Saddam Hussein knew the war was over. He could not have Kuwait, so he wasn't about to let anyone else benefit from its riches. As the 1991 Persian Gulf War drew to a close, Hussein sent men to blow up Kuwaiti oil wells. Approximately 600 were set ablaze, and the fires literally towering infernos burned for seven months. The Gulf was awash in poisonous smoke, soot and ash. Black rain fell. Lakes of oil were created. As NASA wrote, "The sand and gravel on the land's surface combined with oil and soot to form a layer of hardened 'tarcrete' over almost 5 percent of the country's area." Scores of livestock and other animals died from the oily mist, their lungs blackened by the liquid.