Which of the following is NOT a recommended practice for machine guarding?

• A. Installing physical barriers.
• B. Using safety interlocks.
• C. Providing a safe operating procedure.
• D. Relying solely on administrative controls without guarding.

Answer: (D)

The main idea here is that machine guarding relies on physical protections and safety devices, not just on procedures or human behavior. Installing physical barriers creates a solid boundary that blocks access to moving parts. Safety interlocks add a fail-safe by stopping the machine if a guard is opened, preventing injury even if someone tries to reach in. A safe operating procedure helps workers know how to operate the machine safely, but it doesn’t stop the machine or physically prevent contact on its own.

Relying solely on administrative controls without guarding isn’t a sound practice because it depends entirely on people following rules, which can fail in real-world conditions. Without physical guards, a worker could still be exposed to hazards if someone forgets a step, bypasses a procedure, or is distracted. The best approach combines engineering controls—guards and interlocks—with clear procedures and training to reduce risk comprehensively.