Quote Originally Posted by riverrat29 View Post
If it is polystyrene foam board the building is usually WELL out of the date range of a building that has asbestos. These buildings are from the 40's and 50's primarily and asbestos is a fibrous product. It does not mean it is not possible , but I think you are fine. I would ask the seller where it came from. Most likely it was a re-roofing job on a commercial building where they throw away allot of good insulation product.
I was an asbestos consultant in the 90's and I kinda agree with what you wrote. Like you said, it's probably fine but it COULD have been contaminated during a renovation at some point. Asbestos was used in just about everything under the sun until the 70's and was gradually phased out during the 80's. Raw asbestos is fibrous but if it's processed far enough it just looks like dust and you can't tell for sure without looking at it under a scope.

I oversaw a lot of (flat) roof jobs that ripped up asbestos/tar membranes and put down 2"-3" foam board covered with a new membrane. Most contractors I met will bid to toss whatever insulation was underneath because they couldn't guarantee it's condition or performance. So I also agree that makes it a likely source for lightly used foam board. Don't know what the red stain would be though. Any gruesome murders in the area lately?