The Japanese government has set the goal of achieving carbon neutrality by 2050 (NetZero 2050). As part of this effort, it enacted the Act on Carbon Dioxide Storage Business (CCS Business Act) in 2024, targeting the commercialization of CCS by 2030. Based on its “CCS Long-Term. Roadmap,” the Japan Organization for Metals and Energy Security (JOGMEC) has selected nine projects as “Advanced Efforts for Commercialization of CCS,” aiming to start commercial operation by 2030. Specific project areas have been already designated in the Tomakomai region and the Tokyo metropolitan area and preparations for exploratory drilling are underway.
However, CCS implementation remains limited worldwide. There is little proven track record of safely storing CO₂ over the long term.. In Japan, a demonstration project off the coast of Tomakomai injected a cumulative total of approximately 300,000 tons of CO₂ and it has been under monitoring since 2019. Significant questions remain regarding the ability to safely contain CO₂ for decades to centuries.
This article introduces the incident of CO₂ leakage from an underground storage at the Illinois Basin – Decatur Project (IBDP) that occurred in Illinois, USA, in 2024 and outlines key points to be considered when evaluating the safety of CCS projects in Japan.
Outline of IBDP
The CO2 leak occurred at the Illinois Basin–Decatur Project (IBDP) in Decatur, Illinois. The IBDP is being carried out by the Midwest Geological Sequestration Consortium (MGSC), which is a collaboration led by the geological surveys of Illinois, Indiana, and Kentucky, with grain major Archer Daniels Midland (ADM) participating as a key collaborating company.
ADM provides CO₂ generated during the corn-based bioethanol production and operates the injection equipment and monitoring systems. From 2011 to 2014, the pilot project that injected 1 million metric tons of anthropogenic CO2 into a sandstone reservoir approximately 2,000 meters depth was conducted. Following the subsequent monitoring period, commercial-scale CO₂ storage operations commenced in 2017, and to date, approximately 3.8 million tons of CO₂ have been stored.
Leak Accident Came out in 2024
In September 2024, an anomaly detected in monitoring well instruments revealed a CO₂ leak. Investigations confirmed that corrosion in a pipe installed within the monitoring well had caused CO₂ to escape.
On September 19, the U.S. Environmental Protection Agency (EPA) announced a proposed enforcement order to ADM for alleged violations of the Safe Drinking Water Act. On September 27, ADM notified the EPA that it had temporarily suspended CO₂ injection at the second monitoring well due to the potential leakage of the injected fluid.
According to the EPA investigation, the leaked CO2 had migrated into unauthorized zones, above the confining the Mt. Simon sandstone (depth approximately 1,700 to 2,100 meters), which serves as the storage reservoir. This migration of injected fluids into an unauthorized area could potentially violate UIC Class VI regulations applicable to CCS projects and ADM’s operating permit.
UIC Class VI requires a 50-year continuous monitoring period after injection completion. In 2021, however, ADM proposed shortening the post-injection monitoring period to 10 years and reached an agreement with the authorities.
Response after leakage and resumption of press-fitting
ADM responded to the leak by plugging the monitoring well with CO2-resistant cement to the depth where the leak was confirmed. Additionally, ADM adjusted the depth of the monitoring well and installed a new monitoring well.
The EPA deemed these measures appropriate, and ADM resumed CO₂ injection on August 29, 2025.
CO2 Leakage Accident and Challenges in Information Disclosure
Challenges remain in information disclosure following the CO2 leak incident. According to reports, some members of the Decatur City Council testified that they first learned of the leak from news reports. ADM explained to reporters that its instruments had detected the leak as early as March, meaning approximately six months had passed before the EPA announced its proposed enforcement order.
This city council member stated that had they known about the leak beforehand, they might have opposed the city council’s approval of the expanded underground storage permit issued in May. Given these circumstances, it is difficult to say that ADM shared information adequately with stakeholders such as the municipality and residents in a timely manner.
Key points that Japan’s CCS projects should consider
The CO2 leak incident in Illinois provides important insights for considering how Japan should proceed with CCS projects.
First, it is essential to establish a system to ensure that stakeholders such as municipalities and residents can routinely access the information necessary for monitoring storage operations. It cannot be ruled out that the failure to disclose the leaks despite the operator’s recognition may have distorted local government’s decision-making. Business operators must establish a system that enables the government or local authorities to obtain real-time and detailed information serving as the basis for decisions making regarding permits and approvals for their projects.
Second, it is necessary to consider leak detection methods or environmental impact assessment beneath the seabed, and verification of countermeasure effectiveness. Most CCS projects planned in Japan involve storage beneath the seabed, and detecting and responding to leaks is expected to be more difficult than on land. While government advisory committees have presented model calculations suggesting leaks would not spread significantly, more detailed consideration on how to respond to actual accidents and how to allocate responsibility is needed.
Furthermore, there are no dedicated safety standards equivalent to the U.S. UIC Class VI, and it remains unclear what events would constitute a “violation” on the CCS projects in Japan. Based on the IBDP case, it is essential to organize and review in advance the reporting obligations during leaks, response procedures, responsibility allocation, and the nature of regulations.
Even though various parties have pointed out that numerous technical and institutional challenges remain for CCS projects, the government and industry appear to be rushing toward commercialization without thorough verification. This hasty approach can lead to an underestimation of risks and inadequate disclosure or concealment of information.
The leak incident at the IBDP in the United States calls into question the very premise that positions CCS as a “safe and established technology.” The Japanese government and operators must conduct more detailed prior consideration on how to share information and respond in case of accidents. It is also crucial for society to demand transparency and accountability.
Reference
Research Institute of Innovative Technology for the Earth (RITE) present
CCS Technical Workshop 2026, Tokyo, 21 January 2026, presentation material
CCUS at Decatur, Illinois: Past, Present, Future (PDF)
US Department of Energy:
Midwest Geological Sequestration Consortium (MGSC) , Carbon Storage Atlas Phase III（Link）
Midwest Geological Sequestration Consortium
ILLINOIS BASIN DECATUR PROJECT Final Report
An Assessment of Geologic Carbon Sequestration Options in the Illinois Basin: Phase III, Written by Sallie E. Greenberg, Ph. D. （PDF）
JBC articles
【News】Progress on CCS projects: Not a solution for thermal power decarbonization
【Report】Risks of CCS Pointed Out by IEA
【News】Check FoE Japan’s New CCS Animation Videos
【News】CCS Policy Seminar: Who Was It Really For?
Other Information
EPA : EPA Announces Proposed Order Requiring Archer Daniels Midland Co. to Take Actions to Ensure Safe Operation of its Carbon Sequestration Well in Decatur, Illinois （Link）
Carbon Dioxide Migration Along Faults at the Illinois Basin—Decatur Project Revealed Using Time Shift Analysis of Seismic Monitoring Data（Link）