I once worked for a firm, and they had wood block floors, As well as being most comfortable, they had the advantage should anything drop on them,E.G.-- Cast -iron components there was a lesser chance of it smashing , But the heavy machine shops/fitting environments were concrete floors, I guess for strength in holding down the heavy machinery, The old guys were want to sweep a little amount of sawdust around the foot of their machines at night, this soaked up any oil creeping out of the machines thus the concrete floor was always free of massive oil staining, Guess todays insurance and health people would have forty fits.