Hinkley groundwater contamination facts for kids
Hinkley, California, is a small town in the Mojave Desert. From 1952 to 1966, a company called Pacific Gas and Electric Company (PG&E) dumped a lot of dirty water near Hinkley. This water contained a harmful chemical called hexavalent chromium. It was used to stop rust in their natural gas equipment.
Hexavalent chromium is a chemical that can cause health problems. In 1993, a legal worker named Erin Brockovich started looking into how this pollution affected people's health. A big lawsuit was filed, and in 1996, PG&E agreed to pay $333 million to the affected residents. By 2016, Hinkley had become almost a ghost town because many people moved away.
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History of the Hinkley Contamination
In the early 1950s, PG&E built special stations to help move natural gas through pipelines. Two of these stations were in Topock, Arizona and Hinkley. They used hexavalent chromium in cooling towers to stop rust. After using this water, they dumped it into unlined ponds near the stations. This happened from 1952 to 1966. PG&E did not tell local water officials about the pollution until 1987.
The Lawsuit and Erin Brockovich
People living in Hinkley filed a class action lawsuit against PG&E. This means many people joined together to sue the company. In 1993, Erin Brockovich, who worked for a lawyer, started investigating illnesses in Hinkley. She found links to the hexavalent chromium.
The case went to a special process called arbitration. This process helps solve disagreements without a full trial. PG&E later decided to settle the case. In 1996, they paid $333 million. This was the largest settlement for a class action lawsuit in U.S. history at that time.
After the lawsuit, PG&E was supposed to stop using chromium 6 and clean up the polluted water. However, the contaminated area, called a "plume," kept spreading. By 2013, the plume was over six miles long and two miles wide. In 2010, PG&E started offering to buy homes and give bottled water to people in Hinkley.
In 2014, California became the first state to say that drinking hexavalent chromium can cause cancer. The state set a safety limit of 10 parts per billion (ppb) for this chemical in drinking water.
What is Groundwater Pollution?
PG&E's Hinkley station uses cooling towers to cool natural gas. From 1952 to 1966, the water in these towers had hexavalent chromium to stop rust. This chemical is now known to cause cancer.
The company stored this water in ponds that were not lined. This allowed the dirty water to soak into the ground and mix with the groundwater. This caused groundwater pollution, affecting the soil and water wells nearby. The polluted area, or "plume," grew larger over time.
The Spreading Plume
The contaminated water plume started about two miles long and one mile wide. By 2013, it had grown to six miles long and nearly two miles wide. In 2015, officials ordered PG&E to clean up the chromium pollution. At that time, the plume was about eight miles long and two miles wide.
Cleaning Up the Pollution
By 2013, PG&E had spent over $750 million on cleanup efforts. Cleaning up the pollution is a very difficult and long process. PG&E built a concrete wall to help stop the plume. They also pumped a chemical called ethanol into the ground. This chemical helps change the harmful chromium 6 into a less harmful form, chromium 3. They also planted many acres of alfalfa plants, which can help with cleanup.
In 2014, water officials noted that the chromium had moved from the upper water layers to the lower ones. This meant that the deeper water was also becoming polluted.
Debates About Chromium and Health
Scientists have debated whether small amounts of chromium 6 in drinking water can cause cancer. A 2007 study found that high doses of chromium 6 caused cancer in rats and mice. However, it is harder for studies to prove if very low levels cause cancer in humans.
In 2013, a PG&E representative said that scientists were still debating the toxicity of hexavalent chromium. This debate was one reason why the cleanup process took so long. In July 2014, California set a safety limit for chromium 6 in drinking water. This was based on new research linking it to cancer when ingested.
California's Safety Limits
California was the first state to set a specific safety limit for hexavalent chromium in drinking water. In 2014, they set the limit at 10 ppb. The U.S. Environmental Protection Agency (EPA) also looked into the health effects of chromium 6. In 2010, the EPA suggested that chromium 6 could likely cause cancer in humans if ingested over a lifetime.
Hinkley in Film
The story of the Hinkley contamination and the lawsuit became a famous movie. The film, called Erin Brockovich, came out in 2000. Julia Roberts played Erin Brockovich in the movie. She won an Academy Award for Best Actress for her role. Erin Brockovich herself said the movie was about 98 percent accurate. She even made a small appearance in the film.
