It's also often found in insulating board materials installed under or around heating appliances. It's extremely fragile and easily disturbed. Sheet vinyl and tiles may contain asbestos if manufactured prior to the mid-1980s. Sheet vinyl can be dangerous to remove because it may be backed with felt containing high concentrations of asbestos. Fibers may be readily released into the air if this backing is disturbed dry.
Tiles are generally safer because asbestos fibers are bound up inside the tiles in a petroleum base.
Cement asbestos-board siding is a very dense, brittle product used primarily in the 1940s, 1950s, and into the 1960s. What to do if it IS asbestos. Leave it alone. Remember, asbestos is a problem only if fibers are released to the air. Asbestos-containing materials that are in good repair and not being disturbed will not release asbestos fibers.