Wonder how that started. My guess is that maybe something to do with electricity.
Unless PA's regs are wildly different, I don't think that ciggies, stoves, sources like that would be an issue. Unless staffing wasn't up to snuff. Wiring might still be an issue, especially in an older building. But starting in a memory wing...that really concerns me.
It’s interesting. I own a home inspection business, and frequently run into home buyers who are afraid of natural gas in the house. I remind them that an electrical issue burning a house down is far more common than a natural gas explosion.
We'll probably never know, at least from the media. They like to report fire disasters, but unless there's some juicy, newsworthy aspect to it, they rarely bother to publish the cause. That's a shame, because we could all benefit from knowing how fires start so we ourselves can be more aware.
Preliminarily, I'm going with smoking or a fire from a misused portable heater. Both are most common in assisted living homes-- heaters especially at the beginning of colder temperatures.