On January 27, a judge tentatively ruled that the state of California can require Monsanto to label its blockbuster herbicide Roundup as a possible cancer threat, despite Monsanto’s insistence that it’s completely safe for humans. 
If California goes forward with the proposal, it will be the first U.S. state to order such labeling.
Monsanto, along with a citrus-grower group, had sued the state, arguing that California officials illegally based their decision to label Roundup on the WHO’s International Agency for Research on Cancer (IARC) 2015 warning that glyphosate, the main ingredient in the herbicide, is a possible human carcinogen. , 
Trent Norris, an attorney for Monsanto, said that labeling bottles of Roundup would have immediate financial implications for the biotech giant, because many people would see the warning and stop buying the product. He said:
“It will absolutely be used in ways that will harm Monsanto.” 
As of May 2016, Monsanto ranked #420 on Forbes’ Global 2000 list, with a market cap of $41.1 billion, and sales of $13.68 billion.
The company said in a statement that it will challenge the tentative ruling.
Roundup is sold in 160 countries and is not restricted by the U.S. EPA, which says it has “low toxicity.” The agency only recommends that people avoid entering a field for 12 hours after it has been applied.
Shortly after the IARC warned that glyphosate could cause cancer, California took its first step in requiring the warning label.
Monsanto says that California is delegating its authority to an unelected foreign body with no accountability to U.S. or state officials in violation of the California Constitution. But according to court papers, attorneys for California consider the IARC the “gold standard” for identifying carcinogens, so they rely on its findings, as do several other states, the federal government, and other countries.
A formal decision on the label has not been issued by Fresno County Superior Court Judge Kristi Kapetan, but she says it’s coming soon. Sam Delson, a spokesman for the state Office of Environmental Health Hazard Assessment, said the state will wait for the formal decision before moving forward with the label. After that, Monsanto will have a year to affix the label to Roundup.
 Associated Press
 SF Gate