Bilge Dumping at Sea: Why Should I Care?

Scientific research on the impact of oil pollution on marine life and coastal communities, combined with evidence of frequent bilge dumping, suggests oily bilge could be harming marine ecosystems and coastal economies.

This is the second entry in a multi-part series revealing the significance of bilge dumping globally.

Last year SkyTruth reported 163 accounts of likely bilge dumping across the world, from Brazil, to the Mediterranean, to Southeast Asia and elsewhere. As we described in our recent post,  bilge dumping is the illegal release of untreated oily wastewater from a vessel’s lower hull. This wastewater, or bilge, appears as an oil slick in the ocean, which eventually disperses and can migrate to vulnerable coastlines.  

Because it happens out at sea, bilge dumping traditionally has been an enigmatic source of pollution and challenging to consistently monitor. Although SkyTruth is working to change that, so far the negative effects of bilge dumping are sparsely documented. To explore the potential impacts of frequent bilge dumping worldwide, we can start by considering the contaminants oily bilge waste contains. Oily bilge waste water is the byproduct of operating ocean-going vessels and, according to the Environmental Protection Agency, contains contaminants such as lubricants, grease, and cleaning fluids, as well as harmful or toxic metals such as arsenic, cadmium, chromium, lead, and selenium, some of which are known or probable carcinogens. Other harmful substances in bilge can include organic chemicals such as benzene, chloroform, hexachlorocyclohexane isomers, and naphthalene

The size of tankers and container vessels that dump their waste can help us understand the amount of pollution they are emitting. Commercial marine vessels are some of the largest machines in the world, with some measuring 131 meters (143 yards) in length; comparable to the size of a small skyscraper. The engines in these vessels can be as large as three buses and have up to 333 times more horsepower than the engine of a midsize car. Their large size makes cargo vessels very efficient for transporting goods; but if the waste from these massive engines routinely ends up in the oceans, their environmental impact can be substantial. Even two decades ago, researchers reported that ocean-going vessels generated millions of tons of waste annually. A 2003 report by the nonprofit conservation group Oceana estimated that in European waters alone “illegal dumping and routine operations of vessels account for between 666,000 and over 2.5 million tons of hydrocarbons of marine pollution per year.” That amount is up to 70 times greater than the Exxon Valdez oil spill and is likely even greater today. Over a 20 year span from 1992 to 2012, the amount of ocean-going traffic has grown by 300%, increasing the likelihood of even more vessel pollution. 

A large research collaboration published by The National Academies Press (2003) found that between 1990 and 1999 vessels (in contrast to pipelines or facilities) in US waters produced the largest oil spills. Additionally, this research reports that 12 percent of the total petroleum hydrocarbons found worldwide in the oceans were from “accidental spills and operational discharges of cargo oil occurring during transportation of petroleum products.” This accounted for 160,000 tonnes of oil annually; the equivalent of four Exxon Valdez oil spills every year. 

Exxon Valdez oil spill [photo courtesy ARLIS, Alaska Resources Library & information Services]

Exxon Valdez oil spill [photo courtesy ARLIS, Alaska Resources Library & information Services]

The negative effects of bilge dumping can be seen in the United Arab Emirates. In 2017, one of the emirates, Fujairah experienced three oil spills in just two months. Locals reported that this contributed to a significant decrease in local hotel bookings and left dead fish and black oil on the shores. Last year, nine Brazilian states and 132 beaches were impacted by multiple mysterious incidents of oil washing up onshore. The cause of these incidents still has not been determined, but one possibility is a series of bilge dumping incidents. The impact occurred in multiple biodiverse tourism areas, specifically in Brazil’s oldest national park

SkyTruth also continues to find oil offshore Nigeria, in the Gulf of Guinea. And while this oil is mostly a consequence of energy infrastructure, we suspect this oil stems from bilge dumping as well. Nigeria’s Niger Delta, which drains into the Gulf of Guinea, experiences periodic water contamination from heavy metals due to extensive energy development, so much so that the delta has been called the “oil rivers.” Over a 38 year timespan, 12,000 oil spills were reported in the delta. Communities often use this water untreated for cooking or drinking as well as for local agriculture and fish farming. 

