The government thus is relieved of the obligation to join all potentially responsible parties (PRPs) and to prove their individual contributions to the hazardous waste sites.

• 这样，政府就从原来的义务中解脱出来了。原来的义务是要使所有潜在责任方结合起来，并证明他们各自对危险废物处置场所承担的责任。