Catechism of the Catholic Church §1801 — excerpt
Conscience can remain in ignorance or make erroneous judgments. Such ignorance and errors are not always free of guilt.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.