Using Respirators for Silica Exposure

Some in the masonry industry have expressed interest in respirator use as protection from harmful exposure to silica. This topic is of paramount importance due to its impact on our workers and the serious health effects of silica exposure. For those new to the masonry industry, exposure to respirable crystalline silica presents serious health risks and even death when the amount of silica breathed by a worker exceeds the permissible exposure limit (PEL). This can happen in two broad ways: acute exposure and chronic exposure. Acute exposure occurs when a worker is exposed to an enormous amount of respirable crystalline silica in a short amount of time. This has occurred in the past in cases of mining, quarrying, or other confined spaces where large amounts of free silica are released into the atmosphere. In the masonry industry, acute exposure would be extremely rare, if not nonexistent. Chronic exposure is more relevant to our industry.

Most of us as masonry contractors do our part to protect our workers from silica exposure. But what about contractors who don't know, or even worse, don't care? This can lead to lung disease and eventually a fatality if a worker is exposed to free silica unprotected for years. Respirable crystalline silica is not merely sand like that found on a beach. Respirable crystalline silica is sand that has been pulverized or otherwise cut into extremely small pieces (100 times smaller than a typical grain of beach sand). Someone could live on the beach their entire life and never be troubled by silicosis-related health issues. However, workers in the masonry industry could very well face these health problems if they are not protected. If a worker operates a masonry saw, chipping hammer, or drill for a number of years without administrative controls, engineering controls, or personal protective equipment (PPE), there could be serious adverse effects. Let’s talk about these different types of protective controls.

Hierarchy of Protective Controls
According to industry leaders and OSHA, there is a hierarchy of controls that should be used when dealing with a hazard in the workplace. Case in point, silica. The hierarchy of controls is based on a descending order, from what offers the most protection to the worker down to the least. As concerned employers, we want to implement the absolute best control first, and if that is impossible, we move down to the next. Here is the descending order of controls by priority:

Elimination
Substitution.
Engineering controls.
Administrative controls.
PPE

Elimination of the hazardous substance should be the primary goal for most hazards. In masonry, most times this will not be a feasible option. Most masonry products contain at least some silica. One could refuse to do the project. That would keep your workers safe and perhaps unemployed. However, products such as sintered stone contain no silica. This would eliminate the hazard of free silica altogether.

Substitution, as a control, is closely related to the concept we just discussed. We can illustrate this control by comparing two stone products. Granite has an extremely large amount of silica, while a calcium carbonate limestone has only trace amounts. An architect or design builder could choose to substitute the greater hazard of working with granite with the much less hazardous calcium carbonate limestone.

Engineering controls are utilized to engineer out the hazard. This is normally where the mason contractor can take control of the hazard. Wet cutting masonry and using a vacuum when cutting or drilling masonry or concrete products are examples of engineering controls to eliminate the hazard.

Administrative controls involve supervisors skillfully managing the job to ensure exposure to silica never exceeds the PEL. This can be done by rotation of employees working around silica, for example. If OSHA's Table One specifies a maximum exposure time of four hours for a particular task, an administrative control would involve rotating employees to ensure no worker exceeds this four-hour limit.

Personal Protective Equipment (PPE) is considered the least desirable control measure due to the continued presence of hazards. This discussion arose from questions about respiratory protection like masks, but several more effective alternatives exist. Ideally, hazards should be eliminated entirely. If complete elimination isn't possible, engineering controls are a strong secondary option. For instance, a properly used wet saw prevents respirable crystalline silica from entering the air, protecting the operator and those nearby from harmful free silica. Immediately resorting to PPE, such as a respirator, means the hazard persists. A worker might wear a mask improperly and still inhale free silica. Even with proper respirator use, other workers in the vicinity remain exposed to airborne free silica. Therefore, a respirator should be the absolute last resort.

Avoid Respirator Use at (Almost) All Cost
With three and a half decades of experience as a safety professional, I strongly advise exploring alternatives to respirator use. Familiarize yourself with OSHA’s Table One, which outlines options for managing silica exposure. Table One specifies tasks, tools, required PPE (if any), and permissible time limits. While avoiding the task itself is often impossible, you can frequently select a combination of tools and time limits that eliminate the need for a respirator. This "sweet spot" has been my focus long before the introduction of the "new" silica standard. For example: cutting masonry with a table saw with integral water delivery system at the point of blade contact is acceptable with no need for a respirator according to Table One. We also went the extra mile and hired an Industrial Hygienist to test different tasks that we performed to ensure we were below the Permissible Exposure Limit. This cleared up some of the questions that Table One did not address. I encourage you to do the same. If there’s a particular task and application that Table One does not address, have an Industrial Hygienist monitor the task in a real life scenario, and you may be surprised that the task does not require a respirator after all. To avoid an OSHA citation, the monitoring system must strictly adhere to OSHA guidelines. Furthermore, as an added incentive to minimize respirator use, any worker wearing a respirator for more than 30 days annually will be subject to the medical surveillance clause, as per the OSHA standard.

Choosing a Respirator if You Must
If it's not possible to find a solution within the hierarchy of controls or from Table One that eliminates the need for a respirator, then the appropriate respirator for the task must be selected. Some applications, such as sandblasting or certain tuck-pointing jobs, necessitate the use of a supplied-air respirator. This device delivers clean air from an unaffected nearby area to the work zone, protecting the user from silica exposure. Other tasks may necessitate a full-face or half-face filtering respirator. These respirators feature specially designed filtering cartridges that capture free silica on the exterior filter before it can reach the user's airway. For tasks with lower silica concentrations, an N95 mask, a two-strapped paper-type mask, can be used. While it fits more loosely than other respirators, it effectively filters out much of the airborne silica.

To easily select a respirator, refer to Table One in the silica standard. This table allows you to match the prescribed respirator type to the specific task, tool, and duration of the task.

Addressing the countless questions and scenarios surrounding silica exposure is impossible in a single article; this merely scratches the surface. However, the MCAA is here to help. Members can ask their questions, and we will assist them in finding the answers. Make it safe, make it personal, make it home!

Using Respirators for Silica Exposure

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