What must be done to openings in machinery for proper protection?

For proper protection of openings in machinery, installing guards or covers is essential. This practice serves multiple purposes: it mitigates the risk of accidental contact with moving parts, which could lead to severe injuries, and it also prevents foreign objects from entering the machinery, which can cause malfunctions or pose additional safety risks. Guards and covers are designed to protect both the machine's operational integrity and the safety of workers nearby.

Using tape to cover openings, as suggested in one of the other choices, is not a durable or effective long-term solution. Tape might degrade quickly due to environmental factors or operational wear and does not provide the robust protection that guards or covers do. Leaving openings exposed for ventilation can create hazardous situations, as it invites the risk of injury and mechanical failures. While closing them off permanently may seem safe, it could hinder necessary operations or maintenance. Therefore, the best practice is to install appropriate guards or covers to ensure safety and functionality.