The resident had used the oven as a heater, according to fire officials.
The SDFD reminds the public during the cold-weather season that CO poisoning is a threat because it is odorless and can kill a person in minutes.
Symptoms include severe headaches, confusion, shortness of breath and mild nausea.
Often the symptoms are similar to the flu, so victims do not necessarily realize they are being poisoned.
The fire department said those affected by possible CO poisoning should get fresh air and open windows and doors immediately.
Those affected should go to an emergency room, where poisoning can be diagnosed with a blood test.
The SDFD warns not use a gas oven as heater and or use a charcoal grill indoors.
For more information, call (619) 533 -4300.