Some environmental experts believe up to 16 million homes contain vermiculite insulation, a product that may contain asbestos. When homeowners discover that this potentially dangerous product is insulating their homes, they often want it removed immediately.

But the EPA suggests that disturbing vermiculite insulation may actually be more dangerous than leaving it alone.

Vermiculite insulation is a loose insulation. You can tell it apart from other kinds of loose insulation by its looks. Most other loose-fill insulation – like cellulose, fiberglass and rock wool – is fibrous and fluffy. Vermiculite, however, is packed and looks somewhat worm-like.

Not all vermiculite is dangerous – you often find vermiculite in potting soil and brake pads.

However, most of the vermiculite sold as attic insulation between the 1920’s and 1980’s came from a mine near Libby, Montana, where there is a natural deposit of asbestos. (See New York Times article for information about the mesthelioma cases and cleanup related to the mine).

If you discover you have vermiculite insulation that is doing its job, and you don’t need to disturb it, then the EPA suggests leaving it alone. Asbestos removal can be dangerous, and it is often expensive because it means hiring professionals. The EPA also recommends sealing any openings between the attic and home, like you might find around light fixtures or heating ducts. (Visit the EPA website for info on vermiculite insulation).

If you do have vermiculite insulation, you can have it tested by a reputable lab to see if it contains asbestos. However, the EPA says those tests are not always accurate, and they recommend assuming the insulation contains asbestos.

If you decide to leave your vermiculite insulation undisturbed, you should stay out of the attic to minimize the risk of exposure to asbestos. If you must go in the attic, be sure to stay on floorboards and try to avoid disturbing the insulation.

If you want to add more insulation, you may be able to do it yourself, but if you want to replace the insulation, you’ll need to call asbestos professionals with the current training and expertise.