Is there a safety margin built into the standards?

EMF standards FAQ

Is there a safety margin built into the standards?

Yes. A safety margin is built into the limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). ICNIRP applies a safety factor of 10 to derive EMF worker exposure limits, and a factor of 50 to obtain the guideline value for the general public.

The reduction factor is designed to account for any scientific uncertainties.

Source: 
1.  ICNIRP Guidelines - 1998 p.511, tables 6 and 7; see section 16.2. Reference Levels. 
2. ICNIRP presentation: EMF Safety Guidelines - The ICNIRP View presented at the ITU Workshop on Human Exposure to Electromagnetic Fields, Turin, 9 May 2013.