A simple explanation of the fact that light magnetic monopoles have not been observed at accelerator experiments is given. It is based on a possibility of violation of C invariance in the electromagnetic interactions. Because of the difficulty of mon
opole registration, two interconnected problems arise: to formulate a theory describing monopole production (it should include a new force beyond the Standard Model of electroweak interaction), and to point the way to monopole observation. We consider a possibility, closely related to some experiments, of a modification of life time of radioactive elements by magnetic monopoles. The first part of the article is devoted to purely electromagnetic impact of monopoles, caused by the vertex M --> M + gamma. The second part, more speculative one, is based on experimental evidences in favour of the existence of some axial vector currents, responsible for a new force, which can stimulate, or suppress, decays of radioactive elements.