Report: Short Term Exposure Limit for Respirable Crystalline Silica
This report investigates whether a short term exposure limit (STEL) should be implemented to complement the workplace exposure standard (WES) of 0.05 mg/m3 for respirable crystalline silica. A STEL is a maximum airborne concentration that a worker can be exposed to in a short period of time (15 minutes) and is set at a higher concentration than the WES.
The report found that if respirable crystalline silica had an 8 hour time weighted average (TWA) of 0.05 mg/m3 then a STEL was not recommended. The report stated that workplaces should not have airborne concentrations of respirable crystalline silica higher than the TWA of 0.05 mg/m3 at any time. Even 15 minutes at a higher STEL concentration could damage a worker’s health.
The report did not recommend a STEL be added to the workplace exposure standard for respirable crystalline silica at this time.