The Zoning Hearing Board may, by special exception, determine that a proposed use is sufficiently similar in character and impact to that of a listed use and that the proposed use may be treated the same as the listed use. The applicant shall have the burden of proof to show that the proposed use would not be a threat to public health and safety and would not generate significant nuisances to adjacent residential areas. This provision shall only apply to a use that is not listed as being prohibited in the applicable district.