of 70 years.
The regeneration of the species was slow because of the breeding habits of the birds.
The last passenger pigeon died in the Cincinnati Zoo.
Humans can bring a species to extinction in a short period of time.
Diphenyl-trichloroethane was used as a pesticide from 1939 until 1973, when it was found to be toxic to humans, wildlife, and the environment.
It was banned in the United States in 1973.
Silent Spring was a book written by Rachel Carson, who raised awareness of the dangers of pesticides.
The risks of its use outweigh the benefits in most situations.
The countries with the highest risk of malaria still use the pesticide.
Despite a treaty to reduce and phase out DDT, its use will likely continue until a safer, effective, inexpensive alternative is developed.
The United States makes a lot of the DDT used internationally.
There is a chance that the products we import may contain trace amounts of the chemical.
The decline and near extinction of birds of prey such as hawks, ospreys, brown pelicans, peregrine falcons, and bald eagles are the results of historic DDT use in the United States.
The proliferation of DDT in food webs was caused by its existence in water sources.
Eggs break before they hatch in birds of prey.
In the case of many, the decline in the birds' populations helped to endanger the species.
In the United States, it is still found in the environment even though it was banned in 1973.
Kudzu was introduced to the United States from Asia in 1876 for decorative purposes and was also used as soil cover to help control erosion in the southeastern United States.
Although it has helped reduce erosion problems, the fast-growing, hard-to-kill vine, Kudzu, can smother other plants and trees by starving them of carbon dioxide, water, and sunlight.
Kudzu photosynthesizes has the ability to fix atmospheric nitrogen, absorb large amounts of water through its roots, and can take root in almost any soil.
The invasion of kudzu can cause a decrease in the number of organisms.
When done regularly, gnashing has been successful in controlling the population of the plant.
Over time, this weakens their tissues and reduces their growth.
The removal of the plant and its roots is one method.
It takes time and money to do this.
The cost of the Invasive species is related to the repair of damage.
It can grow on buildings, railroad tracks, and other vegetation because of its ability to grow quickly.
These structures can be damaged by the weight and roots.
There are many efforts to eliminate the plant.
Kudzu is a federal noxious weed in the United States.
The gray wolf used to roam the United States in large numbers.
The population of gray wolves in the United States plummeted after the colonization of the country.
Humans killed over one million wolves in order to protect livestock and large game animals.
The gray wolf was listed as an extinct species in 1974.
We have a better understanding of the species.
The gray wolf is a keystone species that helps keep the environment in balance by controlling the populations of prey species and providing food for other animals.
With the dramatic decrease in their population, herbivores such as elk and deer became more prevalent and consumed more vegetation, which resulted in decreasing vegetation in areas such as Yellowstone National Park.
Less food for herbivores and soil erosion were caused by vegetation loss.
The gray wolves were reintroduced to the park.
In 1995 gray wolves were relocated to the park from Canada.
The park's population increased over time, and the park's ecology began to return to its previous state.
Increased vegetation along streams is caused by fewer large herbivores.
scavengers got more food from the wolves' kills.
The increase in coyotes killed by the larger wolf led to an increase in smaller animal populations.
The gray wolves were classified as threatened in 2003 because of the success of the reintroduction.
Habitat destruction, lead poisoning from consuming lead shot, and the inability of the birds to adapt to the changing environment caused the decline of the California condor in the 20th century.
In 1987, there were 22 remaining wild condors and 15 in captive breeding programs.
The San Diego and Los Angeles zoos captured the last remaining condors in the wild.
The population of the San Diego Zoo was moved to the San Diego Wild Animal Park.
The birds' genes were tested so that the most unrelated birds could be together.
The World Center for Birds of Prey in Idaho and the Oregon Zoo have breeding programs.
In 1991, condors were released in California and in 1996, they were released in Arizona.
Wild condors can be seen at three sites in California, at Zion National Park in Utah, and in the Grand Canyon area of Arizona.
There are almost 400 birds in the wild.
The birds are not able to reproduce in the wild.
The California Condor recovery project is the most expensive project in the history of the United States.
In the wild, a number of milestone have been reached.
