Make sure your carbon monoxide detectors are working, because carbon monoxide is a poisonous gas that you cannot see or smell. Every home should have a carbon monoxide detector, battery-powered or with a battery back-up.
If you hear the carbon monoxide detector alarm, get out of the building. If you smell natural gas or sulfur odors, stay out of the building and call 911.
You should have your gas, electric, and heating systems checked by a professional before turning them on.