Major Japanese chemical maker Daikin Industries Ltd. conducted blood tests on employees in the past following possible exposure to potentially harmful PFAS chemicals, a source familiar with the matter said Saturday.

It is the first known case of a Japanese manufacturer conducting PFAS blood tests, which took place from the early 2000s to around 2015. Some results showed PFAS blood concentrations that were 500 times the level in guidelines set by U.S. academies, although no impact on health was confirmed, according to the source.

While Japan has not set a safety standard for PFAS blood levels due to insufficient expertise, an Environment Ministry official said the Daikin data, if made public, could be useful for PFAS-related research.

PFAS, also known as "forever chemicals," are a group of over 10,000 synthetic substances that include PFOS, or perfluorooctanesulfonic acid, and PFOA, or perfluorooctanoic acid.

Resistant to oil, water and heat, they are used in various products ranging from fabrics, food packaging and nonstick cookware coatings to fire-fighting foam. But they do not degrade easily and can accumulate in soil and water as environmental pollutants.

Recent surveys in Japan have shown PFAS contamination in tap water and rivers, and around factories, U.S. military bases and Japan Self-Defense Forces facilities, raising concern about possible health risks such as cancer.

Daikin, also a leading air conditioner manufacturer, conducted the blood tests on at least 100 employees who were involved in PFOA production, with some showing at least 10,000 nanograms per milliliter, the source said.

The U.S. National Academies of Sciences, Engineering, and Medicine says individuals exposed to seven PFAS chemicals with blood concentrations of over 20 nanograms per milliliter could face a higher risk to health.

Daikin on Monday explained the blood tests to residents living near its Yodogawa manufacturing plant in Settsu, Osaka Prefecture.

"We conducted blood tests on those who were employees in 2000 and the results were around four- or five-digit figures. We were relieved because we did not confirm any impact on health," the senior official was quoted as saying by the source.

In a nationwide survey conducted by the Environment Ministry in 2020, PFAS chemicals significantly in excess of the government's provisional cap of 50 nanograms per liter were detected in the groundwater in Settsu.

Daikin, which is based in the city of Osaka, declined to comment on the specific exchanges that took place during the meeting with the residents, but it said it is continuing to formulate its "response while the impact of (PFAS) accumulation in the human body remains unexplained."

The company had ceased manufacturing and using PFOA in its domestic and overseas facilities by 2015, according to its website. It also says it has never manufactured or used PFOS.

In line with the Stockholm Convention on Persistent Organic Pollutants, Japan bans in principle the manufacture and importation of PFOS and PFOA.

==Kyodo

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