High levels of CO2. No burner or tank

[Buttercup726]

What cause high ppms of co2 1500 plus with no burner or tank?

some details. Sealed room

burner is unplugged.
gas line is shut off.
6 lights
Multiple fans
Furnace is not running
Room reads 1500 plus
Outside of room reads 1500 plus

Kinda stumped here. What would contribute to high ppms with NO burner or tank.

I’d normally see levels of 400-600

 

[mysticepipedon]

Is something decomposing in there? Like the compost in soil, or a dying plant?

 

[Buttercup726]

Nope. I checked for a dead animal everywhere. Took the sensor outside it immediately dropped to 450. Grabbed a new sensor reading 1500 anywhere I put it.

been giving me a slight headache. But I’m more concerned with where’s its coming from

 

[mysticepipedon]

I don't blame you for wanting to know. I would, too.