Many years ago the TV show "60 Minutes" had an episode that looked at reports of very rare cancers in police officers when using the new "radar guns" to catch speeders, and attempts at covering up the scandal.
The devices arrived with the proper warnings, but supervisors removed the warning labels when officers expressed concerns about "potential cancers" etc...Motorcycle officers were found to take the "radar gun" when it was on (because turning it off, and then on again was cumbersome, and time-consuming), and placed it between their thighs, while plugged-in. Such officers had an unusually high incidence of testicular cancer, which is normally quite rare.
Another group that was involved were officers who mounted the radar gun inside a car on the ceiling, right next to the officer. In those cases, the officers suffered from eye-cancer, also a VERY rare affliction. However, it wasn't just eye cancer in general, it was specifically tumors of the right eye, and left eyes were almost completely free of any tumors. Since the right eyes of the afflicted officers were nearer to the radar guns, and the left eyes were farther away (from the drivers-seat), that fact played a major role in the officers union winning the case. Apparently, a distance of only a few inches is all it takes.
Improved shielding was introduced to help inattentive operators from accidentally using the devices in close enough proximity to cause any damage.
http://www.who.int/peh-emf/publications/facts/fs226/en/
Radars usually operate at radio frequencies (RF) between 300 MHz and 15 GHz. They generate EMFs that are called RF fields. RF fields within this part of the electromagnetic spectrum are known to interact differently with human body.
RF fields below 10 GHz (to 1 MHz) penetrate exposed tissues and produce heating due to energy absorption. The depth of penetration depends on the frequency of the field and is greater for lower frequencies. Absorption of RF fields in tissues is measured as a Specific Absorption Rate (SAR) within a given tissue mass. The unit of SAR is watts per kilogram (W/kg). SAR is the quantity used to measure the "dose" of RF fields between about 1 MHz and 10 GHz.
An SAR of at least 4 W/kg is needed to produce known adverse health effects in people exposed to RF fields in this frequency range.
RF fields above 10 GHz are absorbed at the skin surface, with very little of the energy penetrating into the underlying tissues. The basic dosimetric quantity for RF fields above 10 GHz is the intensityof the field measured as power density in watts per square metre (W/m2) or for weak fields in milliwatts per square metre (mW/m2) or microwatts per square metre (µW/m2).
Exposure to RF fields above 10 GHz at power densities over 1000 W/m2 are known to produce adverse health effects, such as eye cataracts and skin burns.
I never looked into bluetooth, but isn't it in the mega to gigahertz range too? 
