Specifically, the Panama Canal has been added to the list of ports and regions that ban the use of open loop scrubbers.
According to the Canal's NT NOTICE TO SHIPPING No. N-1-2019 “Vessel Requirements”, Section 31 b. (7):
Vessels are not required to changeover to light fuel on their propulsion engines if equipped with a type approved closed-loop exhaust gas cleaning system (scrubbers) kept in operation, during the entire transit. The date and time of the period of operation of this equipment shall be recorded in the engine room logbook.
Moreover, on Section 28 (5) of the same document highlights that:
Residues from the Exhaust Gas Cleaning System (EGCS) washwater are to be collected on board. Discharging these residues into the water bodies under the responsibility of the Panama Canal or incinerating them on board is not permitted.
In light of Panama's announcement, many are the regions and the ports that have already banned the use of scrubbers; Recently, Gard P&I Club provided an updated list with some coastal states and ports that have implemented local regulations with more stringent requirements, restricting or completely prohibiting washwater discharge from open loop scrubbers or prohibiting the use of scrubbers.