Propane is one of the best fuels for a forklift and other construction vehicles. The Occupational Safety and Health Administration provides guidelines for proper and safe propane storage.
OSHA states that all propane containers "shall be located so as to minimize exposure to excessive temperature rise, physical damage, or tampering by unauthorized persons." This is best accomplished with a locked cage that is protected from direct sunlight.
Propane storage indoors must be done in a ventilated structure and may not block normal entrances and exits. Any indoor space must be ventilated to the outside at both the top and bottom of the structure, and the floor may not be set below ground level; propane will settle to the ground otherwise.
Propane storage outdoors must be in an area shaded from the sun and protected from precipitation. Containers must be located at least 10 feet away from any property line and sidewalk or busy thoroughfare.