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What the Dust?  Silica in the Construction Industry - Part 1

April 30, 2018

Silicia_Part1

OSHA is issuing two standards to protect workers from exposure to respirable crystalline silica—one for construction and the other for general industry and maritime—in order to allow employers to tailor solutions to the specific conditions in their workplaces.

Employers were required to comply with all obligations of the standard (except methods of sample analysis) by June 23, 2017. In addition, employers are also required to comply with methods of sample analysis by June 23, 2018.

Please note: the focus of this article deals with construction-related concerns.

Aggregate/Stone Dust:

Is there a difference between normal stone or concrete dust and what is considered really bad stone or concrete dust? Yes, there’s a significant discrepancy between the dust you can see when sweeping a concrete floor after some work has been completed or the dust you are able to see when cutting brick or tile and respirable concrete/stone dust and what experts have identified as really bad dust!

All stone/brick/concrete-related material contains crystalline silica, and the particles contained in these products when crushed or cut that are so small you can’t see them with the naked eye are what hurt and can eventually cause great illness and injury to workers.

The really bad dust is less than 10 microns per particle. Think of a single fleck of flour used for baking compared to a single grain of ordinary beach sand, which measures about 100 microns in size.

If these dust particles are inhaled, they are so small that they are able to travel into the lungs' smallest air sacs, the alveoli, where they can do significant damage. Workers exposed to silica dust on a long-term basis will suffer from diminished lung function and capacity and diminished ability to exchange carbon dioxide for oxygen, in addition to being exposed to other physical hazards that are discussed later.

What Is Respirable Crystalline Silica:

Crystalline silica is a common mineral found in many naturally occurring materials and is used in many construction products and at construction sites. Building materials like sand, concrete, stone, and mortar contain crystalline silica. Crystalline silica is also used to make products such as glass, pottery, ceramics, bricks, concrete, mortar, and artificial stone. Crystalline silica is a problem!

What Is the Danger?

There is substantial scientific confirmation showing that exposure to respirable crystalline silica can increase a person’s risk of developing lung cancer. The World Health Organization’s International Agency for Research on Cancer–the leading international voice on cancer causation–and the National Institutes of Health’s National Toxicology Program have conducted extensive reviews of the scientific literature and have designated crystalline silica as a known human carcinogen.

The American Cancer Society has adopted the WHO and NIH’s determinations.

How Am I Exposed?

OSHA estimates close to 2.3 million workers are exposed to crystalline silica on the job. Being around sand or other silica-containing materials is not hazardous by itself, but it becomes hazardous when specific work-related activities create respirable dust that is released into the air.

Work activities that create respirable dust include cutting, sawing, grinding, drilling, and crushing stone, rock, concrete, brick, block, and mixing mortar or using industrial sand.

Is There a Safe Limit?

In an effort to improve worker safety, OSHA has reduced the amount of silica dust an employee can be exposed to from a Permissible Exposure Limit (PEL) of 250 micrograms of respirable crystalline silica per cubic meter of air (?g/m3), averaged over an eight-hour day, down to 50 micrograms of respirable crystalline silica per cubic meter of air (?g/m3), averaged over an eight-hour day.

The reason for mandating such a low PEL is that silica dust contributes to so many deadly diseases, including COPD, lung cancer, and kidney disease. So there really is no safe level of silica dust exposure for workers.

Conclusion:

Silica safety program requirements are doable and are structured in a pretty reasonable way to help employers and the employees performing the work. Check out our next blog to see what options are available to help your business reduce and eliminate dust exposure for employees.