[en] The air in certain work areas at the Oak Ridge Gaseous Diffusion Plant is monitored for selected radionuclides to assure safety from toxic effects to personnel in the area. Some of the radionuclides that are determined are shown with their Radiation Protection Standard (RPS) values by means of a table. The RPS is the maximum average airborne contamination to which personnel may be exposed for one week without respiratory protection and is expressed as disintegrations per minute (dpm) per cubic meter (m³) of air. It is desirable to make reliable measurements at a level which is 10% of the RPS to ensure that the detection limits are well below the RPS. Thorium, neptunium, plutonium, and uranium all have alpha emitting isotopes and it is their alpha activity which is measured. Results are tabulated