How dangerous is it to consumer 100% CPU for extended periods of time?

I'm writing some simulation software that consistently consumes 100% CPU. HW Monitor and Speccy report a temperature of 53C after running it for around 10 minutes. The fans are very loud as well.

I have the FX-8320 8-core AMD processor using cooling system I got with it (not the greatest I'd imagine).

How dangerous is it to run at such loads on a CPU for extended periods of time? I ran it for about 20 minutes and everything was fine, but I was quite anxious the whole time (fans being very loud and most other processes grinding to a halt). What about one hour? 5 hours? A day? What if this was done consistently for a couple of hours each day?

Can it also wear the vents off? At least that can be inexpensively replaced, though.

don't let it get above 70c and its not

It's a CPU it does its job, as long as its on stock voltage it should be fine. If for some odd reason you feel like removing the heat sink the CPU will hit is heat threshold and will automatically shut down the computer in order to prevent any damage to the CPU. You could probably run it for months at 100% load as long as you have adequate cooling.

Most people say 60c for CPU's.

But people with higher end motherboard and cooling solutions would be the 70c mark.

But, I've seen people with higher end stuff and they still rather keep it at 60c or lower.

I know it's a preference thing, but in regards to OP... the lower the better especially for the full life of the CPU. 

I thought it was obvious I was concerned about temperature and fans... E.g. cooling paste wearing off at much faster rates when at 100% than 1% and such effects.

thermal paste doesn't "wear out". it does loose it's effectiveness after a loooong time, but the heat applied is not going to make a difference. actually, some paste, like AS5, requires several heating/cooling cycles to cure