Federal law? What federal law? There are federal regulations that prohibit smoking in federal buildings, but there isn't a federal law prohibiting smoking in public places (read the Constitution to find out what pervue the Feds have with respect to laws that affect the states and those who live therein).
Are those state laws that prohibit smoking in offices? They have been in effect here in CA for at least 8 years. Also no smoking in restaurants ( know that's a state law).