Needing some help understanding the rules of transporting hazardous material under part 91. I have dealt with hazardous materials under 135 but not 91. The some of the other pilots I fly with are in the same boat and others have no experience with it. We normally fly small amounts of dry ice for specimens and is only labeled with a frozen sticker. I'm new to the company and thought this was odd. I've done some research over hazardous materials and my understanding is hazardous material is still regulated by CFR 175 for part 91 and the only difference is there is no FAR requiring training.