According to the United States Geological Survey (a bureau of the United States Department of the Interior that employs approximately 8,670 people), the Orinoco Belt alone is estimated to contain 900–1,400 billion barrels (2.2×1011 m3) of heavy crude in proven and unproven deposits.[3] Of this, the United States Geological Survey estimated that 380–652 billion barrels (1.037×1011 m3) could be technically recoverable, which would make Venezuela's total recoverable reserves (proven and unproven) among the largest in the world.