The military surplus suits, or as Grizzlyman referred to them, MOPP suits (that stood for Mission Oriented Protective Posture), are loaded with loose carbon to act as a filtering barrier between aperson's skinand an environment contaminated by a chemical warfare agent (nerve, blood, blister agents). Needless to say, there's no comparison in the amounts of carbon in those suits and a Scentlok/Scentblocker suit.
The downside, as I said, the carbon is loose and not bonded with the material. You will turn black when you sweat. Also, they're extremely hot in a warm environment. I remember spendingall day inthose things wearing a gas mask during battle drills. One word described it.... miserable.
I've never invested in carbon clothing, but in cold weather, they'd probably be an effective, inexpensive way to go.

BigTiny,
What branch of service? Anyway, it's obvious that you already know about MOPP suits. We had to wear them on ships during CBR drills. During General Quarters, all ventilation is shut down and that ship is buttoned up and it gets hot, especially down in Guantanamo Bay back when they had Refresher Training there. If I had to pick one environment that I'd describe as "hell on earth" that'd be it... CBR drills in GTMO.

Scent Lok is a laminate, and Scent Blocker resembles the blown insulation you would find in a house....I'm not at all sure about the military styles...

You think they are hot when you are just standing, try wearing them with a protective mask and conducting reconnaisance patrols in a subtropical environment as we did. Surprised that we didn't have heat casualties. No matter how well you are conditioned, these thing would sap you if you had to move much.

I did active duty in the Navy, then I wised up and switched to Air Force for reserve duty. I spent some time at GITMO as well, not my favorite place. When we did a unit eval (USAF) down in Belle Chase one summer, we did have 4 casualties in one day after extended periods in MOPP gear. They were just pass-outs from being dehydrated, nothing serious. There is no way you can drink enough water to stay hydrated for very long in that hot, humid environment.