EHS Spotlight: The Dangers of Dust

Apr 17, 2019, 20:45 PM
Content author:
External link:
Image Url:

March/April 2019

By Megan Quinn

EHS-Spotlight_The-Dangers-of-DustA Midwestern scrapyard that processes scrap from demolition sites routinely receives loads of ferrous scrap coated with crumbling bits of concrete. That concrete contains a potential hazard: respirable crystalline silica, a microscopic, breathable particle that can cause serious or fatal health issues with too much exposure. Silica, or quartz, is in soil, sand, concrete, masonry, rock, granite, and landscaping materials, and it’s used to manufacture tires, plastics, electronics, asphalt roofing, and other products. Processing these materials—especially cutting, drilling, or grinding them—can create tiny crystalline silica particles that can get trapped in the lungs if inhaled. If workers get exposed to enough respirable crystalline silica dust over a long enough period of time, they can develop serious illnesses such as silicosis, a disease that permanently scars the lungs and can be fatal, the Occupational Safety and Health Administration says.

OSHA recently updated its rule for crystalline silica dust to lower the threshold for worker exposure. Dylan Romo, an industrial hygienist with John A. Jurgiel & Associates (St. Charles, Mo.), says the change means scrapyard safety managers need to undertake an exposure assessment, which might include air sampling, and then consider what housekeeping and engineering controls their facilities need to make sure workers aren’t exposed to high levels of the harmful dust. Respirable crystalline silica dust can come from a surprising array of materials in and around the scrapyard, so conducting an exposure assessment is the only way to ensure you are complying with the new standard, he says. “If you have [high levels of] respirable crystalline silica in your facility, unfortunately, it’s not a one-time fix,” he says. “Employers will need to change the way they do business.”

A lower limit

Part of what makes respirable crystalline silica so dangerous is that it’s so small—smaller than pet dander or pollen, Romo says. These particles can get trapped in the smallest parts of the lung, and with enough exposure to the dust, the lungs lose some of their ability to function. “It prevents your lungs from making an oxygen exchange across the bloodstream,” he says. Exposure can also cause lung cancer, chronic obstructive pulmonary disease, and kidney disease. Those exposed to excessive levels of respirable crystalline silica could also develop certain autoimmune or cardiovascular problems, OSHA reports.

 Reports of people getting sick from silica dust date as far back as Greek and Roman times, OSHA says, but the disease began capturing significant public attention in the United States in the 1930s, when workers in West Virginia began falling ill and dying after drilling a tunnel through rock as part of a hydroelectric project. By 1937, Secretary of Labor Frances Perkins “declared war on silicosis,” which later led to OSHA’s first respirable crystalline silica exposure standards. As part of an awareness campaign in the ’90s, OSHA, along with the National Institute for Occupational Safety and Health and the American Lung Association, created the tagline, “If it’s silica, it’s not just dust.”

After more recent studies showed that the previous limit has not effectively prevented silicosis and other illnesses caused by long-term exposure, in 2016 OSHA lowered its respirable crystalline silica exposure limit to the new levels, says John Day, ISRI’s environmental health and safety manager. As of June 23, 2018, the average permissible exposure limit is 50 micrograms per cubic meter and the action level is 25 micrograms per cubic meter averaged over an eight-hour day. The previous PEL was 100 micrograms per cubic meter. There had not been a previous action level.

Many recyclers have already conducted assessments in their facilities using the new standard and have trained their employees on the hazards of respirable crystalline silica dust, but some are still learning what the change might mean for their scrapyards and what they’ll have to do to comply, says David Borsuk, chair of the ISRI Safety and Environmental Council. “It’s important everyone knows there’s an updated silica dust standard, and [companies] have to inform their employees about it and do a risk assessment if they haven’t already.”

A safety manager at one Midwestern scrapyard says he hasn’t yet done a silica-specific exposure assessment because he isn’t sure where to start. Romo says it’s not too late. “They [have missed] the deadline, but we’re only about six months into this [new rule], so I don’t think people need to panic,” he says. “It’s better to call and start the process now than wonder if workers might be exposed without knowing it.”

Identifying the potential sources

The first step in an exposure assessment is to look for dusty areas or work processes that generate dust in your facility. This can be tricky because no two scrapyards process the exact same materials or do their housekeeping in the exact same ways, and the material a facility receives can change from day to day. Respirable crystalline silica dust can come from surprisingly varied sources, Romo says. “In a scrapyard, you’re getting items from all over. You’re not getting a [safety data sheet] for everything, so you have to go by anecdotal evidence” to decide what might be a hazard, he says.

As a general rule of thumb, any dust-generating activity could be a possible source, Day says. Scrapyards that handle tires, plastics, electronics, asphalt roofing, or other construction and demolition debris might be at risk for employee exposure because silica is used in the manufacturing process of these materials, he says. Workers who torchcut scrap, handle it at a sorting station or sorting line, or use equipment such as material handlers in dusty conditions might also be at risk for exposure above the limits OSHA allows. That includes workers who operate shredders or car crushers or work in areas where shredder residue accumulates. In one bizarre case, a scrapyard discovered their car crusher released silica dust because an unscrupulous seller had hidden bricks in a vehicle’s trunk.

