California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 15 - Petroleum Safety Orders-Refining, Transportation and Handling
Article 22 - Loading and Unloading Platforms and Operations
Section 6880 - Loading and Unloading Operations

(a) During the loading or unloading of flammable liquids into or from truck or trailer tanks, no repairs, adjustments, or other operations shall be performed upon a truck, truck engine, trailer, truck tank, or trailer tank.

(b) During the loading or unloading of a tank truck or trailer, the truck engine shall be stopped and the cab shall be unoccupied unless the cargo is moved by means of the truck engine, or an auxiliary engine, with controls located in the cab, in which case the cab may be occupied by the truck operator.

(c) When a tank truck engine or an auxiliary internal combustion engine is being used to furnish power to transfer a flammable liquid, the vapors that may be liberated by such transfer shall be prevented from reaching the truck or auxiliary engine. If necessary, the vapors shall be discharged to a safe location.

(d) During the loading or unloading of a tank truck or trailer a qualified person shall be in control of the operation.

(e) In loading or unloading tank cars, tank trucks and trailers, provision shall be made for the safe disposal of the liquids released by overflow and/or from hoses, spouts or lines.