Our AHJ would have a fit: EMT in the slab! Be it setscrew or compression, I have yet to see an EMT coupling I would trust to carry fault current having been exposed to wet soil.
The high threshholds of OCPDs in motor circuits, the nature of the usage -- craftsmen stomping around with metal in their hands, in a metal building with metal encased motors sitting on a semi-dielectric pad....
I would want separate bonding conductors.
My AHJ would insist on abandoning the old work entirely. End of story.
( I had the 'good fortune' to step in as foreman on just such a 'red tag'. )