Concrete is another major source for silica dust, Day says. Dust that accumulates in the yard could be a potential source, especially if the yard is paved with concrete. Repair or construction projects around the yard, such as cutting into cement or brick, could generate crystalline silica dust. Exposure can come from maintenance and housekeeping actions, too. “You have to think about all your employees, not just the ones on the picking line. We also have to think about the maintenance mechanic who is over at the shop,” Romo says. “If you have a piece of big equipment such as a front-end loader and you go clean that, you’re not always thinking about silica.”

Measuring exposure

After identifying areas in your facility where respirable crystalline silica exposure is possible or likely, determine just how much respirable silica dust is in these areas by conducting air sampling. Call a professional for help, Day suggests. “A good industrial hygiene firm in your area can assist you with testing and can help design a compliance program that is appropriate for your yard,” he says.

Previous air sampling data can give you a general idea of employee exposure, but keep in mind that the data won’t mean much if they do not reflect your current workplace conditions, such as new equipment or changes in the way employees complete their jobs, Romo says. If your facility doesn’t have any previous data to check, or if past data show exposure above the new limit, the industrial hygienist likely will recommend conducting eight-hour air sampling tests for the dusty areas or processes. This involves fitting employees with a sampling device, which they wear throughout their shift. Using information about what types of work your employees do and how often they might be exposed to dust, the industrial hygienist can help determine which employees should be part of the testing process, whether groups of employees who do similar work can be tested as a group, or if some employees do not need to wear the devices. Be sure to inform employees about this testing and what it means, Day says.

Reducing the hazard

If your testing data demonstrate your facility is below the action level, you most likely do not have to make changes to the facility or work habits. You don’t have to repeat the test if the results are below the action level, but you should make sure your results represent “all exposure scenarios, or at least the worst case,” Romo says. Many companies test annually to make sure the results stay below the action level, Day adds.

 If your air testing results are over the PEL or action level, you must make changes to reduce the exposure. Prepare a control plan and train your employees on what the plan entails, Day says. Engineering controls that keep dust out of the air are the most effective tool, Romo says. You can try to isolate workers from the source of the hazard by placing them in a properly ventilated control booth to do certain tasks or add ventilation in dust-producing areas.

Effective housekeeping will also cut down on dust, Romo says. Workers can spray water to keep the dust down—“but only if that doesn’t create other hazards, such as slippery floors,” he says. Another option is to get a vacuum with a high-efficiency particulate air filter. “Vacuuming without the filter just blows the dust everywhere and can create an even greater exposure,” he notes.

Along with reducing the dust, consider limiting employees’ access to dust-producing areas or schedule work so tasks that involve high exposure take place when other employees are not nearby. Respirators for certain employees who routinely work in areas with respirable crystalline silica are the last course of action if engineering or work-practice controls can’t maintain exposure at or below the PEL, Day says. Workers who use respirators must comply with the OSHA standards for respirator use, such as completing a fit test and wearing the respirator properly.

Romo says engineering controls, such as HEPA filter vacuums and wetting down surfaces, are generally better at reducing exposure than respirators. Respirators are not as practical because workers must choose the right fit, maintain them regularly, and wear them properly at all times. Some employees cannot wear respirators because of health conditions or other factors. If the respirator isn’t right for the job or if it doesn’t fit correctly, workers will continue to be exposed to silica dust, he says. “The priority is to reduce the dust first.”

Education and compliance

Whatever changes you make, be sure to document them in a facility exposure plan, share the plan with employees, and inform them which zones of the facility expose them to silica dust. If possible, label the areas with signs, cones, or other indicators, OSHA says. After you create and enact your plan, consider bringing the industrial hygienist back in three to six months to track progress by conducting another air sample. In Romo’s experience, scrapyards are typically able to significantly reduce their exposures before the second round of air sampling. “If I come back and they are below the PEL and action level, we test again in three more months,” he says. “Two back-to-back tests below the action level, and you’re done testing,” he says. However, you will need to maintain the habits that are keeping you under the permissible level. “If in six months your ventilation breaks down, exposure will probably go back up,” he says. Respirable crystalline silica dust won’t go away on its own, but a few changes to day-to-day processes can save lives, he says. “Employers have the power to keep their workers safe.”

Megan Quinn is senior reporter/writer for Scrap.


Silica Dust Resources

• The OSHA guidance manual is a step-by-step guide with detailed information on how to comply with OSHA’s new respirable crystalline silica standard:

• ISRI Environmental Health and Safety offers a fact sheet on respirable crystalline silica dust for recyclers:

• ISRI’s EHS team is conducting a survey of member companies to get a better idea of where respirable crystalline silica hazards are present in scrap facilities. It will share survey results at the Safe Operations Committee meeting at the April board meeting and at

Contact ISRI EHS Manager John Day at or 443/695-3839.

Tiny particles of respirable crystalline silica can cause serious health problems when inhaled. Here’s how to keep workers safe under OSHA’s new, stricter exposure limits.
  • 2019
  • Mar_Apr

Have Questions?