Five years ago Hurricane Maria knocked out Puerto Rico's power grid. They were only "just starting to rebuild" when Fiona hit.

Puerto Rican Carol Ward is a lung cancer patient who requires oxygen around the clock. A black oxygen machine never leaves her side. But the power instability on the island of Puerto Rico puts her life at risk almost daily. 

Ward told "CBS Mornings" lead national correspondent David Begnaud that there have been days where the power went out and the battery backup on her machine died—leaving her without oxygen. 

"There was three days, almost four days without power," said Ward.