In 2007, a condor laid an egg in Mexico for the first time since the 1930s, and in 2009, a second egg was laid.
The decline of the California condor is thought to have been caused by the use of DDT.
The decline of the California condor was not explained by the use of DDT.
Lake Erie was considered dead by 1969 due to a low amount of dissolved oxygen, high pollution concentrations, and large amounts of algae.
The lake is surrounded by a large number of major cities.
The capital of the automotive industry was Detroit, as well as Cleveland, Toledo, Erie, and Buffalo.
The US side of Lake Erie was home to 9 million people by the 1960s.
More than 2 million people have waste systems with waste that frequently reaches the Lake.
In the 1960s, fish die-outs were common.
Local and federal laws reduced the amount of waste dumped into Lake Erie.
Several surrounding states banned high-phosphate detergents, industrial waste dumping was put under strict controls, and municipal sewage was extensively treated before being discharged into the lake.
It is making a comeback.
The dissolved oxygen levels are improving and some game fish have been reintroduced.
The beaches have been closed for a long time.
The improvement is not complete.
The St. James Project is a series of hydroelectric dams built in Quebec, Canada.
There are eleven hydroelectric power stations.
Several rivers' waters were diverted into the major rivers to increase their flow.
The La Grande River's flow was greatly increased while the downstream flow of diverted rivers was greatly reduced, which greatly affected the environment.
The local forest has been submerged behind the dams.
In the affected areas, the waters fill shorelines with dead trees and shoreline plants are destroyed.
The area is prone to earth tremors due to the weight of the artificial rivers and the dams behind them.
There is a risk of harm to the local population and environment as fault lines are present in the valley.
The decline of salmon spawning in the area is one of the changes that have taken place.
As the rivers and streams have been altered, the habitats of the beatiful have been displaced.
As the shores of the James and Hudson bays have been altered, herds of caribou and flocks of Canadian geese have been affected.
The Mississippi and Atchafalaya rivers empty into the Gulf of Mexico, carrying with them pollutants and nutrients they pick up along their courses.
There are pollutants such as sewage, deposition from fossil-fuel combustion, and discharge from industries.
The Gulf of Mexico has a great bloom of algae and plankton in the spring.
The increase in life leads to an increase in death and decomposition.
This depletes the dissolved oxygen in the water and the area becomes hypoxic.
The organisms either die or leave the area.
There is no life in this dead zone.
The Gulf of Mexico dead zone is one of the largest in the world.
Over 400 dead zones have been found throughout the world.
Since 2000, this number has doubled.
When the oxygen levels return to normal levels, the area ceases to function and must start over again.
Fishing income can be affected by dead zones and tourism dollars can be affected as well.
The Aral Sea used to be the fourth largest inland body of water in the world.
Due to the diversion of water from the two rivers that empty into the lake for use in irrigation in this hot, dry region, it has become more saline and has also been dramatically deplete.
The lake's volume has gone down and its salinity has gone up.
Due to the low water levels, the Aral Sea has been separated into three smaller lakes.
The amount of life can no longer be supported by the same amount of biodiversity.
Wetlands have been lost, which has resulted in decreased habitats for birds and mammals, as well as native fish in the lake.
All fish species once found in the Aral Sea have gone extinct or have been extirpated due to the extreme salinity levels in the area.
The economic impact has been very bad.
The fishing industry used to depend on the sea.
The large size of the Aral Sea helped regulate the region's climate, keeping summer heat and winter cold.
The regional climate is not moderated by the loss of a high portion of the water from the lake.
The growing season has been shortened.
The increased pace of snow melt in the Himalayas is due to the salty dust that blows from the Aral Sea and gets deposited on the mountains.
There is an increased use of chemicals to help the growth of crops on the deteriorated soils.
Human health is impacted by these chemicals as well as the increasing population in the area.
Increasing flow back into the Aral Sea is one of the ways that efforts are being made to improve the health of the environment.
A return of fish to the lake is one of the promises of a renewed Aral Sea.
There is hope that most of the past Aral Sea will eventually return to being a productive and thriving environment.
The Three Gorges Dam, the world's largest, was controversial and problematic.
