The results of an experiment aimed at verifying the conclusions drawn in the studies that were performed at the Institute of High-Temperature Electrochemistry (IHE, Yekaterinburg) and which report the observation of neutron emission due to low-temperature dd fusion in Nax-WO3/deuterium systems are presented. Within statistical errors, the excess of the neutron yield above the background level is not observed in our experiment for the interaction of deuterium and deuterium-tritium mixture with oxide tungsten bronze. The hypothesis that hot dt fusion is possible in such systems is not confirmed either. The results of this study cast some doubt on the validity of the conclusions drawn in the IHE reports. At a 90% confidence level, an upper limit on the intensity In of a hypothetical neutron source associated with dd and dt fusion in the single crystals of oxide tungsten bronze is estimated to be 5 × 10-3 s-1.