Re: "Acute Nonlymphocytic Leukemia and Residential Exposure to Power-Frequency Magnetic Fields".

The analyses presented here are available in greater detail elsewhere. They are not the analyses used to present the data in the original report, but we believe that they are reasonable analyses, suggested by the study's own measurement data, earlier published findings, and consideration of the likely sources of chronic residential magnetic field exposure among adults in the Washington State locale. If the association of magnetic field exposure with acute nonlymphocytic leukemia indicated by the analyses in table 1 is causal (and that is an important "if"), then the data suggest that some 25 per cent or more of these cases in the Washington State locale could be attributable to chronic magnetic field exposure--and that would obviously be a very important consequence. The risk, if real, is not trivial. And since protection from some important sources of exposure (such as electric bed heaters) is easily obtained, it seems hard to find any justification for not pursuing further studies of this subject immediately and vigorously.