The Background

It has been nearly five years since the International Maritime Organization (IMO) implemented Annex VI of MARPOL (The International Convention for the Prevention of Pollution from Ships). MARPOL is the primary international convention addressing the prevention of marine pollution by ships. The aim of the January 2020 shipping regulation was to reduce the global cap on atmospheric sulphur output levels in marine fuels from 3.5 percent to 0.5 percent. Two primary options were provided as allowable to meet the criteria, which has long divided the global shipping industry. The most divisive issue was, and has been, an option that allowed shipping vessels to install EGCS (Exhaust Gas Cleaning Systems), informally “scrubbers” as an alternative to operating their vessels on VLSFO (Very Low Sulphur Fuel Oil).

Instead of implementing an end date or a long-term plan to move the industry towards using cleaner fuels, those who are arguing for an amendment to this regulation agree that this secondary option introduced a loophole that has allowed ships to continue relying on Heavy Fuel Oil (HFO) that pollutes the air and sea.

All sides likely agree that the original intent of the regulation was well-meaning, and an effort to encourage the shipping industry to end its long practice of using dirty, polluting heavy fuels and switch to low-sulfur fuels or other more environmentally friendly options. Despite the continuing controversy within the scientific and scholarly communities and eco-movements, the IMO reported that, within the first year of the 2020 regulation, there was a 70% drop in atmospheric sulphur oxide emissions from shipping.  

Fantastic! So, what’s the problem?

The Problem

Based on the dramatic rise of scrubber installations, it’s become evident that greedy and environmentally irresponsible shipping companies would not buy into the idea of switching to greener options, but they would buy and install an EGCS system and continue using dirty fuels. Given that scrubber-installed ships have a clear market advantage over ships without scrubbers, no financial incentive exists because the fuel cost savings in using HFO outweighs the capital, operating, and maintenance costs of the scrubber. The inevitable result of the 2020 sulphur cap has caused a dramatic increase in scrubber installations, which is expected to continue, unless the regulation is amended.

A number of additional problems created by this loophole include:

• The lack of sufficient time to perform long-term studies before the 2020 regulation could have provided critical data to help guide a better-informed decision.
• The lack of LSFO and VLSFO options were anticipated to be more readily available to the industry at a near equivalent cost to HFOs (heavy fuel oils). This is still many years away.
• Well-founded concerns about the implementation, inspection, reporting, and enforcement for scrubber-fitted vessels, particularly in the open seas.
• The global economic cost of the environmental damage caused by the pollutants from scrubber-fitted ships and a clear view of the potential future damage.
• “Dark” or “shadow fleets,” particularly in open waters, whose sole purpose is to avoid imposed sanctions, legislation, and international rules and regulations. Such vessels are known to disable identification systems, tamper with location devices, engage in environmentally risky activities, and use substandard maintenance practices.
• The global economic cost of the environmental damage caused by the pollutants from scrubber-fitted ships and a clear view of the potential future damage.
• Scrubbers are responsible for increasing air emissions and ocean pollution, not decreasing it, as claimed. (Facts and Data are provided below.)
• In the last five years, scrubber installations have increased from approximately 250 ships in 2015 to over 5,000 in 2024.

The Facts and Data

Rather than reducing pollution levels as the IMO regulation intended, scrubber systems simply dump sulphur and a variety of other pollutants directly into the ocean, causing grave damage to the sensitive marine environment at a high economic cost, trading air pollution for marine pollution.

Beyond the data and statistics outlined in thelink, further scientific data has shown these are not the only dangers of shipscrubber wastewater.

• A 2023 study showed that Ocean Going Vessels with toxic scrubbers were 7% non-compliant compared to 2% for non-scrubber-equipped vessels.
• The sulphur content allowed in heavy marine fuels is 100x higher than that allowed for terrestrial transport fuels and significantly higher than low sulphur fuels.
• Scrubber discharge is up to 100,000x more acidic than seawater.
• 80% of scrubber wastewater is often dumped within 200 nautical miles offshore. In addition to its acidity, effluent from scrubbers cause reductions in both pH and alkalinity.
• Hydrocarbon oil residues, plus nine dangerous metals, and ten toxic PAHs (polycyclic aromatic hydrocarbons) contained in scrubber discharge accumulate through the food web, invariably enter human food, particularly in coastal regions.
• PAHs and heavy metals have been linked to cancers and reproductive disorders in threatened and endangered marine mammals, including some killer whales and beluga whales in certain regions.
• Scrubber discharge has been proven to kill plankton at the base of the food chain, alter the biodiversity, reproduction, and grazing habits of Zooplankton, and accumulate in the flesh of aquatic animals.
• Leaching metal from scrubber pipes and fittings can occur in low pH, adding toxic pollutants to sea water.
• Carbon dioxide (the primary greenhouse gas) emissions are higher from ships using HFO with a scrubber system compared to ships using VLSFO without a scrubber due to the extra fuel required to operate the scrubber system.
• Scrubbers using HFO increase sulphur dioxides and nitrous oxide emissions, which cause a 70% increase in particulate matter being released; and an 81% increase in black carbon emissions.
• Exposure to particulate matter in humans can cause premature death for at-risk populations, heart attacks, irregular heartbeat, asthma, and decreased lung function, along with increases in other respiratory symptoms and disease.
• Black carbon emissions from scrubber-fitted vessels are the second-largest contributor to shipping’s climate impacts, and its effects on humans have been linked to cardiovascular diseases, strokes, cancer, and acute respiratory infections in children.