Understanding Silica Dust and OSHA’s 50-Microgram PEL
There are a couple of reasons I love the team over at IQ Power Tools. One is for their dry cut tile saw – you should check it out if you haven’t seen one in action yet. The other is that they seem to love numbers as much as I do. Data-driven geeks of the world, unite! In an article discussing a better understanding of silica dust and Table 1 regulations, they break down how much silica dust you can potentially breathe in by making just one cut in a 60 mm (2.36″) paver.
Just the Facts
- Data comes from cutting a 2.36″ x 4″ paver
- The cut removes 1.18 in³ of material, equalling 45 grams
- Silica makes up roughly 20% of masonry materials
- 20% of 45 grams is 9 grams, or 9,000,000 micrograms, of silica dust
Inhaling Silica Dust (Not Recommended)
The blog post breaks down the math in much greater detail, so check that out if you want more proof. They use a 2.36″ x 4″ paver for their example and show that one cut removes 1.18 in³ of material with a blade that has a 0.125″ kerf.
Based on the weight of the paver, you get 45 grams of removed material.
Since silica makes up roughly 20% of masonry materials, that leaves you with 9 grams of silica in your 45 grams of waste product. Now we have to get scientific and convert grams to micrograms. 1 gram = 1,000,000 micrograms, so our cut produces 9,000,000 grams of silica dust.
Remember that OSHA standard?
It’s 50 micrograms per m³ of air.
The average Pro can inhale up to 840 micrograms of silica dust in an 8-hour day. That one paver cut produces enough silica dust for 10,714 days at the PEL. That’s more than 34 years worth of 6-day weeks and no vacations.
While many companies are motivated by avoiding fines for silica dust violations, individuals need to understand the risks of silicosis. When you see guys with power cutters dry cutting everything in site with no PPE or dust collection, they’re setting themselves up for an unpleasant and possibly early retirement.
OSHA’s PEL is very low, but compliance is far from impossible and your long-term health is at the heart of its intent.