The explosions were horrifying. A quiet residential subdivision south of San Francisco was consumed by a massive fireball in the early evening of September 9. Firefighters who rushed to the scene initially thought that an airplane had crashed into the neighborhood.
No airplanes crashed, but the thought was understandable. By the time the fire was contained, fifteen acres of suburban San Bruno had burned, with thirty-seven homes destroyed. Within one week, six people were confirmed dead and more than four dozen were hospitalized. The damage to people and property was on a scale of an air tragedy.
The cause of the fireball was not an airplane, nor a bomb, but the kind of infrastructure Americans reply upon every day to feed our creature comforts. The fuel for the explosion was natural gas, the gas San Bruno residents relied upon to heat their homes and light their stoves. A pipe built in 1956 to deliver that gas had ruptured, releasing highly flammable fuel into the air. While an investigation into what triggered the fireball is ongoing, residents had complained for years about possible leaks producing odors in the neighborhood.
The tragedy in San Bruno should draw our attention to the infrastructure upon which we rely every day. Millions of homes across the United States are woven together in networks of pipes and wires that deliver heat, electricity, and water to us. Almost every day, this infrastructure serves us so efficiently that we do not notice the dire toll of age and use. Rarely does it fail us on the scale that it did in San Bruno.
It does happen. One January day in 1992, a similar explosion ripped through several apartment buildings on the northwest side of Chicago, killing four people and injuring many more. In the weeks after that explosion, local and national news reported that the sixty-eight-year-old gas mains that produced the explosion were of the same age and type of those found in several other areas of the city, leading to a wave of “around the clock” (in the words of a People’s Gas spokesman) inspections and replacements of pipes in the months ahead.
Chicago received another reminder about the vulnerability of its infrastructure a few months later. In April, contractors working in the Chicago River inadvertently punctured the ceiling of a forgotten freight tunnel below, causing over 100 million gallons of water to flood into the sixty-two-mile tunnel system feeding into the basements of office and retail buildings and knocking out gas and electricity service to much of downtown. Fortunately, no one was injured, but property damage in the Great Chicago Flood exceeded $1 billion. The unusual disaster made international news for days as workers struggled to remove the water pouring into the city’s central business district.
The freight tunnel through which the water poured was forgotten because few in 1992 remembered that Chicago had once used freight tunnels underneath the city. The tunnel system under Chicago’s downtown was built at the start of the twentieth century to transport coal and solid waste via rail to and from the buildings without clogging the above-ground streets. Changes to heating and plumbing led to the end of freight traffic in the tunnels by 1960, and the tunnels became conduits for power and gas lines. What remained beneath the city’s streets lay forgotten.
Our gas mains may not be as utterly forgotten as the freight tunnels were, but they are taken for granted. What happened in residential communities in Chicago in 1992 and San Bruno this year is possible in countless communities across the country. In areas of the United States ranging from Boston to Los Angeles, the networks of pipe branching through cities and suburbs were laid between half a century and a century ago. When we think of gas, it is usually in relation to our monthly utility bills, or in relation to our thermostats and stoves. Few households use stoves more than fifty years old, but those stoves may well be connected to pipes far older than that.
Utilities do perform inspections of their infrastructure but Pacific Gas and Electric conducted regular surveys of its pipes in San Bruno without revealing signs of wear or decay. No doubt depositions in future court actions will reveal the number and thoroughness of those inspections, especially given residents’ recent documented complaints.
The gas mains in San Bruno are only in the news because they failed spectacularly. Those of us who live “on the grid” in metropolitan America are completely dependent upon this mass of technology that sustains our homes and businesses. Most of us do not give it a second thought unless service is disrupted.
Remembering the infrastructure beneath us enough to understand the rigors we put it through and ensure it is properly maintained should not be difficult. We may better understand (to paraphrase historian Harold Platt) our society and culture by studying the historical processes that led to the building and maintenance of our infrastructure. Highly engaging books about the development of networks of pipes, corridors, and wires in the industrialized world include Platt's The Electric City: Energy and the Growth of the Chicago Area, 1880-1930; the volume Technology and the Rise of the Networked City in Europe and America, edited by Joel Tarr and Gabriel Dupuy; and Mark H. Rose's Cities of Light and Heat: Domesticating Gas and Electricity in Urban America. These books should appeal to a larger audience than engineers and urban designers, as they reveal not only the mechanics of infrastructure development but ways in which social and economic forces have shaped where infrastructure is built, how well it is built, and how it is (or is not) maintained. Decisions made decades ago shape even today who gets access to modern amenities, what those amenities are, and the risks we take to enjoy those amenities.
Urban environmental history provides us an understanding of how our modern infrastructure developed and what the potential risks are. Our challenge is drawing upon that knowledge to ensure that oft-neglected infrastructure is maintained to serve us safely and effectively. At Chicago’s Roosevelt University, we have recently developed a sustainability studies major that uses the history of the metropolitan area to discuss present and future efforts to make the systems managing water, waste, energy, food, and transportation safer and more equitable for people and biota affected by the region. This is but one of many possible approaches to using history that may elevate our awareness of infrastructure and its risks. Chicago’s infrastructure failures in 1992 made news for a while and then receded from public memory. Let us work to ensure that the tragedy in San Bruno allows us to develop a better understanding of the networks beneath our feet.