LONDON—A long-term study on the use of the weed killer, glyphosate, by U.S. agricultural workers has found no firm link between exposure to the pesticide and cancer.

Published in the Journal of the National Cancer Institute, the study found there was no association between glyphosate, the main ingredient in Monsanto’s popular herbicide RoundUp, “and any solid tumors or lymphoid malignancies overall, including non-Hodgkin Lymphoma and its subtypes.”

The research is part of a large project known as the Agricultural Health Study, which has tracked the health of 10,000 agricultural workers, farmers and their families in Iowa and North Carolina.

Since the early 1990s, the study has gathered and analyzed detailed information on the health of participants and their families and their use of pesticides, including glyphosate.

“It’s encouraging that the Agricultural Health Study is examining potential health effects of pesticides among actual pesticide applicators,” noted Tony Banks, a commodity marketing specialist for Virginia Farm Bureau Federation. “Study results from computer simulations and lab rats along with use of the precautionary principles tend to raise more questions than answers. These study results are good news for glyphosate applicators.”

David Spiegelhalter, a professor of the public understanding of risk at Britain’s Cambridge University, which has no link to the research, said the findings were from a “large and careful study” and showed “no significant relationship between glyphosate use and any cancer.”

In a summary of the results, the researchers said that among 54,251 pesticide applicators studied 44,932, or 82.9 percent, used glyphosate.

“Glyphosate was not statistically significantly associated with cancer at any site,” the summary said.

Scott Partridge, Monsanto’s vice president of strategy, said the study results clearly showed the weed killer is safe.

“This is the largest study of agricultural workers in history, over the longest period of time,” he told Reuters. “It is the gold standard ... and it definitively demonstrates in a real-world environment that glyphosate doesn’t cause cancer.”

Media: Contact Banks at 804-290-1114.