Jury is still out on EMFs and cancer.

The electric and magnetic fields (EMFs) surrounding electric-power lines and wires should be formally designated a "possible human carcinogen," according to the Aug. 10 report of an expert panel convened by the Energy Department and the National Institute of Environmental Health Sciences.

While hardly a stinging indictment, the conclusion nevertheless falls far short of dismissing the possibility that EMFs pose risks. The recommendation was based largely on human epidemiological studies and cellular research probing possible mechanisms by which EMFs might cause cancer.

For 9 days in June, a 26-member working group reviewed recent studies. At least 20 panel members agreed that although the data are "limited," magnetic fields generated by power-line frequencies might cause leukemia in children and occupational exposures might spawn leukemias in adults.

Data are "inadequate" to link workplace EMF exposure to other malignancies, such as breast cancer (SN: 6/18/94, p. 388) and brain cancer (SN: 1/21/95, p. 44), most panel members concluded. They also considered inadequate the data linking residential exposure and cancer, in part because the quality of the exposure assessments were seen as "a serious limitation."

While the panel concluded that test-tube studies provide moderate support for carcinogenicity at magnetic-field strengths above 100 microteslas (SN: 2/21/98, p. 119), it found less support for risks at the lower fields characteristic of most residential and occupational exposures. Finally, the panel considered but did not rule out the possibility that adverse effects other than cancer--such as sleep disturbances (SN: 1/10/98, p. 29) or the inhibition of a drug's function (SN: 11/29/97, p. 342)--might be triggered by EMFs.