More than half the states in America have enacted smoking bans at private work sites, restaurants and bars in the past decade, but a government report says Southern states lag in adopting such laws.

The report, released Thursday by the Centers for Disease Control and Prevention, shows swift progress in much of the country since 2000 to pass laws to protect nonsmokers from effects of secondhand smoke.

But many Southern states still allow smoking at work sites or bars or restaurants, and seven states have no laws prohibiting smoking in these public places.

“In the span of 10 years, smoke-free workplaces, restaurants and bars went from being relatively rare to being the norm in half of the states and District of Columbia,” researchers wrote in the CDC’s Morbidity and Mortality Weekly Report.

As of Dec. 21, 26 of the 50 states have enacted comprehensive smoke-free laws, and nearly half of residents in the United States — 47.8 percent — are covered by state or local smoke-free laws, the CDC said.

If trends continue, indoor public spaces could be 100 percent smoke-free by 2020, the researchers said.

But states in the South and parts of the West have resisted comprehensive statewide bans. Seven states — Indiana, Kentucky, Mississippi, South Carolina, Texas, West Virginia and Wyoming — have no laws banning smoking in private workplaces, restaurants and bars.

That leaves about 88 million nonsmokers in the United States still exposed to secondhand smoke, the CDC said.

Just three states in the South — Florida, Louisiana and North Carolina — have laws banning smoking in any two of the three venues (workplaces, restaurants and bars), and no Southern state has a smoke-free law covering all three.

According to the surgeon general, measures such as separating smokers from nonsmokers, cleaning the air and ventilating buildings do not fully protect nonsmokers from secondhand smoke, and the only effective measure is to ban smoking in all indoor areas.

“We must zero in on those areas that continue to lag despite studies that show smoke-free policies benefit public health and the local economy with lower health care costs,” Nancy Brown, chief executive of the American Heart Association, said in a statement.

According to the CDC, secondhand smoke causes an estimated 46,000 deaths from heart disease and 3,400 lung cancer deaths among U.S. nonsmoking adults each year.

— Reuters