Nationally tracked source thresholds.
The Terabecquerel (TBq) values are the regulatory standard. The curie (Ci) values specified are obtained by converting from the TBq value. The curie values are provided for practical usefulness only and are rounded after conversion.
Radioactive Material | Category 1 (TBq) | Category 1 (Ci) | Category 2 (TBq) | Category 2 (Ci) |
Actinium-227 | 20 | 540 | 0.2 | 5.4 |
Americium-241 | 60 | 1,600 | 0.6 | 16 |
Americium-241/Be | 60 | 1,600 | 0.6 | 16 |
Californium-252 | 20 | 540 | 0.2 | 5.4 |
Cobalt-60 | 30 | 810 | 0.3 | 8.1 |
Cesium-137 | 100 | 2,700 | 1 | 27 |
Curium-244 | 50 | 1,400 | 0.5 | 14 |
Gadolinium-153 | 1,000 | 27,000 | 10 | 270 |
Iridium-192 | 80 | 2,200 | 0.8 | 22 |
Plutonium-238 | 60 | 1,600 | 0.6 | 16 |
Plutonium-239/Be | 60 | 1,600 | 0.6 | 16 |
Polonium-210 | 60 | 1,600 | 0.6 | 16 |
Promethium-147 | 40,000 | 1,100,000 | 400 | 11,000 |
Radium-226 | 40 | 1,100 | 0.4 | 11 |
Selenium-75 | 200 | 5,400 | 2 | 54 |
Strontium-90 | 1,000 | 27,000 | 10 | 270 |
Thorium-228 | 20 | 540 | 0.2 | 5.4 |
Thorium-229 | 20 | 540 | 0.2 | 5.4 |
Thulium-170 | 20,000 | 540,000 | 200 | 5,400 |
Ytterbium-169 | 300 | 8,100 | 3 | 81 |
[Statutory Authority: RCW
70.98.050 and
70.98.080. WSR 09-06-003, ยง 246-221-236, filed 2/18/09, effective 3/21/09.]