US Rules and Regulations related to Elemental Species

Arsenic
The US Occupational Safety and Health Administration (OSHA) limits exposure to organoarsenicals in air. The permissible exposure limit (PEL) for organoarsenicals is 0.5 mg m³ as a time-weighted average  over an 8-hour period (29 CFR 1910.1000). The PEL (time-weighted average for 8 hours) for arsine (AsH₃)  gas is 0.05 parts of arsine per million parts of contaminated air (ppm) by volume at 25 °C and 760 torr  (Appendix A), or about 0.2mg m³ (29 CFR 1910.1000). The PEL for inorganic arsenic is 10 µg m³ of  air as a time-weighted average over an 8-hour period (29 CFR 1910.1018). The action level for inorganic  arsenic in air is 5 µgm³ as a time-weighted average over an 8-hour period (29 CFR 1910.1018).