"Roger" wrote

Then he committed a sin for which job termination is usually
proscribed at most companies now days. You never, ever enter a vessel
that has been N2 purged unless bringing your own breathing air by
tank or hose. He entered without checking the O2 level and almost
suffocated.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The first post about this said:

The catalyst vessel he was working in was under
nitrogen atmosphere to prevent the catalyst from going pyrophoric. There
was no pressure on the vessel and the
manway was open. He removed is mask to spit, then inhaled before putting it
back on. Instead of passing out, he
instantly went into violent convulsions and dropped the mask. Even with an
attendant equipped with a radio, and a
tripod, winch, and lanyard already set up and attached we only got him out
of the vessel alive by the grace of God.
--
Jim in NC