The International Maritime Organization is calling for further scientific studies on effluent from open-loop exhaust gas scrubbers that end up in the world's oceans.

IMO's Subcommittee on Pollution Prevention and Response (PPR) drafted proposed changes to the 2015 guidelines on scrubbers, having discussed them over the past week in London.

That draft will be sent to IMO's Marine Environment Protection Committee for consideration during its review of the current rules in May during its 74th meeting.