NEW YORK -- As people have become more exposed to sources of electromagnetic fields (EMFs), such as microwave ovens, computer screens and mobile phones, they’ve become more concerned about the effects EMFs have on their health. The World Health Organization (WHO) concluded that current evidence does not confirm the existence of any health consequences from exposure to low-level electromagnetic fields. But the organization also points out that scientists still need to fill in some knowledge gaps about the biological effects of EMFs.

This health issue arises again in the greening of fleets: Hybrid vehicles are another source of EMFs. A New York Times article said that a hybrid’s electrical current, which propels the vehicle at low speeds and assists the engine at higher speeds, causes EMFs. The fields are generated close to the driver and passengers, so some exposure is unavoidable.

Honda said that no federal standards exist for allowable exposure levels of EMFs. And Toyota says that the EMFs in its hybrid vehicles are at the same levels as those in gasoline vehicles, so there are no additional health risks.

Some owners of hybrids have used handheld meters to test their vehicles, and some owners interviewed by The New York Times sold their cars because they were concerned about EMFs. Automakers are not sure how reliable the owners’ measurements are.

Scientists agree that more research is necessary. While it is known that occupants of hybrid vehicles are exposed to EMFs, it is not known exactly how these fields affect the body or whether the levels of EMFs are harmful.