On Thursday, March
18, 1937, a seventh-grade girl named Sibyl sat in a school bus outside the junior-senior
high school building built four years earlier in the unincorporated town of New
London, Texas. In contrast to the
rest of the nation, New London and the surrounding area of East Texas were
prospering from a local oil boom, and many of the school's students came from
families drawn to the area by oil-field jobs. Sibyl had mistakenly left her class early, but rather than
go back inside and look foolish, she had decided just to wait in the bus until
school let out for the day in another twenty minutes or so. Suddenly, at 3:17 PM, she saw the
entire front of the building rise several feet into the air and then collapse
into a huge pile of dust with a thunderous crash. She had just narrowly escaped what turned out to be the
worst school disaster in the history of the United States. Over three hundred children and adults
died either in the explosion itself or as a result of injuries they sustained
in it. The cause? Odorless natural gas.
As you may know,
natural gas has no characteristic odor of its own. By law, a malodorant
must be added to natural gas for non-industrial users such as homes,
businesses, and schools so that a leak will call attention to itself by means
of smell. One of the compounds
used, butyl mercaptan, is so stinky that the average human nose detects it at a
level of 0.33 parts per billion.
That concentration amounts to one teaspoon of malodorant in a cube of
air about 25 meters (80 feet) on a side.
While gas leaks and explosions still occur, the chances of detecting a
leak before it causes an explosion are much better when the gas contains a
malodorant.
Flammable gas has
been used for domestic light and heat since the early 1800s, but until the
discovery of large supplies of natural gas, piped-in gas was a relatively
costly type of utility that was confined to cities. By contrast, the oil wells around New London freely produced
so much natural gas that it was (and still often is) considered a waste product,
and was flared off near wells in towering flames that burned day and night and
could be seen for miles. The oil
companies piped some of it around in what were called bleed-off lines to supply
power for their own operations, and because many of New London's residents were
already familiar with oilfield equipment and piping, tapping a nearby gas line
for free raw natural gas became a common practice. Although it was technically illegal, someone with the
requisite skills could install his own private gas line to an oil lease's
bleed-off line, and enjoy free gas instead of paying the local gas utility for
it.
It is a matter of
record that a couple of months before the 1937 explosion, W. C. Shaw,
superintendent of the New London schools, authorized a janitor to disconnect
the schoolhouse from the local gas utility and tap a nearby bleed-off line
instead. Mr. Shaw apparently
viewed this as a cost-saving measure, similar to the earlier decision when the
school was built to forego the usual steam-boiler-radiator heating system, and
instead install an extensive gas piping system and some seventy gas space
heaters instead.
In My Boys and Girls Are in There, a recent
book on the tragedy, historian Ron Rozelle notes that many subsequent summaries
of the disaster tend to blame Superintendent Shaw for endangering the lives of
his charges with the decision to use free untreated bleed-off gas. The critical question, which Mr.
Rozelle doesn't answer in the book, is whether the local gas company was adding
malodorant to its product at the time.
Such a practice was widespread by 1937, but by no means universal. If the utility's gas was odorless as
well, then the decision to switch to bleed-off gas made no difference, because
the leak that caused the explosion would not have been any easier to detect. The main reason that the explosion was
so severe and extensive was that the poured-concrete school building had a
single, poorly ventilated, and uninterrupted crawl space beneath the entire
front part of the building, under eight inches of solid concrete floor. Since natural gas (primarily methane)
is lighter than air, this crawl space formed a good container for thousands of
cubic feet of gas, which was touched off on that fatal day when a shop teacher
switched on an electric sander in the basement.
While the New
London explosion dominated national news for a week or so, it faded quickly as
other events diverted the public's attention. Like war veterans often do, survivors of the explosion
usually refused to talk about it afterwards. However, one survivor, fifth-grader Carolyn Jones, had the
courage to make a speech to the Texas House and Senate in Austin only a week
after the explosion, urging that safety measures be passed to prevent another
disaster like the one at New London.
The result? Two laws: one requiring all natural gas for
domestic purposes to contain a malodorant, and the other requiring that anyone
working on residential natural-gas lines for residential use must be trained
and certified for such work by the state of Texas. The publicity of the New London disaster furnished
ammunition for the passage of similar laws in other states, so that eventually,
all natural gas sold for household use would carry its own portable detection
system, namely, a bad smell.
The New London
explosion and its aftermath form a familiar pattern: first an innovation (the use of natural gas for domestic gas
supplies was fairly new in the 1930s); then a tragedy resulting from inadequate
safeguards, ignorance, or other factors; then regulations, or a change in good
engineering practices, or both, all inspired by the tragedy. It would be nice if engineers were able
to anticipate everything that could go wrong in a novel situation. But human ingenuity being both fallible
and limited, sometimes we have to learn from mistakes, and the more costly the
mistake in terms of lives, the faster we learn. While nothing will ever bring back those three hundred lives
lost on that East Texas afternoon seventy-six years ago, it is some comfort to
know that their lives were not lost in vain, and that gas users around the
globe are safer as a result.
Sources: I thank
Andrea Nelson and Stephen Paul for bringing my attention to Ron Rozelle's book My Boys and Girls Are in There (College
Station: Texas A&M University
Press, 2012), which I relied on for most of the material in today's column. I also referred to the Wikipedia
articles on the history of manufactured gas, thiols, and tert-butylthiol.
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