Cal. Gov. Code § 7927.600

Whenever a city and county or a joint powers agency, pursuant to a mandatory statute or charter provision to collect private industry wage data for salary setting purposes, or a contract entered to implement that mandate, is provided this data by the United States Bureau of Labor Statistics on the basis that the identity of private industry employers shall remain confidential, the identity of the employers shall not be open to the public or be admitted as evidence in any action or special proceeding.