 Yeah, so if you look at the weed killers or like the AFFF or PFOAs, which is what is at issue with the firefighters, it really starts with population-based epidemiological studies, which show the trends and association between products and injuries. And then experts, and they're highly skilled experts. Some of them are based in professors. Some are in the commercial industry. And they're looking at what we call Bradford Hill criteria. And so they look at the overall picture of the science.