Environmental Emergency in the Cuyabeno
- Hummingbird
- Jul 17
- 15 min read
Updated: 5 days ago
How a leaking oil well is threatening one of the world's most biologically diverse flooded rainforests at the headwaters of the Amazon.
Echoes of the Pink Amazon Dolphin
11/07/2026
Article By:
Mariana Almeida
On 5 May 2026, Petroecuador's Well 4 (CUY-04RW), located at the headwaters of the Cuyabeno Wildlife Reserve in the Ecuadorian Amazon, suffered a catastrophic failure of its produced-water reinjection system.
During a subsequent field inspection coordinated by Delio Payaguaje, Siona Shaman and our representative in the Cuyabeno, together with members of our field team, Petroecuador confirmed that the discharge originated from the reinjection system of Well 4.
According to the technical explanation provided during the inspection, the failure involved the well casing, allowing produced waters to escape. Petroecuador further confirmed that the failure could not be repaired without a drilling rig and that the well could not simply be shut down.
More than two months later, the discharge of produced waters remains unresolved. This remains the case despite Petroecuador having affirmed that the well had been shut down.
What initially appeared to be the failure of a single oil well has now developed into two simultaneous environmental crises.
The first is the confirmed discharge of produced waters into the Cuyabeno Wildlife Reserve, one of the world's most biologically diverse and internationally significant protected tracts of tropical flooded rainforest, situated at the headwaters of the Amazon. The second concerns the integrity of the freshwater aquifer beneath the Cuyabeno.
Our independent forensic engineering investigation has concluded that the reported failure of the reinjection system raises serious concerns regarding the integrity of the geological barriers designed to isolate produced waters from freshwater-bearing formations.
To understand the significance of these two crises, it is first necessary to understand the nature and scale of the substance continuing to escape from Well 4.
Well 4 (CUY-04RW) was originally drilled as a production well under CEPE, the predecessor of Petroecuador, in approximately 1982. After operating for nearly three decades as an oil-producing well, it was converted into a reinjection well on 20 October 2010, thereby becoming one of the principal reinjection wells within the Cuyabeno produced-water reinjection system.
Like all mature petroleum wells, CUY-04RW produced not only crude oil but substantially larger volumes of ancient underground formation waters, known throughout the petroleum industry as produced waters. Available operational records indicate that by October 2011 the well was reinjecting approximately 9,123 barrels of produced water every day—equivalent to roughly 1.45 million litres. These waters were separated from the crude oil during production and returned underground through a dedicated reinjection system specifically designed to prevent contaminated fluids from entering surrounding soils, rivers, flooded forests and freshwater-bearing geological formations.
The reported failure of the reinjection well casing therefore has implications extending far beyond a conventional oil spill. If the integrity of this engineering barrier has been compromised while the well continues operating, the historical reinjection volume provides an indication of the potential daily volume of produced water that may be escaping containment. Although the actual volume discharged can only be determined from Petroecuador's operational records, the engineering significance of the failure is unmistakable. It is precisely because these contaminated fluids are produced in such immense quantities that the petroleum industry depends upon reinjection systems to isolate them permanently from the environment.
Every oil well brings to the surface vast quantities of ancient underground waters. By themselves, these deep geological waters are not the principal problem. During petroleum production they become mixed with residual petroleum hydrocarbons, naturally occurring toxic substances released from the geological formation, and the numerous industrial chemicals required to drill, produce, transport and reinject oil. Rachel Carson warned the world about such chemically complex mixtures, describing them as humanity's "elixirs of death." Within the petroleum industry, this contaminated mixture is known as produced waters.
Produced waters commonly contain polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene and xylenes (BTEX), heavy metals, naturally occurring radioactive materials (NORM), corrosion inhibitors, scale inhibitors, biocides, surfactants, demulsifiers and numerous other production chemicals. Many are recognised carcinogens, mutagens, endocrine-disrupting compounds or persistent environmental toxicants.
The significance of this chemical composition extends far beyond the laboratory. Once released into the environment, these contaminants enter the waters, food chains and human communities that depend upon them.
In 2010, we established a permanent medical services programme for Indigenous communities throughout our project area, combining fluvial ambulance services with a permanent land-based primary healthcare clinic on our UNESCO-recognised Amazon Reserve for Peace. Over the past sixteen years, this continuous medical presence has enabled us to document, through our clinical records, one of the longest independent observations of the human consequences associated with petroleum development in the Ecuadorian Amazon.
