Check out second hand smoke - even not smoking is lethal.
Roy Castle was a UK entertainer who never smoked except other peoples smoke. He died of lung cancer from his audiences smoke.
n 1992, entertainer Roy Castle was diagnosed with lung cancer. A lifelong non-smoker, he adopted a positive attitude to his situation and courageously devoted much of the last year of his life to promoting the work of the charity, to which he gave his name. With the money raised from his moving Tour of Hope, the Roy Castle International Centre for Lung Cancer Research was built.
This is his memorial anti cancer site.
http://www.roycastle.org/