Previously, we discussed silica as a mineral – where it’s found and the industries most likely to be affected by the new OSHA silica standard. As a quick review, we discussed that silica is a naturally-occurring mineral commonly found in quartz, sand, and sand-type products including mortar, grout, and cement. We also said that the real hazard with silica is the fine particles – the ones you can’t see. These fine particles can get into your lungs and cause damage.
Before we get into specifics about the new silica standard, let’s answer some basic questions – sort of a Silica Frequently Asked Questions.
Q: Where do we usually find the silica that has the harmful dust?
A: Mostly in concrete and masonry applications where there can be a lot of dust generated – mixing, sawing, drilling, hammering, etc. It’s these types of activities that break down larger pieces into smaller particles (the fine dusts), and it’s these smaller particles that can get into the lungs and be harmful. Additionally, these activities are common to construction which is why the new silica standard is targeted more to construction applications than general industry.
Q: How do I know if my dry concrete or dry grout masonry mix contains silica?
A: Silica will be listed as an ingredient on the Safety Data Sheet. Additionally, the bag label should list silica on the label and have the warning symbol indicating a respiratory hazard.
Q: If the concrete or grout contains silica, does that mean my employees are overexposed to silica?
A: Not necessarily. The truth is, there’s no way to correlate the amount of silica in a concrete mix or grout mixture with airborne silica exposure. The amount of silica that’s in the air depends on how the powder is handled, how long it’s handled, the percentage of silica in the mix, etc. However, we can say that if the concrete or grout mix contains silica, your workers could be overexposed. The only way to absolutely determine if your workers are not overexposed is to conduct an exposure assessment.
Q: If my concrete or grout does not list silica as an ingredient, does that mean that there’s no silica in it?
A: Not necessarily. It may mean that the amount of silica contained in the concrete or grout is below what is considered to be hazardous levels (0.1%) or the manufacturer may not know that the mixture contains silica, and consequently did not list silica on the Safety Data Sheet.
Q: If I have silica in my mixes, do I need to do an exposure assessment?
A: No. You do not need to do an exposure assessment. The new construction standard contains information (Table 1) which identifies specific tasks that, when completed according to the guidelines, will keep you in compliance without doing an assessment.
Q: Is there a similar Table 1 for general industry?
A: No. But if you can obtain objective information (e.g., other exposure assessments), you may not need to conduct exposure assessments.
Q: If I have silica in my mixes and I want to do an exposure assessment, can I do this exposure assessment myself or do I need to have a professional do it?
A: Yes and No. The sampling is relatively easy and you can do the sampling yourself, but you will need to send the samples to a laboratory for analysis. There are lots of laboratories that can do silica analysis.
Q: What is the cost for a silica analysis?
A: The cost for analysis is about $125 per sample, depending on the lab you use. I’d recommend that you take at least two samples for comparison (more if possible – 6 samples is ideal).
In summary, if you are using anything that has concrete, grout, or cement-like material, you probably need to be thinking silica potential. If you know you’re using silica-containing materials, then you probably need to be thinking exposure assessment or exposure control (Table 1 – Construction). OSHA has published a fact sheet on the new silica rule for Construction and a separate fact sheet for General Industry. Click HERE to view the Construction Fact Sheet and HERE for the General Industry Fact Sheet.
Next: The OSHA Standard