How is it possible to safely use carbon monoxide as a fuel?
During WWII many cars were powered by a gasogene engine, which transformed wood or charcoal into a synthetic gas composed by $\ce{CO}$, $\ce{N2}$, $\ce{H2}$ and $\ce{CO2}$. Thus the use of $\ce{CO}$ (albeit not as a pure gas) as a fuel is not something new (the former use of piped coal gas for house heating and cooking has already been mentioned above). I am not sure however about how safe those gasogene engines were.