CERCLA Section 107(f)(2). The full text of the law may be found here.

1. FEDERAL. - The President shall designate in the National Contingency Plan published under section 105 of this Act the Federal officials who shall act on behalf of the public as trustees for natural resources under this Act and section 311 of the Federal Water Pollution Control Act. Such officials shall assess damages for injury to, destruction of, or loss of natural resources for purposes of this Act and section 311 for those resources under their trusteeship and may, upon request of and reimbursement from a State and at the Federal officials discretion, assess damages for those natural resources under the State's trusteeship.

2. STATE. - The Governor of each State shall designate State officials who may act on behalf of the public as trustee for natural resources under this Act and section 311 of the Federal Water Pollution Control Act and shall notify the President of such designations. Such State officials shall assess damages to natural resources for the purposes of this Act and such section 311 for those natural resources under their trusteeship.