NFPA Journal - Spring 2022 - 47

J
ust past 8:30 in the morning on July 17, 2007, a tanker
truck filled with a volatile solvent arrived at the Barton
Solvents facility, a chemical distribution company and
tank farm in the sleepy town of Valley Center, Kansas, just
north of Wichita.
The driver parked his rig next to a cluster of 40 steel storage
tanks, and a Barton supervisor arrived to do a safety check before
unloading the cargo of VM&P naphtha (varnish maker and painters
solvent), a highly flammable liquid substance commonly used to
make adhesives, resins, inks, and other products. Since flammable
liquids travelling through a hose or sloshing in a tank can become
charged with static electricity, the supervisor clamped a conductive
cable between the truck and an electrical ground station, a common
technique known as bonding and grounding. By bonding the truck
with the facility's tanks and other equipment, any static charges could
be given a free pathway to dissipate harmlessly into the earth. At least
that was the idea.
Instead, as the last of the solvent was being drained from the truck,
a single static spark-likely many times less powerful than the shock
you feel from touching a doorknob-flickered to life inside the 15,000gallon
storage tank and ignited the naphtha vapors. A sudden violent
blast lifted the steel container into the air like a rocket, hurling it 130
feet away, according to a report on the incident by the US Chemical
Safety Board. Two adjacent tanks ruptured in the explosion, spilling
thousands of gallons of flammable liquid and igniting an inferno that
spread in a chain reaction to other tanks, causing them to over-pressurize
and ignite. Steel tank tops 10 to 12 feet in diameter, as well as
valves, pipes, and other steel parts, were launched into the air with
explosive force and rained down on the nearby community. One of the
heavy steel lids struck a mobile home 300 feet away, and a pressure
valve hit a neighboring business 400 feet away, the CSB report found.
About 6,000 residents in Valley Center had to be evacuated from the
toxic black cloud wafting from the disaster. No deaths were reported,
but 12 people, including a firefighter, required medical attention.
While incidents like Barton make it clear that static electricity is
not to be taken lightly, its destructive potential seems to escape broad
public attention. Even in the safety world, static is rarely given top
billing as a hazard of major concern. Until recently, no one had a
sense of how often static ignitions like Barton occur, or what the main
causes of these incidents are. NFPA's guidance on the topic, NFPA 77,
Recommended Practice on Static Electricity, which was first published
in the 1940s, remains one of the organization's most under-the-radar
documents, a fact even its committee members freely admit.
But efforts are underway to change all of that. Early last year, the
NFPA 77 technical committee asked the Fire Protection Research
Foundation to help it better understand how effective the guide has
been at preventing static incidents and what, if anything, should
change in upcoming editions. The Foundation enlisted researchers
from the United Kingdom to scour international news reports,
academic journals, insurance claims, and other sources to create
a tally of recent static incidents from around the world and what
caused them. The work uncovered nearly 90 incidents since 2001
where static caused an ignition or an explosion, a number that surprised
many of the project's technical panel members. 
NFPA .ORG/JOURNAL * NFPA JOURNAL | 47
Even in the
safety world,
static is
rarely given
top billing as
a hazard of
major concern.
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