Managing construction site silica exposure

Managing Silica Exposure

Millions of construction and manufacturing workers in the United States are exposed to silica dust as a routine part of their daily activities.  Exposure to silica dust can lead to a myriad of lung ailments.  Since your lungs cannot expel inhaled silica dust, the effects are cumulative – that is, they get worse with each incidence of exposure.

Silica Dust

Silica is found in many common construction materials: cement, sand, mortar, thinsets, grout, brick, cmu blocks, and glass and ceramic tiles.  Any activity that involves the handling, mixing, grinding or cutting of these materials can generate silica dust.  Silica and most other particulate matter are known lung irritants. 

Silicosis

Silicosis is a lung disease cause by the inhalation of silica dust.  Once inhaled, these particles imbed themselves deep in the crevasses of the lungs.  The lungs respond by forming scar tissue around the foreign matter.  Over time, this scarring of the lungs makes breathing difficult.  There is no cure for Silicosis, but it can be prevented.  

There are three types of silicosis: acute, chronic, and accelerated.  Acute Silicosis causes coughing, weight loss and fatigue within a few weeks or years following the inhalation of silica.  Chronic Silicosis appears ten to thirty years following exposure and usually affects the upper lungs accompanied by severe scarring.  Accelerated Silicosis usually occurs within 10 years following high levels of silica exposure.

Symptoms

Silicosis is usually accompanied by tightness in the chest, difficulty breathing and wheezing.  Associated diseases and ailments such as asthma, bronchitis, lung cancer, COPD, kidney disease and tuberculosis often follow.

Who is at Risk?
Anyone who handles or mixes powdered construction materials; generates dust from the processing, cutting, grinding, installation or demolition of construction materials; or is in the proximity of generated silica dust - is at risk.

Sources of Silica Dust

While not an inclusive list, these are the most common sources of silica dust exposure in the swimming pool industry:

·      Raw materials such as cement, sand, gravel, mortar, thinset, grout, filter media.

·      Cutting or grinding of concrete, stone, tiles, brick and cement blocks.

·      Mixing or processing of concrete, cement, grout, over spray from dry-mix shotcrete (gunite), mortar, thinset.

·      Excavation activities in silica borne soils

New Regulations

OSHA has established new permissible exposure limits (PELs), which were last evaluated in the 1970’s.  Workers' exposures are now limited to a new PEL of 50 micrograms of respirable crystalline silica per cubic meter of air (μg/m³), averaged over an 8-hour day. 

Who is affected by these Rules?

Everyone has a duty and responsibility to reduce silica dust exposure.  Even if you do not have direct employees, you are responsible for work place safety on your projects.  You are liable for worker injuries, if you are aware of and allow unsafe working conditions to occur/continue.  As a direct employer, you obviously are responsible for the safety of your employees.

Because Silicosis oftentimes manifests itself well after silica exposure, you may experience employee claims years later.  Then it is too late and impossible to document PEL’s and employee exposures.  It is best to have a written exposure reduction policy, provide the proper respiratory protection and have employees sign acknowledgement forms.

Because it is virtually impossible for construction managers to monitor and document the precise PEL’s on various outdoor job sites, it is best to institute a personnel protection plan that includes reducing generated silica dust and the use of approved respiratory protection devices.

Particulate exposure

As a matter of work place safety, the exposure to all inhaled dust and particulate matter should be controlled.  Many other swimming pool products such as diatomaceous earth, powdered chemicals and common dirt & dust are also proven lung irritants.

For more information about the new exposure limits and how to protect yourself and your employees visit:
OSHA: www.osha.gov/silica/
American Lung Association: www.lung.org/lung-health-and-diseases/lung-disease-lookup/silicosis/
 
Paolo Benedetti, SWD, Principal 
 Aquatic Technology Pool and Spa 
www.AquaticTechnology.com 
 International Swimming Pool Consulting and Design, Aquatic Consulting, Watershape Consultants, Expert Witness, Hydraulic Design, Landscape Architecture, Construction Management 
Office: 408-776-8220 
Email: info@aquatictechnology.com 
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