Acute effects of 1,1,1-trichloroethane on human olfactory functioning.

Background: Animal experiments indicate that 1,1,1-trichloroethane can cause degeneration of the olfactory epithelium. The effects of 1,1,1-trichloroethane on human odor perception still have not been investigated. The goal of this study was to learn more about acute effects of 1,1,1-trichloroethane.

Methods: Twelve healthy, nonsmoking students were exposed to 200 and 20 ppm (control) 1,1,1-trichloroethane in an exposure chamber for 4 hours according to a crossover design. Olfactory functioning was investigated with the Sniffin' Sticks. The test includes the determination of the detection threshold for n-butanol and an odor identification test.

Results: After 1 hour of exposure to 200 ppm 1,1,1-trichloroethane, no effects on olfactory functioning were observed. After 4 hours, the olfactory threshold for n-butanol was slightly (p = 0.04) elevated.

Conclusion: The threshold shift may be caused by different mechanisms, including inflammation of the olfactory mucosa or degeneration of receptor cells.