The labor commissioner shall immediately inspect a scaffold, ladder, or device concerning which complaint is made. He shall attach to every scaffold, ladder, or device that he inspects a certificate stating that he has made the inspection and has found the same safe or unsafe as the case may be. If unsafe, the commissioner shall at once, in writing, notify the person responsible for the scaffold, ladder, or mechanical device of the fact and shall prohibit the use of it by him or by any other person until all danger is removed by alteration, reconstruction or replacement as the commissioner may direct. Such notice may be served personally upon the person responsible or by affixing it conspicuously to the scaffold, ladder, or device declared unsafe.