Depending on your station setup, you may be required to perform an exposure evaluation per FCC Part 97 Rules. For example, you’re required to perform an evaluation if PEP power delivered into your antenna is over 50W on 2, 6, or 10m, over 75W on 12m, or over 100W on 15m. Many amateur radio operators will never need to perform an evaluation, but it’s good to know when and why we might need to.
Here’s a link that provides great information and lots of links to get you caught up on what you need to know:
http://www.arrl.org/fcc-rf-exposure-regulations-the-station-evaluation
You’ll find a table listing power levels above which you will be required to perform an evaluation, and more information on RF safety in links from that page. Make sure you read and understand these rules before pushing the power!