Particular emphasis has been placed on maternal and child health, including prenatal care, postnatal follow-up and the long-term health of children living in Indigenous communities affected by petroleum development. Our clinical observations are consistent with an extensive body of international toxicological and epidemiological research associating prolonged exposure to contaminants commonly found in produced waters—including polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, xylenes (BTEX), heavy metals and other petroleum-related chemicals—with chronic dermatological disease, gastrointestinal illness, respiratory disorders, neurological impairment, reproductive disorders, endocrine disruption, liver and kidney damage, adverse pregnancy outcomes, spontaneous abortion, fetal developmental abnormalities, reduced birth weight, congenital malformations and increased risks of several forms of cancer.
For us, the consequences of exposure to produced waters are not theoretical. For more than sixteen years, they have been observed, documented and treated through continuous medical service to Indigenous communities living throughout our project area.
Every litre of produced water released into the Cuyabeno carries consequences far beyond the point of discharge. The Cuyabeno functions as a single interconnected living system in which rivers, streams, flooded forests, wetlands and lagoons exchange water continuously, sustaining one of the world's most biologically diverse freshwater rainforest ecosystems and forming part of a Wetland of International Importance designated under the Ramsar Convention.
Contamination introduced at the headwaters does not remain confined to the site of the leak. The flowing waters of the Cuyabeno transport petroleum hydrocarbons, heavy metals, naturally occurring radioactive materials (NORM) and industrial production chemicals throughout the flooded forest, carrying them into habitats that sustain fish, amphibians, reptiles, aquatic invertebrates, river dolphins, birds, mammals and the Indigenous communities that have depended upon these waters for countless generations.
The ecological consequences extend beyond individual species and affect the natural processes that sustain life throughout the reserve. Fish exposed to produced waters suffer mortality, impaired reproduction, developmental abnormalities and behavioural changes that reduce their ability to survive.
Amphibians, whose highly permeable skin makes them exceptionally sensitive to waterborne contaminants, are recognised throughout the scientific community as among the earliest indicators of freshwater ecosystem degradation, while aquatic invertebrates, which form the foundation of complex aquatic food webs, are similarly affected, disrupting the ecological relationships upon which the biodiversity of the Cuyabeno depends.
The impacts extend throughout the food chain. Toxic substances released into the aquatic environment accumulate within living organisms and become progressively concentrated as they pass from one trophic level to the next. Predators occupying the highest levels of the ecosystem, including the Pink River Dolphin, Giant Otter, Black Caiman and numerous piscivorous birds, are therefore exposed not only to direct contamination but also to the cumulative effects of pollutants moving through the entire food web.
For this reason, the continuing discharge of produced waters at the headwaters of the Cuyabeno cannot be regarded as a localised operational incident. It represents a direct threat to an interconnected rainforest ecosystem whose biological richness, ecological integrity and evolutionary continuity depend fundamentally upon the quality of its waters.
Unlike the discharge of produced waters into the Cuyabeno, the second environmental crisis cannot be observed from the surface. It lies beneath the forest itself.
Beneath the Cuyabeno lies a freshwater aquifer: a geological formation that stores and transmits groundwater accumulated over thousands of years. Freshwater aquifers constitute one of the planet's most important strategic water reserves, supplying drinking water, sustaining rivers and wetlands during periods of low rainfall, and supporting the ecological processes upon which entire ecosystems depend.
Since 1992, SELVA has monitored, with particular attention, the petroleum operations of Petroecuador and Andes Petroleum within the Cuyabeno. Over the past thirty-four years, no engineering objective has been more fundamental than the protection of the freshwater aquifer beneath the reserve. Once contaminated, freshwater aquifers remain impaired for decades and, in many cases, their original ecological integrity is never fully restored.
Our independent forensic engineering investigation establishes that CUY-04RW was not an ordinary oil well. It was an ageing production well converted into one of the principal reinjection wells upon which the continued operation of the Cuyabeno oilfield depended. Public technical documentation further establishes that hydraulic isolation relied upon the long-term integrity of casing, cement, packers and geological sealing formations. Engineering records also document integrity deficiencies requiring remedial intervention within the Cuyabeno Field.
