Most vermiculite contains small amounts of asbestos, and can therefore have the same negative health effects. However, some experts think that the heat used in the puffing up process may cause the asbestos to decompose, resulting in a less toxic product. Perlite is made from a silicate volcanic rock. It is a very dusty material and is sometimes treated with silicone. Breathing any type of dust can be harmful to health and should be avoided if at all possible.
Some sensitive people can react to the silicone.
WHAT TO DO If insulations are well sealed from the living space, they cannot introduce fibers, particles or gases into the air breathed by the occupants. In new construction, an airtight house will insure that the insulation remains where it belongs. Infiltration not only allows outdoor air to enter the house, it also can bring with it bits of insulation and outgassing fumes. Reducing infiltration can therefore reduce the chances of insulation contaminating the indoor air. Of course, when tightening up a house to control infiltration, fresh air should be introduced mechanically, since we all need fresh air to breathe.