The FCC does set recommended exposure levels for RF radiation. At cellular frequencies (800 MHz band), the recommended maximum exposure for the general public is 580 microwatts per square centimeter (µW/cm2).
If you work around this equipment, you should be familiar with the exposure guidelines. A good overview is available right on the FCC's own website:
http://www.fcc.gov/oet/rfsafety/cellpcs.html
