“I will be getting my first SEM/EDS shortly, and to obtain the required operating permit from my safety group, I need a written procedure for handling LN2. Specifically I need a written procedure for filling the 3 L dewar on the EDS detector from a 50 L dewar mounted on a cart. I plan to make the transfer by using a lab source of LN2 to pressurize the 50 L dewar and have obtained all the valves and fittings required to do this from another SEM lab. I would appreciate copies of the procedure.”

This question recently posed to the Microscopy List Server unleashed a flurry of comments, not only on the safety of various LN2 procedures but on the safety of other materials as well. Also discussed was the necessity of formal LN2 handling procedures.