The test substance was administered to test animals via nose-only inhalation for 6 hours per day for 5 consecutive days at targeted dose levels of 42, 84 and 168 ppm. A concurrent control group was exposed to filtered air on a comparable regimen.

Vapors of the test substance were generated using 1-, 2-, and 3-jet Collison nebulizer for Exposure Systems 2, 3, and 4, respectively as follows: Using a regulator compressed nitrogen was supplied to the nebulizer to generate an aerosol of the test substance.

Additional test substance was manually added to the nebulizer during the exposure as needed. Prior to entering the nose-only system, all test substance aerosol was vaporized or removed by a liquid trap. A siphon was placed in-line prior to the nose-only system to adjust the concentration as needed. Using a rotameter-type 􀂡ow meter, a portion of the test substance atmosphere was siphoned to the in-house vacuum source. Filtered supply air was mixed with the test substance atmosphere prior to entering the nose-only system. Control animals were exposed to compressed nitrogen mixed with 􀂠ltered supply air using an exposure regimen equivalent to the test substance exposures. Aerosol formation was not observed in any test substance exposure system. TEST ATMOSPHERE - Brief description of analytical method used: Analyzed exposure concentrations were determined at approximately 35-minute intervals using a gas chromatograph (GC) - Samples taken from breathing zone: yes

Male and Female Sprague-Dawley Rats