I noticed small bits of red, green, blue plastic in my bags of "Organic" "OMRI certified" soil from the big box store. What it leads me to believe is that the "compost" that they use is the same compost that most cities provide - shredded partially composted material from the city yard waste programs, which includes the trash picked up by the lawn mowers and the herbicides that were sprayed on those plants. It would explain why some people have their seedlings killed when potted in these soils. I have also seen postings that some of these also include small amounts of sewage in them.
So I am wondering if running this material through a composting cycle would be worth the effort.
I am starting to think that just getting shredded trees from arborists and composting that would be better.