Radionuclide Safety Data Sheets

Carbon - 14 (14C)


Beta Energy: 156.4 keV (maximum)
49.5 keV (average)(100%)

Physical Half-Life: 5730 years
Biological Half-Life: 10 days (Whole Body)
Effective Half-Life: 10 days (Bound / Whole Body)
Effective Half-Life: 40 days (Unbound / Bone)
Specific Activity: 4460 millicuries / gram
Maximum Beta Range in Air: 25.400 cm = 10.0 inches
Maximum Beta Range in Water / Tissue: * 0.030 cm = 0.012 inches
Maximum Range in Plexiglas / Lucite / Plastic: 0.025 cm = 0.010 inches
* [Fraction of C-14 beta particles transmitted through dead layer of skin (0.007 cm) = 17%]



Committed Dose Equivalent (CDE):
(Fat Tissue)
2.08 mrem / uCi
(ingestion / inhalation / puncture)
Committed Effective Dose Equivalent (CEDE): 2.50 mrem / uCi (ingestion)
Annual Limit on Intake (ALI): 2 mCi (ingestion: labeled organic comp'd)
2000 mCi (inhalation: carbon monoxide)
200 mCi (inhalation: carbon dioxide)

* [1.0 ALI = 2 mCi (ingested C-14 organic comp'd) = 5,000 mrem CEDE]

SHIELDING: none required (< 3 mm plexiglass)



PERSONAL RADIATION MONITORING DOSIMETERS (Whole Body Badge or Finger Tabs): Not Needed (beta energy too weak).

Half-Value Layer (Water): 0.005 cm = 0.05 mm
Tenth-Value Layer (Water): 0.017 cm = 0.17 mm

Dose Rate from a 1.0 millicurie isotropic point source of C-14:

1.0 cm 1241.4
2.0 cm 250.4
15.2 cm 0.126
20.0 cm 0.0046



Derived Air Concentration (DAC):
1.0E-6 uCi/mL (labeled compound)
9.0E-5 uCi/mL (carbon dioxide)
7.0E-4 uCi/mL (carbon monoxide)
Airborne Effluent Release Limit: 3.0E-9 uCi/mL (labeled comp'd)
3.0E-7 uCi/mL (carbon dioxide)
2.0E-6 uCi/mL (carbon monoxide)
* Applicable to the assessment & control of public doses (10 CFR 20.1302). If this concentration was inhaled or ingested continuously over 1-year would produce a TEDE of 50 millirem.

Urinalysis: Not required; however, may be requested by RSS personnel after a C-14 radioactive spill or suspected intake.

Unrestricted Area Removable Contamination Limit: 1,000 dpm / 100 cm2
Container Labeling Quantity [10 CFR 20.1905]: > 1,000 uCi



Organic Compounds - most organic compounds are NOT very volatile under normal circumstances and the probability of these being inhaled as vapors is therefore small. In circumstances where such substances are inhaled it would be prudent to assume that once they enter the respiratory system they are instantaneously and completely translocated to the systemic circulation without changing their chemical form.

Gases - the inhalation of CO and its retention in body tissues has been studied extensively. Since gas has a relatively low solubility in tissue water, doses due to absorbed gas in tissues are insignificant in comparison with doses due to the retention of CO bound to hemoglobin. CO2 in the blood exists mainly as a bicarbonate.

Carbonates & Carbides - It is assumed that inhaled or ingested C-14 labeled compounds are instantaneously and uniformly distributed throughout all organs & tissues of the body where they are retained with a biological half-life of 40 days.