good point, what if you run an oven for 12 hours on a day like thanksgiving, there is no co emmisions from that...that has me curious to why... different type of burning system or something?

We are burning natural gas which is the cleanest burning of the fossil fuels.

Cooking in a gas oven does not require a constant flame. A residential oven is a well insulated box that holds in most of the heat, so that once the desired temperature is reached, only short bursts of flame are needed to maintain that temperature. Same way with a gas range; it doesn't need to stay on long enough to be a deadly hazard.
The cleanliness of the burn is irrelevant, natural gas still gives off deadly carbon monoxide just the same as every other incendiary cooking fuel. The rule is: "If in doubt, vent it out".

Although it is best to err on the side of safety I do wish to point out that a properly adjusted natural gas system produces no carbon monixide; just c02 & moisture.

All incendiary fuels produce carbon dioxide. If enough CO2 is present in the living environment, it can displace enough oxygen that asphyxiation can occur, meaning that it doesn't have to be poisonous CO (carbon monoxide), it can just smother a person to death. However...
Natural Gas heating systems are the leading cause of carbon monoxide deaths in the United States, according to the U.*. Consumer Product Safety Commission. When a natural gas heating system malfunctions, it produces odorless carbon monoxide. With no fumes or smoke to give warning, poisoning victims are easily asphyxiated by the carbon monoxide. Detectors are available that warn of carbon monoxide and/or explosive gas (methane, propane, etc.)

Be better to leave the oven open with a pan of water than use a dryer for heat.