Air quality, dust control and other environmental concerns are fast becoming top priority within many stone fabrication businesses. Many shops have been shut down, forced to close or file for bankruptcy due to the fact that they have not complied with local, state and federal requirements. In the past few years I have received numerous questions regarding these issues and the following are a few of my responses.
Q. We just had OSHA come into our shop and equip all of our shop employees with silica monitors. They removed them the other day and told us that two of our guys had unusually high amounts of silica. I don’t understand how this can be. Our shop is totally wet. We don’t do anything dry, not even for a minute. I thought silica had to be in dry dust form in order to be breathed in and if we did it wet it wouldn’t be a concern. Can you shed any light on this?
A. Yes, I have seen this problem numerous times in a totally wet shop, and here is what I have discovered. If your shop operates for only one shift, the floor will dry over night and leave a light dust of silica on the floor. When your employees come in the next day, they walk across the dry floor and kick up the dust. If the monitors were on your workers, they would pick up the silica dust.
To prevent this problem, make sure to rinse the shop floor down at the end of the shift. This is not just a light misting but rather a heavy and thorough rinse. In the morning, before anyone walks on the floor, take a hose and wet the floor to contain any residual dust. This should greatly reduce the amount of dust on the floor and make your employees and OSHA very happy.
Q. We have been told that granite and some marbles contain asbestos and using them in a home can be a problem? Is there any truth to this?
A. There is a partial truth to this. There are some stones that do contain asbestos; however, the asbestos is in very small amounts and it is contained and encapsulated in the stone. In order for asbestos to be a concern, the stone would need to be ground up and sprayed in the air.
This grinding is not likely to happen in someone’s home. You may be thinking, “What about in the shop when we are cutting the stone?” It is still not a problem since the amount of asbestos is extremely small. In addition, if you are cutting the stone wet, you should have no problem at all.
Q. I know you are a big advocate of cutting and doing everything in the shop wet, Fred, but there are some instances where we have to make small cuts dry. What do you recommend to contain the dust
A. There are several ways to contain the dust. There are dust collection tables that work by creating a vacuum and removing the dust into a collection device. You can also build your own dust collection booth with a large exhaust fan. If you do make your own booth, be sure that you don’t exhaust the dust into the open air. You will need some way to collect the dust. There are other devices that are also made for this purpose. I would suggest following up with your stone tool suppliers.
Q. I know you have addressed this problem in the past, but I still have a few customers who come into my showroom and are concerned with radon gas being emitted from granite. First, is this a concern? Second, is there a document that I can hand out to them to show it is not a concern?
A. This topic has been brought up a lot in recent years and a lot of misinformation and rumors are being spread. The fact is granite does emit radon, but in such minute quantities that it is of no concern, like the concern about asbestos we discussed earlier. The Marble Institute of America has had several studies done to show that radon in granite is not harmful. To better educate your consumers, you can redirect them to information about radon gas found on the MIA Web site.
About the author: Frederick M. Hueston is a worldwide expert on stone installation, failures, fabrication and restoration. He is the founder of the National Training Center for Stone & Masonry Trades (ntc-stone.com) and Stone University (stoneuniversity.org). He can be reached at Fhueston@aol.com.