This is the VOA Special English Health Report.

Smoking is the world's leading preventable cause of death. In the United States, smoking rates are down from the past, but cigarettes still cause about one-fifth of all deaths.

Nonsmokers are also affected. Thousands in the United States die each year from heart disease and lung cancer from breathing other people's tobacco smoke. Secondhand smoke also causes breathing infections in young children. It can even cause sudden death in babies.

A worker in Harrisburg, Pennsylvania, last year takes a cigarette break. The state has since banned smoking in most public places.

In recent years there has been a strong push for local and state governments to ban public smoking. The American Lung Association says half of the fifty states have passed smoke-free laws. Some measures are weaker than others. But many are comprehensive bans -- they include restaurants and bars as well as other workplaces.

Wisconsin and North Carolina both approved smoking bans on the same day this month. Wisconsin passed a comprehensive ban that will take effect in July of next year. 

North Carolina passed a ban on smoking in restaurants and bars; it takes effect in January. The new law may not go as far as some would like, but the action is historic. North Carolina is America's top tobacco producing state. 

Other proposals are being debated across the country.

Opponents argue that smoking bans cause job losses in restaurants and bars. As a compromise, some bans exclude these establishments. But new research rejects this argument.

Elizabeth Klein, an assistant professor at the College of Public Health at Ohio State University, was the lead author. She says the study was the first to compare the economic effects of different kinds of smoking bans. She says the study looked at restaurants and bars because research suggests that people who drink alcohol are also more likely to smoke. 

The study examined employment records for eight cities in Minnesota for a three-year period through two thousand six. These cities have differing policies on public smoking. The study also included two cities with no such restrictions.

Professor Klein says the employment differences were so small that they could not be considered significant. Communities with the strongest policies had nine fewer employees per ten thousand community members than those with partial bans or none at all.

The study appears in the June issue of Prevention Science.

And that's the VOA Special English Health Report, written by June Simms. Transcripts, MP3s and podcasts are at voaspecialenglish.com. I'm Steve Ember.