Medical staff at a hospital are using protective equipment that has had its use-by date extended because of the coronavirus pandemic, a union says.
Staff working at Barnsley Hospital have been given the equipment, including face masks, with new stickers covering the original use-by dates.
A spokesman for the GMB union said it was "disrespectful and dangerous".
The hospital said the equipment had been given "accelerated age testing" and was safe to use.
In a statement Ben Kirkham, of the GMB, said: "Giving horrified workers out of date equipment is disrespectful and downright dangerous.
"Slapping stickers over the use by date won't make masks work and keep staff safe.
"It's scary enough working in over-stretched, coronavirus-riddled hospitals with colleagues dropping like flies.
"Unless the staff are appropriately protected, so many will end up with symptoms there won't be enough staff left to look after the patients."
Barnsley Hospital said the equipment was not compromising safety because it had been tested before being issued.
A spokesperson said: "Our masks are supplied through the national NHS Supply Chain and are rigorously tested to British Safety Standards to ensure they are both safe and appropriate to use clinically.
"The safety of our staff and the patients we treat is of paramount importance to us and we would not compromise this.
"NHS Supply Chain and Public Health England have worked nationally with manufacturers and independent testing houses to formally test certain products, to see if it is possible to extend their life via accelerated age testing.
"The products that pass these stringent tests are subject to re-labelling with a new shelf-life as appropriate and can continue to be used safely.
"All masks that do not meet the required standards are destroyed."