Heavy oil has been sullying the beaches of northeastern Brazil since early September. The cause remains elusive. [Photo courtesy tvBrasil via Creative Commons license]

Recently, an environmental activist and resort director contacted SkyTruth after repeatedly discovering remnants of oil and tar washing up on beaches near Singapore and the Strait of Malacca, one of the world’s busiest shipping lanes. This local activist continues to report regular incidents that they believe may be the result of bilge dumping. 

When oil washes up onshore, our Southeast Asian source states that it sometimes can be small and relatively easy to clean up, but at times, when it’s a bad spill, “it can be barrels full of it, or it can be thick tar balls, sometimes five to six inches across — so large that they look like they came out of a pipe,” he told us. The oil releases a “distinct petroleum smell” and “if it gets in amongst the rocks it can take months to clean out,” he told us. “If it washes up on a beach at high tide, it melts in the sun and is terribly messy to clean up.” Most incidents happen during the northeast monsoon season when the region gets stronger winds; however, outside of this season oil still lingers. “I can almost always walk down a beach and find some,” he told us. 

Video of oil globs from suspected bilge dumping washing up on a beach in Southeast Asia in February 2020. Video by anonymous.

Studies from oil spills suggest that oil at sea disperses over a period of days to weeks, and some of this oil can wash up on coastlines, potentially harming ecosystems and soiling beaches. Vessel bilge dumping incidents typically receive less attention than large oil spills: they are much smaller-scale events, but occur more frequently and potentially can have a significant cumulative effect. The substantial scientific literature analyzing the effects of large-scale historical oil spills — most notably BP’s Deepwater Horizon and the Exxon Valdez — could help shed light on the potential impacts of bilge dumping.

The impact of oil on a community’s natural environment can be very prominent, and it varies. When a slick disintegrates, its components can weather into dense tar balls which pile up on shores, as well form a messy sludge coined chocolate mousse. Well-protected clean-up teams are needed to carefully remove oil from coastal areas.

One unsettling outcome from oil in the water is its effects on marine life — from acute to progressive diseases. After the Deepwater Horizon oil spill, dolphin deaths from lung and adrenal lesions increased, and reproduction decreased, which scientists believe could be linked to exposure to oil. In addition, a multi-state natural resource damage assessment estimates that as many as 102,000 birds were killed or harmed during the Deepwater Horizon spill. Mangroves and coral reefs in Brazil, Panama and Singapore have been harmed by oil in the water. Human health can also be affected. One survey from an oil spill in Pakistan in 2003 found those who lived near the coastline experienced eye, skin, and respiratory health symptoms, asfumes and a mist of oil in the air.” Far worse, years after an oil spill offshore Spain, some cleanup workers of the spill showed signs of genetic mutations in their blood, potential catalysts for more serious disease. 

Lastly, oil spills have triggered social and psychological distress. After the Deepwater Horizon disaster, some impacted individuals were found to have high oil related stress and PTSD related symptoms. This discomfort led to lengthy lawsuits and ongoing political protests by citizens who felt that the energy company responsible, BP, was not taking full responsibility. 

Bilge dumping is unlikely to trigger such large-scale reactions. However, based on what SkyTruth has documented over the past year, we believe that bilge dumping could be the stealthy, less recognized cousin to large oil spills, that cumulatively leads to large amounts of oil in ocean waters and coastlines. Perpetrators often evade prosecution and accountability, leaving communities to bear the impacts and costs. 

Although scientific research on bilge dumping per se is limited, harmful impacts of oil pollution on marine life, human health, and coastal communities are well documented. Given the dozens of likely bilge dumping incidents SkyTruth has revealed over the past year, and the concerns expressed to us by coastal residents, we believe bilge dumping could be a sleeper source of oil pollution in the sea. It’s time to do something about it. 

 

A Systematic Search for Bilge Dumping at Sea: 2019 in Review

What can a year’s worth of bilge dumping data tell us?

This is the first entry in a multi-part series revealing the significance of bilge dumping globally. 

