Table 1.
Measured HAPs in RIOPA with available cancer unit risk factors.
| Compound | WOE |
Unit risk (per μg/m3) | Sourcec | |
|---|---|---|---|---|
| IRISa | IARCb | |||
| Acetaldehyde | B2 | 2B | 2.2 × 10−6 | 1 |
| Benzene | A | 1 | 7.8 × 10−6 | 1 |
| Carbon tetrachloride | B2 | 2B | 1.5 × 10−5 | 1 |
| Chloroform | B2 | 2B | 2.3 × 10−5 | 1 |
| Ethylbenzene | NC | 2B | 2.5 × 10−6 | 2 |
| Formaldehyde | B1 | 1 | 1.3 × 10−5 | 1 |
| Methylene chloride | B2 | 2B | 4.7 × 10−7 | 1 |
| MTBE | NC | 3 | 2.6 × 10−7 | 3 |
| p-DCB | NC | 2B | 1.1 × 10−5 | 3 |
| Styrene | NC | 2B | 5.0 × 10−7 | 4 |
| Trichloroethylene | NC | 2A | 2.0 × 10−6 | 3 |
| Tetrachloroethylene | NC | 2A | 5.9 × 10−6 | 3 |
Abbreviations: IARC, International Agency for Research on Cancer; IRIS, Integrated Risk Information System; WOE, weight of evidence.
a
IRIS classification: A, known carcinogen; B1 and B2, probable carcinogens; NC, not classified.
b
IARC classification: 1, carcinogenic; 2A, probably carcinogenic; 2B, possibly carcinogenic; 3, not classifiable as to carcinogenicity to humans.
c
Sources: 1, IRIS (U.S. EPA 2005); 2 and 3, CalEPA (2005); 4, Caldwell et al. (1998).