While it is nice to have a generator in the event of a power outage, they can also be very dangerous if not properly installed. Running a gas powered generator within a garage or enclosed space can lead to the build up of carbon monoxide. Carbon monoxide is an odorless and tasteless gas that is poisonous to breathe. Even if the area housing the generator is vented, it may not completely rid carbon monoxide from the area.
Never operate a generator indoors! It needs to be moved outside away from doors and windows. Make sure the generator does not get wet. If necessary place a canopy-like structure over the generator to keep it dry.
Only plug your generator into an outlet designed to handle that kind of power. Never plug it into a wall outlet.
Other items you should never use inside a home include charcoal grills, hibachis, lanterns and portable camping stoves.
On another note, you should install battery-operated carbon monoxide detectors within your home and make sure to test them on a frequent basis.