"Sustainability" is the popular buzz word at manufacturing gatherings, and vegetable oils are the darling of that dance.  Rapeseeds, Soybean, Sunflower and everything "under the sun" are being explored as an alternate to mineral oils.  Vegetable oils will outperform mineral oil in standard lubricity tests, have lower mist generation, higher flash points and lower dermal sensitivity.  But there are some trade-offs, such as poor hydrolytic stability, and sticky machines.  An article from straight talking Mr. John Burke throws more light on it.  Be sure to look at the summary Comparison Chart at the end.