It has been two and a half years since high levels of PFOA were discovered in the tap water in Kibi-Chuo Town, Okayama Prefecture.

On April 24, 2026, local activated carbon recycler Man-ei Industry filed a request for environmental mediation with the Okayama Prefecture Environmental Pollution Review Board. Man-ei Industry maintains records showing that it received activated carbon containing PFOA from Daikin Industries, leading the company to conclude that Daikin was the source of the contamination.

PFOA discharged from activated carbon containing PFOA that Man-ei Industry had been storing on property close to the dam, which is why Kibi-Chuo Town’s tap water was contaminated. The town is suing the company for damages and holding it accountable.

However, it remained unclear which company had supplied the PFOA-containing activated carbon to Man-ei Industry.

Because PFOA does not decompose naturally and needs to be managed by humans, it is frequently referred to as the “forever chemical.” Daikin is one of the world’s eight major PFOA manufacturers and began developing the substance shortly after World War II. The company produced large quantities of PFOA until 2015.

Is it true that the contamination in Kibi-Chuo Town is caused by Daikin’s PFOA? How, where, and when has Daikin’s PFOA been disposed of over the years? Are there any unidentified contaminated sites or places that might get contaminated in the future?

Daikin must conduct an immediate investigation and provide an explanation.

PFOA detected at 90,000 times the national water quality standard

PFOA is a type of organic fluorinated compound known as a “PFAS.” Among the more than 10,000 types of PFAS, PFOA is known to pose a significant risk of cancer and to have severe health effects on pregnant women and children, and its manufacture and import are prohibited.

Tap water containing PFOA was being supplied to the Enjo district within the town. This area is home to approximately 1,000 people across about 500 households in Kibi-Chuo Town, which has a population of about 10,000. In October 2023, a prefectural official reviewing water quality data from various municipalities noticed the issue, leading to the suspension of the water supply.

In a blood test conducted by the town, 709 residents were tested, and 619 of them—87%—had levels exceeding 20 ng/mL, the threshold at which the U.S. government guidelines recommend intervention. High exposure levels were also particularly prevalent among children aged 2 to 12; of the 65 children tested, 53—82%—exceeded this threshold.

According to U.S. government guidelines, levels of 20 ng/mL or higher require “medical intervention to address the risk of kidney cancer, testicular cancer, ulcerative colitis, thyroid disease, and other conditions.”

The prefecture was responsible for identifying the source of the contamination.

The source of the contamination was a materials storage yard located not far from the site where the highest concentration was detected. The yard contained 580 one-ton Flexible Intermediate Bulk Containers (FIBC) filled with activated carbon. Having been left outdoors for many years, the bags had torn, and the activated carbon had scattered. The PFOA, exposed to rain and wind, seeped into the ground and flowed through the river into the dam that serves as the source of the town’s tap water.

The prefecture collected activated carbon samples at 30 random locations and tested the concentrations, detecting a maximum of 4.5 million ng/L. This concentration was 90,000 times the national water quality standard of 50 ng/L.

Activated carbon left in a yard upstream of the dam for 15 years

The owner of the activated carbon was quickly identified.

“Man-ei Industry,” a local activated carbon recycling company, is a long-established firm founded in 1921. One of its core businesses is “activated carbon recycling.” Activated carbon is used to remove PFOA from water. Because it absorbs PFOA in water, it is highly valued by water treatment plants and companies that handle PFOA.

They collect activated carbon that has absorbed chemical substances from suppliers and process it at its own factory. Once the activated carbon is in a condition that allows it to absorb chemicals again, it is returned to the suppliers.

However, the company could not keep up with the volume, and excess activated carbon began to pile up on its premises. Man-ei Industry leased a storage yard from the town and began storing the activated carbon there around 2008. The company left the activated carbon there for 15 years, which led to the leakage of PFOA. The town billed Man-ei Industry for a portion of the costs, including expenses for purchasing alternative water due to the water supply being unusable and for water pipe replacement work.

Meanwhile, it remained unclear which company had supplied Man-ei Industry with the PFOA-contaminated activated carbon.

However, it is crucial to identify the company in question. In 2008, Man-ei Industry started storing activated carbon upstream of the dam. The ensuing poisoning of the tap water might have been avoided if Man-ei Industry had been made aware of the need to properly handle and dispose of PFOA, as its detrimental effects on human health had previously been established internationally.

