An investigation by DW, in collaboration with the European non-profit newsroom Lighthouse Reports and eight other European press outlets, has found that the illegal dumping of bilge water at sea remained common.
During the investigation DW and its reporting partners talked to several whistleblowers and experts, who described a cat-and-mouse game in which seafarers use different techniques to bypass pollution safeguards and try to avoid detection by the monitoring technology employed by some governments.
Satellite imagery and data provided by the environmental group SkyTruth helped identify hundreds of potential dumps across the globe in 2021. The satellites used by SkyTruth cover less than 20% of the world’s oceans. According to the group’s estimate, the amount of oily water dumped into the oceans this way could amount to more than 200,000 cm/3 (52.8m gallons) annually.
International regulations require that large vessels treat the bilgewater with an “oily water separator” before it is discharged into the ocean. Each litre of bilgewater pumped into the sea after treatment is permitted by the IMO a maximum residual-oil proportion of 15parts
per million, or 15mg of oil per litre of water. The remaining mixture is stored in tanks onboard and later discharged at harbour in port reception facilities.
All big vessels are required to have working separators. But many ships were claimed to circumvent the system entirely.
DW and its partners spoke to five whistleblowers with years of experience working on container and chemical cargo vessels who say they have witnessed illegal bilge dumps. All of them requested anonymity out of fear of losing their jobs or being blacklisted for future opportunities.
Almost all of the whistleblowers detailed a similar method for bypassing the oily water separator: a small, portable pump. “It’s very easy,” one man who had witnessed it in operation on several occasions told DW. “You can assemble this portable pump in five minutes and then detach (in) five minutes and hide (it) if someone is coming.”
The pump is used to transfer the oily water into a different tank — in most cases, the sewage tank. On the high seas, ships are allowed to dump their sewage untreated. Then, the toxic mix is quietly released into the ocean, often under the cover of night or during inclement weather, when there is a lower chance of getting caught, according to several seafarers DW talked to. At night it is harder for authorities to verify the crime, and
bad weather can prevent the deployment of surveillance ships and planes.
Because the illegal dumps happen at sea, it is difficult for authorities and researchers to track them. That is why satellite imagery is used to monitor the seas for pollution. When a vessel discharges oily wastewater illegally, it usually creates a spill kilometres long and with a very distinct shape.
A system set up in 2007 by the European Maritime Safety Agency (EMSA), uses radar satellites to “see” through cloud cover and at night to identify possible spills. It alerts the respective member states when one is found. In some cases, substances such as algae can be mistaken for spills, which is why experts review the imagery. By cross-referencing the
location of the spills with ship-location data, EMSA can sometimes identify the possible polluter immediately.
This mechanism, called CleanSeaNet, has detected tens of thousands of possible oil slicks, and statistics show a reduction of illegal dumps in EU waters. Illegal dumps “still regularly occur in European waters,” according to EMSA, and the number of spills detected and prosecuted remains low. Individual member states do not always follow up on the alerts, and, when they do, it is often not quickly enough. The longer it takes authorities to
verify a spill in situ, the less likely they are to find oil, as spills begin to dissipate. In 2019, only 1.5% of spills were verified within a critical three-hour time frame. Polluters are only caught in a fraction of cases.
The satellites are also not able to monitor EU waters continuously, meaning that there is a window of several hours each day during which oil spills can go unnoticed. SkyTruth combined data and assumptions from EMSA with calculations of satellite coverage. Based on that the group estimated that every year nearly 3,000 slicks were caused by vessels discharging mineral oil into EU waters. That averages out to more than eight per day — the majority of which go unseen by satellites.
EMSA does not make its detailed detections public. But, using the same publicly available satellite imagery that the agency uses, vessel-tracking data and machine learning provided by SkyTruth, DW and its partners were able to identify more than 1,500 potential illegal dumps globally from July 2020 through to December 2021. For about 180, it was possible to identify the vessel based on tracking data. These cases include repeat offenders and bilge dumping in protected areas.
DW did not publish the vessels’ names, as the findings could not be independently corroborated with visual evidence. The preliminary data by SkyTruth identifies slicks from moving vessels with a high confidence. But the imagery cannot distinguish between mineral oil slicks and those caused by vegetable or fish oil.
Because it is so difficult to enforce the law, financial incentives to dump remained high. “The likelihood of the polluters’ being fined a large amount is minimal,” said Bussau, the Greenpeace marine biologist. “There is still a certain incentive, for cost reasons, to
illegally dump oil at sea,” he said.
Often only a small group of people were privy to the illegal activities: the crew members working in the engine room.
Although the ultimate responsibility for what happened aboard lay with the captain and the ship’s operating company, whistleblowers said the dumps often happened without the captain’s knowledge. Captains were required to sign the ship’s oil record book, a log in which the chief engineer is obliged to record transfers and discharges, but “it’s very difficult
for [the captain] to assess what is written there or to even understand what is going on in [it],” one of the whistleblowers said.
The oil books are also easy to falsify, according to the whistleblowers and experts, and not always thoroughly reviewed. Even when authorities check the records, Greenpeace’s Bussau said that “only a fraction of these crimes are detected.” And that there were,
unfortunately, “many black sheep on the high seas”.
