A new internal audit has found a government program to improve worker safety has failed to do its job. Labor Department investigators say the Occupational Safety and Health Administration failed to collect data, carried out incomplete inspections and missed out on identifying hazardous workplaces because it misspelled company names or didn’t realize two subsidiaries had the same owner. The report also criticizes the Bush administration’s move to restrict the number of companies subject to special attention, saying better oversight might have improved workplaces where fifty-eight workers lost their lives.