|End point/Concentration/Rationale: Absence of mortality.|
Total uncertainty factor: 10
A total uncertainty factor of 10 was considered sufficient because the effects are attributed to n-hexane itself and no relevant differences in kinetics are assumed. Mortality from n-hexane exposure is preceded by CNS depression, and variation in susceptibility for CNS-depressing effects is not very great in the human population.
|Modifying factor: None|
|Animal-to-human dosimetric adjustment: Not applicable|
|Time scaling: Because a steady-state blood concentration will be reached within 30 min of exposure, no increase in effect-size by exposure duration is expected from 30 min to 8 h. Therefore, the AEGL-3 values for the 1-h, 4-h, and 8-h durations are set equal to the 30-min AEGL-3 value. The 10-min AEGL-3 value was derived from the 30-min AEGL-3 value by time-scaling using the equation Cn × t = k, with n = 3.|
|Data adequacy: The database is very poor. Available data for derivation of AEGL-3 values were predominantly from toxicokinetics studies. Adequate toxicity studies are lacking.|
aThe 10-min AEGL-3 value of 12,000 ppm (42,240 mg/m3) is higher than the lower explosive limit of n-hexane in air of 1.1% (11,000 ppm). Therefore, extreme safety considerations against the hazard of explosion must be taken into account.
bThe AEGL-3 values for the 30-min, 1-h, 4-h, and 8-h durations are each 8,600 ppm (30,000 mg/m3), which is higher than 50% of the lower explosive limit of n-hexane in air of 1.1% (11,000 ppm). Therefore, extreme safety considerations against the hazard of explosion must be taken into account.