Simplify the following text for a Grade 2 native English-speaking person.
Original: Lead ( II ) sulfide is non-toxic , unless the lead and sulfur are heated to decomposition and toxic compounds of lead and sulfur oxides are produced ( such as in roasting lead ore ) . Lead sulfide is insoluble and a stable compound in the pH of blood and so it is the least toxic form of lead .
Simplified: It is one of the least toxic forms of lead .