Which factor should NOT influence the selection of respiratory protection?

The selection of respiratory protection should be based on factors that directly impact the safety and effectiveness of the equipment being used in hazardous environments. One of the primary considerations is the potential for exposure to harmful substances, which includes the concentration of toxic vapors and the oxygen levels present in the atmosphere. These factors directly affect the risk to the responder's health and the type of protection required.

While the ability to refill SCBA (Self-Contained Breathing Apparatus) cylinders is important for operational logistics and the duration of use, it does not directly influence the selection of the respiratory protection equipment itself. The proper selection is primarily influenced by the nature and level of hazards present rather than the logistics of refilling cylinders. Thus, while it is a consideration for practical use during operations, it should not dictate the type of respiratory protection chosen.