Scifi Corporate Security 3
Here is a hazardous-duty trooper with a special sealed suit with gas mask and personal air supply. He wields a breach-loading, single-shot 40mm grenade launcher, which probably has various gas grenade types, along with high explosives. He also has a pistol, because grenade launchers aren't fantastic at point blank range.
The body, backpack, and arms are from Stargrave sprues, but the head is from the Wargames Atlantic Cannon Fodder sprue. I'm still not totally happy with the Cannon Fodder box (mostly because of the awful guns), but I'm getting plenty of mileage out of the heads.
The pictures don't show it, but the barrel of his grenade launcher has been drilled out, and it looks very nice.