Final answer:
If underground utility operators are not registered with One Call, the responsible action is to contact them directly prior to excavation to ensure safety and compliance with legal requirements.
Step-by-step explanation:
If underground utility operators are not members of One Call, the correct course of action is to make every effort to contact these operators directly before attempting excavation.
One Call systems, also known as Call Before You Dig services, are designed to prevent damage to underground utilities. However, not all utility operators may be registered. Proceeding with excavation without proper notification can lead to serious safety hazards, service disruptions, and legal consequences.
Therefore, the best practice is to identify all underground utilities in the excavation area, including those not covered by the One Call service, and reach out to them directly to ensure that all necessary precautions are taken before beginning any digging or excavation work.