{"data":{"id":"us/10-cfr-appendix-c-to-part-20","jurisdiction":"us","citation":"10 CFR Appendix C to Part 20","heading":"Appendix C to Part 20—Quantities 1 of Licensed Material Requiring Labeling","body":"Radionuclide Quantity (µCi)\nHydrogen-3 1,000\nBeryllium-7 1,000\nBeryllium-10 1\nCarbon-11 1,000\nCarbon-14 100\nFluorine-18 1,000\nSodium-22 10\nSodium-24 100\nMagnesium-28 100\nAluminum-26 10\nSilicon-31 1,000\nSilicon-32 1\nPhosphorus-32 10\nPhosphorus-33 100\nSulfur-35 100\nChlorine-36 10\nChlorine-38 1,000\nChlorine-39 1,000\nArgon-39 1,000\nArgon-41 1,000\nPotassium-40 100\nPotassium-42 1,000\nPotassium-43 1,000\nPotassium-44 1,000\nPotassium-45 1,000\nCalcium-41 100\nCalcium-45 100\nCalcium-47 100\nScandium-43 1,000\nScandium-44m 100\nScandium-44 100\nScandium-46 10\nScandium-47 100\nScandium-48 100\nScandium-49 1,000\nTitanium-44 1\nTitanium-45 1,000\nVanadium-47 1,000\nVanadium-48 100\nVanadium-49 1,000\nChromium-48 1,000\nChromium-49 1,000\nChromium-51 1,000\nManganese-51 1,000\nManganese-52m 1,000\nManganese-52 100\nManganese-53 1,000\nManganese-54 100\nManganese-56 1,000\nIron-52 100\nIron-55 100\nIron-59 10\nIron-60 1\nCobalt-55 100\nCobalt-56 10\nCobalt-57 100\nCobalt-58m 1,000\nCobalt-58 100\nCobalt-60m 1,000\nCobalt-60 1\nCobalt-61 1,000\nCobalt-62m 1,000\nNickel-56 100\nNickel-57 100\nNickel-59 100\nNickel-63 100\nNickel-65 1,000\nNickel-66 10\nCopper-60 1,000\nCopper-61 1,000\nCopper-64 1,000\nCopper-67 1,000\nZinc-62 100\nZinc-63 1,000\nZinc-65 10\nZinc-69m 100\nZinc-69 1,000\nZinc-71m 1,000\nZinc-72 100\nGallium-65 1,000\nGallium-66 100\nGallium-67 1,000\nGallium-68 1,000\nGallium-70 1,000\nGallium-72 100\nGallium-73 1,000\nGermanium-66 1,000\nGermanium-67 1,000\nGermanium-68 10\nGermanium-69 1,000\nGermanium-71 1,000\nGermanium-75 1,000\nGermanium-77 1,000\nGermanium-78 1,000\nArsenic-69 1,000\nArsenic-70 1,000\nArsenic-71 100\nArsenic-72 100\nArsenic-73 100\nArsenic-74 100\nArsenic-76 100\nArsenic-77 100\nArsenic-78 1,000\nSelenium-70 1,000\nSelenium-73m 1,000\nSelenium-73 100\nSelenium-75 100\nSelenium-79 100\nSelenium-81m 1,000\nSelenium-81 1,000\nSelenium-83 1,000\nBromine-74m 1,000\nBromine-74 1,000\nBromine-75 1,000\nBromine-76 100\nBromine-77 1,000\nBromine-80m 1,000\nBromine-80 1,000\nBromine-82 100\nBromine-83 1,000\nBromine-84 1,000\nKrypton-74 1,000\nKrypton-76 1,000\nKrypton-77 1,000\nKrypton-79 1,000\nKrypton-81 1,000\nKrypton-83m 1,000\nKrypton-85m 1,000\nKrypton-85 1,000\nKrypton-87 1,000\nKrypton-88 1,000\nRubidium-79 1,000\nRubidium-81m 1,000\nRubidium-81 1,000\nRubidium-82m 1,000\nRubidium-83 100\nRubidium-84 100\nRubidium-86 100\nRubidium-87 100\nRubidium-88 