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The Journal Gazette

  • Cathie Rowand | The Journal Gazette Columnist Christer Watson

Tuesday, June 04, 2019 1:00 am

Let science, not courts, judge chemical safety

Christer Watson

In the past year, three lawsuits have been decided about the most common herbicide in the world. The chemical involved is glyphosate, although it is often sold with the name Roundup.

In all three cases, the juries decided that Roundup had caused a person's cancer. The suit decided last month involved the highest award, $2 billion. The two previous awards were for $289 million and $80 million.

These cases are a big deal. They are also a pretty terrible way to decide how we, as a country, will treat our environment.

If glyphosate is dangerous, we shouldn't use it at all or in limited situations. If glyphosate is not dangerous, we should be more permissive. The best way to decide where on the spectrum glyphosate should be is not through a jury system. The best way is through careful studies that can be reviewed by the appropriate scientific community.

Unfortunately, the jury system and the scientific community appear to be making different choices.

Glyphosate accounts for roughly 25% of all herbicides used worldwide. A lot of people use it on a regular basis. All three cases involve the same form of cancer, non-Hodgkin's lymphoma.

This type of cancer involves a person's immune system. The plaintiffs in all three cases are terminally ill and had extensive exposure to the herbicide. For example, the first case involved Dewayne Johnson. He was a school groundskeeper who used it frequently as part of his job.

A significant fraction of non-Hodgkin's lymphoma cases do not have a known cause. If there is a cause of these cancers, either environmental, genetic or something else, we should continue to work hard to find it.

Unfortunately, the scientific process has not yet been terribly clear here. In 2015, the World Health Organization's International Agency for Research on Cancer issued a report about glyphosate. The organization reported that glyphosate was a “probable carcinogen.”

That label is actually more ambiguous than a typical reader might think. There is some evidence that glyphosate can break DNA, which is one step in causing cancer. Several steps are necessary, however. As context, this organization has used the same term to describe very hot drinks and red meat.

The company, Monsanto, that makes glyphosate has also done itself no favors. For example, the company has funded reports on glyphosate, then hidden that fact from journal publishers. In another situation, company employees wrote a paper, then paid outside scientists to pretend they were the authors.

Such behavior is reprehensible and should be punished. It does not, however, mean that glyphosate causes cancer.

Several national health organizations have been heavily researching this issue, both before and after the 2015 report. For example, the U.S. government's National Cancer Institute funded a study published in 2018 that looked for evidence of a connection between glyphosate and several different types of cancer.

The 2018 study used data from the Agricultural Health Study, which is a long-term study of the health of farmers and their spouses. There were about 57,000 people in the study, all from Iowa and North Carolina. All participants were licensed to use restricted-use pesticides. The study started in 1993, with follow-up several years later.

The farmers and their spouses were asked extensive questions about which pesticides they used. A record of cancer diagnoses are available from both states as well. By comparing these two data sets, the scientists hope to identify potential sources of cancer.

They found there was no statistical relationship between non-Hodgkin's lymphoma and glyphosate use. Even heavy users showed no effect. The scientists also analyzed 49 other types of cancer. There were no statistically significant correlations.

There was weak evidence of a link to acute myeloid leukemia among the very highest users of glyphosate. Weak evidence, in this situation, means that it might be a random fluke, like getting 4 heads in a row on a coin toss. The standard response to this result should be a heavier, more involved study to see whether the connection disappears with better numbers or is real.

As a result of previous studies with similar results, the U.S. Environmental Protection Agency wrote an interim decision that glyphosate, when used correctly, does not cause non-Hodgkin's lymphoma. European agencies have made similar rulings.

That process was well done, and we should rely on it. If we instead use juries to decide the issue, we might end up basically banning, through financial punishment, a useful herbicide without strong evidence.

Christer Watson, of Fort Wayne, is a professor of physics at Manchester University. Opinions expressed are his own. He wrote this column for The Journal Gazette, where his columns normally appear the first and third Tuesday of each month.