A (breathing zone) may pertain-to an employee.Logical formLearned from2 sentences. (Breathing apparatus facepiece) can be to a suit.Logical formLearned from2 sentences. A (breathing apparatus) may be operated in a mode.Logical formLearned from2 sentences. (Breathing apparatus) may be operated in a mode.Logical formLearned from2 sentences. A use of a (breathing apparatus) can be acceptable.Logical formLearned from2 sentences. Devices can be useful for a (breathing apparatus).Logical formLearned from2 sentences. A (breathing apparatus) can be inoperative.Logical formLearned from2 sentences. Practice can be in a use of (breathing apparatus).Logical formLearned from2 sentences. (Breathing zone silica levels) can be high.Logical formLearned from2 sentences. Death may occur from stoppage of breathing.Logical formLearned from2 sentences. Electrical shock may cause loss of a (breathing function).Logical formLearned from2 sentences. A (breathing apparatus) may be required.Logical formLearned from2 sentences. Administration of oxygen may obstruct a (breathing action).Logical formLearned from2 sentences. Contaminants may contain (breathing apparatus).Logical formLearned from2 sentences. Divers may use (breathing gas).Logical formLearned from2 sentences.