BOSTON (AP) — Gov. Mitt Romney signed a workplace smoking ban into law Friday. Beginning July 5, smokers will be prohibited from lighting up in restaurants, bars and clubs across Massachusetts.

The bill exempts some private clubs and fraternal organizations, including American Legion halls. Cities and towns would be allowed to create exemptions for nursing homes.

Massachusetts joins five other states — New York, Connecticut, Maine, Delaware and California — that have already approved statewide bans.

Workplace smoking bans have already been adopted in about 100 cities and towns in Massachusetts, including Boston.