A smoke-free workplace lowers the risk of lung cancer for smokers and those exposed to secondhand smoke (exposure raises the risk of lung cancer by 12–19%). Smoking cessation lowers the risk of heart disease, stroke, and upper respiratory infections. A smoke-free workplace is also beneficial for the health of non-smokers because it reduces exposure to secondhand smoke, which can aggravate asthma and other respiratory diseases. Smoking bans not only benefit the health of employees but also increase productivity and reduce work-related accidents. According to research conducted by the University of California, San Francisco (UCSF), workers who don't experience tobacco-induced stress tend to be more focused at their desks, which leads to improved job performance and less employee turnover. Additionally, non-smoking workplaces are deemed "healthy" by insurance companies, so they usually offer better coverage than smoking environments. The net result of these factors is that a smoke-free workplace is beneficial for employers as well as employees.