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Is Toxic Hexavalent Chromium in Our Drinking Water?

Updated on October 16, 2017
Do you live in such an area?
Do you live in such an area?
Chromium trioxide
Chromium trioxide

Do we really know what toxic stuff pours from our taps?

Our planet is full of industrial waste – it’s in the land, air and water. Some of it is considered toxic and some of it isn’t, of course. Moreover, a very small amount may be okay, but too much might cause cancer or other health problems.

Hexavalent chromium (HC) is one of six oxidation states for the chemical element chromium. All of these compounds are used in industrial applications throughout the world. Hexavalent chromium is considered carcinogenic, though the level at which it becomes carcinogenic is a subject of debate. In varying levels, it is often present in the tap water in industrialized countries of the European Union as well as the United States.

At this point you may wonder: should people be concerned about the presence of HC in their tap water? Let’s explore this potentially worrisome issue:

Use of Hexavalent Chromium

Hexavalent chromium (also called chromium 6) is used in the production of stainless steel, glass, paint, plastics, cement and dyes. Exposure to airborne HC can occur during stainless steel welding, thermal cutting or chrome plating. A Web site dedicated to the dangers of hexavalent chromium states that people working with HC should use safety controls such as respirators, fume extractors and clean air sources.

Dangers of Hexavalent Chromium

According to the Web site for the Center for Disease Control and Prevention, the National Institute for Occupational Safety and Health (NIOSH) considers HC compounds to be potential workplace carcinogens. In particular, exposure to airborne HC has been linked to an increase in the risk of lung cancer. Many other problems such as skin ulceration have been associated with the use of HC.

Keep in mind that trivalent chromium (or chromium 3) is considered healthful and sometimes used in vitamin supplements.

The United States

In 2010, the Environmental Working Group (EWG), a non-profit consumer advocacy organization, studied the drinking water in 35 American cities and discovered measurable amounts of HC in 31 of these municipalities. Norman, Oklahoma had the highest reading for HC – a whopping 12.9 parts per billion (ppb). The city average was .18 ppb.

According to the article “Probable carcinogen hexavalent chromium found in drinking water of 31 U.S. cities” on the Web site for The Washington Post, the Environmental Protection Agency may eventually set a limit for HC in tap water. The agency is reviewing the chemical after the National Toxicology Program, part of the National Institutes of Health, called it a "probable carcinogen" in 2008.

Also, scientists have recently found evidence that HC causes cancer in laboratory animals when ingested. It has been linked in animals to liver and kidney damage as well as leukemia, stomach cancer and other cancers.

Hinkley, California

Hinkley is almost certainly the most famous American city for which high levels of HC have been detected in drinking water. In the 1990s, .58 parts per million (ppm) of HC was discovered in Hinkley’s groundwater. (The United States Environmental Protection Agency has indicated than .10 ppm is the safe level for chromium, though no safe level for HC has been provided by the agency.) People in Hinkley showed a higher than average incidence for developing cancer, and the company spewing the HC into the ground water for 30 years, Pacific Gas and Electric (PG&E), eventually had to pay in 1996 damages of $333 million.

According to a similar story on the Web site for the Christian Science Monitor, Sam Delson, a spokesman for California's Office of Environmental Health Hazard Assessment, said the agency is preparing a public health goal of .06 ppb that would be one factor in determining safe exposure levels.

A movie about the HC found in Hinkley’s drinking water was released in 2000. The movie was entitled Erin Brockovich, which identifies the woman who discovered the HC contamination, as well as the cover-up attempt by PG&E. Actress Julia Roberts starred in the movie, for which she won the Academy Award for Best Actress.

Other Contaminated Cities in the U.S.

In June 2009, the groundwater in Midland, Texas showed 5.25 ppm of chromium, higher than the level at Hinkley. In Davenport, California, airborne levels of HC ten times higher than California environmental standards were detected coming from a Cemex cement plant. In January 2011 HC was detected in drinking water in Milwaukee, Wisconsin.

In the aforementioned article of The Washington Post , the famous Erin Brockovich stated, "This chemical has been so widely used by so many industries across the U.S. that this (the EWG report) doesn't surprise me. Our municipal water supplies are in danger all over the U.S. This is a chemical that should be regulated."


If you’re uncertain about the purity of your community’s tap water, you should filter your drinking water or purchase purified or distilled water. And if you have a well, check the purity of the water from time to time. Also, anybody who lives in a heavily industrialized area should be especially watchful for toxic chemical such as HC that could contaminate sources of drinking water.

For more information about the dangers of hexavalent chromium, please click on the following link:

Please leave a comment.

© 2011 Kelley


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    • profile image

      plumbing supplies 6 years ago

      We should all agree to this information. I guess drinking water that comes directly from the faucet is not safe anymore to drink.

    • profile image

      dj7it 6 years ago

      Agreed! Good hub!

    • Kosmo profile image

      Kelley 6 years ago from California

      That's a very good science project! Drinking water from just about any river on the planet is not a good survival strategy! Drinking tap water is not a good idea either, especially if you live around industrial zones or any place where toxic chemicals are regularly used. My lecture is over. Later!

    • RealHousewife profile image

      Kelly Umphenour 6 years ago from St. Louis, MO

      One of my girls won 1st place in the science fair using this topic - the test results between the water that came out of our tap had very few differences in the water we sampled from the St. Charles River ..........eeewwwww

    • Kosmo profile image

      Kelley 6 years ago from California

      Thanks for the compliment, kislany! Since 1986 I've avoided drinking tap water. For one thing, I can't stand the smell of chlorine! And you never really know what other toxic crap is in there. Later!

    • kislany profile image

      kislany 6 years ago from Cyprus

      Great info actually. I never drink tap water and always buy bottled one. I just don't know what chemicals pass through the tap to my body. Rated your hub as useful.

    • Kosmo profile image

      Kelley 6 years ago from California

      Thanks for the comment, IN2Deep. Everybody should be wary of drinking tap water on a regular basis. Later!

    • IN2Deep profile image

      IN2Deep 6 years ago

      Wow -this was some really great useful information.

    • Kosmo profile image

      Kelley 6 years ago from California

      Thanks a lot, ImChemist. I hope the story passed muster, as they say. Later!

    • ImChemist profile image

      ImChemist 6 years ago

      Thanks for this great information , i rated it useful.