The asphalt, the bitumen, essential to the quality of our highways, may have dangerous properties for those who lay it, and are exposed to fumes and contact.
Bitumen, of which dozens of varieties exist, is a product originating from the fractional distillation of crude oil. It is primarily composed of Polycyclic Aromatic Hydrocarbons.
Direct contact with fumes is considered carcinogenic (classified as 2B/3 by IARC, but remember that Diesel Exhaust is 2A ). WHO and IARC have listed Bitumen as a High Priority for setting up a Monograph during the 2010-2014 period.

Human data exists concerning lung, head & neck, bladder cancers. But the elements are not absolutely demonstrative.
There could even be activation of elements of the TRAIL pathway, which might be protective.
However recently dispersion agents have been introduced into the bitumen products, often propylenediamine derivatives, but also from other classes. Some are described as "these products are very aggravating for the skin"