02/17/2006

Margins of Safety Provided by COSHH Essentials and the ILO Chemical Control Toolkit

COSHH Essentials, developed by the UK Health and Safety Executive, and the
Chemical Control Toolkit (Toolkit) proposed by the International Labor
Organization, are 'control banding' approaches to workplace risk management
intended for use by proprietors of small and medium-sized businesses. Both
systems group chemical substances into hazard bands based on toxicological
endpoint and potency. COSSH Essentials uses the European Union's Risk-phrases
(R-phrases), whereas the Toolkit uses R-phrases and the Globally Harmonized
System (GHS) of Classification and Labeling of Chemicals. Each hazard band is
associated with a range of airborne concentrations, termed exposure bands,
which are to be attained by the implementation of recommended control
technologies. Here we analyze the margin of safety afforded by the systems and,
for each hazard band, define the minimal margin as the ratio of the minimum
airborne concentration that produced the toxicological endpoint of interest in
experimental animals to the maximum concentration in workplace air permitted by
the exposure band. We found that the minimal margins were always <100, with
some ranging to <1, and inversely related to molecular weight. The Toolkit-GHS
system generally produced margins equal to or larger than COSHH Essentials,
suggesting that the Toolkit-GHS system is more protective of worker health.
Although, these systems predict exposures comparable with current occupational
exposure limits, we argue that the minimal margins are better indicators of
health protection. Further, given the small margins observed, we feel it is
important that revisions of these systems provide the exposure bands to users,
so as to permit evaluation of control technology capture efficiency.

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AplusA-online.de - Source: Annals of Occupational Hygiene