Safety Messages

During the nights of Dec. 2 and 3, 1984, a Union Carbide plant in Bhopal, India, began leaking 27 tons of a deadly gas called methyl isocyanate (or MIC). Not one of the six safety systems designed to contain such a leak was operational allowing the gas to spread throughout the city of Bhopal. Half a million people were exposed to the gas. About 8,000 died the first week and 20,000 have died to date. More than 120,000 people still suffer from ailments caused by the accident and subsequent pollution of the plant site. The ailments include blindness, extreme difficulty in breathing and gynecological disorders.

October 1990: The USS Iwo Jima amphibious assault ship deployed to the Persian Gulf for Operation Desert Shield. The USS Iwo Jima docked at Bahrain shipyard for emergent repairs, but as the ship was leaving port, one hour after the propulsion plant was brought online, bonnet fasteners for a 4-inch valve supplying steam to the ship's service turbine generator failed catastrophically and 850 degree superheated steam at 600 psi escaped into the manned compartment. Nine sailors were killed instantly, one more fatally injured.

DC-10 Certification: The draft Failure Mode and  Effects Analysis was modified by Douglas to minimize design deficiency. A ground test failure in May 1970 was blamed on human error. In retrospect, poor design was downplayed as a root cause. During November 1970, internal memos between Convair and Douglas discussed proposed fixes to the cargo door problem but none was implemented. The Federal Aviation Administration certified the DC-10 on July 29, 1971, with an unsolved design deficiency. In March 3, 1974, a Turkish Airline DC-10 crashed in France killing all 346 people aboard. The cause of the accident was faulty latches on the cargo door which allowed the differential pressure in the cabin at 11,500 feet altitude to force the door to swing open to the outside of the plane where it was ripped open off its hinges by the air stream. After this accident, the entire DC-10 fleet was finally grounded and the cargo door locking system was redesigned and the problem eliminated.

On April 26, 1986, two huge explosions blew apart Unit 4 of the Chernobyl Nuclear Power Plant in the Ukrainian SSR. At least 31 workers and emergency personnel were killed immediately or died from radiation sickness soon after the accident. The nearby village of Pripyat, where most Chernobyl plant workers lived, had to be evacuated and sealed; some 200,000 residents of the area were evacuated. Radioactive debris was carried by clouds over most of northern Europe; long-term effects still being debated, but increased childhood thyroid cancer in Belarus and Ukraine is tied to the accident. This was the worst nuclear accident in history.

Experience has shown that multiple, unrelated and sometimes benign perturbations have challenged our systems in complex ways we would have never expected. High-consequence scenarios can emerge as a result of the occurrence of multiple unrelated events. Traditional system safety evaluations (e.g., Failure Modes and Effects Analysis) often model the response of the system to a single perturbation (failure or process deviation). Accident scenarios predicted by these models tend to be incomplete. From a risk management point of view, relying solely on such analyses, may cause relatively unimportant issues to receive excessive attention, while other important issues may go unidentified.

Strokes are a major cause of death in our society today. Strokes are difficult to identify and manifest themselves differently in different people. Early identification of the symptoms of a stroke often makes the difference between life and death.