I've just had a massive problem with the Blue bag Makro/Booker restaurant grade charcoal. I had two bags at the weekend, the first was 50% slag, so a big waste of money
But it gets worse - the second gave off a lighter fluid type smell while lighting. My best guess is that got contaminated with chemicals from the instant lighting rubbish at the factory but I can't be sure. It settled down and smelled ok once it was fully greyed, but I wouldn't be happy using it in my smoker
That bag will be going back to Makro this week but I'm getting a bit annoyed with that stuff as the last three bags I've had have been sub-standard.
And before you fan boys point it out, I know you've not had any problems with the same stuff. MAybe I'm just unlucky.