Over 11,000 cases have been filed against Monsanto—and now its parent company, Bayer AG—alleging that Roundup, Monsanto’s glyphosate weed-killer, causes cancer. This case, with Edwin Hardeman as plaintiff, is only the second to go to trial. But as in the first case, the court sided with the plaintiff.

Monsanto developed glyphosate, which it sells under the brand name Roundup, in the 1970s, and since then it has become the world’s most popular herbicide. (The company doesn’t release specific sales numbers, but this much is known.) The most important development in its connection to cancer happened in 2015, when the World Health Organization labeled it a “probable” carcinogen. Studies have variously indicated that it does and does not cause cancer; the science is muddled as much of the research is industry-funded (or comes directly from Monsanto itself), and the industry obviously has a vested interest in findings that mark glyphosate as clean.

Last summer, the first case on whether glyphosate causes cancer went to court; initially, a jury awarded the plaintiff, a school groundskeeper, $289 million, though that was later reduced to $78 million, and Monsanto/Bayer is still appealing that verdict.

In this case, Hardeman, who used Roundup consistently on his property for decades, finds himself in a two-part trial. The first part, which just concluded, aimed to decide whether glyphosate caused Hardeman’s cancer, and whether Monsanto misled him, and the public, about the safety risks of the product. In a unanimous verdict, a six-person jury decided that glyphosate was a “substantial factor” in Hardeman’s cancer, according to the New York Times.

The second part of the trial, beginning Wednesday, will decide the possible liability of Monsanto, whether the company knowingly downplayed the connection between glyphosate and cancer in order to sell more product.

In response to the verdict, reports Reuters, Bayer’s shares took their biggest drop in 16 years, reducing the company’s valuation by a whopping $9.1 billion.

We’ve reached out to Monsanto for a statement and will update if they respond.