STATUS REPORT
on
COMBUSTIBLE DUST
NATIONAL EMPHASIS PROGRAM
Office of General Industry Enforcement
Directorate of Enforcement Programs
October 2009
Background
Fires and explosions fueled by combustible dusts have long
been recognized as a major industrial hazard. A November 2006, Chemical Safety
Hazard Investigation Board (CSB) report described the occurrence of nearly 280
dust fires and explosions in U.S. industrial facilities over the past 25 years,
resulting in approximately 119 fatalities and over 700 injuries.
OSHA initiated its Combustible Dust National Emphasis
Program (NEP) on October 18, 2007, to inspect facilities that generate or
handle combustible dusts that pose a deflagration/explosion or other fire
hazard. The NEP was based in large part on a Region III Special Emphasis Program
that had begun in 2000.
Although OSHA, at present, does not have a specific standard
on combustible dust hazards, there are several existing OSHA standards that
apply to combustible dust handling facilities. The NEP focuses on these
standards, as well as the General Duty Clause.
Following a massive sugar dust explosion at Imperial Sugar's
Port Wentworth Georgia facility on February 7, 2008, that killed 14 workers and
injured many more, OSHA revised the Combustible Dust NEP to focus on industries
with more frequent and high consequence dust incidents, and to include more
inspections. The revised NEP targets 64 types of industries. In addition, all
sugar refineries (beet and sugarcane) in Federal jurisdiction will be
inspected. OSHA also strongly recommended that all State Plans participate in
the NEP.
Number and Types of Inspections Conducted under the NEP
The Combustible Dust National Emphasis Program applies to 64
industries (SICs / NAICs), including wood products, food products, metal products,
chemicals, pharmaceuticals, rubber and plastic products, paper products, furniture,
electric and sanitary services, transportation equipment, durable goods, and
textile mills. Each area office is required to conduct at least four inspections
per year. The figures below include inspections data from October 2007 through
June 2009. Since the inception of the NEP, more than 1000 inspections have
been conducted, including inspections conducted by State Plan States. (See
Figure 1). To date, 11 states have adopted OSHA's NEP and an additional four
states have plans to adopt the program.
Total Number of Inspections Conducted
Figure 1. Number of Inspections Conducted
The wood products, food products, chemicals, metal products
and rubber / plastic products industries account for more than 70 percent of
inspections under the NEP. See Figures 2 and 3 below for the types of
industries inspected along with their numbers and percent distributions.
Figure 2. Types of Industries Inspected by Percent
Figure 3. Types of Industries Inspected by Number
Enforcement Findings
OSHA has found more than 4900 violations (See Figure 4) at
the facilities inspected pursuant to the Combustible Dust NEP. This includes not only combustible dust related violations, but also violations such
as lockout/tagout, walking and working surfaces, and other hazards.
Total Number of Violations
Figure 4. Total Number of Violations
Percent Total VIolations Cited As Serious
Figure 5. Percent Total Violations Cited as Serious
Because hazards associated with combustible dust normally
result in fires and/or explosions, the injuries would generally be burns, possibly
resulting in death. OSHA categorized 74 percent of violations found at the
facilities under Federal jurisdiction as serious. 34 percent of violations in
State Plan inspections were also characterized as serious (See Figure 5).
Violations Related to Combustible Dust Hazards
Under the NEP, the Hazard Communication standard is the
standard most frequently cited with respect to combustible dust related
hazards, followed by the housekeeping standard (see Figures 6 and 7). OSHA's
housekeeping standard at 29 C.F.R. 1910.22 not only applies to typical
housekeeping hazards but also applies to dust accumulation hazards. In several
instances, OSHA found combustible dust accumulations ankle deep and covering an
entire room.
Employers were also cited for violations of personal
protective equipment, electrical equipment for hazardous (classified) locations,
first aid, powered industrial trucks, and fire extinguisher standards during
these inspections. OSHA compliance officers also found that compressed air in
excess of 30 psi was being used for cleaning purposes. As well as violating an
OSHA standard, the use of compressed air to clean accumulated dust would create
a dust cloud and can result in deflagration or explosion if the ignition
sources are present. OSHA issued General Duty Clause citations for this
practice (see Figure 6 and 7).
Combustible Dust Related Violations
Figure 6. Number of Combustible Dust Related Violations
Figure 7 shows that 20 percent of combustible dust related
violations pertain to housekeeping, 27 percent to Hazard Communication, and 11
percent each to electrical, personal protective equipment, fire extinguishers
and hazards addressed by the General Duty Clause.
