I appreciate that this post is way off topic, but given the wealth of knowledge available here I thought I would post my question.

Yesterday whilst going for a walk at a local beauty spot, I came across a portable amateur radio station that had a Buddipole setup approximately 12 ft off the ground and TXing on 20m using 500 watts !!!.
I was shocked that this guy was using so much power with so many people in close proximity, and said so. I got a very short unpleasant answer.

I have been trying to find information on what is the recommended "safe" distance
for operators ( public ) when using a portable / mobile station. Can anyone help with this please ?

Regards to all

Stephen