A comparison of direct-reading instruments for the measurement of hexavalent chromium during stainless steel welding

Hexavalent chromium (Cr(VI)), a known human carcinogen, is a potential exposure concern for workers performing tasks such as welding, soldering or brazing. Traditional monitoring methods for Cr(VI) require the use of a closed-face cassette with a polyvinyl chloride filter, followed by analysis using high-performance liquid chromatography with an ultraviolet and visible light detector, to measure an 8-hr time weighted average (TWA). Utilizing this method can produce a substantial lag time between sampling and results. The use of a direct-reading instrument would provide a useful tool to enable real-time estimation of Cr(VI) for rapid assessment of exposure controls. For this study, three direct-reading instruments were compared with the traditional sampling method: the TSI DustTrak 8520, the HazDust EPAM 5000 and the GRIMM 1.109. A total of 10 side-by-side sampling events were carried out in three different workplaces where welding of stainless steel was being performed. Results from all three instruments found they performed well when compared to the traditional method based on linear regression modeling, and with all R2 greater than 0.80. This study demonstrated potential value for using direct-reading instruments to quickly estimate Cr(VI) in air during welding operations.