If you light up a cigarette, it will snuff out your chances to land a job with health-insurance giant Humana Inc. The health insurer said Wednesday that it will no longer hire workers in Arizona who smoke or use other tobacco products, part of a trend of employers who are cracking down on tobacco use among workers. To enforce the tobacco ban that starts Friday, Humana will test new employees for nicotine use during a pre-employment urine drug screen. Humana representatives say it makes sense for a company in the health-care field to lead by example. Smoking's harmful effects on human health are well-documented, and Humana seeks to promote health and wellness--starting with its workers.