The uncertainties regarding the link between electromagnetic fields and human health are a source of confusion for electric appliance manufacturers and have in some cases led to inconsistencies in product safety standards.

Induction-heating stoves emit electromagnetic fields within the same frequency band as video display terminals, which commonly take the form of computer screens.

Since 1993, member firms of the Japan Electronics and Information Technology Industries Association have voluntarily lowered the electromagnetic field exposure limits on their VDTs to levels to 0.25 milligauss at frequencies between 2 kHz and 400 kHz.

This is well below the 62.5 mG limit set by the International Commission on Non-Ionizing Radiation Protection.

Under certain circumstances, however, the radiation emitted by some of their IH cooking devices — whose frequency bands overlap with those of the VDTs — exceed the ICNIRP levels.

One reason behind the seemingly incoherent policy and lack of information regarding electromagnetic field exposure is that research on the fields’ impact on humans is still incomplete.

Indeed, the scale and nature of the fields vary with frequency in a complex way, and not all frequencies have been fully researched.

Manufacturers have pointed out that while the current debate over effects on human health is centered on electromagnetic fields in the extremely low frequency range of 60 Hz, the frequency range of the fields emitted by an IH stove is much higher — ranging from 17 kHz to 24 kHz.

They also pointed out that the ICNIRP limit is more stringent than what research has shown is necessary.

The stoves should not be linked to the electromagnetic field issue at the present time, they said.

JEITA, whose member firms include Hitachi Ltd., Matsushita Electric Industrial Co., Mitsubishi Electric Corp. and Sanyo Electric Co., introduced its voluntary guidelines in the hope of easing user concerns, even though it believes its products have no harmful effect on health, association spokesman Hisami Dejima said.

“We, as manufacturers, must give top priority to dispelling consumers’ fears,” he said.

But one simple question remains. Why should one firm take two different approaches for products that emit electromagnetic fields of the same nature? Some critics allege that manufacturers follow stringent safety standards adopted in other countries for goods that they export, but not for those limited to domestic use.

“What we have done (to reduce emissions for) computer screens is based on what is technically achievable,” said Matsushita Electric spokesman Tetsuo Egawa, who acknowledged that as exposure to the fields decreases, the lower the chance for human health to be affected.

Egawa added that Matsushita plans to provide safety information on electromagnetic fields for consumers in the near future while it develops technological advances to further reduce emissions for IH cooking devices.

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