Beryllium Exposure Limits
Action Level (AL) – means a concentration of airborne beryllium of 0.1 microgram per cubic meter of air (µg/m3) calculated as an 8-hour time-weighted average (TWA).
Time-weighted average (TWA) PEL – The employer must ensure that no employee is exposed to an airborne concentration of beryllium in excess of 0.2 μg/m3 calculated as an 8‑hour TWA.
Short-term exposure limit (STEL) – The employer must ensure that no employee is exposed to an airborne concentration of beryllium in excess of 2.0 μg/m3 as determined over a sampling period of 15 minutes.
Action Level
(AL) 1
µg/m3
(AL) 1
µg/m3
Permissible Exposure Limit
(PEL) 1
µg/m3
(PEL) 1
µg/m3
Short-Term Exposure Limit
(STEL) 2
µg/m3
(STEL) 2
µg/m3
0.1
0.2
2.0
µg/m3 – microgram per cubic meter of air
1 calculated as an 8-hour TWA
2 as determined over a sampling period of 15 minutes
1 calculated as an 8-hour TWA
2 as determined over a sampling period of 15 minutes