I hit up scofield last night for a few hours. I got there at 2 or 3 and fished till 7. The fishing was slow till I moved and talked to a couple of guys and they showed me what they were using. I started catching a few and got caught up in the moment and forgot to open the tent doors to let the carbon monoxide(?) out then I noticed my lantern was getting very dim so I grabbed my other bottle of propane and twisted the one I thought was empty off. I put the new one on then tried to light it. My lighter would not light. I started to get a very bad head ach. So I decided to bag it I opened the door and about fell over with all the oxegen going into my lungs. I was to cold to fold the tent up so I drug it while it was set up to the truck. It was the hardest thing I think I have ever done I could not breath I almost pased out a dozen or so times. when I got to the truck I lit the lantern and it worked just fine. I think because it had oxegen to light. I got in the truck and started it got warmed up. Jumped out and packed it all up and drove home with a pounding head ach. So lesson is dont forget to vent the tent while burning propane.