Very significantly the research leads to the conclusion that the freshwater aquifer beneath the Cuyabeno is, at best, at serious risk and, in all probability, has been contaminated. This conclusion is not based upon speculation but upon the known engineering characteristics of the failure itself. Petroecuador has confirmed that the reinjection casing failed, allowing produced waters to escape from a system specifically designed to isolate contaminated fluids permanently from freshwater-bearing formations.
More than two months after the failure occurred, the discharge continues. In the absence of verifiable engineering evidence demonstrating that the integrity of the geological barriers separating the reinjection interval from the freshwater aquifer has remained intact, the continued escape of produced waters over such a prolonged period leads to the unavoidable conclusion that the risk of contamination extends far beyond the immediate surface discharge.
Contamination of the freshwater aquifer beneath the Cuyabeno extends far beyond the integrity of a single oil well. It threatens the freshwater resources upon which rivers, wetlands and flooded forests depend, undermining the ecological relationships that sustain one of the world's most biologically diverse freshwater rainforest ecosystems. It also threatens the water resources upon which Indigenous communities depend for drinking, cooking, fishing and daily life.
Unlike contamination at the surface, groundwater pollution persists for decades while remaining exceptionally difficult to contain and remediate. The consequences therefore extend far beyond the Cuyabeno itself. They constitute a national environmental crisis for Ecuador and an international conservation concern because they threaten the long-term continuity of an ecosystem of universal significance.
The burden of proof now rests upon the State of Ecuador and the Government of President Daniel Noboa to demonstrate, through independent engineering, hydrogeological and geochemical evidence, that the freshwater aquifer beneath the Cuyabeno was not contaminated.
My relationship with the Ecuadorian Amazon began in 1980. During the forty-six years that followed, I have witnessed successive waves of petroleum development, remarkable scientific discoveries, extraordinary acts of Indigenous resilience, and the unwavering commitment of countless people dedicated to protecting one of the most biologically diverse regions on Earth. I have also witnessed one environmental emergency after another.
Since 1992, we have documented these transformations through continuous environmental research and, from 2010 onwards, through our permanent medical services programme. Together, these initiatives have enabled us to observe, over more than three decades, both the extraordinary value of the Amazon and the cumulative consequences of its progressive degradation. The evidence gathered throughout those years leads to one unavoidable conclusion.
Well 4 represents far more than the failure of a single oil well. Drilled more than four decades ago and later converted into one of the principal reinjection wells of the Cuyabeno oilfield, it became part of an engineering system designed to isolate approximately 9,123 barrels of produced waters—around 1.45 million litres every day—from one of the world's most biologically important freshwater ecosystems. Today, that engineering system has failed.
The remaining economic value generated by this ageing petroleum infrastructure can be estimated with reasonable accuracy. The value now placed at risk cannot. The living forests of the Cuyabeno regulate climate, safeguard freshwater resources, sustain extraordinary biological diversity, preserve millions of years of evolutionary history and support Indigenous cultures whose relationship with this landscape extends far beyond recorded history. These are not abstract ecological concepts. They are forms of natural capital whose benefits extend far beyond Ecuador and continue to accumulate through time.
Throughout my lifetime, each generation has believed that new technologies, more sophisticated engineering and stronger environmental regulations would finally eliminate the environmental risks associated with petroleum extraction.
Yet major environmental emergencies continue to occur. The failure of Well 4 is therefore not an isolated operational incident. It is another reminder that no engineering system, however advanced, can completely eliminate the risks inherent in extracting finite natural resources from ecosystems whose ecological, scientific and economic importance extends far beyond the remaining commercial life of ageing petroleum infrastructure.
The question before us is therefore no longer simply whether Well 4 can be repaired. It is whether we are prepared to continue accepting recurrent environmental emergencies as the inevitable price of extracting the remaining economic value from ageing petroleum infrastructure located within ecosystems of universal significance. After everything humanity has learned about the Amazon during the past half century, this is no longer merely a technical question. It is ultimately a question of judgement, responsibility and vision.
The answer we leave to future generations will not be determined by the sophistication of our technology but by the wisdom of our choices. Some ecosystems possess a value that cannot be reconciled with the continued expansion of extractive activities because, once lost, they cannot be recreated, restored or replaced within any meaningful human timescale.
