From my quick Google search, it seems that no it is not: https://www.medicalnewstoday.com/articles/323419

Some people believe that black mold exposure is a serious health concern. However, no conclusive research suggests that exposure to this type of mold causes conditions such as cancer or lung disease.

And then later in the article:

However, some people may be more sensitive to mold sporesTrusted Source than others, and they may develop respiratory symptoms after inhaling even a small number of spores. In large quantities, mold spores can cause ill health in almost anyone.

So basically it seems that you should allow it to take over in your home. And if you're experiencing respiratory issues then mould in your home, then mould might be the culprit. But also don't panic if you see a little or if you see it in a place you don't spend a lot of time.