The final standard, which is expected to prevent at least 79 cancer deaths over a 45-year working lifetime, also includes a 15-minute short-term exposure limit (STEL) of 5 ppm and an action level of 0.5 ppm.
* Exposure limits - eight-hour time-weighted average (TWA) permissible exposure limit (PEL of 1 part BD per million parts air [ppm]); short-term exposure limit (STEL) of 5 ppm over a 15-minute period; and an action level of 0.5 ppm.
For compounds for which ACGIH finds the toxicology data insufficient to calculate a short-term exposure limit
(STEL), excursion limits from the TLV are based on practical application of a log-normal concentration distribution.
The rule reduces the permissible exposure limit (PEL) of beryllium to 0.2 micrograms per cubic meter of air over the course of an eight-hour shift, as well as a new short-term exposure limit
of 2 micrograms per cubic meter of air over a 15-minute period.
The American Conference of Governmental Industrial Hygienists has established a threshold limit value of 100 ppm and a 15-min short-term exposure limit
of 150 ppm for DPGME (5).
A statement signed by the presidents of both groups further stated that short-term exposure limits
(STELs) are appropriate for selected lab operations involving hazardous chemicals.