NASA Earth Observatory image modified by SkyTruth
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All oil slick detections presented in this report are based on analysis of satellite imagery and have undergone human review. However, satellite imagery alone cannot determine the precise composition, concentration, or source of detected slicks. As such, these detections should not be interpreted as definitive evidence of pollution or illegal activity. Some slicks may originate from natural seeps, including those located near offshore infrastructure. All interpretations are made to the best of our ability using available data, and are intended to support transparency and further investigation, not to assign liability.
New Report Exposes World’s Most Polluting Offshore Oil Infrastructure Using Satellite Technology
The global climate crisis demands an urgent reduction in fossil fuel production, yet the oil and gas industry continues to expand—particularly offshore. In 2024, the majority of new large-scale oil and gas extraction projects were located offshore, reflecting a broader industry shift toward deepwater drilling, posing severe and compounding threats to marine ecosystems and the climate. The situation is being exacerbated by the industry’s shift toward stationary, floating production and storage vessels (FxOs) that make it economical to drill in deeper waters as near-shore wells become depleted. Often converted from aging vessels, these floating facilities present serious risks to workers, local communities, and the environment.
As part of the Open Ocean Project, SkyTruth is making detailed data about threats from FxOs and conventional fixed infrastructure (i.e., oil platforms and loading terminals) available to the public for the first time. Building on our earlier work to map the locations of all offshore infrastructure published in Nature in 2024, we have analyzed satellite imagery to quantify three core elements of the offshore oil and gas sector’s environmental footprint:
- Oil pollution: The presence of oil on the water around offshore facilities; naming the most severely-polluting infrastructure sites in the world for the first time.
- Greenhouse gas (GHG) emissions: This includes emissions from the operation of offshore oil and gas (O&G) facilities and the vessels that support them.
- Methane flaring by offshore oil facilities: The commonplace practice of burning off unwanted methane generates CO2 as a byproduct, which contributes to climate change.
Key Takeaways
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- We documented widespread oil pollution associated with offshore oil and gas facilities. This report highlights a shortlist of ten of the most polluting sites observed during our 16-month monitoring period. These sites stood out for the frequency and extent of oil slicks detected in satellite imagery, and together were linked to at least 216,000 gallons (over 5,100 barrels) of oil on the ocean surface.
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- Floating production and storage vessels (FxOs) are a significant source of chronic oil pollution. Despite representing a small fraction of offshore infrastructure, FxOs account for four of the ten most polluting assets we observed globally.
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- The most polluting offshore oil and gas infrastructure is concentrated in West Africa, particularly Nigeria, which hosts five of the ten most polluting FxOs observed. The United Kingdom, Norway, Angola, and the United Arab Emirates are also home to multiple facilities among the worst polluters.
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- In 2023, offshore oil and gas operators flared over 23 billion cubic meters of natural gas, injecting about 60 million metric tons of CO2 into the atmosphere. Flaring is globally distributed, but the largest sources were linked to infrastructure in Iran, Nigeria, and Mexico.
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- Vessel traffic to offshore oil and gas facilities generated at least 9 million metric tons of CO₂ in 2023 — a carbon footprint larger than many small countries. Most of this pollution comes from tankers and support ships transporting oil or servicing offshore infrastructure. Despite being vastly outnumbered by fixed platforms, FxOs account for 3 of the top 10 facilities with the highest CO₂ emissions from visiting vessels.
Cerulean detected slicks associated with Virini Prem.
The rankings and observations presented here are based on analysis of publicly available satellite data, primarily from Sentinel-1, covering the period between June 2023 and October 2024. Due to limitations in satellite coverage, these results do not represent a complete global inventory and should be interpreted as minimum estimates, as satellite coverage limitations mean many spills likely go undetected. For example, the most polluting FxO that we observed, the Virini Prem in Nigeria, showed oil slicks in 18% of all satellite images, suggesting it may release oil every five days on average.
With nearly three-quarters of new oil production volumes located offshore, monitoring these operations is more crucial than ever. As these are stationary facilities, this environmental damage is recurring repeatedly in the same ecosystems and communities, compounding threats to human health and wildlife. Unlike polluting vessels that may leave a jurisdiction before they can be caught, infrastructure’s inherent fixed location allows government agencies to pursue regulatory solutions and enforcement action to mitigate chronic pollution, to ensure marine protections and progress towards meeting climate goals.
Summary of Findings
Oil Pollution
We identified a shortlist of ten offshore infrastructure sites that stood out for the frequency and extent of oil slicks observed via satellite imagery between June 1, 2023 and October 29, 2024. Collectively, these sites were responsible for at least 216,000 gallons (>5,100 barrels) of oil detected on the ocean surface during the study period.
