We have a nice stand of poison Hemlock. Thankfully I'm not sensitive to touching it. I've mowed it before, but I try to do it when the air is moving or at least limit my exposure. This year it's a fraction of what it was, but we've still got plenty. I don't think I've used weed killer in my life, but this is one plant that had me thinking about it. If there were ever a reason to pull out the weed killer, this plant would be it.

That said I'm not 100% sure this is poison hemlock in the pics. I can't recall how to tell it from look alikes.