In 2012 the French Professor Gilles-Eric Seralini published his famous toxicity study, which showed how rats fed on a diet containing NK603 Roundup tolerant GM maize or given water containing Roundup, at levels permitted in drinking water and GM crops in the U.S., suffered severe liver and kidney damage.
This was not the first independent study showing the possible damage being caused to health by glyphosate-based herbicide but it was the most high profile long-term study.