While our monitoring documented pollution from many other offshore facilities, these ten were among the most consistently and heavily polluting that we observed. Although FxOs represent a small (but growing) minority of total offshore infrastructure, they appear to pose significant risks for chronic oil pollution, with four of the 10 most polluting assets being FxOs. Frequently polluting infrastructure sites can be found across the world’s ocean, but are most concentrated in West Africa. Of the 10 most polluting FxOs we observed, five are located in Nigeria, followed by Angola, Ghana, the United Kingdom, and Brazil. Ownership data for these assets is not always transparent, but we are prepared to release all known data on these severe polluters to accelerate advocacy and enforcement efforts.
The following graphics identify the ten most frequently polluting FxOs and fixed oil infrastructure sites observed during our analysis:
Most polluting FxOs
Most polluting Fixed Oil Infrastructure Sites
Most polluting FxOs and Fixed Oil Infrastructure Sites Combined
Vessel traffic and greenhouse gas emissions
To comprehend the environmental footprint of offshore oil and gas, it is important to not only consider the impact of infrastructure itself, but also that of the vessels required to transport product, workers, and materials to and from the infrastructure sites.
Vessel activity varies widely, but FxOs tend to have more frequent visits from vessels than fixed infrastructure, as they are involved in the offloading and transportation of oil as well as production. Despite the fact that there is more than an order of magnitude more fixed oil infrastructure than FxO operating locations, three of the top 10 offshore oil facilities with the most CO2 emissions from visiting vessels are FxOs. In 2023, voyage-level emissions from vessels visiting offshore infrastructure are estimated to be around 9 million metric tons of CO2 – a likely underestimate given the fact that some vessels servicing fossil fuel infrastructure do not publicly report AIS coordinates. The structure with the top visiting vessel emissions in 2023 was the Chevron Richmond Long Wharf, an oil import terminal in California, which had 516 visiting vessel voyages that year. The second highest emitter from visiting vessels in 2023 was a Liquefied Natural Gas (LNG) terminal in India associated with Petronet LNG Limited, which had just 8 voyages; however, each voyage crossed long distances, mostly from India to the US. All of the top 10 most visited oil infrastructure assets, fixed or floating, are sites where oil and gas are loaded or offloaded for transport, and not the platforms that are producing oil.
Methane flaring
During the oil extraction process, natural gas — composed primarily of methane — is also commonly produced. Methane can be handled by capturing it for sale, re-injecting it into bedrock, burning it to convert it to CO2 (a practice known as flaring), or venting it directly into the atmosphere. There are significant initiatives aimed at limiting the practice of flaring due to its ecological impacts and health risks to workers and local communities. Understanding the patterns of flaring activity associated with FxOs and fixed oil infrastructure is crucial for both the evaluation of climate initiatives focused on the reduction of GHG emissions, and also for indicating behaviors of concern, such as intentional venting of unburned methane.
In 2023, the total offshore flaring volume estimate was 23.07 billion cubic meters (BCM), producing an estimated 60 million metric tons of CO2. This represents a decline from pre-2020 figures but a slight increase since 2022. The countries flaring the greatest volumes of gas were Iran (3.10 BCM), Nigeria (2.51 BCM), and Mexico (1.95 BCM). This represents a significant, and previously overlooked, contribution to carbon dioxide emissions and air pollution from the production phase of offshore oil and gas.
Looking Ahead
Our research demonstrates that policymakers must account for the substantial site-specific pollution burden imposed by offshore fossil fuel development. FxOs and other infrastructure are causing significant local contamination globally, with demonstrable impacts on marine ecosystems and significant risks for food security, public health, and coastal economies.
The increasing deployment of FxOs to access deeper offshore reserves indicates this is not merely a legacy issue with aging infrastructure, but a growing environmental challenge. As the industry pushes further offshore, these findings should inform regulatory decisions about proposed extraction projects worldwide. When evaluating offshore drilling proposals, decision-makers must weigh not only the climate impact of greenhouse gas emissions against claimed economic benefits, but also consider the documented risks of chronic oil pollution, increased vessel traffic, and persistent methane venting and flaring.
While this report does illuminate major aspects of the environmental footprint of offshore oil and gas operations, it does not provide a full accounting. For example, this report does not address leaks and emissions of methane from O&G infrastructure, a potentially significant contributor to climate change that has been systematically overlooked and/or underestimated by regulators and industry; and it does not address pollution and greenhouse gas emissions associated with offshore pipeline operations. The Open Ocean Project will continue expanding transparency about the true costs of industrial activities at sea, including offshore oil and gas extraction. Future research priorities include more comprehensive accounting of carbon and methane emissions from offshore infrastructure, deeper analysis of patterns in pollution events, and tracking of “dark vessels” that operate without disclosing their locations—potentially engaging in illicit activities.
By making this critical data publicly available, we aim to empower communities, regulators, and advocacy organizations with the information needed to hold polluters accountable and ensure marine protection. As satellite technology and open-source analytical tools continue to advance, they will drive unprecedented transparency and accountability in this historically opaque sector of the fossil fuel industry.
