Nitrogen is a colorless, odorless, odorless inert gas and can't support life while it is not harmful to the human body itself though, but when the nitrogen content in the air is increased, the oxygen content is respectively reduced, making it difficult for people to breathe. If pure nitrogen is inhaled, it will suffocate and cause death due to severe hypoxia. In order to avoid an increase of nitrogen content in the air in the nitrogen generator workshop, the nitrogen produced from the air separation plant shall not be discharged indoors. When repairing nitrogen-filled equipment, containers and pipes, it is necessary to release it to air first, and allow the operation after the oxygen content is sufficient for human. During the overhaul, one should be supervised and the nitrogen valve should be carefully guarded to prevent personal accidents from being accidentally exposed to high purity nitrogen.