Q: We have recently put an air freshener in our bird room. When we mentioned this to several people, there were a few that said that they can be very dangerous for the birds. Do you know anything about this?

A: I have been hearing rumblings about possible problems concerning this for quite some time. In the last year, however, I have heard about several cases that appear to be well-documented. They concern all types of air freshenersfrom those hung in cars to the more expensive ones you plug into outlets. There have also been negative reports about some scented candles. The negative effects reported range from slight respiratory problems to acute death in birds. There was one report of birds that did not die until the day after exposure to a burning scented candle. All reports concerned birds that were in apparently excellent health prior to the use of these products. After death, the birds were examined by a pathologist, and the only thing found was congestion in the lungs.

The supposed culprits are known as volatile oils, usually listed on the labels as essential oils. The most common one is pine, but there are also many other scents that are created by the use of essential oils. Some of the more common ones are vanilla, peach, potpourri, cinnamon and spiced apple.

Whether or not a problem is caused is related to many variables. The three most important variables are how well the area is ventilated, how much essential oil is used in the manufacture of the product and the length of exposure. Due to the fact that candles are burned, they will release a much higher concentration in a shorter amount of time than regular air fresheners.

The use of these oils is no longer confined to air-freshening products. Some manufacturers have begun to use these oil-based fragrances in household cleaning products. A good rule of thumb for those who wish to play it safe is if it smells good, read the label to see if essential oils are used If there is no content or ingredient list, find another product.