IARC's final conclusion (IARC 2002) is as follows: Overall, extremely low frequency magnetic fields were evaluated as possibly carcinogenic to humans (IIB), based on the statistical association of higher level residential ELF magnetic fields and increased risk for childhood leukaemia. Thus, although the evaluation is based on epidemiologic studies of childhood leukemia, the classification applies to all human exposure to ELF MFs, and thus also to occupational exposure. This interpretation has been discussed and confirmed with an IARC representative on their ELF MF panel (Cardis E, personal communication). Because enough workers are exposed to ELF MFs to clearly meet the criteria for occupational exposures set by Siemiatycki et al. (2004), we are surprised that they did not include it in their list of possible occupational carcinogens.