Roundup, one of the most powerful herbicides on the market, has an ingredient that causes cancer. California recently added glyphosate, one of the key ingredients in Roundup, to a list of chemicals classified as carcinogens. Soon, the state may require warnings that advise consumers accordingly.

As CNN reported last month, more than 800 non-Hodgkin’s lymphoma patients are suing Monsanto, claiming Roundup gave them cancer.

California keeps a list of carcinogenic chemicals because of a law commonly called Proposition 65, which “requires businesses to provide warnings to Californians about significant exposures to chemicals that cause cancer, birth defects or other reproductive harm.”

The decision to add glyphosate to that list stemmed from the International Agency for Research on Cancer’s assessment that glyphosate is “probably carcinogenic to humans,” said Sam Delson, deputy director of OEHHA.

Monsanto, the maker of Roundup is challenging the determination. They recently sued California to prevent the addition of glyphosate to the list, but the California Supreme Court rejected the challenge – allowing the chemical to be added. California is flying in the face of international opposition, with multiple studies concluding that glyphosate is not a carcinogen.

The determination will have wide ranging impacts, and other states could follow suit. While there is still dispute over glyphosate, it is important to be aware of potential chemical impacts before using products.