The majority of ships that called at Singapore's port in the first quarter of this year complied with tighter sulphur emission regulations, the Maritime and Port Authority of Singapore (MPA) said yesterday.

About 96 per cent of ships used compliant fuel, based on pre-arrival notifications submitted to MPA. This excludes ships installed with open-loop scrubbers that switch to using compliant fuel upon arriving in Singapore, the authority noted.

Under the International Maritime Organisation's (IMO) 2020 sulphur regulations, which came into effect on Jan 1, ships are prohibited from using fuels containing more than 0.5 per cent sulphur, compared with the previous 3.5 per cent limit.

Shipowners or operators can install scrubbers or gas exhaust systems to reduce emissions to continue using high-sulphur fuel up to the 3.5 per cent limit.

MPA conducted 326 inspections of foreign-and Singapore-registered vessels in the port from January to March. A total of 12 ships, which were not fitted with scrubbers, were found to be using fuel that marginally exceeded the sulphur limit.

"This was likely due to remnant residues of high-sulphur fuel in the fuel oil tanks and piping. It is expected that in time, the fuel oil tanks and piping will be properly flushed with the continual use of compliant fuel," MPA said.

Two foreign-registered ships were found to be using non-compliant fuel and were allowed to depart from the port only after they had switched to using compliant fuel.

No ship installed with an open-loop scrubber was found to be operating its scrubber in the port, MPA added. To protect the marine environment and ensure clean port waters, Singapore has prohibited the discharge of "wash water" used in ships to scrub engine exhaust.

No Singapore-registered ships were detained by the port state authorities for non-compliance with IMO 2020 regulations in the first quarter of the year, MPA said.

Mr Goh Chung Hun, MPA's director of marine, said: "By engaging the industry proactively, providing the necessary technical guidance and maintaining an adequate supply of compliant fuel in Singapore, we have ensured a high degree of compliance with IMO 2020 sulphur regulations."

Singapore is committed to reducing the environmental impact of shipping and will continue to play its part to make shipping clean and sustainable, he added.