You don't even have to go as far as the EPA. You'll have to deal with local Fire Inspector yearly inspections, the County Hazardous Materials inspector, etc.
Bottom line- any chemical- double containment. A fume hood to draw off the fumes. A non-skid floor, as you're dropping water and oil all over the place. Water plumbed to top off the bluing and rinse tanks. Gas for the burners.
How do you get rid of the chemicals legally? You have them picked up by a hazardous waste service. I used to run an industrial battery shop, and was running, shall we say, a "surplus" of spent battery acid. I called around and back then (1995 time frame) a 55 gallon drum was about a grand to dispose of.
As far as the actual bluing, kraig's post sums it up well. You'll need iron mesh baskets for all the little parts, and hooks that hold the action by the bore so you can lift the action out again. Lower them in gradually, at a gentle angle, as the salts will froth and come shooting out of the last part of the barrel that submerges.
Some fans are a life saver- our operation was indoors, and a 90 degree day plus the tanks going meant it was piping hot.
I didn't find leaving parts out around the bluing setup as troublesome as some. Brownells "Hold" is a great chemical to have. You can polish something, spray Hold in it, and leave it 'in the white' next to the bluing setup for months, then wash it off and blue it, and there's zero corrosion.
Our bluing room was about 15 x 15, and if you were facing the four tanks you had a rack for barreled actions to your left, a rinse tank to your right,
a slop sink at your 5 o'clock, and another rack for barreled actions behind you.
Polishing-well, doing it right is way, way harder than it appears. You'd realistically need a 4x polishing setup- i.e.- 4 polishing wheels, with, lets say, 2 hard and two soft wheels. 240 hard, 240 soft, 400 hard, 400 soft, plus some extra wheels. I'd buy a couple of beat Mosins and practice, and be ruthless of you appraisal of your work. Trust me- everyone else will.
Wonder why people get so much for a blued finish?