Kyoto University’s Harada Makes a Breakthrough: “The composition matches”

Which company supplied Man-ei Industry with activated carbon containing PFOA?

The breakthrough came from Koji Harada, then an associate professor at Kyoto University. He analyzed the activated carbon from Man-ei Industry, in which high concentrations of PFOA had been detected.

Analysis of the components reveals the composition of the sample, including the types and proportions of PFAS it contains. Even though it is simply referred to as “PFOA,” there are actually many different types. The composition acts like a “fingerprint,” providing information about when, where, and how the substance was used.

The analysis results were released in November 2024.

The activated carbon stored by Man-ei Industry had the same composition as the PFAS detected in the vicinity of Daikin Industries’ Yodogawa Plant in Osaka. Daikin Industries manufactured and used PFOA for approximately 50 years, starting in the 1960s.

Having obtained the results of Harada’s compositional analysis, Tansa sent a letter of inquiry to Daikin in November 2024.

Tansa demanded an explanation, backed by evidence, regarding the connection between the PFOA-containing activated carbon discharged by Daikin and the PFOA contamination in Kibi-Chuo Town.

The following is Daikin’s response.

“We are unable to comment on the existence of specific transactions or any details regarding them.”

“We have arranged for the activated carbon used in our PFOA removal process to be incinerated through a specialized waste management company. As far as we can confirm, there is no fact that we have commissioned the regeneration of this used activated carbon. We ask that you refrain from any reporting or coverage that suggests a connection between our company and the Kibi-Chuo Town incident.”

Since then, Daikin has continued to deny any connection to the PFOA contamination in Kibi-Chuo Town on its website.

“With regard to the activated carbon used in our PFOA removal process, we have confirmed that we have not outsourced the regeneration of used activated carbon—which was the subject of concerns in Kibi-Chuo Town, Okayama Prefecture—and that the disposal contractor incinerates all of it.”

Tansa also sent a letter of inquiry to Osaka Gas Chemicals. Tansa began interviewing former Man-ei Industry employees and the company’s former president in February 2024. Osaka Gas Chemicals was identified as a business partner involved in PFOA-containing activated carbon during those interviews. However, in response to the letter of inquiry sent in September of that year, they replied as follows.

“There are no records indicating that the ‘activated carbon containing PFOA, which caused the contamination,’ was the activated carbon we commissioned, and we are unable to confirm whether that activated carbon contained PFOA.”

Meanwhile, Man-ei Industry refuses to reveal which company supplied the PFOA-contaminated activated carbon. Time passed as the situation remained deadlocked.

However, Man-ei Industry began to face financial difficulties. This was because the town had filed a claim for damages against the company.

Man-ei Industry reviewed its internal records. It confirmed that, as part of its business dealings with Osaka Gas Chemical, it had been receiving used activated carbon from Daikin.

On April 24, 2026, Man-ei Industry filed a request for pollution mediation with the Prefectural Pollution Review Board.

Daikin and Osaka Gas Chemical have denied the allegations

On April 21, 2026, Tansa sent letters of inquiry to Daikin and Osaka Gas Chemicals. The purpose was to verify whether the contamination of tap water in Kibi-Chuo Town was caused by PFOA-containing activated carbon discharged by Daikin. Both companies responded on April 23, denying the allegations.

Daikin: “With regard to the activated carbon used in our PFOA removal process, we have confirmed that we have not outsourced the regeneration of used activated carbon—which was the subject of concerns in Kibi-Chuo Town, Okayama Prefecture—and that all such carbon has been incinerated.”

Osaka Gas Chemicals: “As the details of our transactions with individual clients constitute customer-specific information, we are unable to comment on them; however, we believe that none of the points you have raised are accurate. Furthermore, when we undertake activated carbon regeneration, we verify that the materials submitted by our clients do not contain any PRTR-regulated substances—including PFOA—that exceed our acceptance standards. To date, we have never confirmed the presence of PFOA in any such materials.”

[Commentary] Daikin Should Reveal the Whereabouts of “Forever Chemical” / Reporter Nanami Nakagawa

Man-ei Industry filed for environmental mediation because it could no longer bear the responsibility on its own.

