Rubbermaid or Sterilite tub fumes

Has anyone read any studies or heard of anything regarding these tubs releasing possibly harmful fumes when subjected to heat? This has crossed my mind a few times and I wanted to see if anyone else had ever heard anything of the sort. What finally encouraged me to ask is something I read regarding not using the clear tubs to breed crickets in because they release a fume that will kill the crickets. This was just something I read on the internet the other day.
I made a cricket egg incubator using a clear sterilite tub and a low wattage light bulb a while back and I have noticed that there is definitely an odor that is emitted by this type of plastic. The odor is stronger when it is exposed to heat. Now whether it is a possible toxic odor to reptiles, I don't know.
I am getting ready to build a couple of snake racks out of HDPE and was going to just use either the rubbermaid or sterilite tubs like a lot of people do, but I'm wondering if there have been any long term studies done on whether the fumes may be harmful to snakes. I think sterilite and rubbermaid tubs are made from polypropylene, which I have been reading is supposed to be a safe non-toxic plastic.
Anyone have any knowledge about this plastic?

I haven't seen or heard about any studies related them being toxic. Back in the day before racks were so popular I was using tub set ups. I can say I've never experienced any problems. I only use the iris tubs in my racks , being that it seems steralite and other companies seem to change their sizes quite a bit. Over time the tubs will lose that "new" smell..