If the oven doesn’t heat, the oven igniter might not be getting hot enough, the oven control thermostat might not be working or the bake or broiler element (in an electric oven) or bake or broiler burner (in a gas oven) might have failed. A tripped thermal switch on the back of the oven may be preventing the oven from heating.
On the side of the burner facing the center of the stove, there are air holes that may be clogged. They help the pilot or spark igniter to light the gas. Make sure your range is powered off and clean out the holes with a fine wire or safety pin.
No. Ovens are designed to heat food only. Ovens emit small amounts of carbon monoxide which doesn’t present a problem for intermittent use. However, if you run the burners or oven for an extended period of time the carbon monoxide could build up and become dangerous.