ICNIRP is the International Commission on Non-Ionizing Radiation Protection. Among other activities, they produce exposure guidelines. Their 1998 exposure guidelines form the basis of the limits in place in the UK. They published new guidelines for the frequency range 1 Hz - 100 kHz in the December 2010 issue of Health Physics.
See full details of the 2010 guidelines
ICNIRP have also published a factsheet on the new guidelines.
