(a) Basis.--The selection of a remedial response shall be based upon the administrative record developed under section 506.¹

(b) Interim response.--An interim response may be taken before the development of an administrative record when, upon the basis of the information available to the department at the time of the interim response, there is a reasonable basis to believe that prompt action is required to protect the public health or safety or the environment. When the department takes an interim response before the development of an administrative record, it shall provide the notice required by section 506(b) within 30 days of initiating the response action. In addition to the information required by section 506(b), the notice shall describe the actions which have already been taken and any additional actions to be taken prior to the close of the public comment period under section 506(c).

(c) Implementation of action.--After the selection of an interim response or a remedial response, the department may implement all or any part of the selected action by doing any of the following:

(d) Orders.--Orders issued under this section include, but are not limited to:

(e) Judicial action.--The department may file an action to enforce an order issued under this section in Commonwealth Court or in any other court of competent jurisdiction. The department may include in the same action a civil penalty assessment under section 1104.² When the department files such an action, its order shall be enforced and its civil penalty assessment shall be upheld unless the person subject to the order or the civil penalty can demonstrate that the department acted arbitrarily and capriciously on the basis of the administrative record developed under section 506 as permitted to be supplemented under section 508.³

(g) Voluntary settlements.--The department, in its discretion, may enter into an agreement with any person, including a person who may be liable under section 701,⁴ to perform any response action when the department determines that such action will be properly done in accordance with the department's standards and after such person has submitted a plan and obtained the department's approval of such plan. Whenever practicable and in the public interest, the department may enter into agreements under this section in order to expedite efficient remedial action and minimize litigation. The decision of the department to use or not to use the procedures of this subsection is not subject to judicial review.

(h) Mixed funding.--An agreement under this section may provide that the department will pay from the fund a certain portion of the total response costs or the cost of certain response actions. The department may enter into mixed funding settlements for that portion of the response costs or damages allocable to persons against whom recovery cannot be obtained by reason of insolvency, dissolution, lack of jurisdiction by Commonwealth courts or other similar reasons. The department may also enter into mixed funding settlements when the financial resources of the known responsible persons are too small to cover the anticipated response costs, or the known and financially viable responsible persons have collectively contributed only a small fraction of the known hazardous substances at the site.