https://www.nbcconnecticut.com/news/local/home-heating-oil-in-connecticut-will-now-be-blended-with-biodiesel/2815515/

Home heating oil is actually regulated to a fair degree so local companies will sell the extra same thing. Also the infrastructure is such that no one is making their own, it comes in large batches that are sold to local companies. The biggest variation might be some company that is doing a poor job storing it between them buying it and delivering it to you so it might be contaminated but that's hopefully rare.