ITV Granada Reports correspondent Rob Smith reports.
The death of a toddler who suffered prolonged exposure to mould should be a "defining moment" for the housing sector, a coroner has said.
Awaab Ishak, two, died in December 2020 from a respiratory condition caused by mould in the one-bedroom housing association flat where he lived with parents Faisal Abdullah and Aisha Aminin in Rochdale, Greater Manchester.
Mr Abdullah had previously complained to Rochdale Boroughwide Housing (RBH) about the mould, an inquest at Rochdale Coroner's Court was told.
Giving her findings on Tuesday, senior coroner Joanne Kearsley said: "I'm sure I'm not alone in having thought, 'How does this happen? How, in the UK in 2020, does a two-year-old child die from exposure to mould in his home?'
"The tragic death of Awaab will and should be a defining moment for the housing sector in terms of increasing knowledge, increasing awareness and a deepening of understanding surrounding the issue of damp and mould."
Addressing the toddler's parents, Ms Kearsley said: "I hope you know that Awaab will, I am sure, make a difference for other people."
In her findings, the coroner described Awaab as "an engaging, lively, endearing two-year-old".
She said Mr Abdullah reported mould developing in the Tweedale Street flat to RBH in 2017 and was told to paint over it.
In June 2020, Mr Abdullah instructed solicitors and initiated a claim over the recurring issue but policy meant any repairs would not be done until an agreement had been reached, the inquest heard.
A health visitor also contacted RBH to raise the issue in July 2020 and an inspection that month found mould in the kitchen, bathroom and a bedroom cupboard needed treatment.
Ms Kearsley said the mould was due to "normal daily living activities" and a lack of effective ventilation.
She said: "I find as a matter of fact that no action was taken and, from July 2020 until December 2020, Awaab continued to have chronic exposure to harmful mould."
Awaab was taken to Rochdale Urgent Care Centre on December 19 with shortness of breath and transferred to Royal Oldham Hospital before being discharged, the court heard.
The coroner said the family should have been told to call an ambulance or take him directly to Royal Oldham Hospital if he had further difficulties.
Awaab deteriorated the next day and his parents were advised by the Community Children's Nursing Team to take him back to the Rochdale Urgent Care Centre.
He went into respiratory arrest and then cardiac arrest while being transferred to Oldham, the inquest heard.
He died after arriving at Oldham.
The coroner said: "Awaab Ishak died as a result of a severe respiratory condition caused due to prolonged exposure to mould in his home environment.
"Action to treat and prevent the mould was not taken. His respiratory condition led to respiratory arrest.
"The medical advice given to his parents led to Awaab receiving suboptimal ventilation of his airway which was unable to prevent his cardiac arrest."
Ms Kearsley said the issue is "not simply a Rochdale problem".
She said she will be writing a report for the prevention of future deaths and will write to the minister for Housing, and Health Secretary Steve Barclay, to raise issues.
Chief executive of Rochdale Boroughwide Housing (RBH) Gareth Swarbrick said: "I am truly devastated about Awaab's death and the things we got wrong.
"We know that nothing we can say will bring Awaab (Ishak) back or be of any consolation to his family. We have and will continue to learn hard lessons from this.
"We didn't recognise the level of risk to a little boy's health from the mould in the family's home.
"We allowed a legal disrepair process, widely used in the housing sector, to get in the way of promptly tackling the mould.
"We must make sure this can never happen again. Awaab's death needs to be a wake-up call for everyone in housing, social care and health.
"We will take responsibility for sharing what we have learnt about the impact to health of damp, condensation and mould with the social housing sector and beyond."
Councillor Danny Meredith, Rochdale Borough Council’s cabinet member for housing, added:" Firstly, my deepest sympathy remains with the family for the tragic loss of their son.
"No one should have to live in the degrading conditions that Awaab Ishak and his family were forced to endure.
"The appalling state of their home and the indifferent response to their pleas for help are shaming and have raised serious questions for our largest social housing provider.
"I will be writing to the chief executive of Rochdale Boroughwide Housing to outline the council’s concerns and will continue to monitor their reaction to this judgement and their ongoing performance in relation to repairs and complaints."