Silica is a general term used for many naturally occurring compounds that are primarily comprised of silicon dioxide (SiO₂). Silica has several crystalline forms called polymorphs which include quartz, tridymite and cristobalite. For the purpose of this program, crystalline silica will be referred to as silica. Silica is commonly found in natural soil, sand and rocks. It is also commonly found in various building materials such as concrete, masonry, paints, abrasives, plaster, mortar etc. 

Certain work activities can generate small dust particles that are capable of being inhaled and are small enough to enter deep into the lungs (respirable particles). Prolonged exposure to respirable particles of silica may lead to numerous adverse health effects such as silicosis, lung cancer, kidney disease, auto-immune disorders and cardiovascular disease. 

Reference Regulations: Silica in General Industry (MIOSHA General Industry Part 590) 

Silica In Construction (MIOSHA Construction Part 690)