Information obtained by the Secretary under this chapter shall be available to the public as provided in Chapter 100 of Title 29, unless the Secretary certifies such information to be proprietary. The Secretary may make such certification where any person shows to the satisfaction of the Secretary that the information, or parts thereof, if made public, would divulge methods, processes or activities entitled to protection as trade secrets or as confidential financial or commercial information. Nothing in this section shall be construed as limiting the disclosure of information by the Secretary to any officer, employee or authorized representative of the state or federal government to effectuate the purposes of this chapter. Furthermore, nothing in this section shall prevent the Secretary from including in the remedial decision record information concerning the cost of the remedy or the manner in which it is performed. Prior to disclosure of information certified by the Secretary to be proprietary to an authorized representative who is not an officer or employee of the state or federal government, the person providing the proprietary information may require the representative to sign an agreement prohibiting disclosure of such information to anyone not authorized by this chapter or the terms of the agreement. Such agreement shall not preclude disclosure by the representative to any state or federal government officer or employee concerned with effecting this chapter.