is defined as the area immediately adjacent to the employee's nose and mouth; a hemisphere forward of the worker's shoulders with a radius of approximately 6 to 9 inches.
is described by a hemisphere of 300 mm radius extending in front of a worker's face and measured from the midpoint of an imaginary line joining the ears.
The worker's breathing zone is described by a hemisphere of 300 mm radius extending in front of their face and measured from the midpoint of an imaginary line joining the ears.