Wow... don't have first-hand experience with that, but interesting problem. Do you have a frontloader or a toploader, and do you soak your son's work clothes separately first? I think my general approach with anything that dirty (which for me was cloth diapers) is to use more water and to soak out most of it and discard that water before starting on the main wash cycle. Hence my question about frontloader or toploader because if you are using a frontloader and not soaking his clothes in the sink first, I'd think a frontloader simply cannot handle that amount of "dirt" with the limited amount of water they use.

Ditto hcjl1440.....

Tell us about your procedures and machine, please.

At a minimum, you're going to want a detergent that contains enzymes - protease for proteins, lipase for fats - in order to get out the sources of the odor. A soak cycle in this followed by a wash and extra rinsing would be a good place to start. If you have a front-loader with a heater that can do a cold-water fill then raise the temp on its own, that would be the best cycle to choose.

Try a diaper pail and a pre-soak in whatever diapers are soaked in, and discard the soaking water.

Have him ask the other workers what they use for laundry.

Also, make sure you are using plenty of water (top-load I hope), a double rinse, and not overloading the machine.

Laundromat.

Seriously.

My machine is a top loader. I have soaked the clothes first - in the machine - and then washed without changing the water. Had not thought about it, but it makes since to dump the "soaked" water and start over for the wash, I will try this. Recently I took the time and washed the same load over and over till the smell was gone - took 3 washes - I think a good soak followed by a clean wash will do the trick. Thanks for your input.