Severity and frequency of industrial accidents are typically used to assess the “absolute” risk associated with the industrial machines and devices (“items”) which are subject to safety certification or self-declaration of conformity. However, the “relative” risk associated with a particular item can further be assessed based on unit severity and unit frequency where the total number of item in use is taken into account. This study first attempts to estimate the total number of each item in use which was recently selected for safety certification or self-declaration of conformity. The appropriateness of such selection is recapitulated based on the relative risk involved. Analysis results indicate that depending on items, the relative risk is differentiated from the absolute risk. Recent selection of items for safety certification or self-declaration of conformity is then revisited for its validity. The relative risk based on unit severity and unit frequency of industrial accidents, together with the absolute risk, may be used to further categorize items for safety certification or self-declaration of conformity in the future.