By Fred Hueston, Ph.D.

Does your shop cut, grind or hone stone dry? Do you grind stone flooring dry sometimes? Dust created from cutting and grinding certain types of stone emits silica in the air. If you or your workers are not using the proper respiratory protection, you could be exposing yourself and your workers to serious health problems.

Breathing silica dust can cause a disease known as Siliceous. More than 250 people each year die from this disease and more than one million workers in the United States are exposed to silica dust. The really bad news is there is no cure for it. The good news: It is preventable. The way to prevent silicosis is simple: cut, grind and polish all your stone wet and you won’t have to worry about it.

Not only is silica a health problem but it can also hurt your wallet and even put you out of business. OSHA is cracking down on silica exposure and imposing fines. In a recent update on OSHA has fined as much as $135,000 for not only protecting employees against silica dust but for not having the proper written HAZCOM and safety programs

What stone types contain silica?

All granite as well as certain slate and some marbles may contain harmful silica dust. Make the assumption that all granites and slates contain silica. Most marble except for a few green varieties have silica. Limestone generally does not contain silica, although there are a few that may. All quartzites and stone containing quartz have silica. 

For more information visit the Washington State Department of Labor and Industry article on silica in the stone fabrication industry. Most states have their own exposure limits and I encourage you to check with your state Department of Labor. OSHA also has a federal limit in which you should be aware. In addition, visit OSHA information on siliceous and protecting yourself.

In addition, make sure you are prepared when OSHA comes calling with the proper safety and HAZCOM program.