[en] As has been reported from Orsay (France), superheavy transactinides with a subsequent α decay are discovered in technical oxide of Hf. In this case spontaneous fission is a competitive or basic process for some isotopes in the chain. According to the data reported the content of superheavy elements corresponds to T/C approximately 9x10¹⁹ years (T is half-life of the hypothetical superheavy element, C is its concentration in a sample). The paper is performed with the aim of duplicating the results of Orsay (France). Studied were: chemically pure dioxide of Hf, Hf technical concentrate (base - 42%-Zr, content of U - 1.5x10^-2%); Hf concentrate purified from uranium (content of U in a sample after extraction was 2x10^-6 g/g). Measurement were taken by large proportional counters and by a detector of multiple neutron emission. The data obtained on the spontaneous fission provide limits for a hypothetical superheavy element (depending on a sample and the type of a detector) of T/C is greater (or equal to) than 2x10²⁰-10²² yeras. Therefore, if superheavy elements are present in samples under test, their concentration is hundreds of times less at least than that reported by the group from Orsay