Methylene chloride is generally the most common at least in Starbucks from my findings. Though that is variable for sources and locations.

There are others with similar or the same effects however. Generally it depends on how regulated the contractions were during the process. Yes it’s still food safe (for now) but build up or higher sudden dosages can cause major migraines and headaches, sensitivity to light, blood pressure changes, extreme nausea and dehydration.

It hits the nervous system really hard and can manifest in the neck from the brain to the spinal cord causing sever pain. I had a customer who was quite allergic and would have skin reactions and swelling in her throat.