With the OSHA Silica Standard now in effect, silica education and awareness should be paramount to everyone’s safety plan.

Know the hazard

Crystalline silica is an extremely common mineral found in granite, sandstone, quartzite, various other rocks and sand that becomes dangerous when it is disturbed. Finished natural and manufactured stone products, including finished countertops, do not present a health hazard themselves. Grinding, drilling or cutting of these materials generates a fine silica dust that, unless contained, will seriously contaminate the air.

Inhalation of respirable crystalline silica can lead to respiratory diseases such as chronic obstructive pulmonary disease (COPD) or silicosis. Silicosis causes inflammatory damage in areas affected by silica, causing scar tissue to form over critical lung components. Nearly 2.3 million laborers are exposed to silica dust every year, and therefore, should be cautious to avoid unprotected exposure.

Know the standard

The 2016 OSHA Silica Standard limits silica exposure to a Permissible Exposure Limit (PEL) of 50 micrograms of respirable crystalline silica per cubic meter of air or 50 µg SiO2/m³ over an eight-hour time weighted average (TWA). Table 1 identifies occupational exposures to silica along with work practices and specified engineering control methods to limit exposure. Employers who follow the requirements of Table 1 are not required to measure silica exposure through air monitoring and are not subject to the PEL. OSHA recognizes using tools equipped with a water delivery system that supplies a continuous stream or spray of water at the point of impact or using tools equipped with a commercially available shroud and dust collection system as the work practice control methods that safely limit silica exposure.

There are alternative exposure control methods available to give contractors more flexibility in their choice of work practices and tools. These methods do require some additional control measures to be in compliance with the OSHA Silica Standard. For alternative control methods, the following applies as explained in the OSHA Silica Standard:

PEL: The employer shall ensure that no employee is exposed to an airborne concentration of respirable crystalline silica in excess of 50μg/m3 calculated as an eight-hour TWA.

Exposure Assessment: The employer shall assess the exposure of each employee who is or may reasonably be expected to be exposed to respirable crystalline silica at or above the action level in accordance with either the performance option in paragraph (d)(2)(ii) or the scheduled monitoring option in paragraph (d)(2)(iii) of Table 1.

Performance Option: The employer shall assess the eight-hour TWA exposure for each employee on the basis of any combination of air monitoring data or objective data sufficient to accurately characterize employee exposures to respirable crystalline silica.

Know your exposure

One way to determine silica exposure is through air monitoring. To many, this may seem like a complicated expensive process. The fact is, it’s really fairly easy once one understands what is involved.

Air monitoring equipment will measure the air quality in a worker’s breathing area to determine silica exposure during a specific work practice. Air monitoring uses a battery-operated vacuum attached to an operator’s shirt collar, collecting air samples right where the operator breathes.

Another way to determine silica exposure is by using objective data provided by tool manufacturers. OSHA defines “objective data” as “information such as air monitoring data from industry-wide surveys or calculations based on the composition of a substance, demonstrating employee exposure to respirable crystalline silica associated with a particular product or material or a specific process, task or activity. The data must reflect workplace conditions closely resembling or with a higher exposure potential than the processes, types of material, control methods, work practices and environmental conditions in the employer’s current operations.” When a manufacturer tests its equipment, if the work practice and materials used match the jobsite conditions, OSHA will allow this data to be used as objective data as part of a written silica exposure control plan.

Once you learn about exposure levels, you can decide what options are best-suited to control silica exposure on your jobsites or in your shop.

Know your material

“Check Twice, Cut Once.” The old saying doesn’t just prevent mismeasurement; it’s also a reminder to check exactly what you’re cutting into. Stone and quartz surfacing countertops contain high amounts of the natural mineral silica. Exposure varies by stone type. Silica exposure can vary depending on the silica content of the stone used.

Know your options

No matter what tool you’re using – a saw, grinder or high-speed polisher — it’s essential to wear personal protective equipment (PPE) such as protective eyewear and ear attenuators. You should also know exactly what you’re cutting into so you can implement proper control methods when exposing hazardous materials.

Whether you’re sizing a piece of tile or cutting blind into a wall, you should be cautious to generate airborne contamination that could contain silica dust or even asbestos particles. Whether you’re using hand or power tools, it’s important to follow the necessary precautions to protect against any unknown airborne contamination. Remember, awareness and education ensures prevention and safety, so if you need a refresher course, take one- your lungs will thank you.

The Natural Stone Institute (NSI) technical module, “Silicosis – An Industry Guide to Awareness and Prevention,” offers tips on controlling silica exposures in stone cutting operations. It is available to workers and employers on the NSI website: www.naturalstoneinstitute.org/silica/Silicosis_Industry_Guide_ Tech_Module_2008.pdf. Other resources from NSI can be found at www.naturalinstitute.org/silica. 

¹DHHS (NIOSH) Publication Number 2015-106, OSHA - HA-3768-2015