@Jordyboy9
Presumably, if you ring your local council's waste disposal section, you'll get the more PC reply that all waste is segregated.
My area's council is running out of landfill capacity (I forget whise powers forbid them to expand capacity) so it is imperative to recycle as much as possible.
Short of naming the insider or how long they'd worked there, you could report what he told you to his HQ and see if they are able to respond, in writing, to the contrary. A minor scoop for you, if they can't claim it was a wind-up.