The issue of magnetic fields represents a risk to worker safety, as also remarked in the new Legislative Decree no. 81/08. For example, welding positions represent a possible risk of transmission of magnetic fields. Through the use of specific probes for detection and using an appropriate protocol measure we are able to assess the amount of emissions produced by such devices, in terms of magnetic induction expressed in Tesla (T), and we are working on a technical and structural changes to be made to various types of welding tools in order to reduce the emission of magnetic fields to the point of lessening the intensity of about one order of magnitude compared to the previous situation.