Dr. Kunio Kanetani reports on the health damage suffered by Daikin Industries workers, April 23, 2025 (photo by Nanami Nakagawa)

Health damage has been reported among workers involved in the production of PFOA at Daikin Industries.

This was discovered by a research team consisting of Kyoto University’s researchers and doctors.

The health damage was reported in three workers at a PFOA factory. They showed symptoms of “interstitial lung disease,” which reduces respiratory function. The three had one thing in common: abnormally high PFOA concentrations in their blood. They also had a history of working in PFOA manufacturing at Daikin’s Yodogawa Plant.

When Tansa interviewed former workers, they said that powder was released into the air during the PFOA production process, but that proper powder prevention measures had not been taken.

The research team warns:

“Like mesothelial tumor caused by asbestos, interstitial lung disease develops more than 20 years after exposure to PFOA. The health damage to workers will go beyond 5 or 10.”

PFOA detected in Daikin workers at levels 298 times higher than the national average

The health damage to Daikin workers was reported in a paper in the occupational health scientific journal “Industrial Health” in April 2025.

The paper was written by a research team consisting of Akio Koizumi and Koji Harada of Kyoto University, pioneers of PFAS research in Japan, and doctors with experience treating patients with occupational exposure to harmful substances. The members are as follows:

Kunio Kanetani, Ueni Seikyo Clinic

Kenji Nakamura, Osaka Institute of Social Medicine, Nozato Clinic, specializes in occupational health

Koji Harda, Health and Public Sciences of Kyoto University School of Public Health, Graduate School of Life and Environmental Sciences of Kyoto Prefectural University

Hideaki Akihisa, Himejima Clinic

Tamiki Oshima, Aikawa Clinic

Hiromi Ogata, Mimihara Otori Clinic

Akio Koizumi, Health and Public Sciences of Kyoto University School of Public Health, Social Health Medicine Welfare Laboratory

How did they discover the damage? The starting point was a PFAS blood test that these doctors and researchers had previously conducted.

From September to December 2023, the “Osaka PFAS Contamination and Health Study Group,” to which those doctors and researchers belong, conducted PFAS blood tests on 1,190 people. This was the largest private PFAS exposure survey in the country, targeting residents and commuters in Osaka Prefecture. Tansa also reported on the survey.

The highest level was 596.6 ng/mL. This is 298 times the national average of 2 ng/mL. It was not included in the statistics because including it would have raised the average value and affected the accuracy of the data. This is about 30 times the US guideline value of 20 ng/mL, which is considered to have adverse health effects.

The person with the highest concentration was working in PFOA manufacturing at Daikin’s Yodogawa Plant in Settsu City, Osaka Prefecture.

Interstitial lung disease affects 1 in 100,000 people, but it is 3 in 7 in Daikin’s case

The research team conducted a follow-up study.

The survey participants were seven Daikin workers, including both current and former employees.

All seven were found to have been exposed to PFOA.

The seven people were interviewed in detail about their time working at Daikin, the specific tasks they performed, and the safety precautions they took during those tasks. They were also asked about their health, medical history, and lifestyle habits. Of the five people with “extremely high levels,” a health examination was conducted at a medical institution.

Dr. Kanetani interviewed worker A. When Dr. Kanetani learned of the PFOA concentration in Worker A’s blood, he felt that this was “tremendous data.”

“Are you concerned about the health effects of PFOA?”

In response to Dr. Kanetani’s question, worker A replied, “I have interstitial lung disease.”

Interstitial lung disease is a disease in which the lungs become fibrotic and hard, making it difficult to breathe. Frequent coughing, excessive phlegm, hoarseness and weight loss are reported by worker A. However, when Dr. Kanetani checked the medicines he was given by his doctor, there were none that were effective against interstitial lung disease.

Just to be sure, Dr. Kanetani suggested a CT scan, which revealed several white lines in the lungs, a sign of interstitial lung disease, just as worker A had said.

At the time, Dr. Kanetani thought, “I don’t know if this is the result of exposure to PFOA.” However, his thinking changed 180 degrees.

Daikin worker B was later diagnosed with interstitial lung disease through a CT scan.

Worker C was also found to be suffering from interstitial lung disease. He joined the company in the 1970s and worked in processes that handled PFOA for over 45 years. A lung abnormality was found during a health check before he retired from Daikin. It was severe interstitial lung disease. In 2020, he experienced an acute exacerbation accompanied by a fever and was hospitalized. At one point, he was in a life-or-death situation. His symptoms improved and he was released from the hospital, but he still suffers from severe shortness of breath due to the aftereffects.

Three out of seven people exposed to PFOA developed interstitial lung disease or symptoms of the disease, which is thought to affect approximately 1 in 100,000 people.

In addition, workers D and E, who were not found to have interstitial lung disease, were found to have lung lesions, abnormalities in the lungs.

