Controlled ethyl tert-butyl ether (ETBE) exposure of male volunteers - II.Acute effects

The aim of this study was to evaluate acute effects of ethyl tert-butyl eth er (ETBE) in man after short-term exposure. ETBE may in the future replace methyl tert-butyl ether, a widely used oxygenate in unleaded gasoline. Eigh t healthy male volunteers were exposed to ETBE vapor for 2 h at four levels (0, 5, 25, and 50 ppm) during light physical exercise. The subjects rated irritative symptoms, discomfort, and central nervous system effects in a qu estionnaire. Ocular (eye redness, tear film break-up time, conjunctival epi thelial damage, and blinking frequency), nasal (acoustic rhinometry and ana lysis of inflammatory markers and cells in nasal lavage fluid), and pulmona ry (peak expiratory flow, forced expiratory volume in 1 s, forced vital cap acity, vital capacity, and transfer factor) measurements were performed. Si gnificantly increased ratings of solvent smell (p = 0.001, repeated-measure s ANOVA) were seen during exposures and correlated to exposure levels. Furt hermore, significantly elevated ratings of discomfort in throat and airways were seen during and after 50 ppm compared to the control exposure (p = 0. 02). Increased nasal swelling (p 0.001) and blinking frequency (p = 0.01) w ere noted at all exposure levels, but their magnitudes were not related to exposure levels. A slightly impaired pulmonary function was seen at 25 and 50 ppm, since forced vital capacity (p = 0.02) and vital capacity (p = 0.04 ) differed significantly from the clean air exposure. Although the impairme nts seemed to fall within normal inter- and intraindividual variation and h ave no clinical relevance as such, it cannot be excluded that other individ uals may react more severely than eight healthy male volunteers in this stu dy. (C) 1998 Society of Toxicology.