Which type of soot residue is most likely to be black and easily smeared?

The type of soot residue that is most commonly black and easily smeared is associated with the combustion of materials that contain carbon, such as plastics or rubber. This residue tends to be very fine and can be left behind as a thick, black coating after a fire is extinguished, particularly from fires involving synthetic materials. The composition of these materials results in a soot that is highly carbonaceous and adheres to surfaces, making it easy to smear when touched or wiped.

In contrast, greasy soot, while it can also appear black, typically has a more oily or viscous quality and is not as easily smeared as the fine, dry soot found in plastic or rubber residues. Protein residue, often resulting from the burning of food or organic materials, tends to be lighter and more difficult to see, lacking the distinctive black appearance. Puff back is primarily associated with the backdraft of smoke and combustion gases from heating devices and does not produce the same type of soot residue as plastic or rubber fires.

Understanding the characteristics of different soot residues is essential for effective restoration and cleaning techniques following a fire incident.