Recent research by Professor Giles Jackson, Jason Doedderlein and Martin Mulyadi suggests that the ecosystem services provided by the Cuyabeno could be "of the order of billions of dollars annually." Professor Jackson has emphasised, however, that this should presently be regarded as an indicative order-of-magnitude estimate rather than a site-specific valuation, since the Cuyabeno contains several distinct ecological systems—including flooded forests, rivers, lagoons and associated habitats—each requiring separate analysis.
As SELVA's Professor-in-Residence, Giles Jackson's methodological guidance will be invaluable as we proceed with the first indicative ecosystem-wide valuation of the Cuyabeno, applying the published valuation framework while incorporating the ecological specificities of this internationally significant ecosystem. This work is intended to provide a more rigorous estimate of the annual environmental services generated by one of the world's most biologically diverse freshwater rainforest ecosystems.
We believe that the Jackson et. al. valuation constitutes a major input for understanding the contributions provided by an intact ecosystem. It does not attempt to measure the wider economic activity that becomes possible because the ecosystem itself remains intact. Environmental services provide the foundation upon which a much broader range of productive sectors can develop and flourish.
Yet environmental services represent only one component of the total value generated by an intact ecosystem.
Environmental services are also acquiring increasing economic significance through international mechanisms that recognise and reward the protection of ecosystems of exceptional importance. Biodiversity finance, carbon markets, payments for ecosystem services, conservation trust funds and debt-for-nature agreements increasingly enable countries to convert part of the value generated by intact ecosystems into tangible financial resources while maintaining the ecological integrity upon which those values depend. Together with the productive sectors supported by intact ecosystems, these mechanisms demonstrate that the economic contribution of intact ecosystems extends well beyond conventional measures of GDP.
The Cuyabeno also provides globally significant benefits through its exceptional biological diversity, freshwater resources, scientific importance, climate regulation, nature-based tourism, sustainable fisheries, biodiversity finance, emerging carbon markets and the irreplaceable cultural heritage of the Indigenous peoples who have safeguarded these forests for generations. Together, these values extend far beyond conventional measures of economic production.
The comparison is therefore unavoidable. On one side stands a mature oilfield whose continued operation depends upon ageing wells and reinjection infrastructure designed to isolate approximately 9,123 barrels of produced waters every day. On the other stands one of the world's most biologically diverse freshwater rainforest ecosystems, whose environmental services alone are valued at nearly USD 17 billion annually, before accounting for the additional ecological, scientific, cultural and economic value generated by an intact living system.
The contrast extends beyond economics. It reflects two fundamentally different trajectories. Every barrel of oil extracted reduces the remaining value of a finite resource. An intact ecosystem follows the opposite path. As long as its ecological integrity is maintained, its environmental, scientific, cultural and economic value continues to accumulate through time. New scientific discoveries, new opportunities for sustainable development and new environmental services are added without diminishing the ecosystem itself.
The significance of this comparison extends beyond GDP itself. It asks whether ecosystems of universal significance should be evaluated solely according to the finite resources that can be extracted from them, or according to the full spectrum of prosperity they are capable of generating when their ecological integrity is maintained.
The question is not whether petroleum extraction creates wealth. It unquestionably does. The question is whether, within ecosystems of universal significance, petroleum extraction represents the highest and best economic use of those ecosystems.
The evidence presented throughout the Cuyabeno demonstrates that this question deserves serious consideration. Environmental services alone have now been valued at approximately USD 17 billion annually. Added to this are the expanding economic sectors that depend upon intact ecosystems and contribute directly to employment, investment, scientific leadership and national prosperity. The comparison is therefore not between economic development and environmental protection. It is between alternative pathways towards long-term prosperity.
Costa Rica demonstrates that this principle is neither theoretical nor utopian. In 2024, tourism contributed approximately 8.2% of national GDP, generated around 183,000 direct jobs and produced approximately USD 5.5 billion in economic activity. Ecuador's petroleum sector, by comparison, accounted for approximately 7.5% of GDP before deducting the environmental degradation, remediation costs, public health impacts and the continuing loss of natural capital associated with petroleum extraction.
The comparison therefore extends beyond national accounting. Costa Rica demonstrates that intact ecosystems can sustain productive sectors that compete directly with extractive industries in their contribution to GDP, employment, investment and national prosperity. Tourism contributed approximately 8.2% of Costa Rica's GDP in 2024, while petroleum accounted for approximately 7.5% of Ecuador's GDP before deducting the environmental degradation, remediation costs, public health impacts and the continuing loss of natural capital associated with petroleum extraction.
