Lead monoxide has been used a a Drier in Oil and as a low-fire Flux in making ceramics and Glass. It is also used as a yellow pigment in paints and glazes. Massicot was used as an artists pigment from the 15th through the 18th centuries (Mayer 1969).
Lead oxide may be fatal if swallowed or inhaled. It causes irritation to skin, eyes, and respiratory tract. It affects gum tissue, central nervous system, kidneys, blood, and reproductive system. It can bioaccumulate in plants and in mammals.
A heavy yellow powder that is named Litharge and Massicot. Litharge is the oxidized product of molten lead that has been stirred or atomized to incorporate air then cooled and ground to form the yellow powder.