Half of all U.S. states currently mandate smoke-free worksites, restaurants and bars and, if more states adopt bans, smoking could be prohibited in indoor areas across the nation by 2020, the Centers for Disease Control and Prevention reported.

In the past 10 years, 25 states and the District of Columbia have passed smoking bans, the CDC said.

“Eliminating smoking from worksites, restaurants and bars is a low-cost, high-impact strategy that will protect nonsmokers and allow them to live healthier, longer, more productive lives while lowering health care costs associated with secondhand smoke,” said CDC Director Thomas Frieden. “While there has been a lot of progress over the past decade, far too many Americans continue to be exposed to secondhand smoke at their workplaces, increasing their risk of cancer and heart attacks.”

Although more states are enacting smoke-free bans, nearly 88 million nonsmoking Americans over the age of 3 years old are still exposed to secondhand smoking every year, the CDC said. A 2010 report issued by the U.S. Surgeon General found that there is “no safe level of exposure to tobacco,” and any exposure may lead to organ damage.

“Secondhand smoke is responsible for 46,000 heart disease deaths and 3,400 lung cancer deaths among nonsmokers each year,” said Ursula Bauer, director of CDC’s National Center for Chronic Disease Prevention and Health Promotion.

According to Planet Green Discovery, studies show that employees and bartenders have shown significant health improvements after a smoking ban is enforced. Such enforcement has resulted in decreased respiratory problems for smokers and nonsmokers.