During a structure fire, lead fumes are produced when lead or lead-containing materials are heated to temperatures above 500° C. At these temperatures, lead vapour is released in the form of highly toxic lead oxide fumes. This vapour then condenses into solid fume particles which are released into the atmosphere.
Although the sheer volume of lead that vaporized in the Notre Dame fire was unique, fire restoration practitioners need to be aware of the likelihood that lead may be present in any fire-damaged structure, especially those built after 1978.