Are tart burners safe with guinea pigs?

Question
Hello there,
We recently bought 2 female guinea pigs.  We were told that they are 3 months old.  We had a guinea pig a while back that developed some sort of respiratory infection and it passed away.  We were all devastated.  I was wondering if a tart burner placed in another room would pose a problem?  We keep the piggies in the front of the house and my burner is in the kitchen - more towards the back.  Also, do you recommend salt and/or mineral blocks in their cages?  I read a lot of conflicting information.
Thank you so much for your time and help!!
Sincerely,
Maria

Answer
I have to be honest and say I don't know what a tart burner is, but if it's a type of candle burner, incense or room freshener that very well may be the problem. They shouldn't be exposed to that type of thing at all as it can cause respiratory problems.