Exhaust gas scrubbers offer a safe way to meet IMO 2020 guidelines without harming the world's oceans, according to numerous industry groups, shipowners and scrubber manufacturers.

"Ships operating an inert gas plant have discharged process water from open-loop scrubbers in the port area for over 50 years," the Exhaust Gas Cleaning Systems Association (EGCSA) says in response to Singapore officials banning their use in the Asian port.