The team of three will be sitting in a mud bath for ten hours outside Hednesford's One Stop branch, in Sharon Way, today(fri) in aid of the Cannock & Burntwood First Responders.
Store manager Terry Jay will be joined by colleagues Rachel Smith and Vicky Rhodes, all aged in their 40s.
Ms Smith says: "We will be supported by representatives from the First Responders. We've raised quite a lot of money for them in the past.
"People think that the service is funded by the government and don't realise that it's a charity and as such has to raise it's own funds."
They were due to be be taking part in the challenge from 7.30am to 5.30pm.
The Burntwood First Responders drew national headlines seven years ago when Hollywood star Hugh Grant visited to unveil their response car.