I was listening to the news on my way to work last week, and heard a story about the review conducted after the well-publicized security breach at the White House. Like many people, I was shocked when the story of the fence-jumper first broke. How was it possible that some guy with a knife managed to get over the fence, cross the lawn, enter the White House and get deep into the building before he was stopped? The answer, according to NPR’s reporting of the Department of Homeland Security investigation is that a whole sequence of events made it possible:
It turns out that the top part of the fence that he climbed over was broken, and it didn’t have that kind of ornamental spike that might have slowed him down. Gonzalez then set off alarms when he got over the fence, and an officer assigned to the alarm board announced over the Secret Service radio there was a jumper. But they didn’t know the radio couldn’t override other normal radio traffic. Other officers said they didn’t see Gonzalez because of a construction project along the fence line itself. And in one of the most perhaps striking breaches, a K-9 officer was in his Secret Service van on the White House driveway. But he was talking on his personal cell phone when this happened. He didn’t have his radio earpiece in his ear. His backup radio was in his locker. Officers did pursue Gonzalez, but they didn’t fire because they didn’t think he was armed. He did have a knife. He went through some bushes that officers thought were impenetrable, but he was able to get through them and to the front door. And then an alarm that would’ve alerted an officer inside the front door was muted, and she was overpowered by Gonzales when he burst through the door. So just a string of miscues.
The explanation rang true. Of course it was no “one thing” that went wrong; it was a series of events, no one of which in isolation was sufficient to cause a problem but, when strung together, led to a catastrophic system failure. The explanation also sounded familiar. It is a perfect example of the “swiss cheese” conceptual model of patient safety.
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