Such a BBC article. They tracked down a former employee of the cigarette factory to say:

“The filters would be very good #insulation, and someone had a light bulb moment and probably bought this as scrap off their manager. The word would have spread quickly through the factory that this was indeed a great job, and I would say it was a cheap way of insulating the roof space.”

Before at the very end stating the bleeding obvious, this is a huge fire risk. Don’t do it.

https://www.bbc.co.uk/news/articles/c070eep3k0jo

Ballymena: Cigarette butts and filters used to insulate attic

The last thing you'd expect to find in an attic is cigarette butts and filters, but that's exactly what was uncovered in a County Antrim house.

BBC News

Twisting the fact the fact that employees of a cigarette factory couldn’t afford to buy proper loft insulation, because their wages were presumably so low, but it was alright because the factory let them ‘buy’ scrap butts that would have otherwise been thrown away to fill their lofts, thus making their homes a huge fire risk.

Why is it the story was written as novelty and an act of ‘kindness’ by a company that produced a product that hooked children and blighted lives?

#NorthernIreland

@JugglingWithEggs I'd have thought that cigarette butts were not particularly flammable. Certainly not compared to some of the other things people used to use to insulate lofts, like shredded newspaper and even leaves.