This is the textbook for the "Oxygen Deficiency and Hydrogen Sulfide Hazardous Work Supervisor Skills Training" course I took in Tokyo in fiscal year 2025. ★ All the essential sections for the written exam are marked. ※ These are the most important points directly conveyed by the instructor during the 3-day course. I hope this helps those who will be taking the course in the future. ※ The underlined sections were written with a Frixion ballpoint pen, so they can be erased. ※ The textbook cost 2,420 yen, so hopefully, this will help you save money. (Please check if the textbook matches the course yourself. I am not responsible.) - Title: New Edition: Prevention of Oxygen Deficiency, etc. - Author: Construction Industry Labor Accident Prevention Association Thank you for viewing.