Proper assessment and accurate measurement of workers' exposure to volatile organic compounds (VOCs), particularly in industrial settings, present a real challenge to the safety professional. Total VOC (TVOC) concentrations, which tend to fluctuate over time, can be quite low and their emissions irregular1. In addition, concentrations in non-industrial environments are usually much lower and difficult to detect and track2. Migration pathway(s) as well as source(s) must be identified.

The use of colorimetric tubes is limited, because they are substance-specific, have a large margin of error, are designed to measure higher concentrations, and provide only a "snapshot" of the actual exposure.

Most validated analytical methods yield very accurate data but the media must be sent to a laboratory for analysis. This may take several days and could be cost-prohibitive, particularly if many samples are required as is often the case.

In this applied science study, conducted in a print shop, measurements were made with a photoionization detector (PID), compared, and validated against results obtained through the use of an accepted analytical method (OSHA 7)3. The PID provided continuous, real-time sampling over an extended period of time and yielded accurate, reliable exposure information. Use of a PID, as demonstrated by this study, can help to better diagnose and assess occupational exposure as well as provide for a more efficient utilization of available resources. This technology would also greatly facilitate epidemiological studies.


It is estimated that occupational exposure to various petroleum refinery fractions continues to be quite significant. Almost two decades ago, NIOSH issued a criteria document on refined petroleum solvents4. At the time the number of workers potentially exposed to these products ranged upwards to 600,000. Earlier that same fiscal year (1977), NIOSH forwarded a criteria document to the Department of Labor on exposure to alkanes5. In the latter document it was estimated that up to 2.5 million workers were potentially exposed.

The present study took place in an industrial environment (print shop) where most of the products used contained petroleum solvents (those covered by the NIOSH criteria documents). The use of such products continue to be widespread throughout industry.

Employment in the printing industry is expected to continue rising6. According to US Department of Commerce statistics, a total of 554,500 workers were employed in this industry during 1977. In 1987 this number was 786,600 and in 1995 it was estimated to be 1,008,0007.

The relevance of the above statistics to the safety profession is patently clear. This growing segment of our workforce must continue to be protected from potentially harmful exposures to these chemicals.

This content is only available via PDF.
You can access this article if you purchase or spend a download.