I have used it my whole life, always had pets.
But I've sure been lambasted on a couple of sights in the past for still using it with all the new evidence that it is harmful to caged animals. Even my vet warned me.
Then if I had lost a chinchilla because I felt something I was using caused or aided in it's death I would not use it either.
I did have a very sick chin that seem to get worse sitting on the floor in the shavings. I changed him over to unprinted news print + fleece and his breathing did improve for a while.
I think if you have a sick animal that has developed respiratory problems any thing scented and or dusty can irritated it. There is a smell off the pine though not normally harmful. I even had to be careful of what I cleaned his cage with. Even his dust bath bothered his breathing.
But does it cause problems
?? I don't think so. I would think if it did there would be many many more cases. Everyone would have seen it at least once.
Now that's just my opinion and what I have observed and been told over they years. Eveyone has to do their own homework and come to their own conclusions.
What works for one will not work for all.
My chins go freaking nuts over yogurt.