Having slept since I posted earlier, I feel the need to say more about essential oils. I do not mean to imply that you should not be careful with essential oils. You defintely should be careful. There is a lot of info here on the forum as well as people much more versed in essential oils than I am. Having said that, lavender essential oil is not one prone to causing problems such as volcanos or fast trace so I doubt if the lavender essential oil was the problem in your batch. Too much lavender could irritate the skin, and usage guidelines should be followed, but I was posting about what could make the batch of soap go wrong.