Not the sharpest knife in the drawer, is he?
laugh at him but this happenes even to engineers.
A cformer colleague of mine (not the inventor of buttons on jeans either) had to collect an off-gas stream from a chemical pilot plant. He used a liquid nitrogen cooled cold-trap (nothing more than a glas cylinder with an entrance and an exit, both on the top and some liquid nitrogen around it) He yielded visual ammounts of liquids. He needed to weigth the yield so he screwed on caps to the cold trap sealing it airtight (sigh). Then he wanted to get rid of the ice rapidly forming on the outside of the very cold glas cylinder. To do so he used pressurized air (sigh again). Not for long did he operate the airgun.
He knew and will probably not forget, that he found large ammounts of CO2 in his cold trap. And he learned that glas is hard to see on an x-ray screen.