I got a question for you: Although lead has not been used for writing since antiquity, lead poisoning from pencils was not uncommon. Until the middle of the 20th century the paint used for the outer coating could contain high concentrations of lead, and this could be ingested when the pencil was sucked or chewed.

Answer this question: where does lead in a pencil come from?
Let's think first:
This is the relevant information: Until the middle of the 20th century the paint used for the outer coating could contain high concentrations of lead, and this could be ingested when the pencil was sucked or chewed.
Therefore, the answer is the paint used for the outer coating.