I was said skipper on said jet.
very heavy snow contamination on whole a/c needing extensive de-icing. Full power bleeds off takeoff using apu air for initial climb. Due to high angle of climb and very large amount of residual fluid on fuselage, the contaminent entered the APU intake in unusually large amounts. This manifested itself as thick acrid black smoke in the cockpit at about 500` agl requiring cockpit masks to be donned. Similar smoke in the cabin confirmed that this must be an ir conditioning issue so re-configuiring the bleed airs instantly solved the problem. Bit dodgy for a bit though when it all happens at max t\o wt at 500`!
Landing afterwards became interesting due to lack of available places to go.
Lots of pax complained of throat/eye problems in the air but were ok when offered medical attention.