" From Supplement 7 (IARC, 1987), unless otherwise indicated: I, inadequate evidence; L, limited evidence; ND, no adequate data; S, sufficient evidence; 1, Group 1, the agent is carcinogenic to humans; 2A, Group 2A, the agent is probably carcinogenic to humans; 2B, Group 2B, the agent is possibly carcinogenic to humans; 3, Group 3, the agent is not classifiable as to its carcinogenicity to humans.

h Source: U.S. EPA Carcinogen Classifications (1986). Group A, human carcinogen; Group B, probable human carcinogen; Subgroup Bl, "agents showing limited evidence of carcinogenicity from epidemiologic studies;" Subgroup B2, "agents for which there is 'sufficient' evidence from animal studies and for which there is is 'inadequate evidence' or 'no data' from epidemiologic studies;" Group C, possible human carcinogen; Group D, not classifiable as to human carcinogenicity; NC, not classified.

' U.S. DHHS/PHS/NTP (1998). Class S is sufficient evidence of carcinogenicity in animals. All PAHs in this table that have been evaluated are classified "reasonably anticipated to be human carcinogens (RAHC)."

d Nielsen et al. (1996) "City Air Pollution of Polycyclic Aromatic Hydrocarbons and Other Mutagens: Occurrence, Sources, and Health Effects."

' California Air Resources Board/Office of Environmental Health Hazard Assessment, Benzo[a]pyrene as a Toxic Air Contaminant (1994); Office of Environmental Health Hazard Assessment/California Environmental Protection Agency, Air Toxics Hot Spot Program Risk Assessment Guideline, Part II: Technical Support Document for Describing Available Cancer Potency Factors (1998); Collins et al. (1998).

' For the actual values and a discussion on various approaches by a range of scientific groups to calculating such values of unit risks for cancer for the PAHs and PACs in Tables 10.14 and 10.15, see Nielsen et al. (1995, 1996, 1999b), OEHHA/Cal EPA (1998), Collins et al. (1998), and references therein.

' Recalculated from data in Durant et al. (1996).

' Several of these relative potencies differ from those given in Hannigan et al. (1998); see Table 10.25.

TABLE 10.14 Carcinogenicities of Selected PACs in Emissions and Ambient Air" As Evaluated by the IARC, U.S. EPA, and U.S. DHHS, Cancer Potency Equivalence Factors As Evaluated by CARB/OEHHA (BaP = 1.0), and Human Cell

Mutagenicities Relative to BaP =1.0



0 0

Post a comment