1,000\nRubidium-89 1,000\nStrontium-80 100\nStrontium-81 1,000\nStrontium-83 100\nStrontium-85m 1,000\nStrontium-85 100\nStrontium-87m 1,000\nStrontium-89 10\nStrontium-90 0.1\nStrontium-91 100\nStrontium-92 100\nYttrium-86m 1,000\nYttrium-86 100\nYttrium-87 100\nYttrium-88 10\nYttrium-90m 1,000\nYttrium-90 10\nYttrium-91m 1,000\nYttrium-91 10\nYttrium-92 100\nYttrium-93 100\nYttrium-94 1,000\nYttrium-95 1,000\nZirconium-86 100\nZirconium-88 10\nZirconium-89 100\nZirconium-93 1\nZirconium-95 10\nZirconium-97 100\nNiobium-88 1,000\nNiobium-89m (66 min) 1,000\nNiobium-89 (122 min) 1,000\nNiobium-90 100\nNiobium-93m 10\nNiobium-94 1\nNiobium-95m 100\nNiobium-95 100\nNiobium-96 100\nNiobium-97 1,000\nNiobium-98 1,000\nMolybdenum-90 100\nMolybdenum-93m 100\nMolybdenum-93 10\nMolybdenum-99 100\nMolybdenum-101 1,000\nTechnetium-93m 1,000\nTechnetium-93 1,000\nTechnetium-94m 1,000\nTechnetium-94 1,000\nTechnetium-96m 1,000\nTechnetium-96 100\nTechnetium-97m 100\nTechnetium-97 1,000\nTechnetium-98 10\nTechnetium-99m 1,000\nTechnetium-99 100\nTechnetium-101 1,000\nTechnetium-104 1,000\nRuthenium-94 1,000\nRuthenium-97 1,000\nRuthenium-103 100\nRuthenium-105 1,000\nRuthenium-106 1\nRhodium-99m 1,000\nRhodium-99 100\nRhodium-100 100\nRhodium-101m 1,000\nRhodium-101 10\nRhodium-102m 10\nRhodium-102 10\nRhodium-103m 1,000\nRhodium-105 100\nRhodium-106m 1,000\nRhodium-107 1,000\nPalladium-100 100\nPalladium-101 1,000\nPalladium-103 100\nPalladium-107 10\nPalladium-109 100\nSilver-102 1,000\nSilver-103 1,000\nSilver-104m 1,000\nSilver-104 1,000\nSilver-105 100\nSilver-106m 100\nSilver-106 1,000\nSilver-108m 1\nSilver-110m 10\nSilver-111 100\nSilver-112 100\nSilver-115 1,000\nCadmium-104 1,000\nCadmium-107 1,000\nCadmium-109 1\nCadmium-113m 0.1\nCadmium-113 100\nCadmium-115m 10\nCadmium-115 100\nCadmium-117m 1,000\nCadmium-117 1,000\nIndium-109 1,000\nIndium-110 (69.1min.) 1,000\nIndium-110\n(4.9h) 1,000\nIndium-111 100\nIndium-112 1,000\nIndium-113m 1,000\nIndium-114m 10\nIndium-115m 1,000\nIndium-115 100\nIndium-116m 1,000\nIndium-117m 1,000\nIndium-117 1,000\nIndium-119m 1,000\nTin-110 100\nTin-111 1,000\nTin-113 100\nTin-117m 100\nTin-119m 100\nTin-121m 100\nTin-121 1,000\nTin-123m 1,000\nTin-123 10\nTin-125 10\nTin-126 10\nTin-127 1,000\nTin-128 1,000\nAntimony-115 1,000\nAntimony-116m 1,000\nAntimony-116 1,000\nAntimony-117 1,000\nAntimony-118m 1,000\nAntimony-119 1,000\nAntimony-120 (16min.) 1,000\nAntimony-120 (5.76d) 100\nAntimony-122 100\nAntimony-124m 1,000\nAntimony-124 10\nAntimony-125 100\nAntimony-126m 1,000\nAntimony-126 100\nAntimony-127 100\nAntimony-128 (10.4min.) 1,000\nAntimony-128 (9.01h) 