Human Error

A buildup of trapped air in a 29-year-old pipe triggered an explosion that, for two months, contaminated beaches here with billions of gallons of partially treated waste, according to preliminary findings by a firm investigating the cause of the rupture. If the finding proves true, it would bolster the contention of some city sewage workers that human error resulted in the formation of a giant bubble that burst the pipe.

Friday's tragic Metrolink crash in Chatsworth, which killed 25 people, was not the only fatal rail accident last week. Less than an hour after the Chatsworth crash, a car was struck by a Metrolink train in Corona and the driver killed in a grade-crossing accident. According to the Federal Railroad Administration, 74 people have died in Metrolink crashes since 1999 in California. And in a total of 821 accidents, 90 people have died on the Metropolitan Transportation Authority's L.A.-Long Beach Blue Line from its inception in July 1990 to July 2008.

Union Carbide Corp. today blamed equipment failure and human error for an Aug. 11 poison gas leak at its Institute plant that sent 135 people to hospitals. The company also said the poison cloud was composed of 650 pounds of methylene chloride, a suspected cancer-causing agent, and 2,800 pounds of aldicarb oxime "decomposition products." By that, the company meant the aldicarb broke down in a storage tank before being released.

Pentagon investigators have concluded that human error was primarily responsible for the shooting down of an Iranian jetliner by a U.S. warship, according to published reports. The official report on the disaster that killed 290 people last month says that the sophisticated radar equipment on board the cruiser Vincennes functioned well, ABC News reported Tuesday.

Re Robert W. Welkos' article "Why 'Being Human' Misfired" (May 17): His portrait of why the film is failing to reach audiences is revealing of the business machinations of Hollywood, but not very telling about the movie. Welkos explains that when National Research Group asked people how they'd like to see a movie about a man searching for his place in the world, "only 2% of males over 25 said it was their first choice of a film to watch this weekend while 1% of males and females under 25 said it was their first choice."

Three cheers for Lisa Paulson of the Veterinary Medical Center in Woodland Hills, the first interviewee to reflect knowledge in The Times' focus on coyotes ("Pet in Fenced Yard Falls Prey to Coyotes," Aug. 1). It is not the fault of the coyote when family pets or even children are mauled; the fault is human. Developers as well as residents are guilty parties in the transaction of building and buying a home, respectively. To purchase a house in a well-forested area (or one that was well-forested)

Sheriff Sherman Block told the Board of Supervisors on Tuesday that human error contributed to the escape of 14 inmates from a maximum-security jail, and then he asked for money to beef up fences and add security alarms. "Certainly there was some human failure and there were structural deficiencies," said Block, who acknowledged that the escape early Sunday morning from the Peter J. Pitchess Honor Rancho--the largest jailbreak in county history--has been an embarrassment.

A nine-foot-long aluminum beam left inside the engine compartment of the space shuttle Atlantis that damaged the craft was the result of human error, investigators in Cape Canaveral, Fla., concluded. Routine worker fatigue, inexperience or scheduling were ruled out as causes of the mishap, officials said. The beam, part of a work platform, banged around inside the compartment and caused about 25 dents and dings when the shuttle was lifted into an upright position in an assembly room on Oct. 3.

A human error in running a computer has delayed 450,000 federal tax refunds by a week, but the IRS said there is no comparison with the computer problems that made a disaster of the 1985 filing season. "The situation was uncovered immediately and remedial steps were taken so that no taxpayers were inconvenienced," IRS spokesman Frank Keith said of the latest problem.