(a) Agreements not prohibited
Nothing in this Act prohibits any agreement to insure, hold harmless, or indemnify a party to such agreement for any liability under this Act.
(c) Relationship to other causes of action
Nothing in this Act, including the provisions of subsection (b), bars a cause of action that a responsible party subject to liability under this Act, or a guarantor, has or would have, by reason of subrogation or otherwise, against any person.