When a startling piece of news relating to the roof-contracting industry crosses my radar I have a tendency to jump on it, but it has taken me months to make a public mention on this topic. On Oct. 18, 2011, the International Agency for Research on Cancer (IARC) announced thefinding of its working group that evaluated occupational exposures to oxidized bitumens and their emissions. The group found that occupational exposures to bitumens during roofing are “probably carcinogenic to humans.” The report defines bitumen as a substance “produced by distillation of crude oil during petroleum refining,” which includes asphalt used in the manufacture of many roofing products.