The U.S. Environmental Protection Agency is warning homeowners that their vermiculite insulation might be contaminated with asbestos. Vermiculite insulation is used throughout the country and is described by the EPA as a “pebble-like, pour-in product and is usually gray-brown or silver-gold in color.” The problem with vermiculite insulation is that the vast majority of the vermiculite sold in the U.S. comes from an old mine in Libby, Montana, that is highly contaminated with asbestos fibers.

Insulation containing asbestos from Libby was often sold under the brand name Zonolite, but may have been purchased under different brand names.

“You should assume that vermiculite insulation is from Libby and treat the material as if it contained asbestos by not disturbing it or by using a trained professional if it needs to be removed,” EPA officials warn. “Since the Libby mine was estimated to be the source of over 70 percent of all vermiculite sold in the U.S. from 1919 to 1990 and vermiculite from Libby was contaminated with asbestos, further testing is not necessary to take the appropriate precautions.”

The EPA further warns that improperly trained professionals may accidentally contaminate an individual’s entire home or business with asbestos if the vermiculite insulation is improperly removed. It is not recommended that individuals open their walls to check for vermiculite. Adhesives and drywall in older homes and buildings may also contain asbestos unrelated to the Libby mine.

“Any disturbance could potentially release asbestos fibers into the air,” the EPA said in a statement. “It is not possible to say whether your exposure may result in disease. Exposure to asbestos increases your risk of developing lung diseases including asbestosis, lung cancer or mesothelioma, and disease may not occur until decades after exposure. The risk of disease increases as the level, duration and frequency of exposure increase.”

The EPA recommends not storing any boxes in attics that contain vermiculite insulation or allowing children to play in attics that have vermiculite insulation. It is best to leave vermiculite insulation undisturbed in attics and walls and do not attempt to remove the insulation alone.

Individuals who have been exposed to asbestos and experience symptoms of lung disease or mesothelioma should seek medical attention and legal representation. Common symptoms of mesothelioma include worsening shortness of breath, lumps in the chest, dry or bloody coughs and fatigue. Mesothelioma is often fatal if not caught early and hard for medical practitioners to catch early unless they have specialized training.