Described is a breathing system that covers a person's head with a flexible hood material. One aspect provides a protective hood, including: a flexible hood material having a closed top portion and a neck portion; a viewing window disposed within the flexible hood material; a breathing inlet disposed in the flexible hood material and providing for breathing air to enter into an interior of the protective hood; an exhalation valve disposed interior to the protective hood; and a sealing arrangement disposed at the neck portion of the flexible hood material; wherein at least a portion of expelled gas from the exhalation valve is released into an interior of the protective hood and rinses the interior of the protective hood.