Batches of surgical face masks delivered to care homes and GPs during the coronavirus pandemic have been recalled because they are faulty, Sky News has learnt.
The masks, which are out of date by as much as seven years but were deemed safe to use, have been withdrawn after faults were reported with the straps and nose protection which hold them in place.
In a recall notice issued by the Department of Health and Social Care on 26 June, care homes were told they must immediately stop using the Cardinal Healthcare IIR masks and destroy them because of "a risk to staff" if the masks degrade.
More than 80 different batches of the mask have now been recalled.
They are understood to have been part of a stockpile built up in 2009 in case of a flu pandemic and their shelf life extended after testing by the manufacturer.
It has left some care home bosses and doctors concerned that staff and patients could have contracted the virus despite using the personal protective equipment because of the fault, which was first identified in May.
In the notice sent to staff this week the Department of Health and Social Care warned: "Although these masks meet the breathability, filtration and splash resistance requirements of BS EN 14683, in light of ongoing monitoring, further complaints reported and testing from the manufacturer on the masks, the MHRA [Medicines and Healthcare Products Regulatory Agency] recommends that all lots of this product are disposed of locally.
"There is a risk to staff wearing the mask if the foam strip on the mask flakes and enters their airway or mouth. There have also been complaints of the ties and/or stitching coming away from the mask."
It follows a warning issued in May after complaints were made about the masks because of faults preventing them from staying on correctly. It also comes after the masks were found to have passed their expiry date - some by as much as seven years.
In the recall notice, the department states: "You will see that boxes have been labelled with a new expiry date. This is because they were subject to shelf life extension testing by the manufacturer in 2013/2014 and passed a number of relevant tests to support a new expiry date.
"When potential issues were identified in May, a sample size of seven lots was put through additional testing by the manufacturer in June 2020. Six lots did not pass a material inspection of the foam strip."
On 22 May, a full month before the masks were withdrawn from use, advice was issued about a small number of batches of the PPE which stated: "The first fault has been identified by the stitching coming away from the ties. The second fault has been identified on the foam nose strip which breaks down with the application of a small amount of pressure and friction causing particles to be dislodged."
Staff were told not to use the masks but they were not withdrawn in full.
Sky News also understands the same masks were issued to GP surgeries and have also now been withdrawn, leading to concerns that thousands of medical and care staff may have been affected.
Speaking about the impact on GPs, Dr Richard Vautrey, British Medical Association GP committee chair, said: "Practices rightly queried it when they received out-of-date masks earlier this year, but were reassured they were safe.
"Therefore, it is extremely concerning to hear that, after further testing, some have been found unfit for use. Staff may have been using these masks for some time assuming they were safe and will be naturally very worried.
"We now need urgent clarification over how many practices and other providers are affected, and how faulty masks will be replaced. Everyone knows what a shambles the PPE situation has been and as the NHS begins to reintroduce more non-COVID services, demand for proper protection will continue.
"Crucially, questions must be asked about how unsafe equipment was approved for use on the front line, and if anyone has come to harm as a result those responsible need to be held accountable."
The PPE was issued to care homes and others during the early stages of the crisis when supplies were short. The masks were manufactured by Cardinal Health.
The company was forced to withdraw thousands of medical-grade gowns at the start of the year amid fears they had been contaminated.
A Department of Health and Social Care spokesperson said: "The safety of health, care and all frontline staff is our top priority.
"We were made aware of a defect with some Cardinal Health Type IIR surgical masks. Last week we issued advice to health and care providers to check if their stock included these masks and to dispose of them.
"The issue is now resolved."
Cardinal Health has been contacted for comment.