Table 4.

Cancer inhalation unit risk (IUR) values and excess cancer risk estimates for VOCs with carcinogenic potential.

Substance	Highest Mean Concentration (µg/m3)	IUR (Source)	Excess Cancer Risk
Benzene	4.6	2.2 × 10−6–7.8 × 10−6 (U.S. EPA) 1	1.0 × 10−5–3.6 × 10−5
Ethylbenzene	2.9	2.5 × 10−6 (CalEPA)	7.3 × 10−6
Aggregate Risk			4.3 × 10−5

¹ Represents U.S. EPA’s lower and upper bound range of the IURs.