Why no one has suggested this is a mystery to me... get a pocket sheath fixed blade. You can either find or make a pocket sheath, even one that clips to the pocket, pretty easily. Anything that folds will perpetually get dirty and need to be cleaned at your job. A fixed blade has 0 moving parts and only needs to be wiped down.
As for the specific blade, it sounds like you need something around a 3" blade or a little bigger. I am not a fixed blade guy, so others will have to take over the specifics, but a more simple carbon steel may work, maybe something like an Izula.