Lifetime exposure to modern diesel exhaust does not induce tumors or precancerous changes, according to the first comprehensive study of the matter. The study exposed laboratory rats to EPA-compliant 2007 heavy-duty engines for 80-hour weeks for as long as 30 months. UTMB’s Lance Hallberg and colleagues concluded lifetime exposure did not induce tumors or pre-cancerous changes in the lungs and did not increase tumors related to diesel exhaust in any other tissue. The news also appeared in Trucking Info.