What must be maintained in proper operating condition according to safety standards?

Maintaining both existing and new systems in proper operating condition is crucial according to safety standards. This ensures that all machinery and equipment, regardless of their age or efficiency, operate safely and effectively. Safety standards are established to protect personnel, minimize risks of accidents, and ensure that performance standards are met over time.

Existing systems may have undergone wear and tear or may not have been designed with today's safety standards in mind, making it vital to regularly assess and maintain them to prevent failures. Similarly, new systems, while built to modern specifications, can also present issues if not properly maintained.

By focusing on both categories of systems, organizations can systematically evaluate potential hazards, conduct necessary repairs, and implement updates to maintain a safe working environment. Hence, the importance of maintaining both existing and new systems is underscored in safety protocols, making this answer the correct choice.