Out of sight, beyond the horizon, lies a world of activity taking place in the sea. The ocean encompasses over 70% of the globe, yet most of us only see its edges from the coasts. We’ve built many of humanity’s largest and most advanced societies along coastal regions, yet because the ocean is so remote, much of what happens there remains mysterious.  

You might think of crime at sea as violence (piracy), abuse of natural resources (illegal fishing), or pollution (oil spills). However, at SkyTruth, we’ve recently focused on combating another very troubling action on the water: a serious crime known as bilge dumping. While not as well known as pollution like the Great Pacific Garbage Patch, bilge dumping is a phenomenon that should not be overlooked, and yet it often is. 

Bilge dumping occurs when a vessel illegally releases untreated, oily wastewater into the ocean. This wastewater, known as bilge, collects in the ship’s lower hull and needs to be emptied regularly. Since the 1970’s an international law known as MARPOL has required that bilge water be treated to remove the oil before the bilge can be legally discharged into the sea. When a vessel circumvents treatment and dumps directly into the ocean, its wastewater creates an oily slick on the water. Radar satellite imagery captures these distinctive slicks — dark and opaque — because oil smoothes the surface of the water. This dense oily slick lingers in the water until it’s broken apart by wind and wave action, dispersing toxins and globs of oil that can harm coastal communities and marine ecosystems. Vessel operators probably commit this crime as an act of convenience: to save money or time cleaning up after themselves, imposing on others the negative consequences.

SkyTruth has observed likely bilge dumping incidents around the globe many times since 2007. But in 2019, we started seeking out these incidents more systematically. We focused our daily monitoring efforts on some of the world’s major shipping lanes and on areas where we’ve found problems in the past, cataloguing every incident of bilge dumping we found through imagery. Our intent was to better understand the scope of this recurrent problem. We noted that when we went to look for oily slicks, we always found more! Unfortunately, we began to expect to see them; they were occurring somewhere within the areas we monitored almost every day. And our monitoring only covered a small part of the ocean. 

In total, between January and December 2019, we found 163 slicks averaging 56 kilometers in length. We almost always found bilge dumps using Sentinel-1 imagery:  high-resolution C-band Synthetic Aperture Radar satellite data made available by the European Space Agency. Although this imagery is sparse over the open ocean (see our blog post showing the coverage provided by these and other imaging satellites), it is collected regularly in coastal areas and provided coverage of several areas we considered likely to experience bilge dumping. Figure 1 documents each bilge dump incident we discovered, identified as red dots (note that because our monitoring was not covering the entire ocean, the lack of red dots in many areas on this map doesn’t necessarily mean those areas are free from bilge dumping).

 

Figure 1: Likely bilge dumping events identified by SkyTruth in 2019.

Our work suggests that bilge dumping isn’t sporadic; we repeatedly detected this illegal behavior in shipping lanes across the world, usually surrounding areas with significant energy development or active commercial ports, and often in areas with a “chokepoint” of marine traffic congestion. Bilge dumping was commonly seen in Southeast Asia, the Persian Gulf, and the Gulf of Guinea. Less frequently, but notably, we discovered it off the coast of Brazil, in the Mediterranean Sea, and in the Gulf of Mexico. In some cases, we have been able to identify the polluters, by correlating Automatic Identification System broadcasts (used to prevent collisions) from ships, with the time and location of oily slicks. 

In 2020, SkyTruth is working towards automating this process so we can routinely monitor much more of the ocean. We plan to use machine learning techniques to scan available satellite imagery daily, with the hopes of identifying these slicks automatically. Near real-time detection will allow authorities and the public to respond as soon as they receive notice of the slick, meaning more perpetrators (who might still be nearby, or headed into port) can be caught, and timely actions can be taken to mitigate potential environmental harm.

Figure 2. Likely bilge dump incidents identified by SkyTruth in 2019 by region.

The next segments of this series will explore bilge dumping in more depth, includingWhy should you care?” “How can this be happening?” and “What can be done about it?” We work as  space detectives —  investigating meticulously from above, revealing as much as we can down to the most pressing and actionable details. As we increase monitoring, automate the detection of offshore pollution with the use of machine learning, and raise public awareness, polluters will learn that they are being watched. We believe that more transparency leads to better behavior, better management, and better outcomes for Planet Earth. At SkyTruth, we are working to stop this illegal pollution by giving it the scrutiny it deserves. 

