Yes, it is as safe as cellphones. In fact, our smart data loggers use cellphone SIM cards and comply with international health and safety guidelines. They connect to the 3G network and transmit using radiofrequency waves. In order to conserve battery life, the smart loggers are only active when they are transmitting the data once a day.
The product has been tested and certified to be compliant to the Federal Communications Commission (FCC) for unlicensed transmissions: Radiated Emissions FCC 47CFR Part 15.109 Subpart B (2016), ICES-003 Issue 6 January 2016.
The peak instantaneous exposure measured in any direction from the meter was less than 2% of the publicly acceptable limit for most frequencies and less than 25% of the publicly acceptable limit in all cases.
For more information about cellphone technology, we recommend you speak to your cellphone provider.