Farmers in the U.S. are pouring out tens of millions of gallons of excess milk, amid a massive glut that has slashed prices and has filled warehouses with cheese.

More than 43 million gallons’ worth of milk were dumped in fields, manure lagoons or animal feed, or have been lost on truck routes or discarded at plants in the first eight months of 2016, according to data from the U.S. Department of Agriculture. That is enough milk to fill 66 Olympic swimming pools, and the most wasted in at least 16 years of data requested by The Wall Street Journal.