Mortar manufacturers were looking for a material that would stand up to heat, would be durable, and had insulating capability and strength. That is why they looked to asbestos. Until the 1980s, asbestos made up 90–95% of the mortar mixes in the United States. Builders preferred having it in the mix and used it when constructing private homes, office buildings, shopping centers, hospitals, and schools. Asbestos mortar mixes were thought to be significantly stronger than cement-based mortars.
Almost every piece of brick and mortar constructed before the mid-1980s has asbestos in it as a primary component. To increase the tensile strength of the mortar mix, asbestos was added because it was cheap and available. Chrysotile asbestos is a naturally occurring mineral in California, Montana, New England, and Quebec. Also known as “white asbestos,” this type of asbestos is the most commonly used in the United States, accounting for about 95% of all the asbestos used in buildings.
Although asbestos-containing materials generally pose little harm to health if left intact, destruction of the material can cause particles of asbestos to be released into the air. Micro-abrasions on the inner surfaces of the air sacs and the alveoli are caused if chrysotile fibers are inhaled into the lungs. As time goes by, mortar can break, and as it is exposed to the weather, it can fall apart. However, home renovation or additions are even more dangerous for an existing structure with asbestos because breathing in even small amounts of the fibers can be dangerous. Therefore, any attempt at removal should be done by a licensed asbestos contractor.