California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 14 - Petroleum Safety Orders-Drilling and Production
Article 17 - Identification of Wells and Equipment
Section 6556 - Identification of Wells and Equipment

(a) Every producing or injection well shall have placed in a conspicuous place, the name or number of the well. The operator and the name or number of the lease on which the well is located shall be clearly identified at the entrance(s) to the property or at the well site.

(b) Each stationary tank or vessel containing flammable, corrosive, or hazardous liquids or gases shall be identified by a letter, number, name or combination of these. Such identification should include information which either conveys the health and/or physical hazards of the substance in the tank or vessel or may be used to identify the hazards from readily available literature such as material safety data sheets. The identifications shall, when practical, be located so as to be legible from the location at which the tank or vessel is operated or controlled.

NOTE: National Fire Protection Association (NFPA) 704 may be used as a hazard identification method on stationary tanks or vessels.

(c) Pipe lines containing flammable, corrosive, or hazardous liquids or gases shall be identified to indicate their contents or purpose when such identification is practical and the correct operation of the valves of the line is essential to the safety of employees. The identification of the lines shall be by name or color placed on the lines or on the valves in the lines and shall be legible from the place at which the valves are operated. This shall not prohibit identification by the use of both a name and a color. Identifications shall be maintained so as to be legible.

EXCEPTION: Drilling and well servicing equipment.