Until now, the company had neither acknowledged it was the source of the contamination nor apologized to the affected residents. However, the business cannot survive if it is unable to pay compensation. It was only when the company found itself cornered that it finally took action.

Man-ei Industry even appealed to the very residents they had harmed. They met with some members of an organization formed by concerned local residents. When one member suggested, “Couldn’t you appeal to the party that supplied you with PFOA-contaminated activated carbon to highlight the harm your company has suffered?” Takahiro Maeda, the president of Man-ei Industry, reportedly looked startled and seemed to see a glimmer of hope.

Filing for environmental pollution mediation is only the first step toward resolving the issue. To date, neither the contamination has been cleaned up nor compensation provided.

Kibi-Chuo Town’s tap water pollution indicates that there may be PFAS contamination across the nation and that this is only the tip of the iceberg.

PFAS are known as “forever chemical.” Unless treated by humans, they hardly ever break down naturally.

Nonetheless, no one knows exactly how much PFAS has been produced to date or where it is located.

The Japanese government and local authorities bear the primary responsibility for this situation.

Since the early 2000s, the dangers of PFAS have been recognized internationally. For example, as early as 2006, there was an international movement to phase out PFOA—a substance manufactured by Daikin and detected at high concentrations in Kibi-Chuo Town.

However, the national and local governments have not managed PFAS under the Waste Management and Public Cleaning Act or imposed producer responsibility.

This stance was also evident in interviews with the relevant authorities.

In November 2021, an official from the Ministry of Economy, Trade and Industry shared the following views with Tansa.

“We have already banned the manufacture and import of PFOA and PFOS. As for emissions (environmental pollution and human exposure), that falls under the jurisdiction of the Ministry of the Environment and the Ministry of Health, Labour and Welfare.”

However, officials at the Ministry of the Environment have no intention of taking responsibility.

“While it is true that the Ministry of the Environment has jurisdiction over waste disposal, Man-ei Industry’s activated carbon is not waste but a recyclable ‘material,’ so it falls under the jurisdiction of the Ministry of Economy, Trade and Industry.”

What about Okayama Prefecture, which is responsible for the health and well-being of its residents?

“Since these are materials, they are not subject to supervision under the Waste Management and Public Cleansing Act.”

Subsequently, the prefecture changed its position, stating, “Since the materials were not in a condition suitable for reuse, we will classify them as waste rather than materials.” However, when asked whether it would take action against Man-ei Industry in accordance with the Waste Management and Public Cleansing Act, the prefecture said it would not.

“We will not take action against events that occurred before the material was classified as waste. Nor will we conduct an investigation into the business that delivered the activated carbon to Man-ei Industry.”

The local government of Kibi-Chuo Town has also refused to disclose information regarding Man-ei Industry. To this day, it has not made public either the name of Man-ei Industry or the amount of the damages claim. A claim for damages is a significant matter that affects the town’s budget. Article 96 of the Local Autonomy Act specifies matters that require a resolution by the town assembly, and the amount of a damages claim is one of them.

No government agency, prefecture, or town is willing to take responsibility.

Nevertheless, just because the government is negligent and irresponsible doesn’t mean Daikin can get away with this.

As one of the world’s eight major PFOA manufacturers, Daikin has been producing and using PFOA for over 50 years. Beyond the case in Kibi-Chuo Town, the company must disclose when, where, and how it has processed these substances. It has a responsibility to reveal the whereabouts of these massive quantities of “forever chemical.”

Tansa has been investigating Daikin since 2021. Over the past five years, a series of new facts have emerged, yet Daikin has continuously refrained from offering explanations. Five years ago, the company did not even acknowledge that it was responsible for the PFOA contamination in Osaka. Now, however, it has been compelled to admit that it is partially responsible for the contamination.

During its period of rapid postwar economic growth, Japan experienced numerous serious cases of environmental pollution, such as Minamata disease. As the concept of “Business and Human Rights” becomes the global norm, there is no future for economic practices that result in victims.

In addition to the pollution mediation petition filed by Osaka residents, Daikin must take this situation in Okayama seriously.

(Originally published in Japanese on April 24, 2026. Translation by Mana Shibata.)

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