Treated lumber?

Hi Everyone. One question.
The trailer's parked in the back yard, the windows are in the hands of UPS headed my way, (thanks to EBAy and Lil Bear; the local camper dealers are extremely proud of their windows)
, and a whole lot of other doo-dads and thingamabobs are cluttering my shed.
I was working on the final draft of my plans and I was wondering why I hadn't noticed anyone using treated plywood, or treated lumber in general, for the floors and underframes of their TTT's? I realize it's a little heavier and more expensive, but is there some other reason no one seems to be using it? Aside from it being toxic when it burns, unfortunately, should a teardrop catch fire with someone in it, noxious fumes are going to be the least of their worries.
I was just curious. I'm sure there must be a reason and I was wondering what it was.
Thanks for all the great information I've found on this forum.
Have a great day.
Brian
The trailer's parked in the back yard, the windows are in the hands of UPS headed my way, (thanks to EBAy and Lil Bear; the local camper dealers are extremely proud of their windows)

I was working on the final draft of my plans and I was wondering why I hadn't noticed anyone using treated plywood, or treated lumber in general, for the floors and underframes of their TTT's? I realize it's a little heavier and more expensive, but is there some other reason no one seems to be using it? Aside from it being toxic when it burns, unfortunately, should a teardrop catch fire with someone in it, noxious fumes are going to be the least of their worries.
I was just curious. I'm sure there must be a reason and I was wondering what it was.
Thanks for all the great information I've found on this forum.
Have a great day.
Brian