Which of the following can be the cause of a leak in a facepiece seal?

A leak in a facepiece seal can occur when the fit of the head harness is compromised. This can happen if the user has hair styled in a ponytail or bun that interferes with the sealing surface of the facepiece. Proper sealing is crucial for personal protective equipment, especially in hazardous environments, as any break in the seal can allow contaminants to enter the facepiece, rendering it ineffective. Ensuring that hair is secured and does not obstruct the facepiece gasket is essential for maintaining a tight fit.

While other factors like dentures, corrective lenses, or age may affect comfort or usability, they are not as directly related to the physical seal of the facepiece as hair styling can be. For example, dentures typically fit well within the mouth and do not interfere with the facepiece's perimeter, and corrective lenses are generally accommodated in the design of the facepiece itself. Age may affect the wearer's flexibility and ability to adjust the equipment but does not inherently disrupt the seal created by the facepiece.