Fumes, hazardous exposure limits

Beryllium, beryllium-containing aUoys, and beryUium oxide ceramic in soHd or massive form present no hazard whatsoever (31). SoHd shapes may be safely handled with bare hands (32) however, care must be taken in the fabrication and processing of beryUium products to avoid inhalation of airborne beryUium particulate matter such as dusts, mists, or fumes in excess of the prescribed workplace exposure limits. Inhalation of fine airborne beryUium may cause chronic beryUium disease, a serious lung disease in certain sensitive individuals. However, the vast majority of people, perhaps as many as 99%, do not react to beryUium exposure at any level (33). The biomedical and environmental aspects of beryUium have been summarized (34). 

The adopted values for TWAs for airborne vanadium, including oxide and metal dusts of vanadium, is 0.5 mg/m3 the values for fumes of vanadium compounds is 0.05 mg/m3. These limits are for normal 8-h workday and 40-h work-week exposures. The short-term exposure limit (STEL) is 1.5 mg /m3 for dusts (25). A description of health hazards, including symptoms, first aid, and oigan involvement, personal protection, and respirator use has been published (26). 

Diethanolamine is irritating to the skin, eyes, and mucous membranes. Protective clothing, gloves, eye protection, and a respirator are recommended. Ideally, diethanolamine should be handled in a fume cupboard. In the UK, the long-term (8-hour TWA) exposure limit for diethanolamine is 13mg/m (dppm). Diethanolamine poses a slight fire hazard when exposed to heat or flame. 

Determination of the concentrations of a hydrochloricInitric acid in a mixture. Prepare an external standard mixture for gas chromatographic analysis as follows. Add nitric acid (0.5 g) and hydrochloric acid (0.1 g) to dichloromethane (10 ml) followed by scrubber solution (10 ml). Stir for 15 min then dilute to 50 ml with dichloromethane. Generate a mixed acid vapour environment by placing a small beaker containing the acids in equal volume on a hot-plate stirrer inside a fume cupboard and heat gently. Sample the atmosphere as detailed in (a) but for 10 min. Note the volume sampled. Make 0.5 pi duplicate injections of standard and sample and hence determine the concentrations of the acids in the sample by direct comparison with peak areas of the standard (external standardisation). From this data and the volume of atmosphere sampled determine the short term exposure limit. By comparison with HSE recommended limits would this atmosphere pose a hazard (See Figures 9.15-9.17.)... 

Most of the listed exposure limits refer to single substances or closely related groups, e.g. cadmium and compounds, isocyanates etc. A few exposure limits refer to complex mixtures or compounds, e.g. white spirit, rubber fume. However, exposure in workplaces is often to a mixture of substances and such combinations may, by their nature, increase the hazard. Mixed exposure requires assessment with regard to possible health effects, which should take into account other factors such as the primary target organs of the major contaminants and possible interaction between the latter substances. 

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