That's one of the factors I considered when I closed my business about 1-1/2 years ago. Part of my business was refilling portable propane cylinders. The law requires me to have $1 Million minimum liability insurance. Because I also made an occasional gas hookup (on the order of 2 or 3 times a month), I had to have a higher LP Gas license than just a dispenser. The insurance company noted my license level, and charged me as if I was a full-fledged gas company with servicemen making hookups all day long. They claimed they had no category for limited exposure. The insurance climbed to alost $4,000 just for that part of the business; It was not my primary income, so I wasn't making enough money at it to cover the insurance. Back when insurance costs were reasonable, it was a profitable part of the business.
For that and many similar reasons, most having to do with regulations, codes, insurance, licensing, taxation and paperwork, I decided to hang it up.