not quite the same as abandoned warehouses or factories ..
but the friend of a friend of mine's dad who was an ardent urban explorer. he used to scavenge historically significant remnants
from historic buildings that were going to be razed ... and he was killed on site ...
i've never been in situations where parts of the building were falling in, but i have been in sites where the floors had huge breaches
and squatters + pilferers had smashed thousands of fluorescent light bulbs so beryllium dust was all over the place, and they had stolen tens of thousands
of dollars worth of copper ... it was a good time !
i usually get permission from the owners, and have i have insurance ( i do this sort of thing for work )
i would suggest without hesitation that before people do this sort of thing, they get up to date on their tetanus-shots ... lockjaw is kind of a drag..