Respiratory protection against inorganic arsenic (7440382) is briefly discussed. Because some inorganic arsenic compounds have a significant vapor pressure, NIOSH eliminated certain types of respirators, such as half mask respirators, from its list of currently recommended protective equipment for workers exposed to inorganic arsenic. Current NIOSH recommendations for personal respiratory equipment for use with inorganic arsenic compounds were given. These included full face coverage to prevent eye and facial irritation, high efficiency particulate filters for nonvolatile inorganic arsenic compounds, and air purifying respirators with an acid gas canister for arsenic compounds that have a high vapor pressure, such as arsenic-trichloride (7784341). Engineering controls were recommended to reduce and maintain arsenic exposures below the recommended standard of 2.0 micrograms per cubic meter. The author states that these controls, rather than respirators, should be used to attain compliance with the standard, except in cases of emergency or when installing or testing engineering control equipment, performing maintenance, or other nonroutine operations, when respirators should be used.