Asbestos in Fire Doors and Other Building Materials
Fire doors are common in many public buildings, particularly theaters, and are also an integral component of marine vessels. These doors usually are made of heavy timber or other material, overlaid with steel. The frame is lined with fireproof gaskets so that when the fire door is closed, an air-tight seal is maintained. Fire doors are rated according to how many hours they can withstand a fire before they collapse or burn through.
Prior to the 1980s, the core of a fire door as well as the gaskets and liners were likely to contain one of three types of commercial asbestos. The most common of these was chrysotile, or "white" asbestos. Most of the U.S. supply of chrysotile was mined in northwestern Montana and upstate Vermont. During the heyday of the asbestos industry, chrysotile made up between 97 and 98% of the market. Consequences of long-term exposure to chrysotile include asbestosis (a build-up of scar tissue in the lungs), pleural plaques (stiffening of lung tissue) and mesothelioma cancer.
Hazards Associated with Fire Door Products
Fire doors that are intact and new pose relatively little risk of exposing people around them to asbestos. Asbestos materials generally do not emit fibers into the atmosphere when they are in good condition. Asbestos hazards begin to develop when products like fire doors are damaged by heat or water, or when they simply undergo wear and tear due to age and use. The individual asbestos fibers begin to come loose from the surrounding material, and can then be inhaled.
Individuals working in factories where fire doors were manufactured were likely to have sustained some degree of asbestos exposure while on the job as few safety measures were employed until the late 1900’s. The main threat existing from asbestos fire doors today occurs during the course of a fire when damaged doors can release asbestos fibers into the air. Firemen, rescue workers, maintenance personnel, cleanup crews, and demolition workers would be most likely to come into contact with this asbestos. Maintenance workers caring for existing fire doors might also be exposed if they came into contact with worn or damaged gaskets.Sources
Bowker, Michael. Fatal Deception: The Untold Story of Asbestos (New York: Touchstone, 2003)