Last month, we took a look at general respiratory protection in the countertop fabrication industry, and this month, we expand on that topic by exploring silica dust exposure and silicosis. Silica dust is the number one airborne contaminant in countertop fabrication shops, and it may exist anywhere stone, quartz surfacing or concrete slabs are being cut.
Silica has recently become a hot topic among countertop fabricators since the Occupational Safety and Health Administration (OSHA) announced a proposal to decrease the allowable limits for silica exposure. Although this proposed rule change has caused quite a stir in the industry and very few fabricators agree with it, the proposal has already had an impact by raising awareness of the issue.
Silicosis Cases Decline but Still Common
The problem with excessive exposure to silica dust is that it can accumulate in the lungs and cause a potentially fatal chronic disease known as silicosis. Although cases of silicosis have fallen and the mortality rate from the disease has decreased over the past 50 years, the National Institute for Occupational Safety and Health (NIOSH) reports that approximately 100 people die in the U.S. every year from complications associated with the disease, and from 2011 to 2013, 12 of those people were under 45 years of age.
In addition, 2015 marks the first time a countertop fabricator in the U.S. has been diagnosed with silicosis, joining the ranks of Italy, Spain and Israel. According to the Centers for Disease Control (CDC), the man was exposed to silica dust from quartz surfacing for 10 years. Quartz countertops are 70 to 90 percent crystalline silica, and with the material’s surge in popularity, excessive exposure must be addressed in fabrication shops. However, it is important to note that silica is also present in nearly all types of natural stone, including granite and soapstone, and concrete.
Protecting Employees and Ourselves
Countertop fabricators can take several steps to control silica levels in their shops and limit exposure to workers. The first step in the process is monitor the air in order to determine just how much silica dust is present. This will not only help protect the health of anyone present but will also help you stay in compliance with federal and state regulations. If levels above what is permissible are found, employers are mandated to take corrective action to reduce worker exposure.
The methods that can be used to reduce silica exposure fall into three categories: engineering controls, work practices and personal protective equipment (PPE). Each of these categories should be considered part of a hierarchy. If engineering controls do not sufficiently lower silica levels, changes in work practices must be attempted, and if levels are still too high, employees in the area must be fit for and provided with appropriate PPE.
Engineering Controls
- Employ water-spraying systems to keep dust from becoming airborne.
- Use remote-controlled saws and other tools to keep people out of the exposure zones.
- Modify handheld grinders to deliver water to the point of contact.
- Replace dry grinders with wet-edge routers.
- Use tools under a shroud and vacuum with a HEPA filter.
- Install local exhaust ventilation (LEV) systems.
- Use combinations of the above.
Work Practices
- When cleaning, use HEPA vacuums or wet sweepers rather than dry sweepers or compressed air.
- Replace filters frequently.
- Increase flow on water systems.
- Wet slabs before fabricating.
When cutting, grinding and polishing countertops onsite, control silica dust exposure by performing as much work as possible under controlled shop conditions, and use LEV systems when wet methods are impractical. In addition, try to use tools equipped with dust shrouds, and clean up all dust with a HEPA-filtered vacuum as soon as possible.
Respiratory Protection
When engineering controls and work practices have failed to lower silica dust levels, employers are required to provide respirator protection to employees, but this means much more than simply making PPE available. Employers are required to create a respiratory protection program that meets the OSHA Respiratory Protection Standard (29 CFR 1910.134). Such programs include the following requirements:
Selecting the proper respirators- Fit-testing employees for respirators
- Completing medical evaluations for all employees required to wear respirators
- Training employees how to properly use respirators
- Observing that employees are using and maintaining respirators properly
When respirators are required to be worn in areas with high levels of silica dust, at minimum, the PPE must be a NIOSH-approved N95 respirator. When silica levels are higher than 10 times the limit, half-face respirators may not be used. Instead, you must use respirators that offer more protection, such as full-face respirators, which are effective in environments that are 50 times higher than the current federal exposure level. Another option is to purchase powered air-purifying respirators (PAPRs), which are more comfortable and easier on the body than pressure-demand respirators are.
For Further Information
Further information on silica dust exposure and silicosis can be found in a variety of ways. A great deal of current information is available online, and you may also tap into other resources, including state and federal OSHA offices, which provide free consultation services for small-to-mid-sized businesses (SMBs). You can also contact trade organization, such as the Marble Institute of America (MIA), which has been recognized by OSHA for making comprehensive training resources available.
A few of the helpful materials you can access online are as follows:
- MIA Technical Module – Silicosis: An Industry Guide to Awareness and Prevention
- CDC Workplace Safety & Health Topics – Silica
- OSHA Fact Sheet – Crystalline Silica Exposure Health Hazard Information
- OSHA Training Materials – Silica
- OSHA eTools – Silica Advisor
- OSHA/NIOSH Hazard Alert – Worker Exposure to Silica during Countertop Manufacturing, Finishing and Installation
