What is the most common source of high lead levels during building demolition?

The most common source of high lead levels during building demolition is associated with the hot cutting of coated steel. When buildings constructed prior to the 1980s are demolished, they may contain old paint that is high in lead content. Hot cutting techniques, such as welding or cutting with torches, can create high temperatures that not only cause the coating to release lead into the air but also generate lead-containing fumes and particulates. This method significantly raises the risk of lead exposure for workers handling demolition materials.

While wet cutting of concrete and dust from drywall materials can lead to various health hazards, including silica dust exposure, they do not typically involve the release of high quantities of lead like hot cutting can. Paint application refers to the use of lead-based paints, but this occurs long before demolition and does not directly contribute to lead levels during the demolition process itself. Thus, hot cutting of coated steel is the correct answer, as it poses a direct and immediate risk of lead exposure during demolition activities.