“…Occupational health professionals have stated that chemicals and mental load factors were the most difficult areas to assess (Lehtola, 2005; Pääkkönen, Rantanen, Jokitulppo, & Palmroos, 2003; Rantanen & Pääkkönen, 2000; Vainio et al, 2005). Many other studies have noted that even experts have difficulty in assessing the exposure of risks and the estimation between homogenous groups varies extensively (Mäkinen, 2003; Mäkinen, Hämäläinen, Forsman, & Liesivuori, 2002; Rappaport, Kromhout, & Symanski, 1993; Vainio et al, 2005).…”