Crystalline silica, or silicon dioxide (SiO2), is an abundant natural material found in soil, stone and sand. It is also present in many construction materials such as brick, mortar and concrete. It becomes respirable when any of the afore-mentioned materials are cut or broken down by any other method. Typical activities that can create silica dust or respirable crystalline silica include blasting, chipping, cutting, grinding and drilling.
More than 85% of workers exposed to respirable crystalline silica work in the construction industry. Other industries where workers are exposed include: asphalt roofing materials, concrete products, cut stone, dental laboratories, foundries, jewelry, porcelain enameling, pottery, railroads, ready-mix concrete, shipyards, structural clay products, and support activities for oil and gas operations.


Inhaling Crystalline Silica can have debilitating and fatal effects. It is important to note that the effects of inhaling crystalline silica are cumulative and can go unnoticed for up to 10 years. Below are some of the illnesses that can be caused by excessive inhalation of crystalline silica:

  • Silicosis – a disease where the lungs react to trapped particles of silica by scarring and forming hard nodules. When these nodules become large, it becomes difficult to breathe and can result in death. Silicosis is irreversible and continues to worsen even after exposure has ceased.
  • Lung Cancer
  • Tuberculosis (for those with silicosis)
  • Chronic Obstructive Pulmonary Disease


OSHA has reduced the Permissible Exposure Limit (PEL) of Crystalline Silica for workers to 50µg/m3 averaged over an 8hr day. With the reduction in the PEL, employers now must:

  • Measure how much silica their employees are exposed to if it is likely to be above the action limit of 25 µg/m3 averaged over an 8-hour day
  • Provide their employees with protection from crystalline silica if over 50µg/m3
  • Limit worker access to areas where silica levels are above the PEL
  • Take measures to control the dust where silica levels are above the PEL
  • Provide respiratory protection where dust control measures fail to reduce the silica levels to below the PEL
  • Offer alternative housekeeping practices to those that expose workers to silica whenever feasible
  • Develop and execute a written "exposure control plan" that details work that involves exposure to silica and protection measures
  • Offer regular medical examinations for workers exposed to the action level for over 30 days per year.


The control principles that apply to Respirable Crystalline Silica are like those that apply to all mechanically generated dust exposures.

  • Position personnel so they are out of the dust either in enclosed and filtered cabins or so they are working upwind of dust emission;
  • Design and operate processes and activities to minimize emission, release and spread of dust;
  • Use sharp cutting tools that minimize the generation of large quantities of fine dust;
  • Use wet processes to prevent dust generation;
  • Use water suppression to prevent dust spread;
  • Ensure ore passes are not emptied below the brow point and crusher chutes are kept full;
  • Use water curtains and rubber curtains to prevent dust release, particularly at conveyor transfer points and chute draw points;
  • Use ventilation, either dilution or extraction, to control dust spread and dust release;
  • Ensure suppressed dust is captured by scrubbing or filtering so it cannot be re-entrained in workplace air;
  • Apply good house-keeping practices to prevent dust build-up;
  • Provide training in the health effects of dust and its control;
  • Where adequate control of exposure cannot be achieved by other means, provide, in combination with other control measures, suitable PPE. For most exposures to RCS this will be a P1 or P2 (MERV 16) efficiency half face respirator. Ensure training is provided in the use and limitations of respiratory protective equipment (e.g. have a clean-shaven policy). Face fit testing is also recommended, as per AS 1715 (1994).


The operator enclosure, where your operator spends the most time, is the easiest and most cost-effective environment to control and has the most impact on reducing operator exposure levels to below PELs. Sy-Klone offers a simple, cost-effective three-step solution with its RESPA® Complete Cab Air Quality System. This system is designed to protect operator health, increase operator comfort and productivity, decrease operational costs, and it is endorsed by the International Society of Environmental Enclosure Engineers (ISEEE).
Sy-Klone's patented air quality products are effective at providing clean air to your HVAC system. These products have been proven in mining, waste, forestry, and agriculture and are available as a first-fit option from many original equipment manufacturers. One: Begin with the Fresh Air Component–The RESPA® CF2.  This fresh air system dramatically extends filter life and reduces the frequency of costly HVAC repairs by delivering more than 100 CFM of precleaned and filtered (EPA or HEPA) fresh air to the HVAC system. Additional interchangeable filter options include Gas+HEPA ABEK1 P3 filter and Ammonia+HEPA P3 (extended length only), and Odor+HEPA (standard-length only).
Step Two:  Add a Recirculated Air Component with RESPA® PFX, RESPA® CFX2, or RESPA FFX2. These customizable recirculation filtration options will optimize the cab to protect cab electronics, increase operator protection, and reduce harmful particulate buildup on your expensive HVAC evaporator coils!
Step Three: Add Intelligence with the RESPA Advisor®+ Pressure + CO2 Monitor. This easy to install unit gives you real-time information on cab pressure, when to change filters in your RESPA system, monitors C02 levels, and data logs can be downloaded. The monitor is an essential part of the complete RESPA Cab Air Quality System. The installer can customize the unit to display pressure in inches of water column or Pascal, the pressure level at which the unit alerts, and the volume of the audible alarm. It is included with most RESPA-CF Fresh Air systems. You will always know when your cab is positively pressurized, as required by the ISO 23875 and OSHA Silica Regulations.

Benefits of a Three-Step System:

Sy-Klone's patented Air Quality products are economical and cost effective at providing clean air to your HVAC system. Reduce operator exposure to harmful particulate, dramatically extend filter life, and lengthen the life of your HVAC system and cab electronics with our powerful and unique products. Sy-Klone's Cab Air Quality products have been proven in Mining, Waste, Forestry, and Agriculture, and are available as first-fit options from many original equipment manufacturers.

  • Meets requirements for ISO 23875 Cab Air Quality Standard compliance
  • Meets criteria specified by new OSHA Silica Rules, including precleaning, MERV16 filtration, positive pressurization and settled dust removal.
  • Protect Operator health
  • Increase Operator comfort and productivity
  • Decrease operational cost
  • Endorsed by ISEEE (International Society of Environmental Enclosure Engineers) as a Best Practice Component

For more information, Contact Sy-Klone International about our patented RESPA® Cab and Enclosure Air Quality Products, which are cost-effective tools at providing clean air to your HVAC system and keeping recycled air safe and breathable by greatly reducing respirable contamination.

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