The dam on the Yangtze River in China is being used to provide hydroelectric power throughout the country.
At least 1.2 million people were displaced by the construction of the dam, and priceless archeological sites were flooded.
Many industrial and agricultural areas, mines, and waste sites were flooded, and the potential for water pollution is still present.
The pollutants can affect both water and bottom soil.
Natural recycling and cleaning processes are reduced because of the dam because there is less downstream flow of water.
When the water flow of a dam is slowed, more silt is deposited on the bottom, which can slow shipping and block flood control gates.
The Three Gorges Dam has issues and threats.
Cropland and forests have been lost in the flooded areas.
Downstream of the dam, the benthic environment is not as rich in nutrients as it should be.
The spawning and migration patterns of some fish below the dam have been disrupted by the dam.
There has been increased saltwater intrusion into the drinking water at the mouth of the Yangtze River due to the decreased water flow of the river.
With less freshwater being held in the ground, the saltwater from the ocean takes its place.
Huge waves were created by the slippage of large amounts of earth into the water when the reservoir started filling.
The ecological impact of the Three Gorges Dam project is not all bad.
For at least 10 percent of China's population, it has the ability to generate cleaner energy from the largest hydrostation in the world.
Reducing air pollution and carbon dioxide emissions from fossil fuel combustion will diminish China's reliance on imported energy.
Commercial fishing boats can travel a long distance along the river.
Water available for irrigation below the dam has increased, while seasonal flooding downstream has been lessened.
There are no definitive answers and the pros and cons of the Three Gorges Dam are valid.
The demand for freshwater in the region has increased due to the growth of Southern California.
A water diversion project was constructed to divert water from other parts of California to meet the needs of Los Angeles and the rest of the south.
A huge network of aqueducts, pumps, and dams was built to transfer water from northern and eastern California to Southern California.
Water was diverted from the Owens River Valley to the Colorado River in 1916.
Due to the continually expanding population, a new aqueduct was added in 1941 to bring water from Mono Basin north of the Owens Valley.
The aqueduct was expanded again in the 1950s to get water from Northern California.
The drying of Owens Lake and the desertification of the Owens Valley have been caused by the massive diversion and consumption of water from these regions.
Local farmers were angry and violent because of the lack of water and sabotaged part of the aqueduct in 1924.
Los Angeles took their water and destroyed their lives.
Even more was taken as the water was eventually pumped to feed the aqueduct.
The Mono Basin experienced the same fate.
The water from the creek that fed Mono Lake was diverted to the aqueduct.
The water level became more acidic.
The change in the water led to dramatic changes in the ecology of Mono Lake.
Brine shrimp populations declined and migratory bird populations left the area.
Due to the drop in water level, a land bridge was exposed, making the eggs of some birds easy prey for other birds.
The Mono Lake Committee and the Audubon Society were able to get protection for Mono Lake and its streams in 1994.
The potential for desertification was avoided as the water level rose.
The Owens Valley and Owens Lake were slower to gain protection.
In 2006 courts ordered that some water be returned to the Owens Valley from the city of Los Angeles.
The land along the banks of the river is slowly returning to life after the river flowed.
China instituted a "one-child" policy in 1979 because of food shortages and famine.
People of the ethnic Han majority in China were required to have only one child.
The law doesn't apply to minority groups or rural areas.
The consequences of having more than one child without a permit is a heavy fine.
People have lost jobs, land, livestock, healthcare, and other privileges.
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Many Chinese families prefer a male child because of social and cultural pressures.
The chance to have only one child leads to sex discrimination in which a high number of female children are aborted.
It is now illegal to determine the sex of a baby prior to birth in an attempt to alleviate the issue.
China's sex ratio has changed, with 120 males for every 100 females, because of male preference.
There are many benefits to low or declining population growth.
There is more pressure on younger people to take care of their elderly parents because there are fewer working-age individuals.
There are fewer people entering the military and a smaller labor market.
More money is required to care for the elderly as the population ages.
The "one-child" policy has helped reduce the population in China.
Pressures on food supplies have been reduced by it.
People have been able to spend money on things other than child rearing.
