A compound called gunning mix is used to fill cracks and holes that may occur in the lining of electric furnaces. For a gunning mix to work well it needs to be both heat resistant and durable. Today’s gunning mixes that HVAC technicians use in their repair work are considered to be safe.
But for years in the past gunning mixes were made with asbestos to increase their strength and ability to withstand extreme temperatures. The North American Refractory Company (NARCO), for example, once used asbestos in its gunning mix formula, and was taken to court in Kentucky because of it. Though it is no longer used in most applications in the U.S., some countries still make gunning mixes that contain some asbestos. Exposure to these mixes makes people susceptible to some very serious illnesses.
The dangers of asbestos became known to the public in the mid 1970s and the use of construction products containing asbestos was restricted. About this time, workers with occupations like HVAC technician began to develop unusual, sometimes deadly illnesses that were related to their exposure to asbestos and inhaling the tiny fibers many decades before. Many of these people have begun legal proceedings against the companies that made the gunning mixes containing asbestos. Often, these companies knew of the dangers but did nothing to protect their employees.