If you use a vaporizer in the kitchen for humidity, the metals in the water can create an orange flame.
The flame should normally be blue, which indicates complete combustion, which produces carbon dioxide.
An orange flame can indicate incomplete combustion, which produces carbon monoxide.
An ultrasonic humidifier can put metals in the air, which can cause the flame color to be orange or red, which can be alarming if you think that the stove is producing carbon monoxide.
The orange flame color from metals is not a problem other than it reduces your ability to detect a gas problem.
Using distilled water can eliminate the effect. Boiling water humidifiers won't have the problem.