The "one-child" policy will be in place for at least the next ten years because of its success.
Easter Island's civilization ended due to the destruction of the environment.
Easter Island was once home to a thriving society and was located off the coast of South America in the Pacific Ocean.
The people who lived on Easter Island used their resources too much and started to deplete their supplies.
The trees provided shelter, fuel, tools, boats, and nets, and were used for many other functions, providing the basis of the civilization's survival.
People were unable to fish and travel away from the island because they were not able to make canoes and rope.
Food sources declined when resources were not enough.
With a lack of vegetation and trees, freshwater levels declined and crop yields declined.
The islanders died of famine and the islanders fought over the remaining food and resources.
It became commonplace to clash and steal.
When the last people were found on Easter Island in 1722, they were hungry and living in caves.
The decline of the civilization on Easter Island is an example of a tragedy of the commons in which an unregulated resource is overexploited and used unsustainably.
Over time resources are lost and all suffer because it is in every individual's best interest to exploit rather than conserve.
There are many examples of tragedies of the commons.
A man-made closed self-contained network of ecosystems was created with the intention of having eight people live there for two years.
The facility was started outside of Tucson, Arizona.
The designers imagined that the ecosystems would recycle air, water, and other resources needed for survival for all living organisms.
It included a savanna, tropical rain forest, desert, freshwater and saltwater wetlands, an ocean with a coral reef, and lakes and streams.
The extensive planning failed to correctly predict the complicated interactions, and carbon dioxide levels quickly rose to toxic levels, as oxygen was consumed bybacteria in the soil.
Toxic levels of nitrogen oxide were also raised.
Both nitrogen and carbon cycling were failing.
In Arizona, the levels of cloudiness dropped.
Excess nitrogen ended up in the water supply.
In large numbers, species extinctions occurred.
Local ants entered the facility and killed off insects, most of which died off, as well as 19 small animal species, which went extinct.
Other species became pests.
The included were roaches and vines.
The inhabitants were able to produce 80 percent of their food supply despite many obstacles.
Despite the setbacks, the humans were able to survive in the closed environment for the entire two-year plan.
Biosphere 2 was a basis for many unique studies and research.
The experiment shows the massive complexity and non-replicable structures of Earth's natural ecosystems.
The Union Carbide Chemical Co. created the disaster known as the Bhopal gas tragedy.
The worst chemical disaster is the Bhopal disaster.
Several thousand people were exposed to toxic fumes and chemicals after a leak of methyl isocyanate (MIC) gas and other chemicals on December 2, 1984.
The official death toll from the release of gases was 2,259 and the confirmed death toll was 3,787.
The death toll was estimated by other agencies.
558,125 deaths were caused by the leak in 2006 according to the government.
The Chernobyl disaster was the worst nuclear reactor disaster in history.
The city of Chernobyl was part of the Union of Soviet Socialist Republics until 1991, when it became part of the Ukraine.
On April 26, 1986, reactor number four suffered a power output surge during a system test.
When an attempt was made to perform an emergency system shutdown, the power output spike caused the reactor vessel to burst and cause a series of explosions.
There was a spark in the air.
A large amount of radioactive material was sent into the atmosphere by the fire.
350,000 people were evacuated from the worst contaminated areas.
Acute Radiation Syndrome claimed the lives of 28 emergency responders in 1986 and 19 of them later.
4,000 deaths will be attributed to the accident due to increased cancers.
The first reported fire on the river was in 1868.
In 1952, the largest fire caused over $1 million in damages.
Chemicals from many manufacturers were found in the river.
The 1969 Cuyahoga River fire helped spur water control legislation that resulted in the Clean Water Act, the Great Lakes Water Quality Agreement, and the creation of the federal Environmental Protection Agency.
There was a major oil spill in the Gulf of Mexico that flowed for three months in 2010.
The impact of the spill continued even after the well was capped.
It is the largest accidental oil spill in the history of the industry.
The spill began when the drilling rig exploded.
5 million barrels of crude oil had been released before the well was capped.
The marine life in the Gulf of Mexico and the habitats along the coast were damaged by the spill.
