The last engineer working for Hoku Scientific Inc's eastern Idaho polysilicon plant left last month, leaving little hope the facility will ever produce materials for solar panels. The 400-million-dollar plant now has only eight workers, all security guards. Hoku Scientific Inc., based in Hawaii, started building the plant in Pocatello about five years ago, as interest in solar energy grew and polysilicon prices rose. The company predicted it would provide hundreds of higher-paying jobs in the region. But polysilicon prices began to plummet, and Hoku laid off 100 employees in May 2012, just before production was to begin.