Yes, I'm casting a spell now to turn agentben into a pile of dog poos...
I've had a bit of ongaonga coming out the Waimea in Mount Richmond FP. Not fun; immediate, intense, prolonged.
The common ingredient in poisons oak, ivy, and sumac is urushiol. It's vile stuff and can take a few days to really get going. Exposed areas can become weepy, possibly infected, and chronically, maddeningly, itchy.
In general, poison oak grows in the western US, while poison sumac is mainly in the east, and poison oak can be almost anywhere except, strangely, California.
I used to apply a pre-exposure topical cream at the start of a tramping day and wash at the end of the day with Tecnu, a post exposure wash, and I would still get the urushiol rash.
Burning it is a big no-no, as the oil can be absorbed in the lungs, then look out!
I actually bought a machete to hack the worst of it, but was turned off by the number of injuries that occur with machetes, even in the hands of the experienced. I would not advise a machete or any other 'hacking' tool to cut through any unwanted plant: ongaonga, poison oak, or otherwise.