Questions about Silica in The Workplace

01 Apr Questions about Silica in The Workplace

Exposure to silica dust – respirable crystalline silica (RCS) – is harmful and can lead to severe to lung disease. It is known as a significant contributor to lung cancer.

Microscopic Silica

Microscopic Silica

Identifying work processes that produce RCS and having workers wear a respirator during those times are critical for minimizing prolonged exposure.  Worker safety is of utmost importance to every employer as the fines are steep and the loss of human cost is high.

How Do I determine the presence of Crystalline Silica my Workplace?

The first question to ask an employer is about the written exposure control plan.  The plan should contain the following elements:

  • A description of the work tasks that involve RCS exposure
  • Engineering control descriptions, work practices and respiratory protection used to limit employee exposure to RCS for each task
  • Housekeeping measures to limit employee exposure to RCS
  • Detailed procedures used to restrict access to work areas

The process conditions+ to which amorphous silica products are subjected should be carefully studied to determine whether the temperature is high enough to convert to crystalline silica forms. In the extractive industry, mineral compositions are extremely important because crystalline silica often occurs in unprocessed rock in significant quantities. This also applies to rock mining and handling.

Who is Likely to be Exposed?

In the industry, crystalline silica, amorphous silica, and their products are widely used. During the extraction of materials from the earth’s crust, exposure can also occur. Silica is one of the most rock components. OSHA Table 1: Specified Exposure Control Methods When Working With Materials Containing Crystalline Silica summarizes the significant uses of products that may cause exposure to crystalline silica in the respiratory system. Exposure sources are also included in the extractive industries.

How Can Workplace Exposure to Silica be Assessed?

RCS can be detected and measured in workplace air using sophisticated techniques. These are often necessary when the dust production potential exists.

RCS can be detected using a combination of air monitoring or objective data gathered from the type of work data conducted from industry-wide surveys or calculations based on the composite of the substance involved during a specific process or work task.

The exposures should be assessed for employees on each shift, each job classification and in each work area.  Ongoing assessments should be conducted when a change occurs in production including process, control equipment, personnel or work practices.  The employer must conduct a new assessment whenever they feel there could be a problem and the RCS exposure is above the Action Level (AL) identified by OSHA.

If the RCS can be seen, there is a problem

In general, an exposure problem is likely to occur if dust containing crystalline free silica can be seen (It should be noted that respirable dust, which is only a portion of the overall dust, cannot be seen by the unaided eye. However, if airborne dust can be seen, there is probably a problem).

The procedures for the monitoring, sampling and determination of airborne silica concentrations in the workplace and the exposure of the worker to airborne silica must be by standard methods for the sampling and analysis of air at work. The evaluation should provide an overview of the following aspects of the operation:

  • Source of exposure
  • Cause of exposure
  • Number of workers exposed to each source
  • Length of exposure per day
  • Frequency of exposure
  • respirable crystalline silica concentration in the air
    DustCount 8899

    DustCount 8899. Photo by Linda Rawson

  • The effectiveness of existing control strategies and workplace practices
  • Performance capabilities of existing dust controls
  • Existing use of personal protective equipment
  • Methods and procedures used presently or to be used in future
  • Measures and procedures necessary to control exposure

OSHA does allow real-time air monitoring to be a judge of RCS worker exposure.  The Nanozen DustCount 8899 is a great example of the ability to monitor RCS in the workplace and ensure the

worker is safe.

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.

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