SkyTruth 2020: What to Expect in the New Year

Oil pollution at sea, mountaintop mining, Conservation Vision and more on SkyTruth’s agenda.

SkyTruth followers know that we generated a lot of momentum in 2019, laying the groundwork for major impact in 2020. Here’s a quick list of some of our most important projects underway for the new year.

Stopping oil pollution at sea: SkyTruth has tracked oil pollution at sea for years, alerting the world to the true size of the BP oil spill, tracking the ongoing leak at the Taylor Energy site until the Coast Guard agreed to take action, and flagging bilge dumping in the oceans. Bilge dumping occurs when cargo vessels and tankers illegally dump oily wastewater stored in the bottom of ships into the ocean. International law specifies how this bilge water should be treated to protect ocean ecosystems. But SkyTruth has discovered that many ships bypass costly pollution prevention equipment by simply flushing the bilge water directly into the sea.

In 2019 SkyTruth pioneered the identification of bilge dumping and the vessels responsible for this pollution by correlating satellite imagery of oily slicks with Automatic Identification System (AIS) broadcasts from ships. For the first time, we can ID the perps of this devastating and illegal practice.

PERKASA AIS track

Figure 1. SkyTruth identified the vessel PERKASA dumping bilge water via AIS broadcast track overlain on Sentinel-1 image. 

But the Earth’s oceans are vast, and there’s only so much imagery SkyTruthers can analyze. So we’ve begun automating the detection of bilge dumping using an Artificial Intelligence (AI) technique called machine learning. With AI, SkyTruth can analyze thousands of satellite images of the world’s oceans every day –- a process we call Conservation Vision — finding tiny specks on the oceans trailing distinctive oily slicks, and then naming names, so that the authorities and the public can catch and shame those skirting pollution laws when they think no one is looking.

A heads up to polluters: SkyTruth is looking. 

We got a big boost last month when Amazon Web Services (AWS) invited SkyTruth to be one of four nonprofits featured in its AWS re:Invent Hackathon for Good, and awarded SkyTruth one of seven AWS Imagine Grants. We’ll be using the funds and expertise AWS is providing to expand our reach throughout the globe and ensure polluters have nowhere to hide.

Protecting wildlife from the bad guys: Many scientists believe the Earth currently is facing an extinction crisis, with wildlife and their habitats disappearing at unprecedented rates.   

But SkyTruth’s Conservation Vision program using satellite imagery and machine learning can help. Beginning in 2020, SkyTruth is partnering with Wildlife Conservation Society to train computers to analyze vast quantities of image data to alert rangers and wildlife managers to threats on the ground. These threats include roads being built in protected areas, logging encroaching on important habitats, mining operations growing beyond permit boundaries, and temporary shelters hiding poachers. With better information, protected area managers can direct overstretched field patrols to specific areas and catch violators in the act, rather than arriving months after the fact.  It can alert rangers before they discover a poaching camp by chance (and possibly find themselves surprised and outgunned).

To make this revolution in protected area management possible we will be building a network of technology and data partners, academic researchers, and other tech-savvy conservationists to make the algorithms, computer code, and analytical results publicly available for others to use. By publicly sharing these tools, Conservation Vision will enable others around the world to apply the same cutting-edge technologies to protecting their own areas of concern, launching a new era of wildlife and ecosystem protection. In 2020 we expect to undertake two pilot projects in different locations to develop, refine, and test Conservation Vision and ultimately transform wildlife protection around the world.

Identifying mountaintop mining companies that take the money and run. SkyTruth’s Central Appalachia Surface Mining database has been used by researchers and advocates for years to document the disastrous environmental and health impacts of mountaintop mining. Now, SkyTruth is examining how well these devastated landscapes are recovering.

Figure 2. Mountaintop mine near Wise, Virginia. Copyright Alan Gignoux; Courtesy Appalachian Voices; 2014-2.

