Furnace cement was usually a compound that offered a high resilience to extreme temperatures. Until the 1980s, the insulating properties of this product came from the asbestos fibers added in its mixture. This enabled the cement to sustain up to 3000 degrees Fahrenheit.
The continuous heat and the passing of time would put the furnace cement in a friable state. This meant that every time a worker would interact with the machinery, there was a high risk of inhaling poisonous asbestos particles. You could have been exposed if: