The Dangers of Silica

Due to new OSHA regulations regarding silica exposure on the job site, George Nice & Sons held a safety meeting last week to help educate employees on the exposure risks of silica – such as lung cancer, silicosis, chronic obstructive pulmonary disease, and kidney disease – and the protective equipment available.

But what is silica, exactly?

Silica, also known as silicon dioxide or SiO2, is a colorless, white, chemical compound. Silica is made of the most common elements on earth, silicon (Si) and oxygen (O2). It’s also the most abundant compound in the earth’s crust, where it makes up 59% of the total composition. Silica is used everywhere, from industrial applications to the food and beverage industry.

You’ll find silica in a lot of places — food, rocks, plants, medicine, cosmetics, toothpaste, and those little dry gel packs that are packed in with product packaging to absorb moisture. There’s even silica in your body. The most common form of silica is quartz, a component of stone, concrete, and sand. Simply put, silica is everywhere. If you’ve touched a rock or been to the beach, you’ve handled silica. Don’t worry— it’s mostly harmless and can even be beneficial.

However, in our line of work, silica is very dangerous.

The dust created by cutting, grinding, drilling or otherwise disturbing materials such as concrete, granite, and rock can contain crystalline silica particles. These dust particles are very small. You cannot see them. This respirable silica dust causes lung disease and lung cancer. It only takes a very small amount of airborne silica dust to create a health hazard.

The U.S. Department of Labor first highlighted the hazards of respirable crystalline silica in the 1930s, after a wave of worker deaths. The department set standards to limit worker exposure in 1971 when OSHA was created. However, the standards are outdated and do not adequately protect workers from silica-related diseases. Furthermore, workers are being exposed to silica in new industries, such as stone or artificial stone countertop fabrication and hydraulic fracturing.

So how can silica exposures be controlled to keep exposure at or below the permissible exposure limit (PEL)?

Employers must use engineering controls and work practices as the primary way keep exposures at or below the PEL.

Engineering controls include wetting down work operations or using local exhaust ventilation (such as vacuums) to keep silica-containing dust out of the air and out of workers’ lungs. Another control method that may work well is enclosing an operation (“process isolation”).
Examples of work practices to control silica exposures include wetting down dust before sweeping it up or using the water flow rate recommended by the manufacturer for a tool with water controls.
Respirators are only allowed when engineering and work practice controls cannot maintain exposures at or below the PEL.

For construction, the standard includes Table 1, a list of common construction tasks along with exposure control methods and work practices that work well for those tasks and can be used to comply with the requirements of the standard.

What is Table 1: “Specified Exposure Control Methods When Working with Materials Containing Crystalline Silica”?

Table 1 is a flexible compliance option that effectively protects workers from silica exposures. It identifies 18 common construction tasks that generate high exposures to respirable crystalline silica and for each task, specifies engineering controls, work practices, and respiratory protection that effectively protect workers. Employers who fully and properly implement the engineering controls, work practices, and respiratory protection specified for a task on Table 1 are not required to measure respirable crystalline silica exposures to verify that levels are at or below the PEL for workers engaged in the Table 1 task.

OSHA developed Table 1 in response to stakeholders in the construction industry, who indicated the need for guidance and a standard that is different than a standard for general industry. Among the concerns of construction industry stakeholders were the impracticality of exposure monitoring based on short duration of task and constantly changing conditions, such as weather, job sites and materials.

Overall, OSHA estimates that this new rule will save over 600 lives and prevent more than 900 new cases of silicosis each year once its effects are fully realized. It is projected to provide net benefits of about $7.7 billion annually.

“The very best thing you can do to protect a company is to protect the workers who are, in effect, the heart and soul of that company. The two go together.” -Michael Mangum, National Asphalt Pavement Association program director

OSHA will delay enforcement of the respirable crystalline silica standard for construction until September 23, 2017 to conduct additional outreach and provide educational materials and guidance for employers.