Joe Fells, age 16, of Tulsa, Okla., for his question:

WHAT IS RED LEAD?

Rust is a reddish brown substance that forms on the surface of steel or iron when it is exposed to damp air. When used alone, the name means iron rust, which is made up mainly of hydrated iron oxide. Rust is formed when oxygen of the air combines with the iron in a process called oxidation, Moisture Is an important agent for producing the change.

An orange red pigment called red lead is used extensively as a rust preventative for structural steel. The material is made by heating lead monoxide in the open air at a temperature of about 925 degrees.

Red lead is easily mixed with linseed oil and some synthetic resins to make protective finishes. It is also used in making some storage batteries, glass and matches.