After all those good intentions and smug lectures the awful truth comes out. A Korean study has found that out of four different kinds of straws, good old plastic straws had the lowest environmental footprint in 10 of 16 categories. Despite being made from fossil fuels, plastic straws had the lowest carbon footprint and incidentally, were also the least harmful to humans. Paper straws had six times the level of carcinogenic impact and caused twice the level of acidification.