Asbestos fibers are microscopic.
These tiny fibers can be present in the dust in an area where asbestos insulation is disturbed. Usually, however, it takes more exposure than a few trips to the attic to develop the health problems associated with exposure to asbestos. If you are concerned about possible exposure, consult a physician who specializes in environmental or occupational medicine. There are specialized firms that are certified in removing asbestos safely. You may be able to locate these firms through your state, county, or local health department.