Secondhand smoke has been classified as a known cause of lung cancer in humans (Group A carcinogen).
Review Date 2/11/2020
Updated by: Mark Levin, MD, Hematologist and Oncologist, Framington, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.