Except as provided for cylinders of compressed oxygen, no person may load or transport to, from or within the United States a package containing a dangerous good requiring an OXIDIZER label in an inaccessible cargo compartment that is not equipped with a fire or smoke detection system and a fire suppression system.

Cylinders of compressed oxygen must be transported in accordance with the following:

1. No more than a combined total of six cylinders of compressed oxygen per aircraft may be stowed in cargo compartments not equipped with a fire or smoke detection system and a fire suppression system;

2. Except for oxygen cylinders allowed to be transported in the passenger compartment under the conditions given below, oxygen cylinders transported on passenger aircraft or in an inaccessible cargo location on a cargo aircraft must be stowed horizontally as close as practicable to the floor of the cargo compartment or unit load device;

3. When transported in a Class B compartment or its equivalent (i.e. an accessible compartment equipped with a fire detection system), cylinders of compressed oxygen must be loaded in a manner that a crew member can see, handle and, when size and weight permit, separate the cylinders from other cargo during flight. No more than six cylinders of compressed oxygen and, in addition, one cylinder of medical-use compressed oxygen per passenger needing oxygen at destination - with a rated capacity of 1 000 L (34 cubic feet) or less of oxygen - may be carried in a Class B aircraft cargo compartment or its equivalent; and

4. Each cylinder must conform to the requirements identified in US Variation 6 and be packaged as required by US Variation 18.

A cylinder containing medical-use compressed oxygen, owned or leased by an aircraft operator or offered for transportation by a passenger needing it for personal medical use at destination, may be carried in the cabin of a passenger aircraft in accordance with the following provisions:

1. No more than six cylinders belonging to the aircraft operator and, in addition, no more than one cylinder per passenger needing the oxygen at destination, may be transported in the cabin of the aircraft;

2. The rated capacity of each cylinder may not exceed 1 000 L (34 cubic feet);

3. Each cylinder must conform to the requirements identified in US Variation 6 and must be placed in an overpack or outer packaging that conforms to the performance criteria of Air Transport Association (ATA) Specification 300 for Category I or placed in a metal, plastic or wood outer packaging that conforms to a UN standard at the Packing Group I or II performance level; and

4. Oxygen cylinders transported under these provisions must be included in the information provided to the pilot-in-command in accordance with 7;4.1 of these Instructions.