Combustible Dust
Imperial Sugar 2008
Dust
Malden Mills 2004
Kansas 2011
It’s Only Dust
Pictures from actual workplaces
It’s Only Sugar!
Picture from Louisiana
sugar plant three
months after a fire
destroyed a sister plant
in Georgia
Total OSHA fines to
company $8,800,000 for
violations found at the 2
plants
After the fire at the
Georgia plant – why
didn’t the company
clean this plant????
A Chronology of Past Events
• February 7, 2008 – Imperial Sugar Plant explodes
• February 11, 2008 – Fire still burning in parts of plant
• February 24,2008 – 11th worker dies from injuries
• July 2008 – OSHA fines Imperial Sugar Co. $8.8 million
For violations in Georgia and Louisiana
• August 2008 – 14th worker dies from injuries
What’s so bad.
• For the employer the millions of dollars in
OSHA fines and insurance payments not
to mention the cost of rebuilding the plant .
• For the workers and their families – the
cost, heartbreak and pain – That 14th
worker spent 6 months in a burn unit
fighting for his life. A total of 40 other
workers were injured with severe burns.
Between 1980 and 2005 the Chemical Safety Board has
knowledge of over 280 dust explosions resulting in 119 deaths and
718 injuries
That averages to more than 10 explosions per year
Despite the time since the Port Wentworth explosion brought this
issue to the national forefront the explosions continue.
10/30/2011 6 killed, 2 injured Kansas
Important Points Regarding the CSB Data
• According to the CSB, “The combustible dust incidents
the CSB lists…from 1980 to 2005 are likely only a
small sampling, as no federal or state agency keeps
specific statistics on combustible dust incidents, nor
does any single data source provide a comprehensive
collection of these incidents.
• Information about small combustible dust incidents and
near-misses is also generally unavailable.
• Incidents that cause no fatalities, significant injuries or
major fires may not be recorded in the OSHA and fire
incident databases
• The true extent of the problem is likely understated.
• Due to these limitations, the CSB does not represent the
incident data as complete or error free and other
compilations of dust explosion data are available.”
Types of Dust Involved in incidents
Inorganic
4%
Coal
8%
Plastic
14%
Metal
20%
Other
7%
Food
23%
Wood
24%
Combustible Dust Explosions History
Malden Mills
Methuen, MA
December 11, 1995
37 Injured
Nylon Fiber
Combustible Dust Explosions History
Jahn Foundry
Springfield, MA
February 26, 1999
3 dead
9 Injured
Phenolic resin dust
Combustible Dust Explosions History
May 16, 2002
Rouse Polymerics
Vicksburg, MS
5 dead, 7 injured
Rubber Dust
Combustible Dust Explosions History
•January 29, 2003 West Pharmaceutical
Services, Kinston, NC
–Six deaths, dozens of
injuries
–Facility produced
rubber stoppers and
other products for
medical use
–Plastic powder
accumulated above
suspended ceiling
ignited
Combustible Dust Explosions History
• February 20, 2003 – CTA Acoustics
Corbin, KY
– Seven Workers died
– Facility produced
fiberglass insulation
for automotive
industry
– Resin accumulated
in production area
and was ignited
Combustible Dust Explosions History
• October 29, 2003
• Hayes Lemmerz Manufacturing Plant
– Two severely
burned (one of the
victims died)
– Accumulated
aluminum
dust
– Facility manufactured
cast aluminum
automotive wheels
Combustible Dust Explosions History
• October 30, 2011
• Bartlett Grain Elevator
Atchison Kansas
- 6 Workers killed
- 2 Workers injured
Workers were loading
corn onto a train
The Dust Explosion Pentagon
Ignition Source
Ignition
Source
Dispersion
Deflagration
Confinement
Explosion
FIRE
Combustible Dust
Oxygen in Air/Oxidizers
To prevent an explosion – remove one corner of the pentagon
The primary explosion is rarely the end of the story.
Secondary Explosions
• Occur when the blast wave from the initial
explosion causes accumulated dust in
other areas (which may be remote and
unrelated to original explosion) to become
airborne and explode
• Anecdotally many investigators discover that “puffs”
(small unreported explosions) had been observed for
some time prior to the reported incident.
So How Do I Prevent a Dust Explosion?
If one of the five elements of the Pentagon is
missing a catastrophic explosion cannot occur.
= No Explosion
Ignition
Source
Ignition Source
Dispersion
Deflagration
Confinement
Explosion
FIRE
Combustible Dust
Oxygen
FIRE
I in Air/Oxidizers
FIRE
Two elements are difficult to eliminate:
1) Oxygen in Air
2) Confinement within processes or buildings
Ignition
Source
Ignition Source
Dispersion
Deflagration
Confinement
Explosion
FIRE
Combustible Dust
Oxygen
FIRE
I in Air/Oxidizers
But my process doesn’t include dust!
