Cigarette butts: tiny pieces of trash that's just as lethal

Cigarette butts.

Some 4.5 trillion cigarette butts are discarded globally each year, making them the leading item that litters the earth, according to the United Nations.

But whether dropped on the sidewalks, flicked onto beaches, or tossed in the fields, many of the tiny, lightweight butts end up in water bodies, swept there by water systems or rainfall.