The spill created a threat to the environment due to the toxicity of the petroleum, the use of the oil dispersant, Corexit, and the depletion of dissolved oxygen.
There are eight U.S. National Parks that are threatened.
Four species of sea turtles, 1,200 fish, 200 birds, 1,400 mollusks, 1,500 crustaceans, and 29 marine mammals live in the Gulf spill area.
The dead animals had been collected.
The local fishing industry, tourism industry, and other businesses dependent on the Gulf have been negatively impacted by the oil spill.
On March 24, 1989, the Exxon Valdez tanker hit a reef.
260,000 to 750,000 barrels of crude oil were spilled when the oil tanker ran aground.
It's considered to be one of the worst environmental disasters caused by humans.
It was the largest oil spill in the U.S. before the oil spill in the Gulf of Mexico.
The Exxon Valdez oil spill happened in a very remote location.
It was difficult to respond to the spill because the area was only accessible by boat, plane, or helicopter.
Clean-up efforts were hampered by the amount of coastline, rocky coves and inlets.
There was a spill that covered 1,300 miles of coastline and 11,000 square miles of ocean.
The region is home to salmon, sea otter, seals, and seabirds.
The immediate effects included the deaths of 100,000 to 250,000 seabirds, at least 2,800 sea otter, hundreds of harbor seals, hundreds of bald eagles, 22 killer whales, and billions of salmon and herring eggs.
The Oil Pollution Act was passed in 1990.
Double-hull ships provide an additional layer between the oil tanks and the ocean.
There is a provision in the law that prohibits ships from operating in Prince William Sound if they cause an oil spill of more than one million gallons.
The Fukushimi Daiichi plant in Japan was the site of the most recent global nuclear event.
The costal facility was rendered non-functional after the earthquake, aftershocks, and a wave.
The structure was weakened further by multiple hydrogen explosions.
The nuclear disaster is not under control at this time.
Due to the damaged instruments and the danger of entering the reactor, it is not yet known what is happening inside and if nuclear fuel is leaking out of the core.
Radiation levels are monitored throughout the country to make sure they don't go up to harmful levels in the atmosphere and ocean.
People have been evacuated from the area around the nuclear plant.
The effects of this disaster and the activity in the region near Japan are still unknown because there is so much unknown.
It was one of the costliest hurricanes in U.S. history.
The total property damage from the hurricanes and floods is estimated at $81 billion.
On the morning of August 29, 2005, a Category 3 storm made landfall in southeast Louisiana, causing damage from central Florida to Texas.
Between New Orleans, Louisiana, and Biloxi, Mississippi was the worst-hit area.
Most of the people who died in New Orleans were killed when the levee system failed and the waters from Lake Pontchartrain flooded 80% of the city.
The environment was affected by Hurricane Katrina.
Several barrier islands were moved closer to the coastline because of the storm surge.
Hurricane Ivan damaged the region and it was completely destroyed by Hurricane Rita.
The lands that were lost were breeding grounds for animals.
Some of the local marshlands were permanently covered in water from the storm.
In the storm, half of the refuge was lost.
The Mississippi sand hill crane, red-cockaded woodpecker, and the Alabama beach mouse are sea turtle species.
The Gulf coast had been filled in for use as farmland and for the construction of towns and cities.
Natural marshlands help provide a natural protection for the coastline from hurricanes.
Hurricanes can travel further inland if the marshlands are filled in.
The river was originally 103 miles between Lake Kissimmee and Lake Okeechobee.
The river is a major source of water.
Most of central and southern Florida was flooded during the 1947 hurricanes.
Congress authorized the canalization of the river after Florida requested assistance in controlling future floods.
The 103-mile distance between the two lakes was shortened by the U.S. Army Corps of Engineers from 1962 to 1970.
The project caused damage to the river and surrounding lands.
The fast moving water dried the surrounding land faster than the rains replaced it.
As a result, the number of herons, egrets, and wood storks was reduced by two-thirds.
The largemouth bass population declined.
Prior to the channelization, the Kissimmee was not a major source of pollution.
Without the winding distance and slow flow, surrounding lands were not able to effectively filter river water.
The straightened river contributed 25 percent of the nitrogen and 20 percent of the phosphate of the pollutants.
