Spot the OSHA Violation

Is This How You Want Your Workers to Behave?

What’s wrong with this scene?

Answer

This scenario lends itself to the following safety hazards:

√ Safety Hazard 1: somebody might slip on the concrete dust

√ Safety Hazard 2: somebody might breathe in the dust and suffer respiratory damage

√ Safety Hazard 3: the airborne concrete dust is combustible and could result in an explosion

The Moral: Workplace negligence can do serious damage.

Let’s focus on the hazard of airborne combustible dusts.

WHAT’S AT STAKE

Dust Explosions—The Body Count

Major U.S. Dust Explosions

INCIDENT / DATE / WHAT HAPPENED
Imperial Sugar Company
Port Wentworth, GA / Feb. 7, 2008 / 14 workers killed, 38 seriously injured in series of sugar dusts explosions at sugar refinery
Darr Mine
Jacobs Creek, PA / Dec. 19, 1907 / 239 miners killed by coal dust explosions and resulting fires
West Pharmaceutical Services
Kinston, NC / Jan. 29, 2003 / 6 killed, dozens injured in polyethylene dusts explosion in rubber compounding section of plant
Continental Grain Co.
Westwego, LA / Dec. 1977 / 36 killed in grain dusts explosion inside grain elevator
Malden Mills
Methuen, MA / Dec. 11, 1995 / 37 injured in nylon fiber dusts explosion
Jahn Foundry
Springfield, MA / Feb. 26, 1999 / 3 dead, 9 injured in phenolic resin dust explosion
Ford River Rouge
Dearborn, MI / Feb. 1, 1999 / 6 workers killed and 36 injured in secondary coal dust explosion, i.e., explosion ignited by previous explosion or fire
Rouse Polymerics
Vicksburg, MS / May 16, 2002 / 5 killed, 7 injured in rubber dust explosion
CTA Accoustics
Corbin, KY / Feb. 20, 2003 / 7 workers killed in resin dust explosion at automobile fiberglass insulation plant
Hayes Lemmerz Mfg. Plant
Huntington, IN / Oct. 29, 2003 / 1 killed, 1 severely burned in aluminum dust explosion at aluminum automotive wheels plant

HOW DUST EXPLOSIONS OCCUR

The 2 Things that Have to Happen

1. THE AIR CONTAINS A DANGEROUS CONCENTRATION OF DUSTS

Certain dusts mix with air to form a mixture that can explode. But there must be enough of the dust in the air for explosion hazards to exist. The minimum amount/percentage of a dust capable of exploding, i.e., “combustible dust,” is called its Lower Explosive Limit (LEL). Each combustible dust has a different LEL, as depicted in the following table:

Gas / Explosion limits in air and oxygen for chosen gases
% of gas in mixture with air / % of gas in mixture with oxygen
lower / upper / lower / upper
Hydrogen H2 / 4,0 / 75 / 4,0 / 94,0
Carb. Monox. CO / 12,5 / 74 / 15,5 / 94,0
Methane CH4 / 5,0 / 15 / 5,1 / 61,0
Ethane C2H6 / 3,0 / 12,4 / 3,0 / 66,0
Propane C3H8 / 2,1 / 9,5 / 2,3 / 55,0
N-Butane C4H10 / 1,8 / 8,4 / 1,8 / 48,0
N-Pentane C5H12 / 1,4 / 7,8 / - / -
N-Hexane C6H14 / 1,2 / 7,1 / - / -
Ethylene C2H4 / 2,7 / 36 / 2,9 / 79,9
Acetylene C2H2 / 2,5 / 100 / 2,5 / 89,4
Benzene C6H6 / 1,3 / 7,9 / 2,6 / 30,0
Methanol CH4H / 6,7 / 36,0 / - / -
Ethanol C2H6H / 3,3 / 19 / - / -

2. SOMETHING HAS TO IGNITE THE DUST

An explosive mixture of combustible dust will only explode if something ignites it, i.e., sets it off. Sources of ignition typically include heat and electric sparks. How much heat does it take to ignite a combustible dust? Answer: It depends on the particular dust.

8 WAYS TO PREVENT DUST EXPLOSIONS

The key to preventing dust explosions is making sure these 2 things don’t happen.

The following are 8 other things you can do to prevent dust explosions at your workplace:

1. Take cleaning and housekeeping measures to keep dusts off surfaces and prevent them from accumulating in the air.

2. Use dust collection systems and filters to keep dusts out of the air.

3. Inspect the workplace for dust accumulations and residues.

4. Be aware of the combustible dusts that may be present in your workplace.

5. Be aware of the LEL and potential ignition sources of each of these dusts.

6. Don’t use ignition sources like welding torches, electrical equipment, and even matches in areas that contain these combustible dusts.

7. Be aware that heat and electricity from forklifts and other powered mobile equipment can be a source of igniting dust explosions.

8. Know your emergency response and evacuation plan so you’re ready in case a dust explosion or fire does occur.

FOR MORE HELP PREVENTING DUST EXPLOSIONS

Go to SafetySmart Compliance Insider’s Dust & Airborne Contaminants Compliance Center to Protect Your Workers from Combustible Dusts

·  Combustible Dusts & How to Control Them

·  Safety Talk to Train Workers about Explosive Atmosphere Hazards

·  OSHA’s Proposed Rule on Combustible Dusts

·  Congress Prods OSHA to Move Faster on Combustible Dusts Standard

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