Thick black smoke and towering orange flames shot up once again from a flooded Houston-area chemical plant where highly unstable compounds blew up after losing refrigeration.

Rescuers are continuing to search waterlogged neighbourhoods in Houston, Texas, as officials turn their attention to finding temporary housing for those in shelters in the wake of Hurricane Harvey.

Latest: Fires and two explosions have rocked a flooded chemical plant in Texas, sending up a plume that federal authorities described as "incredibly dangerous" and adding a potential new hazard to the aftermath of Hurricane Harvey.