On April 3 this year, a chemical plant found that the nitrogen valve of the ethylene oxide storage tank at the raw material station of the production department was damaged, and at 8:00 a.m. on the 4th, the plant sent three maintenance workers to enter the site for repair, and sent two others to monitor the site. During the repair, none of the maintenance workers wore gas masks. 45 minutes later, the workers began to experience dizziness, nausea, vomiting, chest discomfort and other symptoms of poisoning. After the initial treatment such as oxygen absorption in the medical room of the plant, the workers were sent to the hospital for resuscitation treatment, and no fatal cases occurred due to timely treatment. The main cause of this accident was knowing that ethylene oxide was toxic and working blindly without protection, which led to the accident.