The cup, about a month after it was added to the compost bin in my backyard.
As the Natureworks Ingeo (the brand name for the plastic the cup is made from) site states in its very comprehensive page on the material content, these cups are not made from oil: “If you replace the PET in 100,000 plastic food containers with Ingeo, you can save greenhouse gas emissions equal to driving a car 16,000 miles and an amount of non-renewable energy equal to 19 barrels of oil or 775 gallons of gasoline.” They also use only a very small percentage of the world’s corn, so at this point, they don’t affect food prices. And it’s not corn that the cups are really made of — it’s the sugar from corn; we only need a sugar source. This could include sugar beets, sugar cane, wheat and more.
Moreover, the company says that in the future, “Ingeo will be made from cellulosic raw materials, agricultural wastes and non-food plants.” Ingeo’s overall life cycle analysis is better than plastic cups, but higher than paper (though according to their data, this will change with new materials that are coming next).