i guess it would explain the partial air from outside in hybrids. you dont want to inhale those toxic fumes in pure form. i know it isnt the hvac system because when you recirc it and the outside temp is lower, i get mist in all the windows which shouldnt happen if the vent or fresh air flow is on. mine the dealer checked twice already from their computer.

 

Lithium Ion and NIMH batteries DO NOT have any toxic fumes ever (except maybe when they are constructed or broken open.)

 

it doesnt have to be the fumes from the sealed batt itself but the case, etc.

 

Actually, they can vent toxic fumes. The "H" in NiMH is hydrogen and each module in the battery pack has a safety vent valve. If the module overheats it will vent hydrogen gas. The alternative is pressure buildup which will rupture the module case. All the vent valves are ducted together with tubing and connectors, and the vent tube is routed outside the car. Commercial Li-Ion modules have similar vent valves.