100\nAntimony-129 100\nAntimony-130 1,000\nAntimony-131 1,000\nTellurium-116 1,000\nTellurium-121m 10\nTellurium-121 100\nTellurium-123m 10\nTellurium-123 100\nTellurium-125m 10\nTellurium-127m 10\nTellurium-127 1,000\nTellurium-129m 10\nTellurium-129 1,000\nTellurium-131m 10\nTellurium-131 100\nTellurium-132 10\nTellurium-133m 100\nTellurium-133 1,000\nTellurium-134 1,000\nIodine-120m 1,000\nIodine-120 100\nIodine-121 1,000\nIodine-123 100\nIodine-124 10\nIodine-125 1\nIodine-126 1\nIodine-128 1,000\nIodine-129 1\nIodine-130 10\nIodine-131 1\nIodine-132m 100\nIodine-132 100\nIodine-133 10\nIodine-134 1,000\nIodine-135 100\nXenon-120 1,000\nXenon-121 1,000\nXenon-122 1,000\nXenon-123 1,000\nXenon-125 1,000\nXenon-127 1,000\nXenon-129m 1,000\nXenon-131m 1,000\nXenon-133m 1,000\nXenon-133 1,000\nXenon-135m 1,000\nXenon-135 1,000\nXenon-138 1,000\nCesium-125 1,000\nCesium-127 1,000\nCesium-129 1,000\nCesium-130 1,000\nCesium-131 1,000\nCesium-132 100\nCesium-134m 1,000\nCesium-134 10\nCesium-135m 1,000\nCesium-135 100\nCesium-136 10\nCesium-137 10\nCesium-138 1,000\nBarium-126 1,000\nBarium-128 100\nBarium-131m 1,000\nBarium-131 100\nBarium-133m 100\nBarium-133 100\nBarium-135m 100\nBarium-139 1,000\nBarium-140 100\nBarium-141 1,000\nBarium-142 1,000\nLanthanum-131 1,000\nLanthanum-132 100\nLanthanum-135 1,000\nLanthanum-137 10\nLanthanum-138 100\nLanthanum-140 100\nLanthanum-141 100\nLanthanum-142 1,000\nLanthanum-143 1,000\nCerium-134 100\nCerium-135 100\nCerium-137m 100\nCerium-137 1,000\nCerium-139 100\nCerium-141 100\nCerium-143 100\nCerium-144 1\nPraseodymium-136 1,000\nPraseodymium-137 1,000\nPraseodymium-138m 1,000\nPraseodymium-139 1,000\nPraseodymium-142m 1,000\nPraseodymium-142 100\nPraseodymium-143 100\nPraseodymium-144 1,000\nPraseodymium-145 100\nPraseodymium-147 1,000\nNeodymium-136 1,000\nNeodymium-138 100\nNeodymium-139m 1,000\nNeodymium-139 1,000\nNeodymium-141 1,000\nNeodymium-147 100\nNeodymium-149 1,000\nNeodymium-151 1,000\nPromethium-141 1,000\nPromethium-143 100\nPromethium-144 10\nPromethium-145 10\nPromethium-146 1\nPromethium-147 10\nPromethium-148m 10\nPromethium-148 10\nPromethium-149 100\nPromethium-150 1,000\nPromethium-151 100\nSamarium-141m 1,000\nSamarium-141 1,000\nSamarium-142 1,000\nSamarium-145 100\nSamarium-146 1\nSamarium-147 100\nSamarium-151 10\nSamarium-153 100\nSamarium-155 1,000\nSamarium-156 1,000\nEuropium-145 100\nEuropium-146 100\nEuropium-147 100\nEuropium-148 10\nEuropium-149 100\nEuropium-150 (12.62h) 100\nEuropium-150 (34.2y) 1\nEuropium-152m 100\nEuropium-152 1\nEuropium-154 1\nEuropium-155 10\nEuropium-156 100\nEuropium-157 100\nEuropium-158 