On a closer examination today, it does seem to be powder post beetle holes. Yesterday, when I was brushing the sawdust off the pieces with my hand, I must have been "plugging" up the holes, and that is why I couldn't see them, or they looked very small. Today, I blew away the sawdust, and the holes were visible. They look exactly like the old powder post beetle holes I saw in the beams (ash logs) that were used for floor joists in my old farmhouse when it was built in 1840 (an infestation that was treated many years before I bought the house).
As far as any borates, it seems very laborious to treat each piece of wood. I have over 3500 splits. The infestation seems limited to one area in the woodshed as far as I can tell without pulling all the wood out. I will concentrate on burning this area ASAP.
As far as Permethrin, I looked up several "brands". They all listed about 30 bugs that it is used for. None of the brands mentioned powder post beetles. Perhaps it would kill powder post beetles (I don't know), but once again, I would have to spray each piece since spraying it on the ground around the woodshed will have no effect even though that was mentioned in an earlier post.
It seems anything I found for treating powder post beetles, whether natural or chemical, talked about spraying directly on the affected wood, which would mean treating each piece individually. Another option is covering and conducting a full fumigation. Not going to happen on my end.
What I have decided to do is move any pieces with evidence of powder post beetles to a different area and only bring it in the house as I burn it.