To do this, we are generating a spectral fingerprint using satellite imagery for each identified mining area. This fingerprint will outline the characteristics of each site, including the amount of bare ground present and information about vegetation regrowth. In this way we will track changes and measure recovery by comparing the sites over time to a healthy Appalachian forest. 

Under federal law, mining companies are required to set aside money in bonds to make sure that funds are available to recover their sites for other uses once mining ends. But the rules are vague and vary by state. If state inspectors determine that mine sites are recovered adequately, then mining companies reclaim their bonds, even if the landscape they leave behind looks nothing like the native forest they destroyed. In some cases, old mines are safety and health hazards as well as useless eyesores, leaving communities and taxpayers to foot the bill for recovery. SkyTruth’s analysis will provide the public, and state inspectors, an objective tool for determining when sites have truly recovered and bonds should be released, or when more should be done to restore local landscapes.

Characterizing toxic algal blooms from space: Harmful algal blooms affect every coastal and Great Lakes state in the United States. Normally, algae are harmless — simple plants that form the base of aquatic food webs. But under the right conditions, algae can grow out of control causing toxic blooms that can kill wildlife and cause illness in people. 

 SkyTruth is partnering with researchers at Kent State University who have developed a sophisticated technique for detecting cyanobacteria and other harmful algae in the western basin of Lake Erie — a known hotspot of harmful algal blooms. They hope to extend this work to Lake Okeechobee in Florida. But their method has limitations: It uses infrequently collected, moderate resolution 4-band multispectral satellite imagery to identify harmful blooms and the factors that facilitate their formation. SkyTruth is working to implement the Kent State approach in the more accessible Google Earth Engine cloud platform, making it much easier to generate updates to the analysis, and offering the possibility of automating the update on a regular basis.  We anticipate that this tool eventually will enable scientists and coastal managers to quickly identify which algal blooms are toxic, and which are not, simply by analyzing their characteristics on imagery.

Revealing the extent of fossil fuel drilling on public lands in the Colorado River Basin: Modern oil and gas drilling and fracking is a threat to public health, biodiversity and the climate. For example, researchers from Johns Hopkins University used our data on oil and gas infrastructure in Pennsylvania to examine the health effects on people living near these sites and found higher premature birth rates for mothers in Pennsylvania that live near fracking sites as well as increased asthma attacks.

The Trump Administration is ramping up drilling on America’s public lands, threatening iconic places such as Chaco Culture National Historical Park in New Mexico. Chaco Canyon is  a UNESCO World Heritage Site that contains the ruins of a 1,200 year-old city that is sacred to native people. According to the Center for Western Priorities, 91% of the public lands in Northwest New Mexico surrounding the Greater Chaco region are developed for oil and gas, and local communities complain of pollution, health impacts and more.

Figure 3. Chaco Canyon Chetro Ketl great kiva plaza. Photo courtesy of the National Park Service.

In 2020 SkyTruth will deploy a machine learning model we developed in 2019 that identifies oil and gas drilling sites in the Rocky Mountain West with 86.3% accuracy. We will apply it to the Greater Chaco Canyon region to detect all oil and gas drilling sites on high-resolution aerial survey photography. We hope to then use these results to refine and expand the model to the wider Colorado River Basin. 

Local activists in northwestern New Mexico have fought additional drilling for the past decade. Last year, New Mexico’s congressional delegation successfully led an effort to place a one-year moratorium on drilling within a 10-mile buffer around the park. Activists view this as a first step towards permanent protection. SkyTruth’s maps will help provide them with visual tools to fight for permanent protection.

A new SkyTruth website: We’ll keep you up to date about these projects and more on a new, revamped SkyTruth website under development for release later this year. Stay tuned for a new look and more great SkyTruthing in the year ahead!

Multiple Accounts of Oily Pollution Found in the Mediterranean Sea

SkyTruth recently discovered two oil slicks in the Mediterranean Sea — just the most recent examples of an ongoing bilge dumping problem we’ve found in one of the most heavily used marine water bodies in the world.