1,000\nGadolinium-145 1,000\nGadolinium-146 10\nGadolinium-147 100\nGadolinium-148 0.001\nGadolinium-149 100\nGadolinium-151 10\nGadolinium-152 100\nGadolinium-153 10\nGadolinium-159 100\nTerbium-147 1,000\nTerbium-149 100\nTerbium-150 1,000\nTerbium-151 100\nTerbium-153 1,000\nTerbium-154 100\nTerbium-155 1,000\nTerbium-156m (5.0h) 1,000\nTerbium-156m (24.4h) 1,000\nTerbium-156 100\nTerbium-157 10\nTerbium-158 1\nTerbium-160 10\nTerbium-161 100\nDysprosium-155 1,000\nDysprosium-157 1,000\nDysprosium-159 100\nDysprosium-165 1,000\nDysprosium-166 100\nHolmium-155 1,000\nHolmium-157 1,000\nHolmium-159 1,000\nHolmium-161 1,000\nHolmium-162m 1,000\nHolmium-162 1,000\nHolmium-164m 1,000\nHolmium-164 1,000\nHolmium-166m 1\nHolmium-166 100\nHolmium-167 1,000\nErbium-161 1,000\nErbium-165 1,000\nErbium-169 100\nErbium-171 100\nErbium-172 100\nThulium-162 1,000\nThulium-166 100\nThulium-167 100\nThulium-170 10\nThulium-171 10\nThulium-172 100\nThulium-173 100\nThulium-175 1,000\nYtterbium-162 1,000\nYtterbium-166 100\nYtterbium-167 1,000\nYtterbium-169 100\nYtterbium-175 100\nYtterbium-177 1,000\nYtterbium-178 1,000\nLutetium-169 100\nLutetium-170 100\nLutetium-171 100\nLutetium-172 100\nLutetium-173 10\nLutetium-174m 10\nLutetium-174 10\nLutetium-176m 1,000\nLutetium-176 100\nLutetium-177m 10\nLutetium-177 100\nLutetium-178m 1,000\nLutetium-178 1,000\nLutetium-179 1,000\nHafnium-170 100\nHafnium-172 1\nHafnium-173 1,000\nHafnium-175 100\nHafnium-177m 1,000\nHafnium-178m 0.1\nHafnium-179m 10\nHafnium-180m 1,000\nHafnium-181 10\nHafnium-182m 1,000\nHafnium-182 0.1\nHafnium-183 1,000\nHafnium-184 100\nTantalum-172 1,000\nTantalum-173 1,000\nTantalum-174 1,000\nTantalum-175 1,000\nTantalum-176 100\nTantalum-177 1,000\nTantalum-178 1,000\nTantalum-179 100\nTantalum-180m 1,000\nTantalum-180 100\nTantalum-182m 1,000\nTantalum-182 10\nTantalum-183 100\nTantalum-184 100\nTantalum-185 1,000\nTantalum-186 1,000\nTungsten-176 1,000\nTungsten-177 1,000\nTungsten-178 1,000\nTungsten-179 1,000\nTungsten-181 1,000\nTungsten-185 100\nTungsten-187 100\nTungsten-188 10\nRhenium-177 1,000\nRhenium-178 1,000\nRhenium-181 1,000\nRhenium-182 (12.7h) 1,000\nRhenium-182 (64.0h) 100\nRhenium-184m 10\nRhenium-184 100\nRhenium-186m 10\nRhenium-186 100\nRhenium-187 1,000\nRhenium-188m 1,000\nRhenium-188 100\nRhenium-189 100\nOsmium-180 1,000\nOsmium-181 1,000\nOsmium-182 100\nOsmium-185 100\nOsmium-189m 1,000\nOsmium-191m 1,000\nOsmium-191 100\nOsmium-193 100\nOsmium-194 1\nIridium-182 1,000\nIridium-184 1,000\nIridium-185 1,000\nIridium-186 100\nIridium-187 1,000\nIridium-188 100\nIridium-189 100\nIridium-190m 1,000\nIridium-190 100\nIridium-192 (73.8d) 1\nIridium-192m (1.4min.) 10\nIridium-194m 10\nIridium-194 100\nIridium-195m 1,000\nIridium-195 1,000\nPlatinum-186 1,000\nPlatinum-188 100\nPlatinum-189 1,000\nPlatinum-191 100\nPlatinum-193m 100\nPlatinum-193 1,000\nPlatinum-195m 100\nPlatinum-197m 1,000\nPlatinum-197 100\nPlatinum-199 1,000\nPlatinum-200 100\nGold-193 1,000\nGold-194 100\nGold-195 10\nGold-198m 100\nGold-198 100\nGold-199 100\nGold-200m 100\nGold-200 1,000\nGold-201 1,000\nMercury-193m 100\nMercury-193 1,000\nMercury-194 1\nMercury-195m 100\nMercury-195 1,000\nMercury-197m 100\nMercury-197 1,000\nMercury-199m 1,000\nMercury-203 100\nThallium-194m 1,000\nThallium-194 1,000\nThallium-195 1,000\nThallium-197 1,000\nThallium-198m 1,000\nThallium-198 1,000\nThallium-199 1,000\nThallium-200 1,000\nThallium-201 1,000\nThallium-202 100\nThallium-204 100\nLead-195m 1,000\nLead-198 1,000\nLead-199 1,000\nLead-200 100\nLead-201 1,000\nLead-202m 1,000\nLead-202 10\nLead-203 1,000\nLead-205 100\nLead-209 1,000\nLead-210 0.01\nLead-211 100\nLead-212 1\nLead-214 100\nBismuth-200 1,000\nBismuth-201 1,000\nBismuth-202 1,000\nBismuth-203 100\nBismuth-205 100\nBismuth-206 100\nBismuth-207 10\nBismuth-210m 0.1\nBismuth-210 1\nBismuth-212 10\nBismuth-213 10\nBismuth-214 100\nPolonium-203 1,000\nPolonium-205 1,000\nPolonium-207 1,000\nPolonium-210 0.1\nAstatine-207 100\nAstatine-211 10\nRadon-220 1\nRadon-222 1\nFrancium-222 100\nFrancium-223 100\nRadium-223 0.1\nRadium-224 0.1\nRadium-225 0.1\nRadium-226 0.1\nRadium-227 1,000\nRadium-228 0.1\nActinium-224 1\nActinium-225 0.01\nActinium-226 0.1\nActinium-227 0.001\nActinium-228 1\nThorium-226 10\nThorium-227 0.01\nThorium-228 0.001\nThorium-229 0.001\nThorium-230 0.001\nThorium-231 100\nThorium-232 100\nThorium-234 10\nThorium-natural 100\nProtactinium-227 10\nProtactinium-228 1\nProtactinium-230 0.1\nProtactinium-231 0.001\nProtactinium-232 1\nProtactinium-233 100\nProtactinium-234 100\nUranium-230 0.01\nUranium-231 100\nUranium-232 0.001\nUranium-233 0.001\nUranium-234 0.001\nUranium-235 0.001\nUranium-236 0.001\nUranium-237 100\nUranium-238 100\nUranium-239 1,000\nUranium-240 100\nUranium-natural 100\nNeptunium-232 100\nNeptunium-233 1,000\nNeptunium-234 100\nNeptunium-235 100\nNeptunium-236 (1.15 × 105 y) 0.001\nNeptunium-236 (22.5h) 1\nNeptunium-237 0.001\nNeptunium-238 10\nNeptunium-239 100\nNeptunium-240 1,000\nPlutonium-234 10\nPlutonium-235 1,000\nPlutonium-236 0.001\nPlutonium-237 100\nPlutonium-238 0.001\nPlutonium-239 0.001\nPlutonium-240 0.001\nPlutonium-241 0.01\nPlutonium-242 0.001\nPlutonium-243 1,000\nPlutonium-244 0.001\nPlutonium-245 100\nAmericium-237 1,000\nAmericium-238 