I was exposed to the stuff they spray with last year. I think I would like to see a MSDS on it. In my previous career, I worked for a company that was very particular about safety and worker exposure to chemicals. If someone wanted it, we were REQUIRED to give them a MSDS for what we used.
If it is the same stuff as some popular weed killer, there is growing evidence that it is a carcinogen. I know when I saw them spraying, the stream of poison went so far that it would have been impossible to be selective about what they killed. In this particular lake, it did not kill the underwater hydrilla though - just the stuff on top. I have seen them spray a few times and fished a few weeks afterwards. My experience is that the underwater stuff was not killed but the cabbage and reeds and stuff out of the water was dead. If it is a cancer causing chemical, the MSDS would tell you.