Monsanto told California regulators that they should withdraw their proposal to add the weedkiller glyphosate to a state list of chemicals known to cause cancer, said Reuters. The state Office of Environmental Health Hazard Assessment unveiled the plan in September and said it was required following an assessment by a World Health Organization agency that the chemical is a probable carcinogen in humans. Glyphosate is the most widely used weedkiller in the world. Many genetically engineered seed varieties were designed to tolerate it. In its filing, Monsanto said many safety officials worldwide regard glyphosate as safe, contrary to the finding by the International Agency for Research in Cancer. Some 8,000 comments were filed with the state agency, said Reuters.