From Consumer Wiki
Per California Labor Code, Section 6404.5, (California's Law for a Smoke Free Workplace) smoking is prohibited in all enclosed places of employment with limited exceptions.
An enclosed workplace can be broadly defined as any place of employment, including offices and restaurants, which has four walls and a ceiling. Certain limited locations may be excluded from these requirements. Some of the places specifically excluded are gaming clubs, bars, tobacco shops and 65% of hotel and motel rooms.