Here is a real world exmple for you PA. Last year I was setup in a ground blind next to a stream crossing. I was using my Thermacell so I didn't get eaten alive. I could smell a slight butane odor and was worried about it. A doe walked 12 yards in front of me and didn't spook. That's enough proof for me. Plus this thing is worth spooking a few deer if it keeps you from having to move all the time swatting at skeeters. I have never had a problem with it in my tree stand either.