The oxbows that slowed the water flow were proposed to be returned.
Congress approved efforts to restore the Kissimmee River to its original flow in 1992, with the goal of restoring 43 miles by 2011.
Many of the restored sections of the river have wildlife returning to them.
Increased levels of dissolved oxygen in the water have increased the populations of insects, mollusks, and crayfish, which in turn has increased the populations of fish, birds, and alligators.
The restoration has benefited the entire food chain.
One of the world's rare successes is the restoration of the Kissimmee River.
The Great Smoke of 52 or the "Big Smoke" was a severe air pollution event that occurred from December 5 to December 9, 1952.
Increased coal burning during periods of cold weather combined with windless conditions allowed airborne pollutants to collect and cause the event.
It was not thought to be a significant event at the time.
According to medical reports, 4,000 died and 100,000 became ill due to the effects of the smog on the respiratory system.
According to recent research, the actual number of deaths was closer to 12,000.
The U.K. Clean Air Act of 1956 was one of the changes that followed the event.
The two levels of the river were separated by the falls.
He believed that a canal would provide much needed hydroelectric power to the area, and later he imagined a shipping lane that would circumvent the falls and reach Lake Ontario.
He dug a canal that was 50 feet wide and 10 to 40 feet deep.
In the summer the canal became a swimming hole and in the winter it became a skating pond.
In the 1920s, the canal became a dumping site.
Hooker Chemical Company was granted permission to dump waste in Love Canal in 1942.
The canal was lined with clay.
The barrels were buried 20 to 25 feet deep.
Hooker purchased the canal and bank in 1947.
The dumpsite closed in 1953.
Chemicals were added to the canal dumpsite during the time it was open.
The canal was covered with a clay cap.
The vegetation grew atop the dumpsite.
The site was purchased by the local school board after it was closed.
The Hooker Chemical Company tried to tell the school district about the chemicals below the surface, but the district refused to believe them, so they purchased the land.
The site's potential dangers were explained in the agreement.
Hooker believed they were releasing themselves from all liability.
The board began construction of a new school on part of the site in 1954.
The sewer system was built for a home development on a part of the site.
Construction crews broke through the clay cap while building the sewer system.
Dirt was moved from atop the cap for fill in other locations and holes were punched to build water lines and a highway.
When rain flowed through the toxic dump, toxic waste escaped into the surrounding areas.
An informal door-to-door survey in the summer of 1978 showed a higher than normal number of birth defects.
The New York State Health Department found a high number of miscarriages.
On August 2, 1978, the dumpsite was declared an emergency.
The size of the dumpsite was found to be larger than previously thought.
56 percent of the children who were born between 1974 and 1978 had some signs of birth defects.
Over 800 families were forced to move or leave the area.
The Santa Barbara oil spill happened in January and February of 1969.
It was the largest oil spill in the United States.
The cause of the oil spill was on January 28, 1969 on Union Oil's platform A.
An estimated 80,000 to 100,000 barrels of crude oil spilled into the ocean after the well was capped and then washed onto beaches from Goleta to Ventura and the northern shores of four Channel Islands.
Thousands of sea birds and marine mammals were killed by the spill in the channel.
The framework of the modern environmental movement in the United States was formed as a result of the coverage by the media.
Legislation that led to the formation of the Environmental Protection Agency, as well as policies including the National Environmental Policy Act and the Clean Water Act, were created as a result of the oil spill.
The California Environmental Quality Act was passed in response to the Santa Barbara oil spill.
The Three-Mile Island accident was caused by a partial core meltdown in a pressurized water reactor.
The nuclear accident is the worst in US history.
13 million gallons of radioactive gases were released, but less than 20 gallons of I-131 was released.
The initial mechanical failure was followed by human failure to recognize and correct the problem.
In the end, the reactor was brought under control.
The amount of radioactive material released was small.
There was a predicted increase in cancer cases.
The release of the movie The China Syndrome 12 days before the accident probably influenced the public reaction to the event.
An accident at a nuclear power plant was depicted in the movie.
The decline of new reactor construction was a result of the accident at Three-Mile Island.