Interesting forum thread.
I've been hunting for the 15 years I have been heating with wood pellets for straight softwood. Very hard to find because most people on the east coast are blindly looking for hardwood-only pellets. In actuality, softwood pellets produce 17-20% BTUs by weight. This is due to the structure of softwood - it contains more resins than hardwood does. Many pellet heaters used to heat with round wood and are baptized against softwood, mainly because of the concern over creosote (not an issue when pellet heating) and the fact that you get WAY more heat from a cord of hardwood. The fallacy here is that we all buy pellets by weight and not volume. Even my local sources of heating pellets don't understand this and they perpetuate the myth.
The reason I bring this up is that there is a marketing issue with mentioning that you have softwood in the pellet blend you are marketing.
My experience, from 25 years working as a forester in the Northeast is that all out pellet plants come in one of two flavors. Either they are an existing lumber mill that is manufacturing pellets as a value-added process to increase fiber utilization or they are single-product outfits that buy that wood residue from a mill and convert it into pellets. The good news is that list roundwood going through a lumber mill is debarked and the bark likely does not make it into the pellet.
If you are lucky (like me) you know the source of your pellets. If they come from a hardwood mill, you can feel pretty safe you aren't getting softwood in the mix. Otherwise, you are getting some combination. If you don't know the source, give the pellets a try them and see if you liked the cooked result. At the end of the day, if you can tell the difference (and that bothers you) you might spring for grilling pellets and see if that makes any difference. After all, it's all about the taste in the end...
To me the "cancer concern" expressed about using softwoods is a red herring - softwood pellets burn actually hotter than hardwood ones (see above about the BTU content). At the end of this whole debate is the bottom line that just by smoking meat you are introducing carcinogenic compounds into your food (
https://pubmed.ncbi.nlm.nih.gov/7447916/) . If you really are worried about cancer risk from the type of wood you use, you are way deep into the weeds - you might better pick a different way of cooking meat ... or switch to steamed vegetables ;)