Dr. Kanetani had a hunch: “It’s odd that the probability is so high. It must be related to PFOA exposure.”

In the 1960s, when Dr. Kanetani was a medical student, chemical pollution was occurring all over the country. As a student, he was involved in epidemiological surveys in Sakai City, Osaka, and after graduating, he continued to study the latest in respiratory medicine. As an internist, he treated patients suffering from pollution. He has also written doctor’s opinions in pollution lawsuits, including cases involving asbestos damage.

Inadequate measures to combat PFOA exposure

Further investigation confirmed Dr. Kanetani’s hunch.

The five people who had lung abnormalities had been working at Daikin where they could have inhaled PFOA powder. The powder is made up of very small particles called “nanoparticles,” and if thorough exposure measures are not taken, it can be taken into the human body. Once inside the body, it can cause a variety of illnesses.

Despite this, Daikin’s PFOA exposure countermeasures were lax.

Worker A was engaged in the manufacture of PFOA from the 1970s to the 2010s. He was aware that the work environment was dusty, so he wore a dust mask provided by the company. However, he would sometimes remove the mask when working in an office away from the manufacturing area. Dust would frequently adhere to his clothing.

Worker D was engaged in the same work process as worker A.

Worker C worked next to worker A’s workplace, but the workplace was not airtight, so he shared the same air as worker A.

Worker B started working at the company in the late 2000s. He only wore commercially available gauze and paper masks. During periods of high dust levels, he would ask the company to provide him with a dust mask and wear one.

Worker E was a colleague of worker B. Worker E was in charge of cleaning the containers used to transport PFOA. Worker E was aware of the large amount of dust, but did not take any dust prevention measures.

In an interview with Tansa, worker E said:

“There was a washing machine at work, but it was too much of a bother, so I washed my clothes at home. I used to bring home clothes covered in powder.”

“There were masks and gloves at the workplace, but the male workers in particular took them off because they were hot and bothersome.”

The reason for not responding is that “our company has not written any papers”

On April 23, 2025, the day after the paper was published in a scientific journal, the research team held a press conference in Osaka. The doctors sounded the alarm:

“Interstitial lung disease is advanced by the time symptoms appear.”

“Mesothelioma caused by asbestos can appear 20 or 30 years after exposure. The same goes for interstitial lung disease. It can also appear after retirement.”

Daikin manufactured and used PFOA for approximately 50 years, from the late 1960s until 2012. Dr. Kanetani had this to say about the number of victims:

“It can’t just be 5 or 10 people. We need to continue to monitor the situation.”

Daikin is the only one that has information on PFOA manufacturing workers. Unless Daikin launches its own investigation, there will be no progress in identifying the victims. If the victims are not identified, Daikin and the government will be unable to take any relief measures, and there is a risk that the health damage will worsen.

Tansa asked Daikin CEO Masanori Togawa the following questions in a questionnaire:

1. In light of the contents of this paper, is Daikin Industries going to inform the workers who have previously been involved in the production and use of PFOA at the Yodogawa Plant of the toxicity of PFOA and the risk of developing associated diseases?

 

2. This paper confirms that people who have worked at the Yodogawa Plant have been exposed to high levels of PFOA. In light of this result, is Daikin Industries going to conduct a survey on PFOA exposure among workers who have worked at the Yodogawa Plant in the past and present?

 

3. In light of the contents of this paper, is Daikin Industries going to conduct a health survey on workers who were previously involved in the production and use of PFOA at the Yodogawa Plant?

 

4. Is Daikin Industries going to provide compensation to those who develop interstitial lung disease as described in this paper?

 

 5. It is said that interstitial lung disease, like mesothelial tumor caused by asbestos, develops more than 20 years after exposure. Does Daikin Industries think that people who have worked at the Yodogawa Plant may develop interstitial lung disease in the future?

 

6. This paper is significant because it concerns the health and lives of your workers. As a manufacturer of PFOA, which was the subject of this paper, does Daikin Industries need to have an opportunity to have a dialogue with the authors?

The response came from the Public Relations Group of Daikin’s Corporate Communications Department.

We were not involved in the creation of the paper in question and are not familiar with the details of its analytical methods or accuracy, so we will refrain from commenting on this series of questions.

They said they could not answer the question because it was not their own paper. However, the analysis method and precision are detailed in the paper. And since it was published in the scientific journal “Industrial Health,” it is a peer-reviewed paper. It seems that they “cannot answer,” but rather that they “don’t want to answer.”

Why is Daikin refusing to respond? Tansa has obtained internal documents that are extremely inconvenient for Daikin.

A paper published in the scientific journal Industrial Health on April 22, 2025 titled “High serum perfluorooctanoic acid (PFOA) concentrations and interstitial lung disease in former and current workers in a fluorochemical company”

(Originally published in Japanese on May 20, 2025. Translation by Mana Shibata.)

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