Tar balls have shown up 100 miles (160.93 kilometers) downstream of a railroad bridge collapse last month that sent numerous tank cars carrying petroleum products plummeting into Montana's Yellowstone River, officials said Friday, as dropping water levels and rising temperatures hinder cleanup work.
More than 66 tons (59.87 metric tonnes) of the black, gooey stuff have been removed from the river since the June 24 accident, officials said. Most of the spilled material — a binder for asphalt that sticks to river rocks and gets harder to handle as it warms — is expected to get left behind.
