This may be an emergency. Get everyone to fresh air immediately and call 911. Do not re-enter until responders say it is safe. Once the source is found, a combustion and venting inspection should confirm what caused it.
After the emergency
Once everyone is safe and responders have cleared the building, we can help find the cause and handle any required inspection and filing.
Contact usGeneral guidance only, not a substitute for a licensed inspection or emergency services. For any gas odor, carbon monoxide alarm, fire, or trapped occupant, call 911 first.