Q:

Can ESP32 radiation cause health hazards?

I am using ESP32 chips for a smart health monitoring device.
I will use WiFi 802.11n or Bluetooth BLE/EDR depending on the amount of data to be transferred, so the unit will be mounted on hand, maybe another place of the body.
It can be:

upper back middle
lower back middle
front upper- chest
wrist
arm below the shoulder

I could not find any resources for health risks of ESP32 radiation.
Is there any possibility of getting cancer or any other health issues due to Bluetooth or WiFi radiation of the ESP32? 

A:

Normal RF communications protocols all use non-ionizing radiation, which does not have any serious health concerns. In the worst case, it can heat your body up slightly (like a microwave oven, but at an incredibly low power level compared to the oven. If these were dangerous, we'd all be getting horribly maimed by our phones and laptops.
With that said, because water absorbs 2.4GHz (and thus causes the aforementioned heating), you aren't going to get good signal out if you plan on implanting such a device.
Chart from https://en.wikipedia.org/wiki/Non-ionizing_radiation:

