Case study: The value of “less than” and “non-detects” in monitoring

Personal sampling is conducted in workplaces to establish and document the level of worker's exposure to hazardous chemicals. The results obtained from the monitoring are compared to recognized occupational exposure limits to judge if those limits have been exceeded. When the results come back from the lab as indistinguishable from a known blank or less than an occupational exposure limit some employers stop there. However, these results can often reveal important information about work practices that can be improved to reduce worker's exposure. In this case study, we look at organic vapor exposure during a “qualitative analysis” experiment at a small college and look at the results as a springboard to improve work practices and to teach workplace exposure reduction techniques.