Comparing the safety margins in the European indicative occupational exposure limits and the derived no-effect levels under reach

Abstract

The new European Union (EU) REACH legislation requires Derived No-Effect Levels (DNEL) to be calculated for substances produced in quantities above 10 tonnes/year. Workers are one population that these DNELs are to protect. Meanwhile, the setting of occupational exposure limits (OEL) continues both at the member state and the EU level. Health-based OELs are proposed by the Commission's Scientific Committee on OELs (SCOEL) and eventually result in Indicative OEL Values (IOELV) in EU Directives. According to REACH, IOELVs may under some circumstances be used as worker-DNELs. On the other hand, worker-DNELs will be derived for several thousand substances, far more than the roughly 100 substances for which IOELVs have been established. Thus, the procedure to set health-based OELs may become influential on that of DNELs and vice versa. This study presents a comparison of the safety margins of 88 SCOEL recommendations with those of the corresponding worker-DNELs, derived according to the REACH guidance document. Overall, the REACH safety margins were approximately six times higher than those derived from the SCOEL documentation but varied widely with REACH/SCOEL ratios ranging by two orders of magnitude, from 0.3 to 58. It was also found that the REACH guidance document, although encompassing detailed advice on many issues, including default assessment factors for species and route extrapolation, gives no quantitative guidance on when and how to depart from defaults.