How long would it take vegetable oil to oxidize in an open container?

I'm back home from college and noticed that the vegetable oil that my parents use is stored in a container but the lid is missing. How long would it take for it to oxidize? Is it safe to consume oil that's been exposed to the air for multiple months?

Answer

I would toss it. Oxygen can make the oil rancid and in all truth- opened cooking oil shouldn’t be used past 6 months anyways…or maybe less: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4245579/

Answer

I have no scientific knowledge regarding this, but anecdotally, my dad had a Fry Daddy with no lid that sat on his counter for years and got used 3-4 times per week (we Appalachians like deep frying) and it always tasted fine to me.