Solvent exposure from liquid sampling media

Use of a personal sampling method using a toluene-based solution in a midget impinger led to the suspicion that it would result in toluene exposure to the worker. Field data from three workplaces indicate that in open environments, 8-hour TWA toluene exposures range from 3.6 - 20.1 mg/m3 with a mean of 8.9 mg/m3. However, sampling in semi-confined spaces resulted in 8-hour TWA concentrations up to 189 mg/m3, or 50% of the NIOSH-recommended exposure limit (375 mg/m3). Use of this and similar wet sampling methods in confined spaces requires investigators to be aware of the degree of ventilation in the space; and suggests the need to predict potential exposures before sampling. The vapor pressure method is a rapid, safe and simple way to predict this potential exposure.