Weird Plastic-y coating on floor

[Geritt70]

Hey guys, I was wondering if anybody knows what the plastic rubberish stuff that in on top of some parts of the floor in the cab is. It caught fire when I was welding in new floors and I'm hoping it was safe-ish to breathe in the smoke because I can't fit a respirator under my welding mask. Thanks!

[Dzimm]

Definitely not safe to breathe but I don't think it'll kill ya, at least it didn't kill me...  

 

It's a seam sealant.

[Pete M]

welding blankets are your friends