The decision not to hold a long-awaited investigation was reached last year but no public announcement was made and victims and relatives have only recently been informed.
There were 56 confirmed cases in south-west Edinburgh in the summer of 2012, in what was Scotland’s worst Legionnaires’ disease outbreak in more than a decade.
Criminal proceedings are now being considered against “a number of companies” for health and safety breaches unrelated to the deaths.
Helen Booth, 64, was one of those who fell severely ill with Legionnaires’ in June 2012, when she worked as a council receptionist in the Gorgie area of the city. She said she was “devastated” at the Crown Office’s decision not to hold an inquiry.
She added: “It’s a disgrace. It’s pathetic, really pathetic. But I will not leave it. This is not going to go away.”
Mrs Booth, who was left with scarred lungs as a result of pneumonia caused by her Legionnaires’, said the tragic events five years ago had been “swept under the carpet”.
The Crown Office has informed the families of those who died and the representatives of a number of survivors about last year’s decision.
Lawyers representing victims said they had been left “surprised and disappointed” at the move.
They have spent the past few years trying to launch civil actions against two Edinburgh firms.
But the cases were stalled while the Crown Office deliberated over whether to launch an inquiry, which would have investigated the circumstances of the deaths.
And now crucial documents will remain out of bounds once again while criminal proceedings are ongoing - further frustrating families’ attempts to get answers.
A report by NHS Lothian in 2015 named nine sites as potential sources of the outbreak, which spread through an “aerosol release” of bacteria.
But no definite cause was ever found and no-one was ever prosecuted.
A Crown Office spokesman said: “Crown Counsel are satisfied the [NHS Lothian] report has put all the available information in the public domain, providing a detailed description of the investigation and the steps taken in attempting to identify the source of the infection and that on that basis there is no requirement to hold a fatal accident inquiry.”