A VTS operator observes a tanker on radar suddenly stop, and shortly after receives a report from a nearby vessel of a visible sheen on the water around the tanker's position. What is the VTS operator's most critical immediate responsibility after acknowledging the report?

1. Instruct the tanker to immediately proceed to a designated anchorage.
2. Request all vessels in the vicinity to assist in containing the spill.
3. Implement the local VTS pollution response contingency plan and notify the designated authorities.
4. Immediately broadcast a PAN PAN message on the VTS working channel and VHF Channel 16.