It is claimed that, in a certain experimental apparatus, cold fusion produces I W of heat over and above the input power. Assuming that the origin of the heat is indeed the fusion of two deuterium nuclei to provide a3 He nucleus and a neutron, estimate the whole-body radiation dose in Sieverts received over a period of two hours by a curious but incautious observer of the experiment. The radiation biological effectiveness (RBE) of fast neutrons is 109.