So when I was little, I think 4 yeas old, I was running down a ramp in Louisville's Belvedere. I was with my parents, but I broke away to run downhill. Being little, I fell and face-planted before the term was in wide use. I hit my upper lip hard enough that it split open. Other than the pain, I don't remember much about what followed.
I'm sure my parents applied tissues or something to staunch the bleeding, but it was found that the bleeding wouldn't stop. So off to a hospital I went. I ended up getting three stitches in my lip and was limited to foods I could take through a straw (Kool-Aid, Campbell's Soup, etc.).
I would swear that I was screaming through most of the suturing, but Mom denies that. But since that day, one of the things I would remember upon waking from nightmares was this chocking chemical smell. It was a sensation that would linger for minutes after I woke up.
When I started working in environmental, I started wearing nitrile (non-latex) gloves to prevent contaminating myself with chemicals of concern. The first time I opened a box and the smell hit me, I finally knew where the nightmare smell had come from. The doctor(s) that worked on my lip must have worn nitrile gloves (or something similar) and that smell stayed with me.
I kind of let the connection fade over time, but today I opened a new box and the smell hit me taking me right back.