Depends on the bacon. You can get uncured bacon without any added nitrates or flavorings at all.
They add celery powder instead of nitrates, so they can claim "nitrate free". However, the celery powder just decomposes into nitrates, achieving the same effect
https://www.washingtonpost.com/lifestyle/food/the-uncured-ba...
We buy our pork belly direct from a farm and it hasn't been touched with anything.
Just the "uncured" but still processed bacon that is pretty much just regular bacon