Abstract: On December 18, 2008, an acute occupational poisoning accidents, with one death on spot happened in a chemical plant. Onsite visiting showed that was a case of acute carbon dioxide poisoning. Analysis showed chief causes responsible for this accident were:1. inadequate of the equipment maintenance to ensure the safety measures;2. lack of mechanical exhaust ventilation facilities above the autoclave where potential leakage carbon dioxide may occur;3. though training of workers had been conducted, but it existed gaps for alert on the protection against poisonous and harmful materials. Recommend the administrative sectors should strictly perform their duty according to law, supervise enterprise earnestly, enforce workplaces safety protection, check the relevant facilities, strengthen the instruction to production workers for occupational safety knowledge and understanding on self-protection, for purpose to control and eliminate acute poisoning accident.