Figure 7. Percent Combustible Dust Related Violation Distributions
In the absence of an OSHA standard, OSHA can cite Section
5(a)(1) of the OSH Act, the General Duty Clause, for serious hazards, such as
fire and explosion hazards for which there are feasible means of abatement.
OSHA has referenced NFPA standards 654, 484, 61, and 664 as potential means of
abating combustible dust hazards in citations issued under the NEP. OSHA also referenced NFPA 499 in recommending safe practices for electrical equipment
used in Class II locations, and NFPA 68 and 69 for explosion prevention and
protection techniques. Some of the hazards cited under the General Duty Clause
are listed below.
Examples of General Duty Clause Violations
The following summarizes some General Duty Clause citations
issued by OSHA under the Combustible Dust NEP:
- Dust collectors were located inside buildings without proper
explosion protection systems, such as explosion venting or explosion
suppression systems.
- Deflagration isolation systems were not provided to prevent
deflagration propagation from dust handling equipment to other parts of the
plant.
- The rooms with excessive dust accumulations were not
equipped with explosion relief venting distributed over the exterior walls and
roofs of the buildings.
- The horizontal surfaces such as beams, ledges and screw
conveyors at elevated surfaces were not minimized to prevent accumulation of
dust on surfaces.
- The ductwork for the dust collection system did not maintain
a velocity of at least 4500 ft/min to ensure transport of both coarse and fine
particles and to ensure re-entrainment.
- Flexible hoses used for transferring reground plastics were
not conductive, bonded or grounded to minimize generation and accumulation of
static electricity. A nonconductive PVC piping was used as ductwork. Ductwork
from the dust collection system to other areas of the plant was not constructed
of metal.
- All components of dust collection system were not
constructed of noncombustible materials in that cardboard boxes were being used
as collection hoppers.
- Equipment such as grinders, shakers, mixers and ductwork
were not maintained to minimize escape of dust into the surrounding work area.
Employer did not prevent the escape of dust from the packaging equipment,
creating a dust cloud in the work area.
- Interior surfaces where dust accumulations could occur were
not designed or constructed to facilitate cleaning and to minimize combustible
dust accumulations. Regular cleaning frequencies were not established for
walls, floors, and horizontal surfaces such as ducts, pipes, hoods, ledges,
beams, etc.
- Compressed air was periodically used to clean up the
combustible dust accumulation in the presence of ignition sources.
- Air from dust collector was recycled through duct work back
into the work area without the protection of a listed spark detection system,
high speed abort gate and/or functioning extinguishing system.
- Air displaced during filling and emptying at the packaging
and weighing systems which was discharged into the building was cleaned with a
filter that was not 99.9 percent efficient at 10 microns.
- Exhaust ventilation systems were not installed to control
dust clouds escaping from blending and other processing machinery.
- Bulk material conveyor belts were not equipped with bearing
temperature, belt alignment, and vibration detection monitors at the head and
tail pulleys to shut down equipment and/or notify the operator before the
initiation of a fire and/or explosion.
- Enclosureless systems were allowed indoors where they were
connected to sanders having mechanical feeds; where they were not emptied at
least daily; where they were located in areas routinely occupied by personnel;
and where they were not separated by at least 20 feet.
- Silos, legs of bucket elevators were not equipped with
explosion relief venting.
- Explosion vents on dust collectors and bucket elevators were
directed into work areas and not vented to a safe, outside location away from
platforms, means of egress, or other potentially occupied areas.
- The dust collector's baghouse automatic pulse cleaning
system was nonoperational due to equipment defects. The dust collector systems'
hoods and ductwork were in disrepair with substantial air leaks in the ductwork
created by missing inspection covers, unused opening, incomplete or poorly
designed capture hoods and physical damage.
- A dust collector collecting aluminum dust was located inside
a building and not located outside with appropriate venting and other safeguards
to protect employees in the event of an explosion.
- Dust collectors were allowed to be shutdown periodically
during unloading operations resulting in the creation of dust clouds in the
processing areas. Procedures were not established to shut down related
machinery if the dust collection system shuts down.
- Collection points used for manual cleanup of wood dust and
other foreign material including metal were not provided with magnetic
separators, grates or other types of screening to prevent foreign material from
entering into the dust collection system.
- Automatic sprinkler systems were not provided on
enclosureless dust collectors operating at 5500 cfm capacity, and were not
separated by at least 20 feet from each other when located inside the buildings.
- Process Hazard Analysis was not conducted to determine
whether the process hazards necessitated the installation of approved devices
such as explosion protection systems, interlocked rotary valves, deflagration
vents, and flame front diverters.
