Having been in the heating oil and propane business for 35+ years, and also a mhp owner here is what I have to say about that.
I have no fear of propane tanks. Propane is very safe when handled correctly. You can require evidence of a “leak check” by the propane supplier. Natural gas companies have a worse accident record than propane.
I do fear oil / kerosene tanks. In my MHP I do not accept or set up homes with oil/kerosene heat and am looking for how to get rid of the existing ones. An environmental survey is a very good idea and also inspecting the oil tanks to see they are supported on a non combustible base, are at least 6" above the ground, and show no signs of leakage or seeping.
I dealt with a lot of spills big and small when in the fuel business. I also had a 200 gallon spill in one of my mhps I didn’t know about until Encon had spill contractors on site which resulted in a $22,000.00 bill from Econ for which I was responsible jointly and severally along with my tenant and her fuel company.