A nonprofit organization’s discovery in March that the radiation emitted by some portable induction-heating cooking stoves greatly exceed international limits has raised questions about the products’ safety and what is being done about it.
Though it has not been proved that exposure to electromagnetic fields is linked to health problems, including cancer, some experts are calling on the government and industry to take precautionary measures before science gives its verdict.
However, neither party seems eager to make attempts to limit electromagnetic field exposure from IH cookers, with authorities and manufacturers boasting of the products’ safety, while saying it is the responsibility of the other party to boost awareness of possible risks.
“IH cooking stoves are made to generate electromagnetic fields in an open space,” and it is difficult to keep at a distance from them when cooking, said Takenori Ueda of the Japan Offspring Foundation, the NPO that made the discovery.
Ueda added that IH devices emit the highest level of radiation among all household electric appliances. Microwave ovens are more powerful, but their emissions are countered by stronger shielding.
IH cookers generate electromagnetic fields when an electric current flows through coils under the top plate. Heat is created when the electromagnetic field reacts with the metallic pan atop the plate.
Portable IH units are becoming increasingly popular in Japan as a substitute for a conventional stove. As they do not use gas, they are especially attractive to elderly people who are concerned about fires.
According to the Japan Electrical Manufacturers’ Association, domestic shipments of IH stoves increased 51.8 percent from 191,000 units in 1998 to 290,000 in 2001. Of this figure, tabletop types totaled 225,000 in 2001 alone.
The foundation tested tabletop IH cookers made by Hitachi Ltd., Matsushita Electric Industrial Co., Mitsubishi Electric Corp., Sanyo Electric Co., Zojirushi Corp. and Tescom & Co. The units were tested with a radiation measuring device placed right next to the cooker set on maximum heat with a 12-cm pan on it.
All products registered incredibly high radiation levels, some as high as 1,013 milligauss, according to the NPO.
The highest level was more than 16 times the 62.5 mG limit set by the International Commission on Non-Ionizing Radiation Protection for short-term exposure to such fields. The ICNIRP is currently cooperating with the World Health Organization on research into the health effects of electromagnetic field exposure.
Although the companies acknowledged the NPO’s findings, they said the ICNIRP guideline can be interpreted differently and that radiation levels do not exceed the limit when measuring devices are placed 30 cm away from the device.
But Ueda of the NPO said the figures are not the only problem. The manufacturers failed to disclose information regarding electromagnetic field exposure to consumers, he said.
In 1990 in Japan, the then Posts and Telecommunications Ministry set safety guidelines to protect people from electromagnetic field exposure. The legal limit for electromagnetic fields emitted within the frequency bands used by IH cooking devices — 910 mG — is more than 14 times that of the ICNIRP, but Yasuo Shiga of the Public Management, Home Affairs, Posts and Telecommunications Ministry maintained that the figure simply reflects a different conversion method and that there is no significant difference.
The ministry believes its measures provide sufficient protection. If concerns remain, the industry or individuals should do something about it, Shiga added.
However, the Japan Electrical Manufacturers’ Association said that it is not planning to take any further action regarding exposure to electromagnetic fields.
“We believe that we have already set appropriate safety standards in line with the ICNIRP guideline,” group spokesman Kenji Omi said.
He conceded, however, that no one can be 100 percent sure at this time that electromagnetic fields do not pose any health risks.
Omi added that if there is to be a framework for more stringent safety measures regarding exposure to electromagnetic fields, the government should take the lead in drawing it up.
At the same time he agreed that manufacturers have failed to provide consumers with sufficient information on electromagnetic fields. To this end, the association plans to update its Internet site within the next few months to include in-depth information on the subject.
Omi said the many people who have voiced fears of possible health problems caused by such radiation have unnecessarily fueled public concerns, and thus firms are responsible to explain the situation or IH stoves will be tagged as evil.
“I’ve never heard of any health problems stemming from electromagnetic fields emitted by the (IH) products,” he said, adding that if people are still afraid of adverse effects, they should individually take whatever measures they feel are appropriate.
However, some critics note the case of Manami Matsuhira, a housewife and mother of two residing in Takikawa, Hokkaido.
When she approaches operating electric appliances, such as microwave ovens, she suffers headaches, dizziness and tingling sensations — a condition that some medical experts call electromagnetic hypersensitivity.
She does not have an IH stove at home, but had an experience with the device when she went on a vacation in March last year and stayed in a cottage equipped with one.
When her friend turned the cooker on, her body was thrown backward as if she received a heavy blow — even though she was standing almost a meter away from it, she claimed. She said she immediately left, but headaches, dizziness and tingling continued for about an hour.
“How can I believe what the companies say (about the product’s harmlessness)?” Matsuhira asked, adding that it is almost impossible to convince others that her symptoms are caused by electromagnetic fields because the fields are invisible.
Koya Ogino, a Kyoto University lecturer who specializes in electromagnetic fields, criticized both the government and industry for not taking further precautions.
“If the companies are profiting by selling the products, they should first confirm their safety,” he said.
Ogino is most worried about the potential health complications brought on by long-term exposure, which he believes takes years to surface. There are presently no guidelines anywhere in the world that cover possible long-term health effects.
Citing the European Commission’s policy that precautionary principles be applied when considering restrictions on goods that pose risks to human health, Ogino said Japan is lagging in adopting such a stance.
Noting how the government has not learned anything from past failures to prevent problems, such as pollution-related illnesses and the outbreak of mad cow disease, Ogino said, “It will be too late if we wait until the required research turns up solid evidence.”