- Employees were exposed to explosion hazards due to the
nitrogen blanketing piping disengaging from the mixer/blender during the mixing
process.
- Mixers and blenders used for the production of pulverized collagen
was not dust-tight and not equipped and provided with explosion prevention,
relief and techniques.
- Miter saw was not maintained under continuous suction, thus
allowing escape of dust during normal operation.
- The Coalpactors (hammer mills) used to crush coal and their
connected feed chutes were not equipped with protective systems to prevent or
mitigate a deflagration in the event of an ignition of combustible coal dust
inside the Coalpactors.
- The company had not developed and implemented written
Management of Change procedures for ensuring that potential changes to
production equipment and dust control equipment do not result in fires,
deflagrations and dust explosions.
- Screw conveyors or screw augers were not provided with
deflagration isolation devices, such as, but not limited to, deflagration/explosion
relief venting, containment, or isolation to prevent continued propagation
flame front and over pressure into adjacent building/structures or equipment.
- The employer did not provided adequate maintenance and
design of dust collector systems creating insufficient air aspirations, low
duct velocities and blocked ducts.
- Propane burners with open flames were used in the area where
agricultural products were ground.
- Employees were using electric grinder(s) on a duct entering
a baghouse style dust collector without a hot work permit system.
OSHA found that the majority of facilities inspected under the NEP had
dust collectors located inside the buildings without proper explosion
protections systems, such as explosion vents or explosion suppression systems.
Average Number Violations Issued Per Inspection
The average number of violations per NEP inspection is 6.5
in Federal enforcement as compared to 3.1 for the other inspections (See Figure
8). This means that OSHA is finding twice the number of violations at
combustible dust handling facilities when compared to all other facilities in
general.
Figure 8. Average Number of Violations per Inspection
Average Penalty per Serious Violation
The total citation penalty amount OSHA has proposed under
the Combustible Dust NEP is: $14,848,686. However, OSHA proposed the third
largest fine in its history, exceeding $8.7 million, following Imperial Sugar Refinery
explosion in February 2008. The average penalty proposed per serious violation
during combustible dust NEP inspections is $1233 for Federal OSHA, and $791 for
State Plans.
Figure 9. Average Penalty per Serious Violation
Percent Inspections In-Compliance
OSHA found during the inspection of combustible dust
handling facilities that only 18 to 22 % of facilities inspected were found to
be in compliance with OSHA requirements (see Figure 10). OSHA's goal is that
100 percent of these inspections find compliance with OSHA requirements.
Figure 10. Percent Inspections In-Compliance
Combustible Dust Hazards Training
OSHA has included combustible dust hazards in the Process
Safety Management course it provides its compliance officers for more than
three years. Over 350 compliance officers have received the PSM segment of
training on combustible dust hazards. In addition, OTI, OSHA's Training
Institute, has developed a specialized comprehensive three and one-half day
course on Combustible Dust Hazards and Controls, which it began conducting since
December 2007. Since the inception of this course, more than 200 Federal and
state OSHA personnel have successfully completed it, and more classes are
scheduled. OTI has also conducted two refresher seminars for nearly 1,400
Federal and State Plan personnel across the nation. Training is limited to
OSHA and State personnel.
Combustible Dust Hazards Outreach
In 2005, OSHA issued a Safety and Health Information
Bulletin entitled Combustible Dust in Industry: Preventing and Mitigating the
Effects of Fire and Explosions. This comprehensive guidance highlights the
hazards associated with combustible dusts, the work practices and engineering
controls that reduce the potential for a dust explosion or that reduce the
danger to employees if such an explosion should occur, and the training needed
to protect employees from these hazards. In March 2008, OSHA mailed copies of
this guidance to 30,000 employers in industries it identified as being an
at-risk for dust hazards, a proactive step to remind employers of their duty to
furnish their employees with places of employment that are free of hazards and to
provide them with instruction and information as to how this can be
accomplished.
OSHA is providing other assistance to employers and
employees to protect against combustible dust hazards. Specifically, OSHA has
created:
- a website, specifically dedicated to combustible dust hazards,
- a safety alert, and
- a poster addressing the measures employers handling
combustible dusts must take.
Conclusion
OSHA is taking, and will continue to take, strong enforcement
actions to address combustible dust hazards. The Agency's strong enforcement
of applicable regulatory and statutory requirements combined with education and
outreach to employers and employees is helping to protect the safety and health
of working men and women who may be exposed to combustible dust hazards. However,
OSHA recognized that there are limitations to this approach, and OSHA has also
initiated rulemaking to provide more targeted tools to address combustible dust
hazards.
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