Comment by giantg2

This. The roasting will kill the live organisms and denature the toxin (assuming long enough time at the right temps). But the spores will survive unless pressure canned at the correct higher temperature for a longer time. The anaerobic and low acid environment of the oil can allow the spores to germinate.

Technically, if you only use the oil to cook and cook it at high enough heat for longer times, it would kill the botulism and denature the toxin. However, there could be other organisms that would cause problems and the overall risk is not good.