A report about West Pharmaceutical Services Explosion
On January 29, 2003, an accumulation of dust covering the top
side of a suspended ceiling above a production room at the West
Pharmaceutical Services Inc. plant in Kinston, North Carolina,
exploded, killing six workers and injuring 38 people, including
Because the U. S. Food and Drug Administration regulated West
Pharmaceutical’s customers, housekeeping in the ground-floor
room had been a high priority, particularly around a rubber-processing
batchoff machine. The machine, which sat 3 feet (0.9 meters) below
the room’s suspended ceiling, had operated 24 hours a day,
five or six days a week, since 1987, where rubber strips were
coated by dipping them into a slurry containing Acumist, a finely
powdered grade of combustible polyethylene. The rubber was used
for drug-delivery components such as syringe plungers, septums,
and vial seals.
The combustible polyethylene can become explosive when conditions
for a dust explosion are met: dust of the right particle size;
air or other oxidizer; dust dispersion; confinement, such as in
a building or enclosure; and ignition source. In this case, investigators
couldn't identify the ignition source or the source of the dispersion
mechanism for the dust as it rested in the area above the ceiling.
So what happened? According to a report the U.S. Chemical Safety
and Hazard Investigation Board (CSB) released last September,
the blast and resulting fire, which turned half the 150,000-square-foot
(13,935-square-meter) factory into a charred skeleton, resulted
when the layer of combustible polyethylene dust ignited. Although
plant maintenance crews regularly and assiduously vacuumed the
combustible dust from the walls and underside of the suspended
ceiling, they were unaware that the room’s comfort air system
was pulling the dust up above the ceiling, where it had accumulated
to a depth of 0.25 to 0.5 inches (0.63 to 1.2 centimeters).
If uniformly suspended, combustible dust just 1/32 of an inch
(0.0794 centimeters) deep can create a cloud of optimal explosive
concentration 10 feet (3 meters) high, according to the 2000 edition
of NFPA 654, Prevention of Fire and Dust Explosions from the Manufacturing,
Processing, and Handling of Combustible Particulate Solids. NFPA
654 specifies engineering and construction requirements for dust-tight
segregation of hazardous building zones, classification of electrical
equipment in dusty areas, and special air-conditioning explosion
venting. It also recommends management systems for fugitive dust
emissions, associated housekeeping, and employee training.
CSB member John Bresland says the disaster at West Pharmaceutical
would likely have been avoided had the company understood the
hazard and followed the recommendations of NFPA 654. The CSB has
recommended to the North Carolina Building Code Council that the
state amend its building code to make compliance with NFPA 654
mandatory. The CSB also recommended that North Carolina train
its fire inspectors in NFPA 654.
One of three 2003 explosions
The West Pharmaceutical accident was one of three industrial dust
explosions in 2003 that resulted in worker deaths. On February
20, phenolic resin powder used as a binder in the production of
fiberglass acoustic insulation for the automotive industry exploded
at the CTA Acoustics plant in Corbin, Kentucky. Seven workers
were killed and 42 injured. Eight months later, a flash fire at
the Hayes Lemmerz automotive parts factory in Huntington, Indiana,
escaped from the dust collection hood over the furnace and ignited
aluminum dust from the chip processing. The fire spread out of
control, and a secondary explosion occurred minutes later in the
dust collection equipment. Two Hayes Lemmerz employees were severely
burned, while a third died from the explosion.
Bill Hoyle, a CSB investigation manager, says accumulated dust
in the production areas of both facilities led to the explosions
and deaths at the Kentucky and Indiana factories. As of mid-December,
the CSB had not completed its reports on those explosions.
Because of these three incidents, the CSB has undertaken a major
study of industrial accidents involving dust explosions over the
past 20 years.
"Our preliminary information shows that there have been
150 dust explosions resulting in more than 80 deaths over the
past two decades," CSB representative Dan Horowitz says.
