Detecting, Sampling, and Measuring Silica on Your Job Site

Silica is hazardous. By now, that's common knowledge. But we also know that some minor levels of exposure are relatively harmless. So, a lot of employers are left wondering how they can know whether all they need to do is provide their workers with simple respirators or whether they need to take extra steps to control silica exposure on their worksites.

To help you answer that question for yourself, we'll go over what you need to know about assessing the level of silica in your workplace.

What Is Silica?

Silica is a substance found in limestone, cement, quartz, and a wide range of other materials. When these materials are cut, ground, or drilled – say, in the course of construction projects – the silica is released into the air where it can be breathed in and cause significant health problems.

What Are the Health Risks of Silica?

Silica has been shown to cause damage to the lungs. Workers who have been exposed to high rates of silica for a long period of time can also develop lung cancer or silicosis (a hardening of lung tissues that can result in severe difficulties breathing or death).

Cancer and silicosis are not the only risks associated with silica exposure. It has also been linked to:

• Bronchitis
• Tuberculosis
• Scleroderma
• Kidney problems

The Importance of Knowing Your Silica Levels

These significant health risks make detection, sampling, and measuring silica an important step in ensuring employee safety. The control measures you need to implement will depend on the degree of potential exposure your workers face. Knowing that silica is present, and in what amounts, is the only way to make sure that you are giving the people on your worksite the protection they need.

There are a wide variety of sophisticated tools and equipment that can be used to detect silica and ensure that it stays within the narrowly defined parameters established by OSHA. It is important to note that OSHA has recently decided to make the permissible exposure limits (PEL) for silica more stringent in recognition of the growing body of scientific research linking silica with devastating medical conditions (learn about The Who, What, and Why Behind the New Silica Standard).

The Best Equipment: Sampling Cyclones

OSHA – and all industrial hygiene experts – agree that sampling cyclones are the best equipment to accurately detect and sample silica. This relatively small piece of equipment is attached to an employee’s shirt (ideally placed in close proximity to the worker’s mouth) and collects air samples throughout the day.

Since it follows the employee around as they do their work, this monitoring device provides the most accurate picture of what exposure really looks like in a particular workplace.

It is important to allow the monitoring to happen over the course of an entire work day, since there may be peaks and valleys in silica production depending on the processes and equipment used at any given time.

Why Impactors Are Not an Appropriate Substitute

Although some businesses have used impactors instead of cyclones, it is not necessarily approved by OSHA and the results acquired from an impactor may not be accepted as sufficient evidence that an employer is not in violation of OSHA's PEL regulations.

If you do decide to use an impactor, OSHA suggests getting a waiver for this equipment prior to testing. This will ensure that the results will be accepted and that the money you spend on testing will not be wasted.

Not All Cyclones Are Created Equal

It's also worth that not all cyclones are created equal. Some pieces of equipment may be better suited to different workplaces than others, and different devices may have different flow rates or limits of detection. In addition, some cyclones may work more effectively over longer testing periods.

If you have questions about what cyclone is most appropriate for your situation, carefully consult with the laboratory that is doing your testing. They should be able to advise you.

For industries in which silica exposure tends to be a bigger problem (such as metals, mining, and heavy construction), it may make sense to invest in state-of-the-art equipment.

Accredited Laboratories Play a Critical Role in the Process

Once samples have been collected, getting accurate results is critical. To get these numbers, the samples will be transported to a recognized lab where they will be analyzed to determine how much silica is in the air.

Different labs use different procedures for these calculations, so be sure to ask questions and work with the lab you feel most comfortable with.

The laboratory will return with silica exposure numbers. If these numbers exceed permissible exposure limits, you will need to take immediate steps to mitigate risks. Even if the figures are within acceptable ranges, you may still want to take a more aggressive approach to controlling silica exposure.

One way to do this is to provide workers with enhanced personal protection equipment, such as improved ventilators that filter out silica and other potentially dangerous substances. Another approach is to focus on upgrading housekeeping processes and engineering controls, such as improved local exhaust ventilation. Finally, if possible, it is advisable to replace products that use silica with non-silica-containing products throughout the production process.

Conclusion

Given the new, higher silica PELs, it is increasingly important for employers to appropriately sample and measure the levels of silica in their workplaces. If you discover that your silica levels exceed OSHA's limits, there's no time to lose: start implementing safeguards to protect your employees' short- and long-term health.