Unless you believe in the literal interpretation of the Bible and the "6,000 years" stuff, human evolution took place over a very long time adjusting to the normal levels of radiation present.

Dumping many times this level of man made radiation on top of that - well, scientific tests haven't yet come up with absolutely definite agreement on everything about the increased level - although I personally know of Aussie F111 fitters who walked in front of the radar while testing and got pretty sick - but common sense indicates that a degree of caution would not go astray.