A family may not have been told that the death of their child was linked to an infection at Glasgow’s flagship hospital, Anas Sarwar has claimed.
More than 80 infected children and two deaths have been linked to the Queen Elizabeth University Hospital.
But the Scottish Labour leader said one family had still not been told that their child was affected.
He said it was feared it could be the family of one of the two children who died.
Mr Sarwar told the Scottish Parliament that the infections at the Glasgow hospital campus were the “biggest scandal of the devolution era”.
He said there were still families “fighting for the truth and for justice” over what happened to their children.
First Minister Nicola Sturgeon confirmed that all but one of the families involved had been contacted – and insisted that there had been “rigorous” attempts to get in touch with the relatives who had not yet been reached.
The first minister said a full independent inquiry had already been commissioned into the “incredibly serious matter” of the water-borne infections at the Glasgow hospital campus.
An independent review found that 84 children were infected with rare bacteria while undergoing treatment at the £850m QUEH campus.
More than 30 of the sick children – including the two that died – were found to have infections linked to contaminated water supply
The mother of one child – 10-year-old Milly Main, who was recovering from leukaemia when she went into toxic shock and died in August 2017 – has called for health officials to resign.
Milly’s family only found out about the probable cause of her death in a newspaper.
A review team managed to contact the families of 83 of the children involved, but have been unable to reach one – and Mr Sarwar told MSPs it was “feared” that this was the family of the other child who died.
The Scottish Labour leader said that clinicians had been trying to raise the alarm for years – and that the scandal involved “denials, bullying of clinicians, cover-ups and parents of sick children being blamed for their illnesses.”
He added: “Two children died in Scotland’s flagship hospital due to a water-borne infection.
“One family had to find out by fighting the health board, and the other family may not even know.
“This is the biggest scandal of the devolution era, but inexplicably there are still families fighting for the truth and for justice.”
Ms Sturgeon replied that an “expert panel” had provided individual reports to the families of the patients covered by the review, but had “regrettably and despite extensive efforts” been unable to get in touch with one family.
She said: “I have had an assurance that there have been rigorous attempts to contact the remaining family, and regrettably it has not been possible to contact them.
“I know NHS Greater Glasgow and Clyde will continue to take all reasonable and appropriate steps to contact that family.”
Mr Sarwar said the first minister’s response was “not good enough”, and that someone should take responsibility for the scandal.
He said: “Nicola Sturgeon was health secretary when this hospital was commissioned, and she was first minister when it opened despite an independent review finding that the water supply was not safe.
“But the only people that have paid the price for this scandal have been the families and the whistleblowers.
“Years on, why has nobody taken responsibility? Why have there been no consequences, why are families still having to fight for the truth? Who is going to be held accountable?”
Ms Sturgeon replied that “this is a matter of utmost seriousness”, and said attempts to contact the family would continue.
She said: “I am not disputing that this is an incredibly serious matter – what I am disputing is that the government is not taking this seriously and is not determined to get to the bottom of what happened, from the opening of the hospital right through to now, to make sure families have answers to their questions.”