Silicosis Prevention

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Silicosis Prevention
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Session Objectives

• You will be able to
• Understand what silicosis is
• Identify silica exposure risks
• Take effective precautions to prevent exposure

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What You Need to Know

• Types of silica
• At-risk industries and jobs
• Silica exposure and forms of silicosis
• Precautions and preventive measures
• First aid for silica dust exposure
• Medical surveillance program

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What Is Silicosis?

• Silicosis is a lung disease
• Caused by breathing dust containing silica
• Lungs become scarred and stiffened
• Breathing becomes difficult
• Risk of heart disease and tuberculosis increases

Image credit OSHA
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Silicosis Kills

• Silicosis is disabling, incurable, and sometimes
  fatal
• 2 million American workers are exposed to silica
  dust
• 300 die each year of silicosis

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Types of Silica

• Crystalline silica (free silica)
• Quartz, tridymite, cristobalite
• Abundant in earths crust
• Amorphous silica
• Not in the form of a crystal
• Does not cause silicosis

Image credit OSHA
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How Dust Can Be Hazardous

• Particles are generated by work processes
• Any airborne dust can be a hazard
• Invisible particles go deep into the lungs
• Large particles are removed by mucus
• Silica-containing dust is particularly hazardous

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Why You Might Be Unaware of the Hazards

• Crystalline silica is chemically inert
• It is naturally occurring
• It may not be properly labeled

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At-Risk Industries and Jobs

• Mining
• Construction
• Stone cutting

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At-Risk Industries and Jobs (cont.)

• Foundry work
• Portland cement production
• Glass manufacturing

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At-Risk Industries and Jobs (cont.)

• Ceramics, clay, and pottery manufacturing
• Abrasive cleaning or sand blasting
• Paint, plastic, soap, and abrasives manufacturing
• Electronics production
• Filtration of food and beverages

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Silica Exposure

• Acute exposure
• Chronic exposure
• Concentration, duration, and particle size
• Reporting symptoms

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Chronic Silicosis

• Develops slowly over many years
• Exposure to dust with 10 percent silica
• No symptoms for 15-20 years
• Symptoms get progressively worse
• May lead to life-threatening complications

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Accelerated Silicosis

• Results from shorter exposure at higher
  concentrations
• Develops within 5-15 years
• Detectable by X ray after one exposure
• Progresses even after removal from exposure
• Leads to massive fibrosis and death

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Acute Silicosis

• Develops after 1-3 years of exposure
• Overwhelming concentrations of silica
• Symptoms appear after only 7 months
• Cough, weight loss, and fatigue
• Liquid in lungs
• Fatal within 2 years

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Silicosis Risks

• Do you understand the information presented in
  the previous slides?

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Precautions to Prevent Exposure

• Limit the amount of dust inhaled
• Use engineering controls
• Follow safe work practices
• Make good hygiene a priority
• Use respiratory protection

Image credit Washington State Dept of Labor and
Industries
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Silica Control Program

• Inspect work area
• Review MSDSs
• Monitor exposure levels
• Substitute other materials

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Sampling and Monitoring

• Sampling program
• Full-shift respirable dust samples
• Personal samples
• Area samples
• Gravimetric dust collection

Image credit OSHA
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Engineering Controls

• Use ventilation and dust collection systems
• Isolate silica dust work processes
• Suppress dust with moisture

Image credit Washington State Dept of Labor and
Industries
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Ventilation

• General ventilation systems
• Local exhaust ventilation
• Inspection every 3 months
• Inspection when processes change
• Industrial hygiene surveys

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Safe Work Practices

• Store silica in sealed containers
• Break caked silica loose by vibrating the outside
  of a closed container
• Follow confined space entry procedures
• Dont let dust accumulate
• Use a vacuum for dust removal
• Do not use compressed air for cleaning

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Personal Hygiene

• Change into disposable or washable work clothes
• Vacuum work clothes
• Take a shower
• Put on clean street clothes
• Wash hands before eating, drinking, or smoking
• Dont bring personal items into hazardous work
  areas

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Respiratory Controls

• Wear a respirator when
• Dust exposure exceeds standard
• Engineering controls are not effective
• An emergency creates a sudden great hazard

Image credit Washington State Dept of Labor and
Industries
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Respiratory Controls (cont.)

• Use air-purifying respirator lt 10 times PEL
• Use air-supplying respirator for higher
  concentrations
• Make sure respirators fit well and are worn
  properly

Image credit WA State Dept of Labor and
Industries
Image credit Washington State Dept of Labor and
Industries
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Silicosis Prevention

• Do you understand the information presented in
  the previous slides?

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First Aid

• No first aid for inhalation of silica
• Get fresh air for acute exposure
• Wash eyes
• See a doctor

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Medical Surveillance

• Exposure above the PEL
• Physical exam including
• Medical history
• Chest X ray
• Evaluation for tuberculosis
• Frequency of exams determined by doctor
• Early diagnosis of silicosis can help control
  disease

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Key Points to Remember

• Know which work exposes you to silica
• Use engineering controls to reduce risks
• Wear respiratory protection
• Follow safe work practices
• Practice good personal hygiene
• Stop smoking