You can get details regarding the Federal Communication Commission Radio Frequency Exposure Guidelines at http://www.fcc.gov/encyclopedia/radio-frequency-safety. Additional information may also be found in the user guide that came with the phone. If you no longer have your user guide, most are available by searching on the support page of the mycricket.com website, or on the manufacturer’s website.
Wireless phones emit radio frequency energy during use. The Food and Drug Administration ("FDA") and the Federal Communications Commission ("FCC") regulate wireless phone safety. The FDA and the FCC have created a joint website, "Cell Phone Facts - Consumer Information on Wireless Phones," which states that "[t]he available scientific evidence does not show that any health problems are associated with using wireless phones," while noting that "[t]here is no proof, however, that wireless phones are absolutely safe."