The active ingredient in Roundup, one of the world’s most popular weed killers — and the most commonly used one in the United States — has been declared a “probable carcinogen” by the World Health Organization. The International Agency for Research on Cancer, an arm of the WHO, released the results of its review of five herbicides and pesticides on Friday.

The French-based agency ranks cancer-causing agents on four levels: known carcinogens, probably or possible carcinogens, not classifiable and probably not carcinogenic. The herbicide glyphosate, the active ingredient in Roundup, was classified by IARC as “probably carcinogenic to humans.”

But the classification is not binding, said the IARC. “It remains the responsibility of individual governments and other international organizations to recommend regulations, legislation or public health intervention,” the agency said in a statement. According to the Associated Press, the United States Environmental Protection Agency said it would consider the IARC’s evaluation.

The IARC did clarify that the new ruling is mostly directed at the industrial use of the herbicide, and that use by home gardeners does not fall under the same classification. Glyphosate is employed in more than 750 herbicide products and has been detected in the air, during spraying […]