This year, SkyTruth discovered multiple likely bilge dumps in the Mediterranean Sea; two in just the past month. The Mediterranean Sea covers around 2.5 million square kilometers from Spain to Israel. This area is a very prominent shipping route, but finding so many spills here is surprising considering how closely Europe monitors its waters.

The first slick we identified recently is located in the Ligurian Sea off the northwest coast of Italy; more specifically the Riviera di Ponente. This tourist destination is also called “the coast of the setting sun.” Sentinel-1 satellite imagery captured this 33-kilometer slick on October 20, 2019 at 05:36:16 UTC (Coordinated Universal Time) in waters near the Italian Riviera, approximately 60 kilometers southwest of the coast of Genoa, Italy’s sixth largest city.

The Italian Riviera is a popular tourist destination with abundant culture and history, as well as captivating vistas and water recreation activities. Therefore, spotting this oily slick (shown in Figure 1 below) so close to Italy’s coastline was unsettling.

Figure 1: A vessel (a bright dot within the red circle) suspected of bilge dumping (the long, black streak on this radar satellite image) in the Ligurian Sea.

We suspect the Med Pacific, an oil and chemical tanker, is the vessel responsible for the slick. The figure above (Figure 1) shows the vessel track for the Med Pacific as small red dots along the path of the slick. These small red dots are time and location stamped AIS (Automatic Identification System) broadcasts from the Med Pacific, which define the vessel’s path and align closely with the long, dark slick. This close fit between the time and location of the broadcasts, and the position of the vessel and the slick in the satellite image, strongly supports our identification of the vessel causing the slick. 

This tanker is operating under a flag issued by the nation of Malta. Malta is the southern-most and largest island within the Maltese Archipelago, located south of Italy in the Mediterranean Sea.

Figure 2: A photo of the Med Pacific, courtesy of Vessel Finder.

Bilge dumping is unlawful activity in which a ship releases untreated, oily waste water into the ocean, thereby avoiding proper measures of treatment required for safe discharge. Whether intentional — to save money and time — or accidental, bilge dumping is a serious problem. For a more thorough explanation of this illegal act, it’s damaging impact, and the methods SkyTruth uses to identify the vessels responsible, check out our recent post.  

Pictured below is the second likely bilge dumping incident in the Mediterranean Sea. Figure 3 depicts a recent slick captured on Sentinel-1 imagery on November 7, 2019 at 03:59:49 UTC. This suspected bilge dump is located approximately 83 kilometers north of Egypt and spans 60 kilometers. We were unable to identify the vessel responsible for this pollution, however, it is a textbook example of a bilge dump: It has the linear shape of an oily slick discharged from a moving ship, with a very bright speck revealing the vessel at the narrow end of the slick. In order to avoid getting caught, this vessel might have turned off its AIS or intentionally misreported its location. 

Figure 3: An unidentified vessel suspected of bilge dumping in the Mediterranean Sea off the coast of Egypt.

SkyTruth’s discoveries in the Mediterranean are concerning given that multiple marine programs are in place to protect the Mediterranean Sea from this kind of harm. Currently, the European Union and twenty-one coastal countries and states bordering the Mediterranean are joined together in the Mediterranean Action Plan (MAP), created as part of the United Nations Environment Programme (UNEP) to establish a partnership and commitment to protect their shared marine environment. Eliminating vessel dumping is defined as one of MAP’s main conservation protocols. The Regional Marine Pollution Emergency Response Centre for the Mediterranean Sea (REMPEC) was created from a collaboration between the International Maritime Organization and UNEP, and collaborates with MAP to focus specifically on combating ship pollution and bilge dumping. 

Given this Mediterranean partnership, ocean offenders are clearly not following the established protocols of their countries. In fact, the creator of REMPEC is Malta. As the flag state of Med Pacific, Malta is responsible for ensuring that this vessel operates lawfully. Figure 4 shows the partner countries and states in the Mediterranean Action Plan, as well as two red bounding boxes where the two (Figure 1 and Figure 3) suspected bilge dumps occurred. Note: Malta and Monaco, very small states that are part of MAP, are not shown on the map. 

Figure 4: Partners of the Mediterranean Action Plan. Recent likely bilge dumps shown by red boxes.

