Reducing Silica Risks at the Construction Site

On a construction site, we're always taught to watch out for the big things. Machinery, trucks, falling from heights – all very large and very dramatic ways to get hurt or killed. We spend a lot of time training to be aware of these dangers. But what about the small ones? What about the really small ones?

While you're busy watching out for heavy equipment, you also have to worry about those microscopic pieces of stone that are kicked up into the air by moving trucks, power saws, and, well, everything that moves around you.

Dust Inhalation on the Construction Site

The air quality of a construction site is never all that great. But, too often, construction workers rely on nothing more than their own physical toughness for protection. Your lungs, after all, are very good at cleaning themselves out, so why worry about dusty environments?

Here’s why. While it’s true that your lungs can take care of a lot of the pollutants that enter when you breathe, they are designed to handle basic substances that have been around for millions of years, like airborne dust and maybe a little sand. But they were never designed to handle them in the amounts that are present during a construction project. And they definitely were not made to handle substances that humans have developed, like carbon monoxide from exhaust and finely cut stone materials like concrete and quartz (learn more about Carbon Monoxide: The Silent Killer).

It's this last category that too few workers are concerned about. Stone substances like quartz and sand, which contain silica, are too small to be seen by the naked eye and are odorless. But when you breathe it in, these particles act like glass or sharp sand, scratching the sensitive tissues on the interior of the lung, creating inflammation and scarring, called silicosis.

Prolonged exposure attacks the immune system, leading to conditions like lung cancer, arthritis, lupus, and permanent kidney damage. Sand seems so innocuous. But we’ve all seen what sandblasters and sandpaper can do even to hard surfaces. Imagine how that works on lung tissue.

Types of Silicosis

There are four types of silicosis:

• Chronic simple silicosis comes from long-term exposure (10 years or more) to low levels of silica dust. Symptoms include chronic coughing and shortness of breath, and confirmation must be done through a chest x-ray.
• Accelerated silicosis comes on more quickly (within 5 or 10 years) after exposure to larger amounts of silica dust.
• Complicated silicosis happens when scarring of lung tissue starts to lead to other serious conditions like tuberculosis.
• Acute silicosis comes on very quickly, within a few weeks or months after exposure to high concentrations of silica dust.

The problem is, we are all so busy just trying to keep projects on time, it is very easy to overlook the dangers of this invisible enemy, or worse, dismiss them as insignificant

There's no getting around it. Think about all the places where dust, especially silica dust, flies on construction sites. You're dealing with it any time you work with:

• Cement
• Sand
• Blasting
• Demolition
• Drywall
• Grout
• Paint
• Concrete blocks
• Stonecutting
• Masonry
• Bricklaying
• Mortar

You'll also encounter it when working with old materials like fire brick or insulation that might have degraded from a glassy to a crystalline state, through devitrification.

There are special environmental tests, using measurement tools and mathematical formulas that can determine the Permissible Exposure Limits, which are between 50 and 100 μg/m3, depending on the types of materials present in the dust. But suffice to say, if there is dust, there is danger.

Reducing the Risk of Silica Exposure in Construction

It is often thought that masks and respirators are the key to safe breathing on sites where silica dust is present, but they simply do not work well enough. Paper masks offer little protection against these microscopic pieces of stone, and organizations like OSHA stress that respirators should not be your only line of defense, either. They should be used together with engineering and environmental controls, but never as the primary barrier.

This means that job sites must take complete control over the dissemination of dust at the source, rather than waiting until it gets to the operators’ faces.

It starts by ensuring workspaces have ventilation systems that pull particulates away, rather than just pushing them around. Getting rid of respirable silica helps to eliminate much of the problem.

In addition, there should be plenty of water to spray down surfaces, guiding the particulates away. Water is also essential at the point of contact between power tools and stone surfaces, using sprays or hoses to maintain a constant stream directly at the location of impact.

Another technique uses enclosures, like small tents, to trap particulates in a confined area of operation.

Vacuum collection systems are also recommended as an effective way of removing particulates from the work surfaces and machinery where water may be problematic.

It is very difficult on a construction site to prevent trucks and cars from kicking up dust in their wake, unless speed limits and even signal people are used. Doing so not only prevents dust from being inhaled but also has the added benefit of reducing the risk of struck-by accidents (learn more about Construction Dust: The Risk to Health and How to Create a Safer Working Environment).

An Invisible Long-Term Danger

Silicosis and related conditions tend to be invisible dangers. Unlike an open wound, it is impossible to observe workers getting affected by respirable silica. Unlike cigarette smoke, no clouds of dust come out when a person breathes or coughs. The diseases and conditions that result can easily be misdiagnosed, attributed to other causes (like smoking), and may only appear years after the employee has left the job site.

As such, it is essential that workers turn to their employers or representatives to work together and create a safe workplace immediately. With an invisible but very real enemy, prevention is the only real cure (to learn more about silica in other industries, see Reducing Silica Exposure in Manufacturing).