Skipper, a young black neutered cat, managed to escape from the unit at the household waste site in Willowbrook Road, Worthing, on Thursday morning – moments before its contents were due to be crushed.
It was spotted by staff who called animal charity WADARS.
Billy Elliott, senior animal rescue officer at WADARS, said: “It just seems such a heartless thing to do to discard them in household waste knowing they are getting crushed.”
The incident is not the first of its kind. Before Christmas two kittens were found dumped at the waste site.
Mr Elliot suggested cat owners contact Worthing Cat Welfare Trust, Worthing Cats Protection or WADARS if they want to get rid of their pet.
Skipper is currently recovering at the North Barn Cattery in Lancing.