(a) Liable parties shall be liable to the state for amounts expended for the investigation, identification, containment and cleanup of hazardous substance sites, including the cost of post-cleanup monitoring and maintenance of such sites.

(b) The department or the Attorney General shall act to recover for the fund the reasonable and necessary amounts expended for the investigation, identification, containment, cleanup, monitoring and maintenance of inactive or abandoned hazardous substance sites to the extent the department or the Attorney General can attribute these expenditures to liable parties as set out herein. Recovery of these expenditures by the department or the Attorney General can be either by administrative order or by commencing a civil action in the county where the site is located or where the liable party resides or does business.

(c) The liability of liable parties is not joint and several. Liable parties shall be liable to reimburse the fund only for the costs of investigation, identification, containment and cleanup of hazardous substance sites, including the cost of monitoring and maintenance generally attributable to that party's proportional contribution to the hazardous substance present at the site. In determining proportional contributions among liable parties the following factors shall be taken into consideration:

(1) Total volume of hazardous substance at the site;

(2) The percentage of the total volume of hazardous substance attributable to the liable party;

(3) Good faith efforts of the liable party to ensure proper treatment, storage or disposal;

(4) Any expenditures required by this chapter made by a liable party shall be credited toward its liability.

(d) In no event shall the total liability from any liable party be an amount less than the total cost for the investigation, identification, containment and cleanup of hazardous substances attributable to that liable party except that the total recovery from the liable party shall not exceed the amount expended from the fund plus reasonable costs to the department to obtain recovery from the liable party.

(e) In no event shall the calculation of a liable party's proportional contribution be increased or in any way influenced by the failure of the director to identify other liable parties or by the failure of other liable parties to pay their proportional contribution.

(f) There shall be no liability under this chapter for a liable party who can establish by a preponderance of the evidence that the release or imminent threat of release and the environmental damages resulting therefrom were caused by an act or omission of a third party other than an employee or agent of the liable party.

(g) If the department is unable to calculate proportional contributions among liable parties because of insufficient evidence the department shall commence a declaratory judgment civil action in circuit court in the county where the site is located or where the liable party resides or does business seeking a declaration of apportionment. The court shall take into consideration the factors previously listed.

(h) Any expenses not attributable to a liable party shall be paid from the fund.

(i) All expenditures recovered from liable parties shall be deposited in the fund.

(j) A liable party may elect to satisfy its liability by applying any proceeds from liability insurance or other financial assurance mechanisms which have been provided by the liable party or parties.