CERCLA Sec. 107(a)

Notwithstanding any other provision or rule of law, and subject only to the defenses set forth in subsection (b) of this section--

1. the owner and operator of a vessel or a facility,

2. any person who at the time of disposal of any hazardous substance owned or operated any facility at which such hazardous substances were disposed of,

3. any person who by contract, agreement, or otherwise arranged for disposal or treatment, or arranged with a transporter for transport for disposal or treatment, of hazardous substances owned or possessed by such person, by any other party or entity, at any facility or incineration vessel owned or operated by another party or entity and containing such hazardous substances, and

4. any person who accepts or accepted any hazardous substances for transport to disposal or treatment facilities, incineration vessels or sites selected by such person, from which there is a release, or a threatened release which causes the incurrence of response costs, of a hazardous substance shall be liable for-- . . .
   3. damages for injury to, destruction of, or loss of natural resources, including the reasonable costs of assessing such injury, destruction or loss resulting from such a release. . . .