Respirable Crystalline Silica (RCS) Dust

RCS dust is airborne crystalline silica dust that is respirable to those in close proximity to the source.

Silica is the second most common mineral on earth. It consists of silicon and oxygen atoms which makes up nearly all of what we call "sand" and "rock". Quartz is the most common form of crystalline silica and is found in varying amounts in almost all types of rocks, sands, clays, shales and gravel. Cristobalite and tridymite are found in volcanic rocks.

Crystalline silica is hazardous when it becomes airborne through disturbing the material through common operations such as cutting, sawing, drilling or crushing. CAREX Canada  estimates that approximately 48,000 workers in BC are occupationally exposed to RCS each year. More workers in BC workplaces are exposed to RCS dust than to asbestos or lead.

For more information, see Exposure Health Risks.