Never use a gas generator, grill, camp stove or gasoline, propane, charcoal or natural gas burning device in a confined space.
Carbon monoxide is a poison. You should never use a carbon monoxide releasing fuel inside a home, garage, basement or other confined space. That includes any device that burns gasoline, propane, charcoal or natural gas. Use the device well away from doors, windows and vents that could bring fumes indoors.