10 min 30 min 1 h 4 h 8 h
1,100 ppm (5,170 mg/m3) 800 ppm (3,760 mg/m3) 400 ppm (1,880 mg/m3) 400 ppm (1,880 mg/m3) 400 ppm (1,880 mg/m3)
(Final Report) with Cover Letter Dated 102291. Submitted by Shell Oil Company to U.S. Environmental Protection Agency, Washington, DC. EPA Document No.
TSCATS 88-920000156. Microfiche No. OTS 0534605
Test species/Strain/Number: Rats and guinea pigs, strains unknown, five per sex per species.
Exposure route/Concentrations/Durations: Inhalation, 2,990, 5,850, or 7,970 ppm for 30 min; 14-day observation.
2,990 ppm: Slight ocular and nasal irritation
5,850 ppm: Narcosis and impaired ability to escape
7,970 ppm: No deaths; ataxia and narcosis
End point/Concentration/Rationale: No deaths after 30-min exposure at 7,970 ppm.
Uncertainty factors/Rationale:
Total uncertainty factor: 10 (a larger factor would lead to AEGL-3 values that would conflict with AEGL-2 values)
Interspecies: 3, data were comparable for rats and guinea pigs suggesting no large interspecies differences, and the critical effect is CNS depression.
Intraspecies: 3, interindividual variability for CNS depression by comparable gases generally will not be greater than a factor of 2 or 3.
Modifying factor: None
Animal-to-human dosimetric adjustment: None
Time scaling: Cn × t = k; default values of n = 3 for 10-min value and n = 1 for 1-h value. AEGL-3 values for 4-and 8-h are set equal to the 1-h value because chlorobenzene concentrations in blood reach a steady-state within 1 h and its elimination is rapid. Furthermore, time scaling would result in 4-and 8-h
AEGL-3 values that would conflict with AEGL-2 values and human data.
Data adequacy: Sufficient

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