Erin Brockovich

By George Johnson | March 21, 2013 1:17 pm

Julia Roberts as Erin Brockovich

This week in a piece for Slate about cancer clusters, like the one made famous by the movie Erin Brockovich, I describe how they almost always turn out to be illusions — examples of what the epidemiologist Seymour Grufferman called “the Texas sharpshooter effect.” Here is how I described it in my article: Stand way back and blast the side of a barn with a shotgun and then find some holes that are crowded together. Draw a circle around them and you have what looks like a bull’s-eye.

The pollution that was blamed for the malignancies may be very real — the Brockovich case involved a metal called hexavalent chromium or chromium 6 that had been discharged during the 1950s and 60s into the drinking water of Hinkley, a small town in the Mojave Desert. The people who lived there were naturally afraid of what the chemical might be doing to their health. But long after the movie was gone from the theaters and the residents and their lawyers had received a $300 million settlement, a 12-year epidemiological study was completed. No elevation of cancer was found.

You wouldn’t know that from a story that ran last week on PBS NewsHour. It opens with a visit to Hinkley by science correspondent Miles O’Brien. He tours the town with a local resident, who points out houses that were bought from homeowners by Pacific Gas & Electric and vacated after the utility conceded that cooling water from a nearby gas pipeline station had leached into the aquifer, contaminating it with chromium 6. “The chemical is toxic,” O’Brien tells us, “and causes cancer.”

Then, with no further explanation, the report cuts to a clip from the movie with Julia Roberts (as Brockovich) filling test tubes from a Hinkley irrigation ditch and pulling a dead frog from a dirty puddle in a mostly evaporated swimming pool.

Chromium 6 has indeed been shown to be a carcinogen when inhaled by workers in industry. (One of its many uses is as an anti-corrosive coating for metals.) Less certain is whether the chemical has the same effect on people when it is dissolved in water, even at the levels in Hinkley. I will be writing more about these details in a later post.

The second part of O’Brien’s story goes go on to describe some of these specifics and gives updates on the most recent research about whether aqueous chromium 6, which occurs at various levels throughout the world, is a human carcinogen. There is a lot of good reporting here about how corporate scientists can influence the regulatory process. But throughout all this viewers are left with the impression that there was a cancer cluster in Hinkley, and that was misleading — cruelly so to the people who live there.

Erin Brockovich, part 2

CATEGORIZED UNDER: Cancer, select, top-posts
  • Robert Ford

    Unbelievable! great post, George.

  • Buddy199

    This is what Stephen Colbert means when he refers to “truthiness”.

  • Dr. Lane

    Great information George – we should go further and put this theory to the test! What do you say you drink a glass of chromium 6 dissolved in water daily for 12 years and report back. I suggest a 1:1 ratio just to prove how harmless it is and how misleading it was to Hinkley. We need more reporters like you willing to put their health and well-being on the line to expose the truth to the people.

    • Matthew Slyfield

      Dr. Lane,

      If you are actually a medical doctor you should be aware of the principle that the dose makes the poison. Even water can be toxic in high enough doses.

      • Dr. Lane

        Yes, Chromiumm 6 is as safe as water – that is what you are alluding to, right? Either ban water as dangerous (“toxic in high enough doses”) or make declare chromium 6 as safe. I think a true trailblazer like George Johnson should go right ahead and drink a 1:1 dose of water and chromium every day for 12 years. Wait! Water might be unsafe, right Matthew? Just straight chromium 6, how about 1 oz. every day for 12 years. Let’s work together to set the public straight!!

        • Matthew Slyfield

          No, you are reading my comment bass ackwards and your entire premiss is absurd.

          Even if chromium is toxic and 1 oz every day for 12 years, that does not mean that it is toxic at the levels it existed at in the Hinkley water supply.

          The dose makes the poison. Just because it is toxic at a high dose does not mean it isn’t safe at lower doses.

