End looming for 3 Mile I.

The Three Mile Island plant, site of the nation’s worst commercial nuclear-power accident, will shut down in 2019 if it gets no financial help from Pennsylvania, the owner said Monday.

Exelon Corp.’s announcement comes after what it called more than five years of losses on the single-reactor plant near Harrisburg and its recent failure to sell the plant’s power into the regional grid.

Exelon wants Pennsylvania to give nuclear power the kind of preferential treatment that is given to renewable energies, such as wind and solar.

Exelon and other nuclear-power-plant owners have made the pitch to states that zero-car- bon nuclear plants are better suited than natural gas or coal to fight climate change.

So-called nuclear bailouts have thus far won approval in New York and Illinois, but the potential for higher utility bills in Pennsylvania is drawing opposition from rival energy companies, manufacturers and consumer advocates.

Nuclear plants have been hammered by the natural-gas boom, which has slashed electricity prices.

In March 1979, equipment failure and operator errors led to a partial core meltdown at one of Three Mile Island’s two reactors and an evacuation within a 20-mile radius of the site.

The damaged reactor has since been mothballed.