Silica Awareness PPT-SM-SILICA 1 2014 Silica Every year, over 1 - - PowerPoint PPT Presentation

PPT-SM-SILICA 2014

Silica Awareness

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PPT-SM-SILICA 2014

Silica

• Every year, over 1 million workers are exposed to

silica dust

• Over 250 workers die from silica inhalation every

year

• Hundreds more are severely disabled

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PPT-SM-SILICA 2014

Silica

• Silica is the mineral silicon dioxide (SiO2)
• Three types of rock contain silica

1.Quartz – Most common rock in Earth’s crust

• 2. Cristobalite
• 3. Tridymite
• When ground, these rocks produce a dust that carries

silica

– The finely ground dust is known as “silica flour”

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PPT-SM-SILICA 2014

Silica Dust

Silica dust can be found in numerous industrial

• perations
• Hydraulic fracturing (fracking) and sandblasting

– The sand used in fracking and sandblasting contains up to 99%

silica

• Abrasives such as sandpaper and grinding and polishing

agents

• Drilling, crushing, loading, hauling, and dumping of rock

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PPT-SM-SILICA 2014

Silica Dust

Silica dust can be found in numerous industrial

• perations
• Abrasively blasting, sawing, chipping, drilling, and

grinding concrete and brick

• Dry sweeping or air blowing concrete, rock or sand dust

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PPT-SM-SILICA 2014

Silica Dust

Silica dust can also be found in numerous materials used in the oil and gas industry

• Scouring powders
• Metal polishes
• Paints
• Rubber
• Paper
• Plastics
• Wood fillers
• Cement
• Road surfacing materials
• Foundry applications

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PPT-SM-SILICA 2014

Silica-related Health Hazards

Inhaled or ingested silica causes serious lung damage and lung disease

• Travels through your airways into your lungs
• Inhaled silica particles damage your lungs

– This damage causes scar tissue to develop, narrowing and

eventually blocking your airways over time

• Inhaled silica particles can also damage the DNA in your

cells, causing cancer

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PPT-SM-SILICA 2014

Silica-related Health Hazards

Diseases linked to silica exposure include

• Lung cancer
• Chronic Obstructive Pulmonary Disorder (COPD)
• Tuberculosis (TB)
• Scleroderma
• Renal disease
• Silicosis
• Autoimmune disease
• Kidney disease

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PPT-SM-SILICA 2014

Silicosis

Workers exposed to silica may develop silicosis, an incurable lung disease

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A silicosis patient’s x-ray Silicosis patient’s lung Healthy lung

PPT-SM-SILICA 2014

Silicosis

• Silicosis is a progressive, disabling, and often fatal lung

disease

• Symptoms include

– Shortness of breath – Fever – Fatigue – Loss of appetite – Chest pain – Dry, nonproductive cough – Respiratory failure

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PPT-SM-SILICA 2014

Silicosis

Types of silicosis

• Chronic silicosis

– Results from silica exposure over time – Usually occurs after 10 or more years of exposure to relatively low silica

concentrations

• Accelerated silicosis

– Results from exposure to high concentrations of silica – Usually develops 5-10 years after exposure to very high concentrations of

silica

• Acute silicosis

– Develops from exposure to highest concentrations to silica – Symptoms can develop anywhere from a few weeks later to 4-5 years after

first exposure

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PPT-SM-SILICA 2014

Permissible Exposure Limits

• NIOSH

– Recommended Exposure Limit (REL) = 0.05 mg/m3 – Immediately dangerous to life and health (IDLH) limit

• IDLH = 25 mg/m3 for cristobalite and tridymite
• IDLH = 50 mg/m3 for quartz and Tripoli
• OSHA

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PPT-SM-SILICA 2014

OSHA Guidelines

Employers must

• Provide information and training about silica to workers
• Medically monitor workers who are exposed to silica dust

levels at or above half of the PEL

• Monitor silica in the air by collecting samples
• Control dust exposures through engineering and safe

work practices

• Provide respiratory protection to workers

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PPT-SM-SILICA 2014

OSHA Guidelines

Employers must

• Reduce employee exposure by limiting work involving

silica dust

• Supply vacuums with HEPA air filters
• Report all cases of silicosis to state health departments

and record cases on OSHA logs

• Post warning signs to identify work areas where

respirable silica is present

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PPT-SM-SILICA 2014

NIOSH Recommendations

• Get a medical examination before starting work and

receive a follow-up exam every three years

• Conduct frequent air monitoring
• Blast-clean machines and cabinets
• Use wet drilling or wet sawing
• Use local exhaust ventilation
• When drilling rock, use water through the drill stem
• When sawing concrete or masonry use saws that provide

water to the blade

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PPT-SM-SILICA 2014

NIOSH Recommendations

• Remove dust from equipment using a water hose

rather than compressed air

• Practice good personal hygiene

– Wash hands often, remove PPE after work, shower and

change clothes before leaving work, etc.

• Wear disposable or washable protective clothing
• Post warning signs around silica-contaminated work

areas

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PPT-SM-SILICA 2014 Condition Minimum respiratory protection required to meet the NIOSH REL (0.05 mg/m

3)

< 0.5 mg/m

3* (10 x REL)

Any half-mask, air-purifying respirator with a high-efficiency particulate (HEPA) filter ≤ 0.5 mg/m

3* (10 x REL)

Any half-mask, air-purifying respirator with a HEPA filter ≤ 1.25 mg/m

3 (25 x REL)

Any powered, air-purifying respirator with a HEPA filter, or any supplied-air respirator (SAR) equipped with a hood or helmet and operated in a continuous-flow mode ≤ 2.5 mg/m

3 (50 x REL)

Any air-purifying, full-facepiece respirator with a HEPA filter, or any powered, air-purifying respirator with a tight-fitting facepiece and a HEPA filter ≤ 50 mg/m

3 (1,000 x REL)

Any SAR equipped with a half-mask and operated in a pressure-demand or other positive-pressure mode ≤ 100 mg/m

3 (2,000 x REL)

Any SAR equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode (for example, a Type CE abrasive-blasting respirator operated in a positive-pressure mode) Planned or emergency entry into environments containing unknown concentrations or concentrations >100 mg/m

3 (2,000 x REL)

Any self-contained breathing apparatus (SCBA) equipped with a full facepiece and operated in a pressure- demand or other positive-pressure mode, or any SAR equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary SCBA operated in a pressure-demand or other positive-pressure mode. Firefighting Any SCBA equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode Escape only Any air-purifying, full-facepiece respirator with a HEPA filter, or any appropriate escape-type SCBA

NIOSH Recommendations

PPT-SM-SILICA 2014

Control Methods

• Workers and employers must work together to

prevent silica exposure

• Remove dust by using a water hose, a vacuum, or by

wet sweeping

• Explore alternatives to crystalline silica for abrasive

blasting

• Wear respiratory protection

– Remain clean shaven when wearing respirators

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PPT-SM-SILICA 2014

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