Is there asbestos in your attic?
BTW, There is lots more information on this subject at http://www.epa.gov/asbestos/vermiculite.html
Some houses have a product known as vermiculite in the attic. Vermiculite is a naturally occurring mineral which has been ground up into little particles and was placed in many attics as insulation. Unfortunately, it’s very lightweight and particles can easily become airborne. Most of the vermiculite used for insulating purposes in the United States came from a mine near Libby, Montana, the same location where asbestos was mined for years. The EPA recommends treating all vermiculite insulation as if it is contaminated with asbestos because it was mined at the same location. Even though attics are not part of the living space in a home, because asbestos is so small and lightweight, there is a very good chance that particles have entered the living space of the home through attic access covers, light fixtures and other openings between the attic and the living space. You may want to check your attic to see if you have a material that looks like the stuff depicted in the photographs. If you do, think about contacting and asbestos testing and removal company. It may or may not contain asbestos, but it’s good for you to know.
People are concerned about asbestos because it is a known carcinogen when it is “friable”. Friable means that it can be broken up when squeezed with your hands. When it is friable it can easily become airborne and inhaled into your lungs where it can cause long-term damage. Asbestos insulation in the attic and around pipes is considered friable. Although there is no law in place it says that you must remove it, it’s a serious consideration. Professional asbestos removal contractors can remove it safely. There is lots more information at http://www.epa.gov/asbestos/vermiculite.html
For more related information click on this link: https://safeharborinspections.