The following HTML text is provided to enhance online
readability. Many aspects of typography translate only awkwardly to HTML.
Please use the page image
as the authoritative form to ensure accuracy.
Acute Exposure Guideline Levels for Selected Airborne Chemicals: Volume 7
10 min
30 min
1 h
4 h
8 h
200 ppm
200 ppm
160 ppm
100 ppm
50 ppm
Confidence and Support for AEGLs: AEGL-2 values are protective of human health. The level is based on a NOEL for inhibition of escape response in a behavioral study with rats in which concentrations in the exposure chamber were monitored. The AEGL values are supported by data from human studies in which no effects meeting the AEGL-2 definition were observed at similar concentrations.
AEGL-3 VALUES
10 min
30 min
1 h
4 h
8 h
600 ppm
600 ppm
480 ppm
300 ppm
150 ppm
Key Reference: Du Pont. 1966. Acute inhalation toxicity–progress report. Haskell Laboratory Report No. 161-66. EI Du Pont De Nemours and Company. Haskell Laboratory, Newark, DE.
Test Species/Strain/Number: Rats/CD/6 males.
Exposure Route/Concentrations/Durations: Inhalation, 3,500 ppm, 3,000 ppm/4 h.
Effects: 6/6 rats died at 3,500 ppm, none of 6 rats died at 3,000 ppm.
End Point/Concentration/Rationale: No lethality following 4 h of exposure to 3,000 ppm.
Uncertainty Factors/Rationale:
Total uncertainty factor: 10
Interspecies: 3, based on the similarity of acute effects seen in rodents compared with humans produced by agents affecting the CNS.
Intraspecies: 3, human data suggest that acute effects of volatile anesthetics and gases on the CNS show little intraspecies variability (about 2-3 fold).
Modifying factor: Not applicable.
Animal to Human Dosimetric Adjustment: Not applicable.
Time Scaling: Extrapolation was made to the relevant AEGL time points using the relationship Cn × t = k with the default of n = 3 for shorter exposure periods of 1 h and of 30 min and of n = 1 for longer exposure periods of 4 and 8 h (ten Berge et al. 1986; NRC 2001). The 10-min AEGL-2 was assigned the same value as that for the 30-min AEGL-2 as it was considered inapproprate to extrapolate from an experimental period of 4 h to 10 min.
Confidence and Support for AEGLs: AEGL-3 values are protective of human health. The available indicate a very steep concentration-lethality response curve and the values are based on a no-observed lethality concentration in rats. Additionally, the AEGL-3 values are supported by data from a human study in which the effects noted were milder than those defined by the AEGL-3 definition.
