Construction workers face some of the greatest occupational risks for exposure to respiratory diseases. Many of these exposures can lead to debilitating and even lethal conditions. Some exposures are so severe that they can cause immediate health consequences, such as asphyxiation or tracheal burns. Read more
Where Does Silica Exposure Occur?
There are many construction activities during which workers can be exposed to respirable silica. Generally, individuals responsible for abrasive blasting with sand to remove rust and paint from concrete structures, bridges, tanks, etc., are exposed to the most severe concentrations of silica. Jack hammering, rock and well drilling, concrete mixing/drilling, brick/concrete block cutting/sawing, tuck pointing, and tunneling operations are construction jobs that also put workers at risk for exposure to high concentrations of silica.
Where are General Industry Employees Exposed to Silica?
Any time a surface needs to be cleaned, have any irregularities smoothed out, or prepped to be resurfaced (painted, treated, etc.), there is a risk for silica exposure. This includes cleaning/smoothing molds, jewelry, and foundry castings, finishing tombstones, etching or frosting glass, and removing paint, oils, rust, or dirt from objects needing to be resurfaced.
Workers involved in cement, brick, asphalt pavement, china, and ceramic manufacturing are all at risk for silica exposure, as well as those in the steel and foundry industries. When household abrasives, adhesives, paints, soaps, and glass are manufactured, there is also a risk to workers for silica exposure.
Silica exposure also occurs when refractory brick furnace linings need to be maintained, repaired, or replaced.
OSHA’s Response to Silica Exposure
The Permissible Exposure Limit (PEL) is a regulation established by OSHA. This table indicates the maximum amounts of silica to which workers may be exposed during an eight-hour shift. OSHA also requires workers who are exposed to silica to participate in hazard communication training, and requires worksites to implement respirator protection programs until engineering controls can be put in place. Lastly, OSHA has a National Emphasis Program (NEP) for Crystalline Silica exposure, which serves to identify, reduce, and eliminate the health hazards that often go hand-in-hand with on-the-job exposures.
You can read more about the OSHA standards and regulations in Title 29 of the Code of Federal Regulations. Additional information is also available on the OSHA website.
How Can Employers/Employees Prevent Silica Exposure?
Whenever possible, use alternative materials that do not contain crystalline silica.
Utilize local exhaust ventilation cabinets when feasible, and any other protective equipment/measures.
Use water sprays and other dust exposure control practices.
When requiring a respirator, only use a N95 NIOSH certified respirator. If you have a beard or mustache that may prevent a good seal between your face and the respirator, don’t wear a tight-fitting respirator, as your safety will be compromised.
When abrasive blasting, only use a type CE abrasive blast supplied air respirator.
Wear washable or disposable work clothes. If available, shower immediately after exposure. Vacuum dust from your clothing, or (preferably) change into clean clothes before leaving the worksite.
Attend training and health screenings, monitor exposure, and participate in surveillance programs that compile all of that data to evaluate any adverse health effects caused by silica exposure.
Be mindful of any job tasks or operations that will expose workers to respirable silica, and know how to protect yourself.
Be aware of health hazards that can compound silica exposure, such as smoking increasing lung damage caused by silica exposure.
Do not eat, drink, or apply cosmetics in areas where silica dust is present. This includes lip balm and hand cream. Wash your hands and face outside the worksite and away from dust before performing any of these activities.
Two million workers in the US are at risk of crystalline silica exposure every year. People who work in abrasive blasting, foundry work, stone cutting, rock drilling, quarry work, and tunneling are among those at the highest risk of exposure. These high risk jobs employ more than 100,000 workers annually.
But what exactly is silica, and how dangerous is it? What effects can it have on people who are exposed to it?
What is Crystalline Silica?
Crystalline silica, commonly referred to simply as “silica,” is one of the main elements that makes up soil, sand, granite, and a number of other minerals. Quartz, critobalite, and tridymite are the three most common forms of silica. When workers cut, drill, chip, or grind objects containing silica, fragments small enough for the workers to inhale make break off. Inhaling silica particles can be fatal.
Crystalline Silica is officially classified as a human lung carcinogen, meaning it can cause cancer. Silica inhalation is known to cause silicosis, which is an incurable disease that can cause permanent disabilities or even death. Inhaling silica particles causes scar tissue to form within the lungs, which reduces the lungs’ ability to draw oxygen. People who have lung damage due to silicosis are at a greater risk for lung infections such as tuberculosis.
There are three types of silicosis:
Chronic silicosis is the most common type, and it usually occurs after a person is exposed to a low to moderate amount of respirable silica over 15-20 years. Individuals with chronic silicosis may require chest x-rays to identify lung damage, because symptoms may be much less obvious than in the other types.
Accelerated silicosis, as its name suggests, has a quicker onset than chronic silicosis, because it is a result of high exposures to respirable silica over 5-10 years. Individuals who suffer from accelerated silicosis experience severe shortness of breath, weakness, and weight loss.
Sufferers of acute silicosis have been exposed to extremely high concentrations of respirable silica for as few as three months. Exposure to this much respirable silica for any time up to two years can result in acute silicosis. The onset of symptoms occurs even faster than those of accelerated silicosis due to the higher concentration of crystalline silica exposure. Individuals suffering from acute silicosis experience disabling shortness of breath, weakness, and weight loss, which often leads to death.
Check back with us next time for more information about silica exposure.