Potash was the one significant mineral resource possessed by Belarus, which ranked second in world output in 2000. During the 1980s, Belarus produced 5 million tons per year (calculated based on potassium oxide content), about 50% of the former Soviet Union's output. After the breakup of the Soviet Union, production fell to 1.95 million tons by 1993. A program was then undertaken to raise the quality of potash to world standards to increase exports. Total production in 2000 was 3.79 million tons (more than 80% of which was exported), down from 4.55 million tons in 1999. Potash was mined in the Salihorsk region, by the Belaruskaliy production association. Accumulated waste from the industry has raised environmental concerns. Two plants produced 1.85 million tons of cement in 2000.