720 ILCS 646/100: Second or subsequent offenses.

(a) Any person convicted of a second or subsequent offense under this Act may be sentenced to imprisonment for a term up to twice the maximum term otherwise authorized, fined an amount up to twice that otherwise authorized, or both.

(b) Any penalty imposed for any violation of this Act is in addition to, and not in lieu of, any civil or administrative penalty or sanction otherwise authorized by this Act or any other law.