[en] The three-stage tandem accelerator facility at Brookhaven National Laboratory (BNL) consists of two model MP tandem Van de Graaff accelerators arranged in line so that MP-6 can inject negative ions up to 10 MeV energy into MP-7 providing a three stage mode of operation. The injector accelerator, MP-6, may also be used as a standard two-stage accelerator having been equipped with an external ion source and target room facility. A description is given of recent improvements and current operating status and performance. Improvements in operation have now provided record electrostatic accelerator heavy ion energies for the research program of 125 MeV ¹⁶O⁸⁺ 200 MeV ³²S16⁺ and 255 MeV ⁶³Cu¹⁹⁺