California employers may not knowingly or intentionally permit the smoking of tobacco products at a place of employment or in an enclosed space. This prohibition includes permitting non-employees to smoke in an enclosed workplace. The prohibition also applies to owner-operated businesses.
E-cigarettes and other nicotine-delivery devices, such as vaporizers, are also covered by the smoking in the workplace ban.
A sign stating "No Smoking" or "Smoking Is Prohibited Except In Designated Areas" must be posted at each entrance to the building.
When the smoking in the workplace ban was first enacted, there were exemptions in place for certain employers and specified working environments. Legislation passed in 2016 eliminated most of these specific exemptions, including eliminating the ability of employers to have designated smoking break rooms.
Violation of the law subjects employers to fines of $100 to $500.
You can find more information about Smoking in the Workplace in the HRLibrary.