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La Crosse and Onalaska are among thousands of U.S. cities where drinking water contains a potentially cancer causing but unregulated chemical.

Made famous by the film “Erin Brockovich,” chromium-6 has been shown to cause cancer in mice and rats and is considered a likely human carcinogen by the Environmental Protection Agency.

Tests conducted between 2013 and 2015 found an average of 0.73 ppb in La Crosse water samples and 1.3 ppb in Onalaska’s, according to EPA data. Both measurements are well above the level deemed safe by California authorities, and Onalaska’s is one of the highest in Wisconsin.

Other area water systems, including Fort McCoy’s North Post and Spring Grove, Minn., had measurements above the safe level. Winona’s water supply had one sample with 0.03 ppb in 2013.

A heavy metal commonly found at low levels in drinking water, chromium-6 is used in steel production, chrome plating and in cooling towers. It is also found in the ash from coal-burning power plants.

The nonprofit Environmental Working Group says more than 200 million Americans are drinking water with unsafe levels of chromium-6, which is found in about nine out of 10 public water systems sampled.

EWG estimates that exposure could result in 12,000 Americans developing cancer during the next 84 years.

Only California regulates chromium-6, although EWG contends its 10 parts per billion limit is too high. The nonprofit group points to a 2011 report by the California Office of Environmental Health Hazard Assessment, which set a public health goal of 0.02 ppb.

That regulation came about after residents of Hinkley, Calif., filed a class-action suit against Pacific Gas & Electric for contaminating its drinking water, which the utility settled in 1996 for $333 million. That case was the basis for the movie, which focused on Erin Brockovich, a legal clerk-turned consumer advocate.

After a 2010 investigation by EWG found chromium-6 in the tap water of 31 cities, the EPA began requiring water utilities to test for the compound but has not set a national standard.

The EPA has held off releasing its draft risk assessment until industry-funded studies are completed. The agency expects to release that assessment in 2017.

In a statement, the EPA notes it has a standard of 100 ppb for total chromium, which includes chromium-6, and only one of the nearly 5,000 public water systems exceeded that standard.

Mark Johnson, La Crosse’s water utility director, said he has not researched potential treatment methods, though he said it would probably involve the addition of a chemical to react with chromium so that it can be filtered out. That would likely entail a treatment facilities at each of the city’s 13 wells.

Home water filters said to reduce chromium levels are available for between about $35 and $700. The group did not respond to questions about effectiveness, but EWG provides a buyer’s guide on its website.

Tests conducted between 2013 and 2015 found an average of 0.73 ppb in La Crosse water samples and 1.3 ppb in Onalaska’s, according to EPA data. Both measurements are well above the level deemed safe by California authorities, and Onalaska’s is one of the highest in Wisconsin.


Rhymes with Lubbock. La Crosse Tribune reporter and data geek. Covers energy, transportation and the environment, among other things. Call him at 608-791-8217.

(7) comments


is it just me or does anyone think La crosse and Onalaska should DO SOMETHING to get this known carcinogen out of our water? Wake up Mayor Kabat and LAX City Council..we're being poisoned people!!! OMG


[innocent][innocent][innocent]One man's contaminant is another man's vitamin supplement. It's all a matter of how you look at things.

Lead Poisoning is a Danger for Every Baby and Child. Here's What You Should Know.

Always Look on the Bright Side of Life - Monty Python's Life of Brian


I don't give a rat's behind how high the California limit is. It is now proven that we have this in our water. Something should be done about it. I'm not too surprised though; Onalaska has some of the hardest, nastiest tasting water in the area. I've seen it ruin appliances, showers; (not to mention skin and hair) and now I get to invest in water treatment.[angry]


Walker will think this is a good thing as it might be good for business. If Walker and Stepp have their way, La Crosse and the rest of Wisconsin will be the new Flint.


The La Crosse and Onalaska concentrations of around 1 ppb are well below the California 10 ppb limit. Someone writing the summary is numerically challenged. Let's not go crazy without understanding the risk.


You must work for one of the two cities. Anything that {can} cause cancer shouldn't be in our drinking water period that's why filters are made. When people turn their faucets on it should be clear clean fresh drinking water that gives no one concerns about drinking it.


ANd don't forget that Drumpf and many, many GOPers will do everything they can to dismantle regulatory agencies like the EPA which were created to protect the environment and "we, the people." The City of La Crosse needs to get this substance out of our drinking water since they now know about it. No excuses.

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