Produced from the waste left over in oil refining, HFO poses a huge threat to the oceans in general but to the Arctic in particular.
This sludge-like fuel is almost impossible to clean up if a spill occurs.
In colder waters experts say the fuel does not break down but sinks in lumps that linger in sediments, threatening fragile ecosystems.
In climate terms, this oil is seen as particularly dangerous, not just producing large amounts of planet warming gas when burned, but also spewing out sooty particles called black carbon.
“The black carbon is creating the sort of double whammy impact in the Arctic,” said Dr Sian Prior, from the Clean Arctic Alliance group of campaigners.
“It’s attracting heat while it’s in the atmosphere, and then it settles onto the snow and ice and is speeding up the melting as well.”
The oil was banned from use or transport in the Antarctic in 2011.
Environmentalists have been pushing to expand that restriction to northern waters for years, finally persuading the countries that participate in the International Maritime Organisation (IMO) to enact a ban back in 2021.
The restriction now comes into force in Arctic waters – and while campaigners agree this is progress, they believe there are far too many loopholes that will limit the impact.
According to the regulations, ships that have a “protected fuel tank” will be exempt from the ban.
Countries that border the Arctic will also be able to exempt their own ships from the ban in their own territorial waters.
One of the major players in the region is Russia which has over 800 ships operating in northern waters. They are not implementing the new IMO regulation.
These waiver exemptions will last until 2029 – their impact is likely to be significant with the International Council on Clean Transportation estimating that about 74% of ships that use HFO will be able to continue to do so.
