In this issue, Förster and co-workers1 show that 3-hydroxybenzo[a]pyrene (3OH-BaP), the main urinary metabolite of benzo[a]pyrene (BaP), can reliably be determined in workers with potential exposure to polycyclic aromatic hydrocarbons (PAHs) (see page 10.1136/oem.2006.030809). This may be considered a milestone since BaP features as a parameter for potential exposure to carcinogenic PAHs in many epidemiological studies and risk assessments.2^–5 As a consequence, the determination of 3OH-BaP, which assesses the internal, effective exposure to BaP, potentially could lead to more accurate quantitative risk assessment of PAHs.

PAHs are amongst the most common carcinogens humans are being exposed to via food, air and occupation since PAHs are not only formed during any incomplete combustion of organic material but may also be present in mineral oil products.6 7 Consequently, risk assessment of PAHs has been the focus of research for many years.

Risk is a function of hazard and exposure. On the “hazard” side, it should be considered that, although several PAHs with 5–7 fused rings have been shown to be carcinogenic, not all PAHs have …