Exposure to silica dust is a severe hazard in rock mining, whether it is a granite vein in coal, copper, diamond mine, or other rock cutting activities (i.e., granite cutting, stone dust). Because of hydraulic fracturing, silica can also be a problem in the oil and gas industry. Lung cancer, silicosis, and chronic pulmonary obstructive disease can result from exposure to silica dust, so it is essential to have adequate personal and area dust monitoring equipment to limit worker exposure.

Like the majority of laboratory sample analysis, a sample needs to be collected from the work environment, in particular, those locations that exhibit the biggest risk.  The Respirable Silica sample can include silica, coal dust, and diesel particulate, and is sent to an approved laboratory for analysis, usually using X-ray diffraction techniques (XRD).

What is Needed for Sample?

Related Article OSHA Publishes Silica FAQ

Sampling Methods

U.S. Government/Gobierno de los Estados Unidos [Public domain]
The website of the Occupational Safety and Health Administration (OSHA) describes the process for the collection of a sample to measure airborne silica as follows:

Analytical Methods

The certified laboratory must have approved procedures specified in one of the following analytical methods:

Cheerful Woman in Laboratory
Cheerful Woman in Laboratory. Photo by FreePik

The laboratory must also be accredited to ANS/ISO/IEC Standard 17025:2005 and about Respirable Crystalline Silica (RCS) must also be compliant with ISO/IEC Standard 17011:2004 for implementation of quality assessment programs including their internal Quality Control (QC) program.

The laboratory must use the National Institute of Standards and Technology (NIST) traceable standards for instrument calibration and verification.

The sample is analyzed for polymorphs of crystalline silica, quartz, and cristobalite, which have been classified as Group 1 carcinogens by the International Agency for Research on Cancer (IARC).  The sampling methods eliminate the non-RCS components that might obscure the analysis.  Once the sample is determined to be “clean,” quantitative detection of the Permissible Exposure Limit (PEL) is based on sample air volume.

Silica is Dangerous for Worker’s Health

OSHA has determined that employees exposed to respirable crystalline silica at previous permissible limits of exposure face significant health risks and have amended its existing standards. OSHA’s Final Rule for the Protection of Workers from Exposure to Respirable Crystalline Silica offers two standards, one for Construction and one for the General Industry and Maritime Industry.

This blog was written by Linda Rawson, who is the founder of DynaGrace Enterprises (dynagrace.com), an authorized distributor of the Nanozen DustCount 8899.  For further information, please connect with Linda on LinkedIn, or contact her at (800) 676-0058 ext 101.