On this day in 1988, an explosion rips through an oil rig in the North Sea, killing 167 workers. It was the worst offshore oil-rig disaster in history. The Piper Alpha rig, which was the largest in the North Sea, was owned by Occidental Oil and had approximately 225 workers onboard at the time of the explosion. It was located about 120 miles off the northeast coast of Scotland. On the evening of July 6, a gas leak led to a massive explosion and fire on the rig. A fireball 350 feet high erupted from the platform. The fire emitted toxic fumes that overwhelmed and killed many of the workers. Others jumped more than 100 feet to the sea below to escape the flames and fumes, even though they knew that the fall would most likely be fatal. A couple of workers managed to survive the jump; others somehow avoided death by sliding down pipes into the treacherous waters below, where burning oil was floating on the cold sea. They were then rescued by helicopters and nearby boats. Oil drilling in the North Sea began in the 1970s and has had a mixed safety record. This disaster was by far the largest single incident; most other deaths on the 120 rigs in the sea have been due to bad weather. A 1990 inquiry into the disaster was critical of the safety procedures on the Occidental rig before the disaster, but did not identify the direct cause of the explosion itself. A civil action was resolved in 1997 with a finding that two deceased workers were negligent, but that decision has not been generally accepted.