RoboVent Responds to OSHA Silica Ruling

On March 25, 2016, OSHA released its final rule on crystalline silica exposure, which cuts permissible exposure limits (PELs) in half from the previous limits to 50 micrograms per cubic meter of air (μg/m3). RoboVent General Manager and Co-Founder Jim Reid said, "Our focus on improving lives goes beyond today. In the case of silica, we want to improve lives not only for workers in silica environments, but also for their families, today and in the future."

As a service to manufacturers required to control silica exposure, RoboVent's experts will be available to assist with development of the required written exposure control plan, which identifies tasks that involve exposure and methods used to protect workers, including dust and fume control remedies. Over the next few weeks, we will be adding more resources to this site.

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What is the new rule for silica?

You can find the final ruling here, but the essence is this: Permissible exposure limits (PELs) for crystalline silica have been lowered to 50 micrograms per cubic meter of air (μg/m3) as an 8-hour time-weighted average, down from the currently allowable 100 μg/m3 TWA. The new rule takes effect June 23, and employers have until June 2018 to comply. The rule also outlines requirements for assessing and monitoring exposure, protecting employees, mitigation, recordkeeping and employee communication.

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What is silica, anyway?

Silica is a compound formed by the elements silicon and oxygen (chemical formula SiO4), and it is found in abundance throughout the earth. In fact, it's most common form, quartz, makes up 12% of the earth's crust. Silica is a large component of sand, granite and many other types of rocks. It bonds easily with many metals and metal oxides to form common silicate minerals.

Silica's chemical properties and overall abundance make it highly useful for many industrial applications. It is the main ingredient in glass. It is also found in ceramic tile, cement, bricks and asphalt. Silica is also widely used in metallurgy, agriculture, water filtration, high tech applications such as fiber optics, and as a functional filler for paints, coatings, rubbers and plastics.

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Silica sand
Worker cutting concrete

Who is impacted by the new silica exposure rule?

The rule impacts all industries where workers may be exposed to silica dust or fumes. As you can see from the list of industrial uses above, this ruling will impact a lot of workers across a wide range of industries; OSHA estimates that the rule will affect 2.2 million workers. Construction and shipbuilding industries, which had less stringent standards under the previous rule, should note that they must now comply with the same standard as general industry.

Affected industries include (but are not limited to):

  • — Affected industries include (but are not limited to):
  • — Brick, concrete or pottery manufacturing
  • — Construction (especially applications that involve cutting, grinding or drilling rock, concrete, masonry or tile
  • — Foundries, metalcasting facilities and diecasters
  • — Mining operations
  • — Shipyard and maritime workers
  • — Any industry using abrasive sandblasting
  • — Other industries using sand in their processes, such as hydraulic fracturing

What are the health impacts of silica exposure?

Silica dust and fumes are inhaled into the lungs, where they are implicated in lung cancer as well as chronic bronchitis and other respiratory diseases. As it makes its way from the lungs through the body, silica can also damage other body systems, most notably the kidneys.

Exposure can also lead to silicosis, a serious disease caused by damage to the lining of the lung sacs. Acute silicosis, caused by severe exposure, can cause the lungs to become inflamed and fill with fluid, creating a medical emergency. Chronic silicosis develops with even low-level exposure over time, reducing lung capacity until sufferers need oxygen to survive.

  Video courtesy of OSHA.gov

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What kind of equipment will I need to comply with the new standards?

Many companies have relied on standard ventilation systems to blow contaminated air out of the working environment. These systems are not likely to be efficient enough to meet the new, more stringent standards.

Most indoor operations will need a high-efficiency filtration system that cleans and returns air to the facility. Your system needs to include:

Source Capture

A highly efficient source capture method, such as a hood, that pulls in contaminated air as it is produced. The hood needs to be designed for optimal capture efficiency of the kind of particulate you are producing (e.g. larger dust particles vs. sub-micron fumes).

Dust Collector

A dust collector and filtration system that cleans the air before sending it back to the facility. Most silica-producing applications will require HEPA filters.

Personal Protective Gear

Workers who are directly interacting with silica-producing materials (e.g. cutting or grinding) may also need personal protective equipment while engaged in dust-producing activities.

What will the costs of compliance be?

Because of the serious health impacts of silica exposure, it's not enough to clean out 80% or so of the dust, as it might be if you are working with wood dust or other non-carcinogenic materials. With silica, you need to be aiming for 99.9% capture efficiency and removal. That means following ACGIH recommended practices to the letter, and consulting with a knowledgeable air quality engineer if you do not have this expertise on staff.

The cost of compliance will depend on your initial equipment configuration and exposure levels. However, it might not be as bad as you think. If you have a good existing ventilation system, you probably will not need to install all new ductwork. It may be more of a modification of your existing system, with new hoods and fans and a different filter type.

An experienced air quality engineer can evaluate your current system, identify the failure points, and recommend the most cost-effective solution to meet the new standards. At RoboVent, we use a computer modeling approach called VentMapping to analyze variables such as air currents within the facility, facility layout and equipment options to aid with the design.

Whatever the costs are, the costs of non-compliance are likely to be greater. OSHA is expected to put much higher emphasis on silica exposure once the new rules take effect, and industry should expect to see fines and citations increase. Those fines can easily be in the hundreds or thousands of dollars—each time the company is cited.

So don't be caught unprepared. Take a closer look at your silica exposure levels now, and call RoboVent if you need help.

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