14 CFR § 29.1439

If one or more cargo or baggage compartments are to be accessible in flight, protective breathing equipment must be available for an appropriate crewmember.

For protective breathing equipment required by paragraph (a) of this section or by any operating rule of this chapter—

That equipment must be designed to protect the crew from smoke, carbon dioxide, and other harmful gases while on flight deck duty;

That equipment must include—

Masks covering the eyes, nose, and mouth; or

Masks covering the nose and mouth, plus accessory equipment to protect the eyes; and

That equipment must supply protective oxygen of 10 minutes duration per crewmember at a pressure altitude of 8,000 feet with a respiratory minute volume of 30 liters per minute BTPD.