Earlier this month, the World Health Organization's International Agency for Research on Cancer announced findings that glyphosate, the main ingredient in Monsanto's RoundUp line of pesticides, is probably carcinogenic to humans." The research, published in The Lancet Oncology, relies on studies conducted on the chemical over the last few decades. Use of glyphosate - which the EPA has deemed safe - has soared in the last two decades with the introduction of crops genetically engineered to withstand the herbicide. Glyphosate is also a main ingredient in a new product called "Enlist Duo" recently introduced by Dow Chemical. Widespread use of the chemical has also come under fire because weeds are becoming increasingly resistant to it. Dow has marketed its new product ... as a new tool for farmers battling herbicide-resistant weeds. But agriculture experts say farmers should look at other ways to manage weeds, like cover-cropping, increased rotation and mechanical removal. This week, environmental groups sent a letter to the EPA renewing their calls for the agency to reconsider its decision to approve Enlist Duo. The groups also called on the EPA to reexamine its findings that glyphosate is safe. Monsanto has come out swinging. In a press release, Chief Technology Officer Dr. Robb Fraley said the company is "outraged". Monsanto has demanded a retraction of the report.