Indoor natural gas heaters can be safe if they are properly installed and maintained.
However, like any gas appliance, they can be dangerous if they are not used correctly or if they are not properly maintained. In particular, natural gas heaters can produce carbon monoxide, a colorless and odorless gas that can be deadly if inhaled.
Therefore, it is important to make sure that your natural gas heater is properly installed and maintained, and to use it according to the manufacturer’s instructions to minimize any potential risks. It is also a good idea to have a carbon monoxide detector installed in your home to alert you to any potential problems.