I can't count the number of times I've had to extract both my arms from inside a machine (in doing so losing the information of where precisely i'm holding stuff and the bearings that provides you), wipe off all the grease, dust, grime, etc., thumb through a pile of papers that still get dirty and then mentally translate a 2D drawing to what I'm working on, only to then lose my place and have to work it all out again. Having something voice controlled and right there in front of my eyes would be invaluable.
Industry really is the perfect environment for this. Safety issues notwithstanding (which you can work through), it's really the best application of this technology and you can quickly quantify a RoI from its implementation.