FIRE
Are you sure?
If you work with any solid combustible material, ingredients or
intermediate products or by-products, handling, conveying, or otherwise
manipulating these materials can create combustible dust.
Even materials typically handled and stored wet can become dry.
Definitions and Terminology
What is Combustible Dust?
NFPA 654 (2006) Definitions
• Combustible dust. A combustible particulate solid
that presents a fire or deflagration hazard when
suspended in air or some other oxidizing medium
over a range of concentrations, regardless of
particle size or shape.
• Combustible Particulate Solid. Any combustible
solid material composed of distinct particles or
pieces, regardless of size, shape, or chemical
composition.
• Hybrid Mixture. A mixture of a flammable gas
with either a combustible dust or a combustible
mist.
• Different dusts of the same chemical material
may have different ignitability and explosibility
characteristics depending on variables of
particle size, shape, and moisture content.
• Good housekeeping might seem like an easy
answer.
But housekeeping is only part of
the answer!
• As much as is practical, containment and
dust collection systems are important.
• But they must be installed and maintained
in a manner that keeps them from
becoming an ignition source
NFPA 654, Standard for the Prevention of Fire and
Dust Explosions from the Manufacturing,
Processing of Combustible Particulate Solids
Recommends:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Minimize the escape of dust from process equipment or
ventilation systems:
Use dust collection systems and filters;
Utilize surfaces that minimize dust accumulation and facilitate
cleaning;
Provide access to all hidden areas to permit inspection;
Inspect for dust residues in open and hidden areas (at regular
intervals);
Clean dust residues (at regular intervals);
Only use vacuum cleaners approved for dust collection;
Locate relief valves away from dust hazard areas; and
Develop and implement a hazardous dust inspection, testing,
housekeeping, and control program.
Use dust collection systems and filters
Dust Control
Design of facility & process
equipment
Contain combustible dust
Clean fugitive dust
Regular program
Access to hidden areas
Safe cleaning methods
Maintenance
Inspect for dust residues in open and hidden areas
(at regular intervals);
Like most pharmaceutical manufacturers this was a “clean” facility.
West Pharmaceutical facility destroyed by polyethylene dust
Which accumulated above the tiles in a dropped ceiling
Ignition Source Control
Electrical equipment
Static electricity control
Mechanical sparks & friction
Open flame control
Design of heating systems & heated
surfaces
Use of tools, & vehicles
Maintenance
Ignition Source Control
Electrical equipment
Class II, Division 1 and 2
Class I and Class III may also be an issue
Consider equipment both inside dust
handling equipment and outside
Ignition Source Control
Mechanical sparks & friction
Rotating equipment bearing failure can
lead to very hot surfaces (above the MIT)
Sliding surfaces can develop charges
Steel tools dropping onto concrete or steel
A good mechanical integrity
management system/vibration analysis
system is needed to detect problems in
advance with bearings and other
surfaces
Ignition Source Control
Mechanical sparks & friction
Open flame control
Use of tools & vehicles
Maintenance
All require effective control of Hot Work
Look for permit systems
Ignition Source Control
Design of heating systems & heated
surfaces
Know your materials
Minimum Ignition Temperature (MIT)
Maintain temperature controls
Moisture content may be critical
Primary Applicable OSHA Standards
1910.22 General – Housekeeping
1910.307 Hazardous (Classified) Locations
1910.178 Powered Industrial Trucks
1910.263 Bakery Equipment
1910.265 Sawmills
1910.272 Grain Handling
General Duty Clause
So What Should I Do?
1) Evaluate your workplace for the 5 points
of the explosion Pentagon:
a)
Combustible Dust
b)
Ignition Source
c)
Confinement
d)
Dispersion
e)
Oxygen in Air/Oxidizers
How?
• a) Combustible Dust – Do you see “dust” in
your workplace that is used in your process or is
a by product of your process
• (i.e. At a sawmill sawdust is a by product of the
cutting of logs/boards into product)
• b) Ignition Source -eliminate any possible
sources of ignition, from electricity to static
electricity - a minimum of Class II electrical
features
How?
• c) Confinement – This will depend on the
configuration of the workplace and can be
difficult to eliminate
• d) Dispersion - keep dust from suspension in air
– Use dust collectors
– When cleaning do not re-suspend
accumulated dust in air (DO NOT use air to
“clean” surfaces)
How?
• e) Oxygen in Air/Oxidizers
• Oxygen in the air cannot be eliminated (unless
workers are in SCBs)
• Oxidizers, if present for process, should be
isolated or replaced
So What Should I Do?
If you find that you do have the five elements
or you know you have four and may not be quite sure about number 5
DO NOT DELAY
Seek assistance
We don’t want your site
to look like this!
–