calculated by dividing the respective BCME concentration by 0.19, as shown in Table D-1. Also presented in the table is the cancer risk for the AEGL-2 and AEGL-3 concentrations from a single exposure for 30 min to 8 h. The risk for the AEGL-2 values ranges from 1.7 × 10-4 for a 30-min exposure to 9.6 × 10-4 for an 8-h exposure. The predicted carcinogenic risk for the AEGL-3 values is greater, ranging from 7.4 × 10-4 for a 30-min exposure to 4.1 × 10-3 for an 8-h exposure. It is unknown, however, how well the stated assumptions hold true and predict the carcinogenicity of CMME. Because of this uncertainty and the large differences in methods used to derive the AEGL values compared with extrapolating carcinogenic potency from a lifetime study to a single exposure, the noncarcinogenic end points were considered to be more appropriate for driving the AEGL values for CMME.

TABLE D-1 Estimated Cancer Risks Associated with a Single Exposure Chloromethyl Methyl Ether or bis-Chloromethyl Ether

Exposure 10 min 30 min 1 h 4 h 8 h
BCME
Concentration Not
calculated
0.069 ppm 0.035 ppm 0.0086 ppm 0.0043 ppm
Estimated
cancer risk
1 × 10-4 1 × 10-4 1 × 10-4 1 × 10-4
CMME, containing 10% BCMEa
Concentration Not
calculated
0.36 ppm 0.18 ppm 0.045 ppm 0.023 ppm
Estimated
cancer risk
1 × 10-4 1 × 10-4 1 × 10-4 1 × 10-4
AEGL-2 value
Estimated
cancer risk
0.60 ppm
Not
calculated
0.60 ppm
1.7 × 10-4
0.47 ppm
2.6 × 10-4
0.30 ppm
6.7 ×10-4
0.22 ppm
9.6 × 10-4
AEGL-3 value
Estimated
cancer risk
2.6 ppm
Not
calculated
2.6 ppm
7.4 × 10-4
2.0 ppm
1.1 × 10-3
1.3 ppm
2.9 × 10-3
0.93 ppm
4.1 × 10-3

aAssumes BCME is a 10-fold more potent carcinogen than CMME.



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