Someone asked me a question about how to dispose of liquid
nitrogen. That got me thinking about how it is used, and about
whether is should be considered biohazardous.

If fresh tissue is frozen in the liquid nitrogen, could
some of the bacteria/fungi/viruses from the tissue be frozen
and floating free in the liquid nitrogen? Would these
frozen micro-organisms then be still viable when thawed out,
such as when the liquid nitrogen is thrown on the floor
or outside under a bush?

This concerns not only tissues quickly frozen in liquid
nitrogen, but also tissues in long term storage in
liquid nitrogen.

If the dumping/evaporating of the liquid N2 is done indoors,
is there a chance that the microorganisms become
airborn? If dumped outside on the ground, what happens to
the microorganisms? Does air and sunlight kill them? Would
it be better to let the liquid N2 evaporate in the hood?

I don't know of any way to dispose of liquid N2, other than
dumping/evaporating. Obviously, pouring liquid Chlorox into
the liquid N2 isn't going to work.

Any and all (useful) suggestions will be appreciated and
passed along.

--
Peggy A. Wenk, HTL (ASCP)
Anatomic Pathology
Wm. Beaumont Hospital
3601 W. 13 Mile Rd.
Royal Oak, MI 48073-6769