[RickM]

I believe it's referred to as Black mold. It's been repeatedly reported on the news that many developers have spent major bucks demoing parts of new houses to alleviate mold problems. Things like improperly installed vapor barriers, insulation and shoddy building techniques supposedly create the problem.
Health problem? I think for some it may be but as mentioned probably overblown.
I think the "pros" use a spray bottle of bleach (and another chemical...>???) to kill the stuff. I'd think the use of TSP (Tri sodium phosphate) would work as well.....but dont mix with bleach.