Good question. This other report with a different view and video of the damage said he was making an oxy-propane torch and there are YouTube videos for that, but that doesn’t explain the split tank.
It looks like there is a small propane bottle typically used with a small torch next to the split propane tank in the first report. Maybe he was using that small torch on the propane tank. That is not smart and not in the YouTube videos I watched. There are no obvious burn marks on the the split propane tank.
In the photo of the split tank it is sitting on the ground but the debris field shown in the second report doesn’t show the tank. It must have been blown out of the field of view. From the blood drops on it, it looks like our hero walked over to take a look at it. I guess I would have too.
Perhaps he put acetylene into the propane tank which is very dangerous as it is unstable under pressure and can explode easily. Welding acetylene tanks are filled are filled with an absorbent material to stabilize the gas.
None of this explains why he was in an RV. I doubt he thought it through and decided he didn’t want to blow up the garage instead.
I am surprised I didn’t find other groups discussing this, I guess we are a curious lot.