Police wear masks to protect themselves from auto exhaust.

The masks did not protect against the mustard gas.

Ordinarily, the masks she wore covered and protected her.

"That process creates a lot of dust," he said, and most mechanics did not wear masks to protect themselves.

In addition, masks can protect a person from being infected with contagious diseases.

Wire mesh mask: The mask protects the head and face.

The masks also protect the identity of Klan members, who fear political retribution for their extreme views, he said.

While the mask did protect Fred's face, it did obscure his vision on pass plays to the sides.

The mask wouldn't protect him, not from nerve gas.

"So these masks will protect us from airborne spores?"