According to the Columbus Dispatch:

It is pure luck, or some would say a miracle, that no one was killed or even seriously injured on Saturday afternoon when a gas leak turned an Upper Arlington home into a bomb. Bricks, glass and other debris became projectiles, shooting across the neighborhood with a blast force that slammed other homes.

Because gas leaks aren’t all that rare, it’s vital that investigators determine what went wrong. Most important, finding out why, with hours of warning, the explosion wasn’t prevented. Was this human error, and is there a need to improve future training and emergency protocols?

This was a casualty-free lesson, though a dear one. The insurance claims are likely to be enormous. Dozens of homes are reported damaged. One neighbor’s basement wall collapsed. And all that remains of the house at 3418 Sunningdale Way is splinters and memories.

About noon, mail carrier Tim Nelson noticed the “very strong” smell of natural gas by the Ishidas’ home. He asked a neighbor, Dan Schafer, to report the odor.

At 12:46 Schafer called the suburb’s police nonemergency number to say he might set off a home-security alarm; a Columbia Gas worker was there checking on the source of a gas odor and had asked him to go inside.

A city dispatcher asked where the odor was coming from; leaks inside a home, contained, can explode.

Shafer didn’t know, so the dispatcher told him to call 911 if firefighters were needed. The call was never forwarded to the city’s fire division; in hindsight, Chief Tim Young says firefighters would have responded.

But Chief Tim Young also notes that routinely sending firefighters to check out reports of a gas odor could “overwhelm us and Columbia Gas with unnecessary calls.” Still, he urges people to err on the side of caution: Anyone who smells the rotten-egg odor of gas should report it to their gas company and 911. Leaks aren’t uncommon, and they usually don’t result in explosions. In 2013, Columbia Gas reported 4,774 gas leaks.

The mailman noted he smells gas daily. But in this instance, the odor was strong and the situation ended up being serious. This could have been far worse: According to a national database, there have been 90 natural-gas fires and explosions in Ohio since 1995, causing 11 deaths, 40 injuries and nearly $24 million in property damage.

In the event of another explosion like this, there might be casualties. So it’s vital to identify errors and devise better ways to respond. Fire and building codes and emergency-response protocols are, in essence, an encyclopedia built on the lessons of human error. The safety that we take for granted in our cars, buildings, airplanes and health care is the result of the hard lessons gleaned from past tragedies. And often, a disaster isn’t the result of a single mistake, but a chain of unexpected, unintended circumstances.

Gas pipes snake under our cities and into our homes, and they grow old and suffer damage. The answers from this investigation should provide important lessons.