The danger .....
... is that many of these mold and mildew species are extremely toxic especially to those who have predisposed senstivity. The worst danger is to disturb (any) mold when it is dry and release the spores -- the spores can get aspirated very deeply into the 'end cells' of the lungs and cause 'great' damage. There have been many reported cases of extreme toxicity and even death to those who are 'sensitive'. Such sensitivity is usually cumulative ... from repeated exposures. The CDC website and most state health department websites now (finally !!!!) outline what should be done for mold/mildew control and remediation - its just simple hygiene. Incidentally, these mold/;mildew 'species' are the same that invade most boat system water tanks and cause all the foul taste and other grief .... the spores enter the tankage when you draw down the tank (because they are already living there in the 'adjacent spaces'); such tanks should have filters on the tank vent to prevent such entry by aspiration when you draw water from the tank .... just like they do in most industrial, municipal, pharmaceutical, food processing, beverage processing, biotech water (tank) applications. The NSF specs that make the recommendations and practices (for the RV industry, etc. which only govern the commissioning of 'new' installations) are about 30-40 years out of date in comparison to the current FDA (fFederal Food and Drug Administration) regs. To remediate mold/mildew do what our ancestors did: wet it to prevent 'dusting' it, use a very strong (alkali) soap to dissolve it, then 'whitewash' to prevent it in the future ... just use the strong soap to apply and dry on those surfaces that are subject to mold. The caustic film thats applied and let to dry keep the spores from 'growing'. Our ancestors had been doing that for about 3000 years ... and it worked! Thats why they sought out limestone caves for storage of food, wine, cheese, etc. --- the caustic/alkalai nature of the limestone. Further, the zillions of teeny black spots that seem to 'appear' on boats in the NE after a long rain storm or a period of 'wet humid weather' in early spring through mid-summer .... probably 'artillery fungus' and the cure is the same as above.