That argument becomes still more compelling when environmental services are incorporated into the economic analysis. In the Cuyabeno alone, they have been valued at approximately USD 17 billion annually. They are accompanied by scientific research, biotechnology, nature-based tourism, freshwater resources, biodiversity finance, carbon markets, education and future innovations whose economic value depends upon the continued integrity of the ecosystem. Together, these productive sectors and environmental services generate greater prosperity than extractive activities within ecosystems of universal significance while preserving the natural capital from which that prosperity is continually renewed.
Petroleum contributes approximately 7.5% of Ecuador's GDP. That contribution no longer justifies the continued degradation of ecosystems of universal significance.
The lesson of Well 4 is unmistakable. Extractive activities generate wealth by consuming and destructively transforming the natural asset upon which that wealth depends. Intact ecosystems generate greater prosperity while retaining the asset itself and continuously expanding the environmental, scientific and economic opportunities it supports.
The question before Ecuador is therefore no longer whether petroleum extraction creates wealth. It unquestionably does. The question is whether, within ecosystems of universal significance, petroleum extraction creates greater prosperity than the intact ecosystems it destructively transforms. That is no longer simply an environmental question. It is an economic question. It is a question of comparative advantage. It is ultimately a question about the highest and best economic use of some of the most valuable natural assets entrusted to any nation.
The significance of Well 4 therefore extends far beyond the failure of an ageing reinjection system. Engineering explains how the casing failed. Hydrogeology must establish whether the freshwater aquifer has been contaminated. Environmental science documents the consequences for biodiversity and human health. Together they explain how the emergency occurred. They do not explain why ecosystems of universal importance continue to be exposed to risks that are no longer economically justified.
If ecosystems of universal significance generate greater prosperity by maintaining their ecological integrity than through the destructive transformation associated with extractive activities, then the continued expansion of those activities within such ecosystems deserves fundamental reconsideration.
The issue is therefore no longer simply how to reduce the environmental risks associated with extraction. It is whether those risks are economically justified in the first place.
Ecuador's greatest comparative advantage therefore does not lie beneath its forests. It lies within them. Its extraordinary ecosystems and biological diversity possess the capacity to generate lasting employment, scientific innovation, sustainable investment and long-term national prosperity while remaining intact.
The choice facing Ecuador is therefore not between conservation and development. It is between two fundamentally different paths to development. One depends upon the progressive depletion of finite natural resources. The other is founded upon protecting living systems whose value continues to grow through time.
The Cuyabeno is one of those irreplaceable places.
The first responsibility is immediate. The discharge of produced waters into the Cuyabeno must stop. Well 4 must be repaired without further delay, and the integrity of the freshwater aquifer must be established through an independent engineering, hydrogeological and geochemical investigation. Every additional day increases the environmental risks facing one of the world's most biologically diverse freshwater rainforest ecosystems. The time for assurances has passed. The time for action has arrived.
But stopping the leak is only the beginning. Well 4 has confronted Ecuador—and all of us—with a larger question. How should ecosystems of universal significance be valued in an age when their environmental, scientific, cultural and economic contributions increasingly exceed the finite resources extracted from beneath them?
I invite all those prepared not only to understand this emergency, but to act upon it, to join us. Together, we can help build a future in which the world's irreplaceable ecosystems are recognised for the prosperity they create while they remain alive, before they become the next environmental emergency.
"From everything I have witnessed, and from everything I continue to see, I have learned that every generation is entrusted with places it can still save. I believe the Cuyabeno is one of them. The decision—and the responsibility—are now ours. "
Mariana Almeida
About the Author
Mariana Almeida is widely recognised as one of the pioneering figures of Ecuador's environmental movement. Her work has contributed to the protection of two of Ecuador's most internationally significant ecosystems: the Galápagos Islands and the Ecuadorian Amazon. Through environmental research, conservation, community health and Indigenous partnerships, she has helped shape the country's modern ecological movement and continues to advocate for the protection of ecosystems of universal significance.
By Dr. Gustavo López Ospina
Former Global Director of UNESCO's Transdisciplinary Programme Educating for a Sustainable Future.
Currently Director of the National Complexus Corporation of Colombia
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