June 27, 2025 (FUKUSHIMA) — A methane plume detected near the Fukushima Gas Power Station by the U.S.-based nonprofit Carbon Mapper has triggered concerns over public health risks in nearby communities. Captured by Carbon Mapper’s Tanager-1 satellite, the leak reveals Japan’s lack of robust methane standards—including real-time monitoring, cross-border regulations, and import-based measures. The incident also underscores the perils of Japan’s lingering reliance on liquefied natural gas (LNG), with frontline communities bearing the brunt. 

On March 1, 2025, Tanager-1 identified a methane plume near the 1,180 MW Fukushima Gas Power Station in Shinchi, Soma District. Built as part of the region’s post-2011 disaster recovery efforts, the plant sits near residential communities, agricultural zones, and coastal ecosystems. While the emission rate remains unquantified, the presence of a visible plume signals methane concentrations well above normal atmospheric levels, posing serious climate and health concerns. 

Methane’s climate and health threats 

Methane is a highly potent greenhouse gas (GHG), with more than 80 times the warming potential of CO₂ over a 20-year period. Rapid reductions in methane are considered one of the most effective levers to slow near-term global warming.  

Methane emissions from industrial facilities are often accompanied by volatile organic compounds (VOCs), which are toxic air pollutants linked to respiratory illness, neurological disorders, and long-term cancer risks, particularly among children and the elderly. 

The Fukushima plant’s location compounds the risk. Still recovering from the 2011 earthquake, tsunami, and nuclear accident, the area is home to aging populations and environmentally at-risk communities. Prevailing sea breezes and shifting wind patterns could spread methane and co-pollutants inland, threatening residents and ecosystems alike. 

Image 1: Carbon Mapper’s Tanager-1 satellite detected a methane plume near the Fukushima Gas Power Station in Shinchi, Soma District, Fukushima Prefecture. (Source: Carbon Mapper) 

Regulatory loopholes in methane oversight 

Despite methane’s climate impact, Japan lacks binding regulations specific to methane leak detection, reporting, or mitigation. No laws require real-time monitoring, satellite data integration, or emissions control protocols in the power sector. Even when international satellites detect leaks, such as the one in Fukushima, Japan’s current framework offers limited capacity to respond quickly or transparently. 

While methane reduction efforts are underway in sectors like agriculture—particularly in the rice paddies industry, which is already facing economic strain—the government appears to be giving the powerful gas industry a free pass. Despite growing attention to methane’s climate impact, regulators seem more focused on curbing emissions in sectors that are easier to control, while allowing major emitters like oil and gas to expand with minimal oversight. 

“Methane super-emitters represent a disproportionate climate risk and opportunity — contributing 20–60% of a region's total emissions in some sectors. Granular satellite data like ours can help operators find and fix large methane events from gas fired power plants and other types of infrastructure in the energy sector, resulting in large reductions that, with sustained monitoring, can stay mitigated," said Daniel Bon, Carbon Mapper Program Manager for Energy and Public Health. 

The Environmental Impact Assessment (EIA) Act mandates reviews for large infrastructure projects, but methane is often underexamined compared to CO₂ in practice. The High-Pressure Gas Safety Act and Gas Business Act focus primarily on physical safety of the workers, not climate impacts of methane as a GHG. Local ordinances, including those in Shinchi Town, do not require methane-specific oversight during LNG plant construction or operation. 

Japan’s participation in voluntary frameworks like the Coalition for LNG Emission Abatement toward Net-zero (CLEAN) has promoted industry dialogue—but without enforceable mandates, their impact has been limited. National GHG reporting rules include methane but lack binding reduction targets.  

Lastly, while Japan is making progress on methane data collection—such as through the upcoming launch of the GOSAT-GW detection and monitoring satellite—the real challenge lies in the lack of strong, enforceable regulations and emission reduction measures. 

LNG dependence behind the plume  

Japan imports 94% of its primary energy supply, making it one of the most energy-import-dependent countries in the world. Since the 2011 nuclear shutdowns, LNG has served as a key baseload energy source, touted as a cleaner and more reliable alternative to coal or nuclear power. While the government has pledged to expand renewables and restart nuclear plants, LNG remains dominant and is projected to play a major role through the 2030s. 

But this strategy carries hidden climate costs. In 2023, upstream methane emissions linked to fossil fuel imports, including LNG, totaled 48.6 million tons of CO₂ equivalent. Though often viewed as an upstream issue, the Fukushima case reveals that emissions can also occur within Japan’s domestic infrastructure—during storage, transfer, and combustion.  

The Fukushima leak, spotted by an international satellite rather than Japan’s own systems, underscores glaring oversight gaps and undermines the government’s push to position LNG as a “clean” transition fuel across Asia. 

Methane risks prompt calls for coordinated regional response  

The Fukushima leak is not an isolated case. In February 2025, Carbon Mapper detected a super-emitter plume of approximately 5,700 kg/hr at South Korea’s Incheon LNG terminal. These cases signal broader regulatory gaps in Asia’s expanding LNG-to-power sector and call for coordinated regional policy action.  

As one of the world’s largest LNG importers and a major financier of gas infrastructure across Asia, Japan has an opportunity to set a regional precedent. Strengthening domestic methane oversight within its energy sector could help push for higher transparency and regulatory standards across Asia’s gas supply chains. 

“The Fukushima methane leak is a wake-up call. While further verification is needed, the case highlights persistent gaps in methane oversight. Japan needs to step up—by strengthening domestic monitoring systems and advancing momentum toward regional methane standards across supply chains,” said Dr. Kate Azarova, Methane & HFC Team Researcher at Solutions for Our Climate (SFOC).   

ENDS.  

Solutions for Our Climate (SFOC) is an independent nonprofit organization that works to accelerate global greenhouse gas emissions reduction and energy transition. SFOC leverages research, litigation, community organizing, and strategic communications to deliver practical climate solutions and build movements for change.     

For media inquiries, please reach out to Antonette Tagnipez, Communications Officer, antonette.tagnipez@forourclimate.org.