looks like it's the hydraulics
It's a bit convenient that it happened in front of the camera - almost as though it's staged?
edit: the youtube comments are interesting - his hobby is to film garbage trucks
(, Mon 25 Jan 2021, 14:09, Reply)
Atomised oil/air mix makes contact with a hot component and WHUMP!
(, Mon 25 Jan 2021, 14:39, Reply)
At first I thought of flammable gas in the rubbish.
(, Mon 25 Jan 2021, 14:46, Reply)