Fumes from tractor

[RoyJackson]

Roy, it depends on how cold it is how long I idle it in the barn. In the summer it isn't very long before I back it out. My barn is one of those quonset types, open at the front and open at the top in the back. It does seem that the air gets stuck in there as most of the wind here is N/S and the barn is perpendicular to the wind. The neighbor's grandkids started a grass fire on the weekend and part of my hayfield and pasture burnt. The barn still smells of smoke a week later!

And that's the problem...it's not the fumes you can smell that will kill you, it's the fumes you can't smell.
Diesel exhaust may not have all the carcinogens the gasoline vehicle exhaust has, but there's still carbon monoxide (CO). And your blood has a greater affinity for CO then it does for O2 (Oxygen)