All I can tell you is 'a different smell' almost killed me in the MH.
I have only smelled propane from Wisconsin. 'Assumed' all propane smells the same.
Was overpowered by smell in MH. Smelled like a dirty gray tank.
RV mobile Repair confirmed it was gray tank smell and ordered a service call/repair vent. He stuck his face by the kitchen sink drain and said yup the gray tank.
REAL long story short it was PROPANE! The stove knob had been knocked to the on position and the propane found its way into the sink.
That is why the detector in the rear of the coach never went off it found it's low point into the sink next to the stove.
I had just filled up with propane in Kentucky. I'm here to tell you it did NOT smell like any propane I had ever been around.
Research on line per gov, showed it is allowed that they can put any type of odor smell they want into propane. There are no restrictions that ALL propane smell be the same.
Soooo, just saying be aware of this. I sure wasn't and I just thank GOD that I had all the windows open and it was windy that day I sat in that MH waiting for a gray tank vent the whole time my MH filling up with propane. :R