Some unattended heavy-duty trucks are being scrutinized on YouTube for releasing toxic fumes into the air near downtown Missoula.

Many truckers will idle their trucks while on service calls, a practice commonly used to run air conditioning and other appliances. When I learned about this, the first thing that came to mind was the potentially enormous fuel cost. Still, that doesn't seem to stop the drivers from allowing their engines to run for long periods of time without moving. 

Several companies are testing prototypes to operate vehicles with use of on-board fuel cells that will keep engine oil warm and power all on board electronics. However, it seems in this video recorded by a concerned Missoulian, that is not the case.

"Toxic deadly fumes are pouring down this alley, you have to hold your breath to (pass it). Not right. We need to stop polluting our air," said the unidentified film maker.

What are your thoughts on this practice? Comment below.