The agrochemical giant Monsanto has been ordered to pay $289 million to a former US school groundskeeper who was exposed frequently on the job to the Monsanto product Roundup, the most widely used herbicide in the world, and developed terminal cancer.
It’s a case that hinged on something neither side could definitively prove or disprove: the possibility of a causal relationship between Dewayne Johnson’s Roundup use and his subsequent illness.
As a pest-control manager for a school district in northern California from 2012 to 2016, Johnson used Roundup 20 to 30 times per year. He experienced two on-the-job accidents that doused him from head to toe with a product whose active ingredient, glyphosate, the World Health Organization classifies as a probable carcinogen.
In 2014, he was diagnosed with non-Hodgkins lymphoma, a disease that leaves vicious lesions on his skin. Johnson is now 46. His doctors expect he will die within six months. The physical agony of Johnson’s disease is undeniable, as is the hardship it has brought to his family. His wife now works two full-time jobs to support the couple and their two sons.
His case also reveals a difficult and important truth: It is nearly impossible to definitively determine the specific cause of any single case of cancer. In the absence of that certainty, juries and judges—like the ones that might review the 4,000-plus pending lawsuits against Monsanto by people who believe that Roundup caused their cancer—have to weigh questions of the responsibility makers and marketers of products that contain potentially harmful substances have to the people who use them.
The active ingredient in Roundup is glyphosate. In 2015, the year after Johnson’s diagnosis, the World Health Organization’s International Agency for Research on Cancer classified glyphosate as a Group 2A substance, meaning it is probably carcinogenic to humans. The category includes dozens of other industrial chemicals, as well as the emissions from high-temperature frying, the chemical exposure incurred in work as a hairdresser, and consumption of red meat.
Monsanto argued vociferously in court that there’s no scientific consensus on whether glyphosate causes cancer, which is correct. There are no studies definitively proving glyphosate causes cancer. The US Environmental Protection Agency maintains that the chemical is safe to use.
Whether Johnson had cancer because of his contact with Roundup is as impossible for his doctors or lawyers to irrefutably prove as it was for Monsanto’s to disprove. Instead, Johnson’s legal team had to convince the jury of two things: that Roundup could cause cancer, and that Monsanto failed to warn consumers about the product’s potential risk.
The lawyers produced internal emails showing that Monsanto executives downplayed research critical of glyphosate’s health effects and sought to quietly fund research in support of the product.
After the verdict, Monsanto Vice President Scott Partridge said in a statement that the company will “continue to vigorously defend this product, which has a 40-year history of safe use and continues to be a vital, effective, and safe tool for farmers and others.” Roundup’s future is less a question of whether it will remain on shelves—which it almost certainly will—than what it looks like when it does.
Plenty of known carcinogens are freely available for human consumption. In addition to hazards like radium, neutron radiation, and the human papilloma virus, the IARC’s list of Group 1 known human carcinogens includes alcoholic beverages, tobacco, and estrogen therapy. The last is particularly relevant as an indication of Roundup’s future.
While there is a well-established link between tobacco use and cancer, it is still not possible to say with certainty that any single case of cancer has been caused by the patient’s exposure to tobacco. Years after tobacco companies were ordered to pay billions for ignoring and suppressing evidence of their products’ link to cancer, it remains legal to make, sell, and buy tobacco products. The difference is that the product now comes with stricter sales regulations, higher taxes, and stronger, clearer warnings about the potential risks to users. And given what we know, it would be unethical to insist that people use tobacco regularly in the workplace as a requirement of their job.
Johnson’s case does not prove that Roundup causes cancer. But it is a declaration of a jury’s belief that individuals should not bear the health costs of the market’s unwillingness to find a safer alternative to potentially harmful products—and that companies who sell them have an obligation to be honest about the risks.