More than 40 families affected by the fatal outbreak of Legionnaires' disease in Edinburgh are to sue two companies they believe were responsible.
Lawyers have begun civil action against pharmaceutical firm MacFarlan Smith and North British Distillery.
Four people died and there were 92 cases of Legionnella detected in the summer of 2012.
It was the worst outbreak of Legionnella in 10 years.
The source of the infection is believed to have come from cooling towers.
Nine sites were tested across a wide area to the west and centre of the city. At the very heart of the outbreak around Wheatefield Road, MacFarlan Smith pharmaceuticals was visited nine times and a total of 49 samples were taken.
Next door at the North British Distillery, which was visited by scientists four times, 15 samples were taken.
In April, the Health and Safety Executive said it had been unable to conclusively determine the source.
The Crown Office said there was not enough evidence to prosecute. But now lawyers for some of the families affected have lodged a civil case against both North British and MacFarlan Smith.
Helen Booth, 62, contracted Legionnaires at her work in the Gorgie area. She became increasingly unwell over a weekend in June 2012.
She told BBC Scotland: "Somebody has to be held accountable for it.
"There is blame somewhere and I think it has been swept under the carpet.
"It is not a monetary thing, it's to find out why this happened and will it happen again to someone else. It shouldn't be allowed, someone should be held responsible.
"We need answers, we need someone to stand up and say, look this was our neglect, this was our fault, someone is to blame."
Patrick McGuire, of Thompsons Solicitors said: "We have a situation in our capital city where there's an outbreak that has caused death, that has caused untold damage, and we're told we don't know what has happened or why it has happened.
"They [the families] deserve answers and most of all they deserve compensation and I'm going to be there every step of the way in that process."
Professor Alison McCallum, NHS Lothian director of public health and health policy, said: "I would once again express my sincere condolences to the families of those who died during this outbreak and the patients affected.
"The review of outbreak management and the subsequent public health research has provided valuable information in enhancing the existing knowledge on Legionella outbreaks and control.
"This report allows us to share our experience and findings with other public health teams across the globe."
A North British Distillery spokesman refused to comment.