Hoyle, who is heading the investigation, traveled to Baltimore
in October to attend a meeting of NFPA’s Technical Committee
on Handling and Conveying of Dusts, Vapors, and Gases, which has
jurisdiction over NFPA 654. He asked for help sifting the data
he had assembled on those 150 accidents and for advice on how
the CSB might proceed if, based on final findings, it decided
to recommend a national workplace safety standard for industrial
dust. NFPA 654 is currently in the revision process and a new
edition will be voted on at the June 2005 World Safety Conference
& Exposition® in Las Vegas.
In 1987, the Occupational Safety and Health Administration (OSHA)
adopted a dust safety standard for grain-handling facilities in
response to repeated loss of life from grain elevator explosions.
Other than these regulations and those issued by the Mine Safety
and Health Administration to regulate coal dust, no specific federal
program currently provides comprehensive safety standards to prevent
and control the hazards of combustible dusts such as those found
at West Pharmaceutical, CTA Acoustics, and Hayes Lemmerz.
In its investigation of the disaster at West Pharmaceutical,
the CSB found that plant officials weren’t sufficiently
aware of the dangers of combustible dust, but they hadn’t
violated any laws. When the Kinston plant was built in 1975 and
expanded in 1984, North Carolina had no fire code. In 1991, the
state adopted the Standard Fire Prevention Code published by the
Southern Building Code Congress International (SBCCI). In 1994,
SBCCI merged with two other U.S.model code organizations to form
the International Code Council (ICC). And in 2002, North Carolina
adopted the ICC’s International Fire Code (IFC).
Unlike the extensive coverage various NFPA standards give the
hazards of combustible dust, the IFC contains only a single page
of text in Chapter 13, "Combustible Dust-Producing Operations,"
on the subject, and that page does not include specific engineering
and management system measures to control the hazard.
Chapter 13 references various NFPA standards for combustible
dust hazards but does not mandate compliance. Rather, the IFC
authorizes the authority having jurisdiction to enforce applicable
provisions of NFPA standards to prevent and control dust hazards
on a case-by-case basis and issue operating permits to facilities
that use or generate combustible dust. North Carolina leaves the
issuance of a permit up to individual counties, and Lenoir County,
where Kinston is located, does not require permits. So the West
Pharmaceutical plant was under no obligation to comply with Chapter
13 of the IFC.
Thought dust was inert
Why did West Pharmaceutical maintenance workers regularly see
the accumulations of dust above the suspended ceiling and fail
to remove them? Robert Gombar, an attorney for West Pharmaceuticals,
says they thought the dust was inert—even though the 1990
material safety data sheet (MSDS) for Acumist advises users to
consult NFPA 654.
West Pharmaceutical executives didn’t make the connection
between that MSDS and the potential for dangerous dust accumulations
from the Acumist-containing slurry used in the batchoff machine,
Gombar says. When West Pharmaceutical started using Acumist in
1990, it was in small quantities as a dusting agent, not as an
ingredient in a slurry, which calls for much larger amounts of
the polyethylene resin, greatly multiplying the explosion hazard.
In 1994, however, it began using a concentrated water-based paste
of Acumist powder to which water was added at the plant to form
the anti-tack slurry, into which rubber strips were dipped to
prevent them from sticking together when they came out of the
batchoff machine. Until that time, West Pharmaceutical used a
different slurry containing a different chemical dust, zinc stearate.
The MSDS for this new additive contained no combustibility warnings,
and West Pharmaceutical did not explore the implications of using
Acumist in greater quantities, Gombar says.
When North Carolina adopted the IFC in 2002, the state amended
it to say that building permits were optional for companies producing
combustible dust. Barry Gupton, the liaison between the office
of the North Carolina Fire Marshal and the North Carolina Building
Code Council, says there is currently no petition before the council
to amend Chapter 13 of the IFC to make NFPA 654 mandatory. However,
the council is considering making it mandatory for counties to
require companies to obtain operating permits, which would trigger
application of the North Carolina Fire Code.
West Pharmaceutical has built a new Kinston plant, but that facility
no longer produces rubber, so compliance with NFPA 654 is not
an issue there.