What is the first thing a boilermaker should do before cutting into a tank or vessel?

• A. Determine the content
• B. Vent the vessel
• C. Isolate the area
• D. Check for permits

Answer: (A)

Identify what is inside the tank or vessel before you cut. Knowing the contents tells you what hazards you’re dealing with—flammable vapors, toxic liquids, reactive substances, or pressurized contents—and it shapes every safety control you apply. If hazardous materials are present, you may need to vent or purge, depressurize, inert the space, or use specific PPE and procedures. This knowledge also determines whether permits are required and what isolation or safety steps must be taken. Without knowing the content, you could unleash dangerous vapors, exposure, or a sudden release. So the first step is to determine what is inside, and only then plan the appropriate controls—venting, isolation, permits, and precautions.