The thing about roast pork specifically, which of course you wouldn't know, is that if you roast it with the skin and subcutaneous fat on, the fat fries its way out through the skin and turns it into a tasty, snackable form called "crackling". But it only does this if you turn the oven up really hot at the end, like 230C or so. At that temperature the fat gets quite spitty and smoky. And I think pork fat usually has a lower melting point and smoke point than beef or lamb fat to start with. Foolishly buying cheap supermarket pork when it's on special offer, and discovering it's full of added water, doesn't help either.

I've never had smoke-alarm problems with cheese on toast or fish pie, not even when a fish pie overflowed a bit and got all burnt onto the bottom of the oven.

Peter