That’s the consensus from the acronym agencies of government anyway. That aside, it does make decent firewood and many people burn it to no ill effects.
I’ve burned a fair amount of it and think it’s great wood for all the reasons already mentioned. Burns nice with a big flame and smells pretty good when burning, but can crackle and pop a little. My buddy begs me to get him Sassafras for smoking meat…. Thinks it’s the best for BBQ smoking. Here’s a stack of it..