SEI Alert! - RecordkeepingWorkers who are exposed to respirable crystalline silica dust are at increased risk of developing serious silica-related diseases. OSHA’s standard requires employers to take steps to protect workers from exposure to respirable crystalline silica.

 What Is Respirable Crystalline Silica? Crystalline silica is a common mineral that is found in materials such as stone, artificial stone, and sand. When workers cut, grind, or drill materials that contain crystalline silica, or use industrial sand, they can be exposed to very small silica dust particles. These tiny particles (known as “respirable” particles) can travel deep into workers’ lungs and cause silicosis, an incurable and sometimes deadly lung disease. Respirable crystalline silica also causes lung cancer, other potentially debilitating respiratory diseases such as chronic obstructive pulmonary disease, and kidney disease. In most cases, these diseases occur after years of exposure to respirable crystalline silica.

How Are Workers in General Industry Exposed to Respirable Crystalline Silica?
Workers can be exposed to respirable crystalline silica during the:

  • Manufacture of glass, pottery, ceramic, brick, concrete, asphalt roofing, jewelry, artificial stone, dental, porcelain, or structural clay products;
  • Use of industrial sand in operations such as foundry work and hydraulic fracturing; and
  • Use of sand for abrasive blasting (e.g., general industry and agricultural operations).
 
What Does the Standard Require?
The standard for general industry (29 CFR 1910.1053) requires employers to:
  • Determine the amount of silica that workers are exposed to if it is, or may reasonably be expected to be, at or above the action level of 25 μg/m3 (micrograms of silica per cubic meter of air), averaged over an 8-hour day;
  • Protect workers from respirable crystalline silica exposures above the permissible exposure limit (PEL) of 50 μg/m3, averaged over an 8-hour day;
  • Limit Access to areas where workers could be exposed above the PEL;
  • Use dust controls and safer work methods to protect workers from silica exposures above the PEL;
  • Provide respirators to workers when dust controls and safer work methods cannot limit exposures to the PEL;
  • Establish and implement a written exposure control plan that identifies tasks that involve exposure and methods used to protect workers;
  • Restrict housekeeping practices that expose workers to silica, such as use of compressed air without a ventilation system to capture the dust and dry sweeping, where effective, safe alternatives are available;
  • Offer medical exams—including chest X-rays and lung function tests—every three years to workers exposed at or above the action level for 30 or more days per year;
  • Train workers on the health effects of silica exposure, workplace tasks that can expose them to silica, and ways to limit exposure; and
  • Keep records of workers’ silica exposure and medical exams.
Examples—Dust Control Methods - Employers can protect workers from silica exposures by using dust controls such as:
  • Wet methods that apply water at the point where silica dust is made;
  • Local exhaust ventilation that removes silica dust at or near the point where it is made; and
  • Enclosures that isolate the work process or the worker.
Abrasive Blasting Operations
For abrasive blasting operations employers must protect workers from hazardous dust levels and toxic metals that may be generated from both the blasting material and the underlying substrate and coatings.  Below is information on abrasive blasting materials, health hazards, and methods to protect workers.
 
Alternative Blasting Agents
  • Ice cubes
  • Dry ice
  • Plastic beads
  • Sponge
  • Sodium bicarbonate
  • Ground walnut shells
  • Ground corn cob
  • High pressure water

Blasting Agent Health Hazards
Abrasive blasting operations can create high levels of dust and noise.  Abrasive material and the surface being blasted may contain toxic materials (i.e. lead paint, silica) that are hazardous to workers.

  • Silica sand (crystalline) can cause silicosis, lung cancer, and breathing problems in exposed workers.
  • Coal slag and garnet sand may cause lung damage similar to silica sand (based on preliminary animal testing).
  • Copper slag, nickel slag, and glass (crushed or beads) also have the potential to cause lung damage.
  • Steel grit and shot have less potential to cause lung damage.
  • Slags can contain trace amounts of toxic metals such as arsenic, beryllium, and cadmium.

How to Protect Workers from Exposure to Abrasive Blasting Materials
Each abrasive blasting operation is unique, involving different surfaces, coatings, blast material, and working conditions. Before beginning work, employers should identify the hazards and assign a knowledgeable person trained to recognize hazards and with the authority to quickly take corrective action to eliminate them. Use engineering and administrative controls, personal protective equipment (PPE), including respiratory protection, and training to protect workers involved in abrasive blasting activities.  Engineering controls, such as substitution, isolation, containment, and ventilation are the primary means of preventing or reducing exposures to airborne hazards during abrasive blasting operations. Administrative controls, including the use of good work and personal hygiene practices, can also reduce exposure. When engineering and administrative controls cannot keep exposures to hazardous materials below OSHA permissible exposure limits, respiratory protection must be used.
Engineering Controls
1.      Substitution
·        Use a less toxic abrasive blasting material.
·        Use abrasives that can be delivered with water (slurry) to reduce dust
2.      Isolation and Containment
·        Use barriers and curtain walls to isolate the blasting operation from other workers.
·        Use blast rooms or blast cabinets for smaller operations.
·        Use restricted areas for non-enclosed blasting operations.
·        Keep coworkers away from the blaster.
3.      Ventilation
·        Use exhaust ventilation systems in containment structures to capture dust.
Administrative Controls
Perform routine cleanup using wet methods or HEPA filtered vacuuming to minimize the accumulation of toxic dusts.
·        Do not use compressed air to clean as this wall create dust in the air.
·        Clean and decontaminate tarps and other equipment on the worksite.
·        Schedule blasting when the least number of workers are at the site.
·        Avoid blasting in windy conditions to prevent the spread of any hazardous materials.
Personal Hygiene Practices
·        Prohibit eating, drinking, or using tobacco products in blasting areas.
·        Provide wash stations so workers can wash their hands and face routinely and before eating, drinking or smoking.
·        Vacuum or remove contaminated work clothes before eating, drinking, or smoking.
·        Provide accommodations for end of shift showers and change areas with separate storage facilities for street clothes, protective clothing and equipment.
·        Keep contaminated clothing and equipment out of the clean change area.