 If you're using died diesel fuel and driving on Montana's public roads, you may not know this, but you are breaking the law. The small savings you see at the pump could end up costing you up to $5,000 in fines. Died diesel fuel is not taxed and is intended for off-road use only. Please, do the right thing. Don't use died fuel on Montana's roads. To report violators, you can call 1-888-FUELLAW. Thanks for your help. This message brought to you by the Montana Department of Transportation.