What substance is this?

[Lennox]

In this video Philip Nitschke talks about two substances being increasingly used in suicides. He doesn't mention them by their proper names, I think this is to generate interest in his workshop where he says he'll describe them.

He calls one "Pig Poison" (that's obviously SN) and the other "Middle x powder" (if I even got that right). Their first mentions are at 05:40.

Does anyone know what the so called "middle x powder" actually is?

 

[AnnaJaspers]

I don't know.

 

[kerolox]

 

[Lennox]

Thank you.