That puzzled me for a moment - I think it's " no qualms", typed with too many fingers !
Having looked-up the combustion products of Cedarwood Oil (which I've discovered doesn't only originate in Cedar Wood - now there's a tale ...) I wouldn't completely dismiss Brian's concerns - but - my own view is that unless there is some convincing evidence that there definitely IS a problem, I can't see any need to be too concerned. Kind of, "If it ain't broke, don't fix it".
And - as all my hives put clouds of bees into the air yesterday (the first proper 'flying day' of this season) confirming zero winter losses - yet again - I don't see that any of my beekeeping procedures currently requires re-evaluation. But - if I was losing colonies in significant numbers, then certainly I'd be examining every possible cause.
LJ