Section 4A. (a) Any person other than the department who has undertaken, is undertaking, or intends to undertake a necessary and appropriate response action or who is or reasonably believes that he might be liable pursuant to section five may notify any person he reasonably believes is liable pursuant to section five that the response action has been taken or is being taken or of the notifier's intent to take such response action or to seek contribution, reimbursement or equitable share from other persons, and that the notifier requests the person to whom the notice is being sent either to itself perform or participate in the performance of the response action on an equitable basis or to make contribution or reimbursement or pay its equitable share of the costs of such response action or other liability pursuant to the provisions of this chapter. Said notice shall be sent by certified mail, return receipt requested, and shall (i) identify the person giving the notice and the relationship of that person to the site or vessel, (ii) identify and describe the response action that has been, is being, or is intended to be undertaken, including the expected cost and the duration of the response action, and the nature and amount of actual or potential liability pursuant to the provisions of this chapter, (iii) describe with particularity the legal and factual basis for the notifier's claim that the person to whom the notice is being sent is liable pursuant to section five, and (iv) state said person's proposed contribution, reimbursement or equitable share of such liability pursuant to this section and rationale for such proposal. The person to whom the notice is sent shall respond to the notifier in writing by certified mail, return receipt requested, within forty five days of receipt of the notice. The response shall (i) indicate whether or not, and if so to what extent, the responder will pay contribution, reimbursement or equitable share to the notifier or participate in the performance of the response action or in the discharge of liability pursuant to the provisions of this chapter, (ii) state with reasonable particularity the legal and factual basis for the response, and (iii) request any further information or documentation the responder needs to fully evaluate the notifier's claim.

(b) Within sixty days after the notifier has received the response, the notifier and the responder shall confer in good faith in an effort to resolve all disputes that may exist between them with respect to participation in or funding of the response action or other actual or potential liability in question. Upon request by the responder, the notifier shall provide additional information or documentation reasonably requested by the responder concerning the basis of the responder's alleged liability or the response action or both. Within seventy-five days after the notifier has received the response, either the notifier or the responder may request that any disputes remaining between them concerning any matter described in the notice or response be submitted to mediation, arbitration or such other form of alternative dispute resolution as the parties may agree upon. The costs and equitable distribution of the cost of such dispute resolution service shall be determined as part of the dispute resolution process. In the event that the parties agree to engage in a dispute resolution process, the parties shall complete the dispute resolution process as quickly as feasible, and in any event within ninety days after the agreement for dispute resolution is made.

(c) Only after notice has been given and after the procedures described in this section have been carried out, any person who has given notice pursuant to this section may commence a civil action in the superior court department of the trial court seeking from the notice recipient contribution, reimbursement or an equitable share of the costs of such response action or of such actual or potential liability. Such action shall be brought within the time period set forth in clause (2) of section eleven A. Notwithstanding any other provisions of section four or four A, a person who is joined as a party in any civil action may, but shall not be required to, carry out the procedures described in subsections (a) and (b), above, prior to filing a third-party claim, cross-claim or counterclaim seeking relief pursuant to section four or four A; however such claims must be brought within the time period set forth in section eleven A and are subject to the standards set forth in this section regarding litigation costs and attorneys' fees.

(d) In any civil action in which a claim, third-party claim, counterclaim or cross-claim is filed pursuant to section four or this section, the court shall award contribution, reimbursement or the equitable share of liability for which one or more other parties is found to be responsible, if any. In addition, the court shall award the plaintiff its litigation costs and reasonable attorneys' fees if the plaintiff shows, and the court finds, that the person against whom the civil action is brought is liable and:

(1) failed without reasonable basis to make a timely response to a notification pursuant to this section, or

(2) did not participate in negotiations or dispute resolution in good faith, or

(3) failed without reasonable basis to enter into or carry out an agreement to perform or participate in the performance of the response action on an equitable basis or pay its equitable share of the costs of such response action or of other liability pursuant to the provisions of this chapter, where its liability was reasonably clear. In addition, if a third-party claim, counterclaim or cross-claim is filed pursuant to this section, the court shall award the claimant litigation costs and reasonable attorneys' fees if the person against whom the claim is brought is found liable and failed without reasonable basis to offer to enter into or carry out an agreement to perform or participate in the performance of the response action on an equitable basis or pay its share of the costs of such response action or of other liability pursuant to the provisions of this chapter, where the defendant's liability was reasonably clear.

(e) Where none of the conditions in subsection (d) is found by the court, but the court finds that the defendant is liable for contribution, reimbursement or the equitable share of response costs or of other liability pursuant to the provisions of this chapter, the court shall award the plaintiff only the defendant's equitable share of response costs or of other liability pursuant to the provisions of this chapter.

(f) If the court finds that (1) the plaintiff did not participate in negotiations or dispute resolution in good faith; (2) the plaintiff had no reasonable basis for asserting that the defendant was liable, or (3) the plaintiff's position with respect to the amount of the defendant's liability pursuant to the provisions of this chapter was unreasonable, it shall award litigation costs and reasonable attorneys' fees to the defendant.

(g) Without limiting the generality of the foregoing, solely for the purpose of determining whether or not a plaintiff in a civil action brought pursuant to this section shall be awarded litigation costs and reasonable attorneys' fees, and not for any other purpose, inability to pay or undue financial hardship shall constitute a reasonable basis for failure to agree, pay or participate as requested; provided, that, within forty-five days after the defendant received notice of this claim, the defendant responded in writing to the plaintiff by asserting and demonstrating such inability to pay or undue financial hardship.

(h) In subsections (e), (f) and (g) of this section the term ''defendant'' shall include an original defendant, third-party defendant, defendant-in-counterclaim and defendant-in-crossclaim, and the term ''plaintiff'' shall include an original plaintiff, third-party plaintiff, plaintiff-in-counterclaim and plaintiff-in-crossclaim.

(i) The parties may agree in writing to extend any of the deadlines set forth in this section.