Few studies have evaluated airborne exposures to benzene, toluene, ethylbenzene, and xylenes (BTEX) during operation of two-stroke and four-stroke small engines, such as those in lawn maintenance equipment. Full-shift, 8-hour personal samples were collected during a simulation study to characterize yard maintenance activities including mowing, trimming, and fueling. Short-term, 15-minute personal samples were collected to separately evaluate mowing and trimming exposures. Mean 8-hour time weighted average (TWA) BTEX concentrations were 2.3, 5.8, 0.91, and 4.6 ppb, respectively (n = 2). Mean 15-minute TWA BTEX concentrations were 1.6, 1.8, 0.22, and 1.3 ppb, respectively, during mowing and 1.2, 3.6, 0.68, and 3.3 ppb, respectively, during trimming (n = 3 per task). Measured BTEX concentrations during fueling were 20–110, 61–310, 8–41, and 40–203 ppb, respectively (n = 2, duration 2–3 minutes). These exposure concentrations were well below applicable US occupational exposure limits.
Funding
All funding for this study was provided by Cardno ChemRisk. HA, JM, AI, RR, and KU are employed by Cardno ChemRisk, a consulting firm that provides scientific advice to the government, corporations, law firms, and various scientific/professional organizations. JS was employed by Cardno ChemRisk at the time of the study and Insight Exposure and Risk Sciences at the time of manuscript submission. Insight Exposure and Risk Sciences is a consulting firm that provides scientific advice to similar types of entities as Cardno ChemRisk. Both firms have consulted for oil and gas companies. KU, JS, and HA hold Cardno ChemRisk stock. This manuscript was prepared and written exclusively by the authors. No outside financial support was provided to any of the authors, Cardno ChemRisk, or Insight Exposure and Risk Sciences for preparing the manuscript. JS has served as an expert witness in benzene-related litigation. AI and JM have served as contracted industrial hygienists for an oil and gas company through their employments at Cardno ChemRisk. Our findings may possibly be relied upon in occupational health and exposure assessment research and benzene-related litigation.