These findings in the Mediterranean Sea should not be overlooked. Countries in the Mediterranean region have many ports and popular recreational activities located on their coastlines. These high traffic areas can be negatively impacted by misbehaving vessel operators who could be carrying commodities as innocuous as fruit juice or, conversely, very hazardous cargo, such as oil and chemicals, like the tanker Med Pacific

Bilge dumping is a serious offense. It can harm the health of marine plant and animal species, and damage coastal communities. Despite how heavily the shipping and marine transportation industry is relied on for international commerce, regulations on vessels have progressed more slowly and generally have received less attention than regulations on land polluters. But authorities are starting to pay attention. Come January 1, 2020 the International Maritime Organization is requiring vessels to use a less toxic blend of vessel fuel with lower sulfur concentrations. This will reduce the amount of harmful sulfur oxide pollution going into the air. This new international law will hold vessels around the world to a higher, cleaner standard for fuel.

Taking more steps to protect the waters of the world is important. We hope the addition of more environmental regulations, as well as monitoring existing regulations by SkyTruth and other environmental groups, keeps vessel operators on their best behavior and helps make our oceans clean. 

Unusual Behavior by Tankers Near Brazil Oil Spill

The source of the massive oil spill affecting Brazil remains unclear, but unusual tanker activity raises questions.

For months now, oil has been washing up on the beaches of northeast Brazil. The quantity of oil, the large area affected, and the length of time oil has appeared, have generated international news coverage and concern. Government officials, scientists and non-governmental organizations around the world — including SkyTruth — have been trying to identify the source of the pollution; so far, unsuccessfully. Brazilian researchers have identified a likely location for the origin of the spill based on ocean currents. The oil is a heavy consistency that floats below the surface of the water and Brazilian researchers and government officials have claimed that it is likely from Venezuela, although they haven’t published the chemical analysis data to support this.

Photo 1. Heavy oil has been sullying the beaches of northeastern Brazil since early September. The cause remains elusive. [Photo courtesy tvBrasil via Creative Commons license]

At SkyTruth we have been examining available satellite imagery and evaluating some of the theories put forward on the origin of the spill. We haven’t seen any convincing evidence of oil slicks or sources on the images, and we don’t agree with analyses published by others (here and here) that claim to have solved the mystery. I recently decided to take a look at AIS (Automatic Identification System) ship-tracking data in the region that Brazilian researchers identified to be the likely origin of the spill. When I examined the AIS data, I found some unusual behavior by oil tankers passing through the area. 

AIS is a system in which vessels at sea transmit their location at regular intervals via VHF radio. Initially designed for collision avoidance, this location data is also picked up by satellites and provides a global record of vessel movements. I was aided by Global Fishing Watch’s automated modeling of AIS tracks, developed by data scientist Nate Miller, which identifies loitering events, that is, locations where vessels have essentially come to a stop, and are drifting out at sea. Tankers and cargo ships normally maintain a relatively constant transit speed as they are moving from their point of origin to their destination port. Ships may stop out at sea for a number of reasons, including engine problems, waiting for entry authorization at a port, or even at-sea transfers of cargo or refueling. But spending more than 24 hours adrift at sea represents a financial loss for a tanker and would suggest unusual circumstances.

Of hundreds of tankers that moved through the area in the months before the oil was reported, a handful stood out for having lengthy loitering events near the likely area of origin for the spill. One particular tanker, rather than proceeding directly on a course from Spain to Argentina, stopped for two extended periods (each for approximately 14 hours) just within Brazil’s Exclusive Economic Zone (the EEZ area extends up to 200 nautical miles from shore). The tanker I identified with these unusual loitering events is The Amigo, a 133-meter vessel listed as an Asphalt/Bitumen tanker and flagged to the Marshall Islands. 

Figure 1. Tanker loitering events (yellow circles) detected by Global Fishing Watch analytical tools on the coast of northeast Brazil in July and August 2019 (filtered to events longer than 8 hours). Five loitering events near the area thought to be the likely origin of the spill are shown as larger circles and listed in the table below. The AIS track of tanker The Amigo is shown in red. The EEZ boundary marking Brazil’s waters is in green.

