Don't stay too long near open caskets: 4 in Japan die after inhaling carbon dioxide from dry ice in coffins

At least four people in Japan have died from inhaling carbon dioxide from dry ice used to preserve bodies inside coffins, prompting several agencies to issue a warning on Thursday (Sept 21): Don't stay too close to open caskets for too long.

Those who died were said to have stood too close for too long beside coffins with the remains of their kin, the Yomiuri Shimbun reported. They were between 40 and 70 years old.

Records indicate that the deaths occurred inside homes in Aomori in 2018 and in Okinawa in 2020, as well as funeral facilities in Miyagi and Miyazaki in 2021.

The Mainichi Shimbun, citing Japan's Consumer Affairs Agency (CAA), said that in each case, the victims were found near coffins set up for open viewing.

These incidents emerged as Japan's consumer watchdog and the All Japan Funeral Directors Co-operation (Zensoren), based in Tokyo, on Thursday sought improved ventilation during funeral services.

Dry ice is the solid form of carbon dioxide, or CO2. In typical conditions, CO2 is a colourless, odourless gas making up roughly 0.03 per cent of the air. Concentrations exceeding three per cent to four per cent can lead to symptoms like headaches and dizziness. At 10 per cent, it can impair vision, induce tinnitus and be lethal within a minute.

According to studies by the CAA and other agencies, CO2 concentration in closed coffins can reach as high as 90 per cent. When the casket's lid is removed, the concentration may remain high at about 30 per cent for as long as 50 minutes.

Professor Taro Mizutani, who teaches at Tsukuba University and is now the managing director of the Ibaraki Western Medical Centre, explained that because carbon dioxide is denser than air, it settles.

"Even with an open coffin lid, in confined spaces like inside a coffin, there's a risk of accumulating CO2. Getting close to the coffin, especially if a lot of dry ice is used, can expose you to the threat of CO2 poisoning," he told Yomiuri Shimbun.

Zensoren said the amount of dry ice used to preserve human remains should be adjusted based on a body's size and the duration of preservation. It has requested its members to check for any dry ice-related deaths and to advise those in funeral services of the risks involved.

"By taking the right precautions, such incidents can be prevented. Ensure the body is in a well-aired space and limit the number of visitors at once, allowing them only a brief moment with the deceased," said Prof Mizutani.

The CAA is advising those saying their farewells to the departed to not keep their faces near the casket for long periods of time and to keep rooms well ventilated.

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This article was first published in The Straits Times. Permission required for reproduction.