Vietnam produces large amounts of coal as well as having sizable deposits of phosphates, manganese, bauxite, chromate, and other metal ores. Substantial offshore oil and gas deposits exist in southern waters, and crude oil is an important export; petroleum products are refined as well. Vietnam's industrial development was hampered by more than three decades of war, but as a result of economic reforms that began in the late 20th cent. and accelerated in the early 21st cent., there has been considerable industrial development.