Two-week (ten-day) inhalation toxicity and two-week recovery study of phenol vapor in the rat.

The toxicity of phenol vapor was evaluated in male and female Fischer 344 rats (20/sex/group) via flow-past nose-only inhalation exposure. The test animals were exposed to target concentrations of 0 (air control), 0.5, 5.0, or 25 parts per million (ppm) of phenol in air for 6 hours/day, 5 days/week, for 2 weeks. High pressure liquid chromatography (HPLC) measurement of phenol test atmospheres determined mean (+/- standard deviation) analytical concentrations of 0.0 +/- 0.0, 0.52 +/- 0.078, 4.9 +/- 0.57, and 25 +/- 2.2 ppm, respectively. After 2 weeks of exposure, 10 test animals/sex/group were sampled for clinical chemistry and hematology parameters, and then sacrificed. Histopathological examination included the nasopharyngeal tissues, larynx, trachea, lungs with mainstem bronchi, kidney, liver, and spleen. The remaining 10 animals/sex/group were retained for a 2-week recovery period. Recovery groups of animals were evaluated as described previously and then sacrificed. No signs of toxicity in clinical observations (including overt neurological signs), body weights, food consumption, clinical pathology, organ weights, macroscopic pathology or microscopic pathology were seen during the exposures or at either sacrifice interval. In conclusion, 2-week inhalation exposures to phenol vapor at concentrations up to and including 25 ppm did not produce any adverse effects.