Proudly American
A chimney is not an exhaust hood for a grill
An open hearth does not enclose a portable grill or give it a manufacturer-approved indoor vent. Seeing a wisp of smoke travel up the chimney cannot establish where carbon monoxide is going. A window, ceiling fan or working alarm does not make indoor grilling acceptable. The same practical decision applies to a portable fuel-burning camp stove during a storm: keep it out of the home.
Plan for the coals after cooking
Choose an outdoor cooking location that meets the equipment instructions and local requirements; a garage or carport is not a fallback when it rains. Plan before lighting where the grill can remain outdoors while coals cool. Do not wheel it inside for security after dinner or carry the bucket of gray coals through the house. Keep the exit, windows and outdoor air openings in mind when placing portable cooking equipment.
If charcoal was already burning inside
Get everyone outside into fresh air and call emergency services from outside if a CO alarm sounds, anyone feels sick or exposure is suspected. Do not remain inside to move a lit appliance or wait for symptoms to worsen. Tell responders that charcoal was burned indoors, when it was lit and whether anyone may still be inside. Deal with the fireplace or cleanup after the emergency has been addressed.