Carbon monoxide is produced whenever something is burned incompletely.

Ketones are incompletely burned fat, say the Eades, so that any ketones "you get rid of without actually using them for energy means you are ditching unwanted fat without having to actually burn it off."

This means that incompletely burned compounds are created in addition to just water and carbon dioxide.

There were blackened lumps there, too-though she thought these were the remains of some plant material; one was greenish, maybe a stem of something, incompletely burned.

All were charred, as if they had been set on fire and incompletely burned.

The warm air smelled of cooking grease and incompletely burned fossil fuel.

Lead also fouled the working parts of catalytic converters, devices carried on cars to burn components in gasoline that pass through the engine incompletely burned.

The yellow glow is from assorted incompletely burned carbon-rich species (soot vapors), which if sufficient oxygen is received react completely to CO2 and H2O.

Particles, released when fuels are incompletely burned, can lodge in the lungs and irritate or damage lung tissue.

If the fuel is incompletely burned, the maximum heat potential of the gas is not fully achieved.