" on Tue, 13 Nov
2018 11:46:51 -0800 (PST) typed in rec.woodworking the following:
Are propane or kerosene heaters SAFE to use in enclosed spaces if the heater is not vented to the outside air?

Depends on what you mean by "safe". The issue is the build up of
combustion products, particularly Carbon Dioxide. If you don't have
adequate fresh air,* you may get a lot of incomplete combustion,
leading to Carbon Monoxide production. While breathing CO2 is bad, CO
is really bad to breath. Insidious in a manner that CO2 isn't.

tschus
pyotr

*one of the drawbacks of modern 'airtight' energy efficient
construction is the reduction in air exchange. Sure you used to have
drafts, but you didn't have to worry about the heater not getting
enough fresh air.
--
pyotr filipivich
Next month's Panel: Graft - Boon or blessing?