100\nAmericium-239 1,000\nAmericium-240 100\nAmericium-241 0.001\nAmericium-242m 0.001\nAmericium-242 10\nAmericium-243 0.001\nAmericium-244m 100\nAmericium-244 10\nAmericium-245 1,000\nAmericium-246m 1,000\nAmericium-246 1,000\nCurium-238 100\nCurium-240 0.1\nCurium-241 1\nCurium-242 0.01\nCurium-243 0.001\nCurium-244 0.001\nCurium-245 0.001\nCurium-246 0.001\nCurium-247 0.001\nCurium-248 0.001\nCurium-249 1,000\nBerkelium-245 100\nBerkelium-246 100\nBerkelium-247 0.001\nBerkelium-249 0.1\nBerkelium-250 10\nCalifornium-244 100\nCalifornium-246 1\nCalifornium-248 0.01\nCalifornium-249 0.001\nCalifornium-250 0.001\nCalifornium-251 0.001\nCalifornium-252 0.001\nCalifornium-253 0.1\nCalifornium-254 0.001\nAny alpha emitting radionuclide not listed above or mixtures of alpha emitters of unknown composition 0.001\nEinsteinium-250 100\nEinsteinium-251 100\nEinsteinium-253 0.1\nEinsteinium-254m 1\nEinsteinium-254 0.01\nFermium-252 1\nFermium-253 1\nFermium-254 10\nFermium-255 1\nFermium-257 0.01\nMendelevium-257 10\nMendelevium-258 0.01\nAny radionuclide other than alpha emitting radionuclides not listed above, or mixtures of beta emitters of unknown composition 0.01\n1 The quantities listed above were derived by taking 1⁄10th of the most restrictive ALI listed in table 1, columns 1 and 2, of appendix B to §§ 20.1001-20.2401 of this part, rounding to the nearest factor of 10, and arbitrarily constraining the values listed between 0.001 and 1,000 µCi. Values of 100 µCi have been assigned for radionuclides having a radioactive half-life in excess of 109 years (except rhenium, 1000 µCi) to take into account their low specific activity.\nNote: For purposes of §§ 20.1902(e), 20.1905(a), and 20.2201(a) where there is involved a combination of radionuclides in known amounts, the limit for the combination should be derived as follows: determine, for each radionuclide in the combination, the ratio between the quantity present in the combination and the limit otherwise established for the specific radionuclide when not in combination. The sum of such ratios for all radionuclides in the combination may not exceed “1” (i.e., “unity”).","path":["Title 10—Energy","CHAPTER I—NUCLEAR REGULATORY COMMISSION","PART 20—STANDARDS FOR PROTECTION AGAINST RADIATION"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-10.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:09Z","sha256":"8e559a199e6aea6339ad67709a6baea4713089b0aa57f9dccb0253eec1529a4b","source_id":"us-cfr","stale":true,"prev":"us/10-cfr-appendix-b-to-part-20","next":"us/10-cfr-appendix-d-to-part-20"},"notice":"GroundRules: Original legal text. Not legal advice."}