No telling what crap chems they’re putting in to it, these days.
This is one reason my town voted to ban all retail MJ shops. The medical stuff is grown, tested and distributed to valid outlets to avoid such things. There are two companies that do this in the town I live in. They do not distribute here. How other places do it to accommodate the potheads, I can only imagine.
Where I live, legal pot, grown by state licensed growers, is shipped to state licensed testing centers before being processed, packaged and sold by licensed and strictly regulated retailers who affix state required labels to each and every fraction of a gram sold. So, yes. In this state, at least, a pot buyer does know exactly what he's getting unless he's buying illegal street weed.
But I suppose we could make it illegal again. Then no one would smoke it anymore and the problem will be solved.