Three types of energy that may be locked out using LOTO procedures are electrical, mechanical, and __________

• A. Fluid energy
• B. Thermal energy
• C. Chemical energy
• D. Magnetic energy

Answer: (A)

Lockout/Tagout focuses on stopping anything that could move a machine or release stored energy during maintenance. Fluid energy refers to hydraulic and pneumatic power stored as pressurized liquid or gas in lines, actuators, and reservoirs. Even with electrical power off, that pressure can drive cylinders, open valves, or cause dangerous jets if not properly isolated. By locking out the fluid power source—closing valves, bleeding pressure, and securing lines—you prevent unexpected movement or energy release. Other energy forms like heat, chemical bonds, or magnetic fields can be present, but the typical three categories addressed in LOTO include electrical, mechanical, and fluid (hydraulic/pneumatic) energy, making fluid energy the best fit here.