Safely treating cutting boards is not difficult.
"Butcher Block Oil" aka Cutting Board oil aka Food Grade Mineral Oil is in fact a petroleum based product. Now, there are a myriad of "food grade" products that are in fact made from petro-chemical bases: Non-dairy coffee creamers, commercial frying oils, commercial griddle oils, cosmetics, numerous slaves, creams and lotions, etc.
If the use of the non-reactive, tasteless, odorless and colorless liquid parafin known as "Butcher Block Oil" is objectionable to you, there are a very few safe non-petrochemical oils that can be used to treat your wooden food contact items such as cutting boards, bowls, spoons, spatulas etc.
DO NOT use common oils from nuts, plants seeds etc. These oils are rich in fats and fats WILL go rancid after a short period of time. Aside from the bacteria medium these oils produce, rancidity will transfer off flavors to your food and in many cases will give off objectionable odors.
Many sources will state that coconut oil is safe for cutting boards. CAUTION: Coconut oil (raw or processed for cooking) is just as bad as any other oil mentioned above for the same reasons. A form of coconut oil that has been REFRACTIONATED, that is steam distilled to remove those reactive fats, is SAFE for long term treatment of wooden food preparation items.
While not easy to find, it is available. One easy source is:
https://www.cuttingboard.com/coconut-cutting-board-oil/