My school took field trips to many factories when I was young. The only two I can recall now are the cheese factory and American Greetings, both because of the smell. The cheese factory turned us all off cheese for a few weeks. American Greetings made scented candles, cinnamon at the time, and the fumes burned our eyes and made our noses run. The workers were used to it. Neither of those experiences compare to a visit to a factory that makes surströmming, or fermented herring.
Great Big Story explains surströmming and how it is made. Aren't you glad to be watching a video instead of taking a field trip to this factory?