OAKLAND, Calif. (CN) – An industrial hygienist hired by Monsanto faced off Tuesday against the lead attorney for a couple claiming decades of Roundup use contributed significantly to them both developing non-Hodgkin lymphoma.
Dr. Robert Phalen, a specialist in various environmental hazards and pollutants, told jurors that glyphosate, the main chemical compound in Roundup, is not readily absorbed into the skin. He explained that glyphosate is hydrophilic, or, attracted to water, to which the skin acts as an exceptional barrier.
While he said Roundup is 96 percent water, the rest of the formula comprises 2% glyphosate and 2% surfactant, the compound that helps the glyphosate stick to plants to be absorbed. The mixture also includes “trace impurities” like formaldehyde, which are so small as to be rendered nonhazardous and are even produced naturally in the human body, he said.
“Human skin is waxy and oily. If glyphosate or Roundup gets on the skin, it’s not going to absorb a water-based product like a sponge,” Phalen said. “Very low amounts are going to get through to the skin.”
Any glyphosate that is absorbed, Phalen testified, “is going to be excreted rapidly in the urine.”
He also said Roundup has a “low hazard and low toxicity profile,” and the bottle can be safely handled without gloves, which he did when he visited the home of Alva and Alberta Pilliod in Livermore, California. The Pilliods sued Monsanto after the cancer research arm of the World Health Organization declared glyphosate a probable human carcinogen in 2015.
Alva developed non-Hodgkin lymphoma in 2011, and Alberta was diagnosed in in 2015.
“I know it’s safe,” Phalen said of the product. “I handled it in accordance with the label and that’s what I recommend.” Phalen said he trusted the U.S. Environmental Protection Agency’s assessment of glyphosate as safe. “I’m confident there’s no hazard there,” he said.
His testimony coincided with the EPA releasing its most updated review of glyphosate Tuesday, again finding the most widely used herbicide in the U.S. poses no human health risks.
Brent Wisner, the Pilliods’ attorney, sparred with Phalen on cross-examination over how much glyphosate the couple could have absorbed over the years. Phalen calculated that the highest possible dose Alva could have absorbed was 0.044 milligrams, likening it to 1/95,000 of a teaspoon of sugar. Alberta, he said, was exposed to 0.036 milligrams, equivalent to 1/115,000 of a teaspoon.
Considering the amount of clothing they wore at the time they were spraying Roundup, Phalen based his exposure calculation on how much and how fast glyphosate went through their skin, something he called the “flux,” multiplied by the surface area of skin exposed. Phalen said he used the EPA’s guidelines for exposure assessment, along with industry guidelines promulgated by the American Industrial Hygiene Association.
Wisner challenged Phalen’s calculation, saying he had excluded exposure of body parts other than the hands and legs.
The attorney also attacked Phalen’s testimony on dermal absorption and the studies he used to support his contention that glyphosate is quickly excreted from the body through urine.
Phalen relied heavily on a 1990 study headed by Ronald Wester in drawing his conclusions about how glyphosate penetrates and remains in the skin. The study applied Roundup patches to the bellies of rhesus monkeys, then looked at how much glyphosate was excreted over seven days. The study determined that Roundup did not bind to the skin and could be removed with soap and water.
Wisner assailed the study for ignoring how much glyphosate was excreted through feces, a point that his expert, toxicologist Dr. William Sawyer, made earlier in the trial. Sawyer noted in his testimony that concentrating solely on urine excretion and not feces underestimates how much of the chemical has actually been absorbed in the body.
Wisner also mentioned another series of Monsanto-commissioned studies conducted between 2012 and 2017 by a contract lab called DTL. Those studies looked at the rate of glyphosate absorption on cadaver skin. Sawyer had testified the skin was “cooked,” or heated to 140 degrees Fahrenheit and then frozen prior to testing. The studies consequently showed a dermal absorption rate of almost zero.
When Wisner asked Phalen if he “knew they cooked” the skin samples, Phelan said “I would disagree with the cooking,” noting the lab heated the skin for 45 seconds.
“Isn’t it interesting that the exposures that were observed prior to DTL were much higher than later on?” Wisner asked.
Phalen said he wasn’t sure what Wisner meant.
Wisner also asked Phalen about protective clothing, and whether wearing chemical-resistant gloves or apron would reduce exposure.
“That makes sense,” Phalen said, but he noted that he wouldn’t recommend that the average Roundup use don a chemical suit, since those are meant for use by licensed professional applicators. “If there’s no hazard,” he said, “why would we put someone in a chemical suit? It’s actually quite dangerous.”
Monsanto is expected to wrap up its testimony on Monday.