Since the various industrial accidents have been occurring because of increasing of industrial production and complication of a production system, the demand to introduce the safety system is increasing greatly. In the light of the above background, development of new EMC standard for safety systems is advanced in IEC. This standard is intended to quantify occurrence probability of the dangerous condition resulting from EMC and to provide EMC requirements for the IEC standards of the functional safety. In this paper, we discussed the basic EMC concept for safety systems and the requirement of immunity level in the new IEC standard.