We checked for satellite imagery in the area where the vessel was drifting (July 24 – 26) and unfortunately didn’t turn anything up. So any possible association between this tanker and the oil spill is purely speculative. However, some of the circumstances of the vessel’s operation fit with theories on the source of the spill, so we think its activities should be scrutinized further.

The Amigo is an unusual tanker in that it is outfitted to maintain its cargo at high temperature to keep it from solidifying. When the tanker passed through Brazilian waters off Brazil’s northeast coast, it was en route from Cadiz, Spain to a port near Buenos Aires, Argentina. The loitering events occurred between July 24 and July 26 before the vessel proceeded to Argentina. Port records show that on August 10 the vessel delivered 14,000 tons of bitumen (or at least it was scheduled to offload that quantity of product). AIS confirms that the tanker reached dock in Campana, Argentina on August 10. 

The tanker was coming from Cadiz, Spain though we don’t know if the asphalt was actually from Spain or what quantity was loaded at the port facility in Cadiz. Earlier this year the vessel visited Venezuelan ports and imported Venezuelan asphalt to the US. This article from March mentions The Amigo in the context of US sanctions against Venezuela that were coming into force. Could The Amigo have been carrying a cargo of asphalt that originated in Venezuela?

Figure 2. Movements of The Amigo since January 2019. The tanker’s current location in Turkey is shown.

The terms asphalt and bitumen appear to be used interchangeably to describe a semi-solid form of petroleum. High heat tankers like The Amigo must maintain their cargo at an elevated temperature so that it does not solidify, and can be pumped out of the vessel. Problems with heating might result in product remaining in one of the ship’s tanks and needing to be flushed out. Even under normal operations, heavy oil residue can build up in the cargo tanks and needs to be washed out or removed to free up usable space. International law requires that this be done in port where the oily sludge can be treated, but many ports lack the necessary treatment facilities. If somehow asphalt did end up being discharged directly into the ocean it would be expected to drift below the surface in warm equatorial waters. This might not generate a large surface oil slick that could be seen on satellite images, possibly explaining our frustration here at SkyTruth. 

As mentioned, there are some legitimate reasons for a tanker to be drifting out at sea. But we think it is fair to pose some further questions about this vessel given the severity of the spill in Brazil. What prompted the vessel to halt its normal transit off Brazil? What was the origin of the asphalt carried by the vessel and what quantities were loaded and offloaded? Could the chemical properties of the oil found on Brazilian beaches match this cargo, or any oily residue remaining in The Amigo’s cargo tanks?

But it’s not just The Amigo that’s raising questions for us. We’ve detected loitering events by other tankers in recent months (as shown on the map above and in the table below). We’ve found evidence of likely bilge-dumping by a few vessels in the area. And we’ve noticed that more than a dozen tankers operating in this area turn their AIS off while at sea, apparently in violation of international maritime safety law.

Table 1. Table showing the five tanker loitering events detected near the likely source of origin of the Brazil oil spill, shown as large yellow circles on the map at top.

We hope to find out answers to some of these questions soon, and we will continue to investigate all available data that might help to identify the origin of this devastating oil spill. One problem is very clear: we don’t know everything we need to know about the tanker activity near Brazil, and in many other parts of the ocean. 

Update 19 Nov 2019 – Since posting this last week I’ve had a chance to get some input regarding the Bitumen tanker I identified as of particular interest, The Amigo. The 14,000 tons they were scheduled to offload in Argentina would represent close to the full carrying capacity of the vessel. With estimates of at least 2,000 tons of material recovered from the beaches it seems that the vessel could not be responsible if they delivered a full cargo. 

We remain puzzled by the properties of oil coming up on the beach. It has been clearly reported as floating below the surface which fits with the fact that no large slick has so far shown up on satellite imagery. It has been questioned whether any of the asphalt carried by a vessel like The Amigo would really remain in the water column and be able to float ashore, rather than sinking to the seafloor. So some sort of heavy crude seems to be the most likely source. 

We are continuing to investigate any possible leads on the source of the spill and will share any more information that comes up.