          • Susan Kirk

            I still don’t understand that (the dose is the poison) and I don’t think anyone does, even the toxicologists. It just doesn’t seem right to not consider accumulation within the body and also look at reproductivity toxicity. We are only just starting to understand the pathways within the human body that can be affected by toxins. Plus we are not doing tests on human cells we are using animals. Tell me what regulator does testing based on any new paradigm (including understanding how to assay for toxicity pathways) using human cells? Or any long term studies (animal if need be) on any of the chemicals flooding the marketplace. We need to take more responsibility here.

          • Matthew Slyfield

            The statement is a basic principle of toxicology. It does consider accumulation within the body. Not all toxins will accumulate. Do you have any evidence that chromium accumulates in the body? For substances that can build up in the body you would look at lifetime exposure as the dose.

            As to reproductive toxicity you will have to explain exactly what you mean by that.

            “Plus we are not doing tests on human cells we are using animals.” There is a reason for that. For animals larger than a single cell, body size affects the toxic dose. Toxicologists always refer to toxic doses in terms of quantity per unity body weight. The response to a complete human to a potential toxin might be completely different than the response of a single cell even at a comparable per weight dose.

            “Or any long term studies (animal if need be) on any of the chemicals flooding the marketplace. We need to take more responsibility here.”

            If there is no evidence of toxicity in the general population how is it being responsible to undertake potentially very expensive studies. Despite our “chemical flooded” environment people live longer today than they ever did in the past. If there are so many chemicals out there that are unreasonably dangerous, where are the bodies? If you believe some of the environmental groups out there we should be knee deep in bodies.

            Of course the market is flooded with chemicals. Our bodies, every plant, every animal, every inanimate object you can touch, the very air that surrounds us is made up entirely of chemicals. Without chemicals there would be no life at all.

        • Mark Proeger

          I think your sarcasm in place of a good argument is a bit disappointing. If 300 million was given away and 12 years later there is no elevated cancer, nothing good happened. You can jump on Matthew all you want, but you are still failing to make a reasonable counter point to his very reasonable original point.

  • Renee

    IDK whether it’s carcinogenic or not, but do you really want it added to the streams? Even if it doesn’t cause cancer, what good is it doing the fish and wildlife to let that stuff out into the water willy nilly? Shouldn’t companies have to control their airborne and water effluents, and not put them into the environment we all breathe and live in? If you want an example btw of what it looks like when companies can put any old thing out in their effluents that they want, visit Shanghai. You have to wear a gas mask to go outside there these days, according to an article I read last week. Is that what we want in America?

    • SnorbertZangox

      So Renee, what do you think of the concept of fairness that PG&E should be required to pay the amount of money required to compensate those harmed for the actual damages that accrued? Compare that concept to what I have heard actually happened, PG&E paid about $300 million; each putatively damaged citizen got about $10,000; Erin and her co-conspirators took the rest. PG&E customers repaid the utility.

      Who was helped? Is that what you want for America?

  • gofer1

    Fluoride is a deadly poison, yet it is added to the drinking water when it’s not needed at all. Fluoride is added to toothpaste so it’s totally unnecessary to add to water anymore.

  • harkin

    So PBS cooked up a flawed-premised anti-corporate tirade??? I’m shocked….shocked!

  • Joseph K. Del Valle

    This is an example of 20/20 hindsight for both the activists and the power company. What is not said is what information was available to the parties to the settlement. It seems that, without knowing more, but bearing in mind the presumptive pockets of the power company, information of this kind was not available at the time. Thus, we have to judge the merits of the settlement given the information that WAS available at the time. This blog (though a good assessment of the current science on Chromium 6) offers nothing about the “Erin Brokovich” case.


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About George Johnson

George Johnson writes about science for the New York Times, National Geographic Magazine, Slate, and other publications. His nine books include The Cancer Chronicles: Unlocking Medicine's Deepest Mystery (August 2013), The Ten Most Beautiful Experiments, A Shortcut Through Time, and Fire in the Mind. He is a winner of the AAAS Science Journalism Award and has twice been a finalist for the Royal Society science book prize. Co-founder and director of the Santa Fe Science Writing Workshop, he can be found on the Web at Twitter @byGeorgeJohnson.


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