Transcript Silica

Crystalline Silica
Bryan Seal, CIH, CSP
Steve Delp, CAS
What is it?
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Silica is an oxide of Silicon (metal)
Specifically it is Silicon dioxide
It’s structure is crystalline
Very hard
Quartz
Plain old sand
Where do you find silica?
• Foundries that use sand in mold and core-making
processes
• Steel and other metal processing – used in some
refractories
• Coal mining
• Quarries and cement mills
• Oil and gas well fracking operations
• Construction – concrete cutting, demolition,
removing old pointing
How are you exposed to silica?
• Silica must be inhaled to be toxic
• Dust particles must be small enough to
enter the lungs – Respirable (<10
microns)
• Any operations that create dust – falling
sand, dry sweeping, cutting, grinding,
blowing, shaking, dropping, chopping,
shoveling and any other task that creates
dust.
Health Effects - Silicosis
• These small sharp crystalline particles
collect in the lungs and over time
continuously cut and irritate the lung
tissue.
• This causes scarring which decreases the
oxygen transfer capability of the lung.
• It also decreases the elasticity of the
lungs which decreases flow of air into and
out of lungs
Health Effects - Silicosis
• Silicosis is progressive and can be fatal –
15 – 20 Years
• Silica exposure has also been linked to
lung cancer
• Accelerated Silicosis – 5-10 Years
• Acute Silicosis – A Few Months
• 200 Deaths Per Year
What must employers do?
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Know that there is silica in the workplace
Know what the silica exposure levels are
Provide training to employees
Control or eliminate silica exposures
through engineering controls
• Provide PPE
How workers can help?
• Recognize that silica may be present
• Adopt work practices that minimize
exposure
• Wear PPE
What Is OSHA Doing?
• Standards (Prerule – OMB Fall 2009)
• General Industry
• 1910.94, Ventilation
• 1910.1000, Air contaminants
– Table Z-1, Limits for air contaminants
– Table Z-3, Mineral dusts Silica PEL - 0.1 mg/M3 - Respirable
• Construction Industry
• 1926.55, Air contaminants
• 1926.57 Ventilation
Guidance – General Industry
• "Crystalline Silica Exposure" Health Hazard Information for General
Industry Employees. OSHA Publication 3176, (2002). Discusses
what silica is, what are its hazards, and what employers and
employees can do to protect against exposures to silica.
• Crystalline Silica Exposure Health Hazard Information OSHA Fact
Sheet, (2002) Provides information regarding silicosis disease and
exposures.
• Crystalline Silica Exposure in General Industry. OSHA Health
Hazard Information Card. Provides health hazard information and
good work practices for workers.
Guidance – Construction Industry
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Crystalline Silica Exposure Card for Construction. OSHA, (2002). Discusses
what silica is, what are its hazards, and what employers and employees can
do to protect against exposures to silica.
Crystalline Silica Exposure in the Construction Industry. OSHA.
"Crystalline Silica Exposure" Health Hazard Information for Construction
Employees. OSHA Publication 3177, (2002). Discusses what silica is, what
are its hazards, and what employers and employees can do to protect
against exposures to silica.
Crystalline Silica Exposures in Construction. OSHA (Ellen I. Roznowski),
(1997, July). Includes case studies and OSHA enforcement data.
Controlling Silica Exposures in Construction OSHA Publication 3362-04,
(2009). Provides information on the effectiveness of various engineering
control approaches for several kinds of construction operations and
equipment, and contains recommendations for work practices and
respiratory protection.
Enforcement
• National Emphasis Program
– National Emphasis Program – Crystalline Silica (CPL
03-00-007, 1/24/2008)
– Local Emphasis Program – Concrete Block and Brick,
Concrete Products and Ready-Mixed Concrete (CPL
2012-06) – Pittsburgh Area Office
Letters of Interpretation (LOIs)
• 02/11/1991 1910.1200
Label requirements for crystalline silica.
• 03/27/1998 1910.1000 & 1926.55
Special emphasis program for silicosis.
• 05/12/1999 1910.134(a)(1) & 1910.134(a)(2)
Respirators for silica dust must be selected based on exposure levels.
• 04/27/2005 1910.1000 Table Z-1; 1910.1000 Table Z-3;
1910.1200; 1910.1200(d); 1910.1200(g)
Requirements for maintaining Material Safety Data Sheets (MSDSs) for
coal including coal dust, fly ash, and silica dust.
Wrap-up
• Identify, Quantify, Control
• Questions??
• Thank you for your attention