Regardless of what it is Chuck, it is definitely producing Carbon Monoxide. That huge flame impinging on the cover like that will do it. You can probably detect an aldehyde odor from the incomplete combustion. Make sure your orifice is correct. If it's new, make sure it's not set up for natural gas (PG&E) if you're using it with Propane. Natural gas orifice is larger that that for propane and will allow way too much LP gas to pass, possibly causing what you are seeing. What the other guys mentioned are all good tips too. Just wanted to give you another possibility.