I read the article about ELECTRIC BOAT and the fatalities.Here at NGSS INGALLS in PASCAGOULA you have
to be vigilant about entering tanks and making sure they have been tested by safety and posted.
   I have seen some large inner bottom tanks that we are inspecting for closure.They are tested but as far
as i know the test is at the man hole entrance.I think i will direct a question to NGSS safety dept. about
testing a large tank that is large in area.That is how do we know that there is 20 % oxygen deep in the
tank?
 

  DONK