“I made the mistake of taking a past girlfriend up to Kitt Peak National Observatory to fill the instrument cryostat with liquid nitrogen. It was one of the largest cryostats at the facility and took a long time to fill. The entire time there was a huge plume of cold nitrogen gas coming out of it, visible for several feet. After we were finished, she started complaining of feeling sick to the point that she thought she was going to vomit. It lasted for several hours. A few years later she started showing signs and symptoms of fatigue and depression and was being medically treated for it. I always felt guilty that I exposed her to the nitrogen gas, as I had no idea how toxic it was because I had never been sent on an OSHA approved cryogenic liquid training course.”