The FCC has issued orders that each Amateur Radio Station evaluate the amount of RF exposure to people that can result from your station's operation. The start date for this regulation has been changed several times but must be done starting September 1, 2000 for all stations.
Stations running less than 50 watts (RMS) output are generally considered to be in compliance but if you take the time to use the exposure calculator from the University of Texas at http://n5xu.ae.utexas.edu/rfsafety/ you can be much more certain of your compliance. I recommend that you use the calculator and enter the results into your Station Log. Should you ever be questioned, you have proof that you did your evaluation (the "olde" Blue paranoia).
A full discussion of this topic is available at http://www.arrl.org/news/rfsafety/ from the ARRL.