Building materials (siding, flooring, etc.) leading up to the 1970's included asbestos, partly due to its resistance to fire. As health issues related to asbestos became more known this practice of using asbestos in building materials was mostly halted in the 1980's.
Some homes built before the '80s have had asbestos mitigation measures taken, some have not. At this point, it is unknown how many (if any) of the homes in the Marshall Fire had asbestos in their building materials.