Monsanto's controversial Roundup herbicide is the world's top-selling weed killer. But tens of billions of dollars in sales and profits are at stake because of questions about the safety of glyphosate, the product's key ingredient.

Does Roundup cause cancer? Is it linked to cases of non-Hodgkin Lymphoma? Are GMO crops allies or enemies in the fight for a more sustainable environment?

More than 11,200 lawsuits have been filed, claiming that Roundup causes cancer. A major trial is now underway in federal court in San Francisco. A 70-year-old California man alleges that he got sick because he used Roundup on his property for many years. The trial is hearing a range of opinions.

This episode features former Reuters correspondent, investigative journalist, and advocate Carey Gillam-- the author of “Whitewash —The Story of a Weedkiller, Cancer and the Corruption of Science.” Carey's book won the Rachel Carson book award from the Society of Environmental Journalists.

We report on the rates of non-Hodgkin lymphoma cases in recent years, and examine calls for transparency, the need for independent, rigorous science, and why European regulators take a different view of pesticides and food safety than U.S. authorities.