Hydrogen -3 (Tritium)

Physical Characteristics

  • Half-life: 12.3 years
  • Emissions: Beta particles with a maximum energy of 18.6 keV and an average energy of 5.7 keV.
  • Maximum Range: 4.7 mm in air; 0.006 mm in tissue
  • Fraction transmitted through the dead layer of the skin: none

Dose Rate and Shielding

  • Dose rate to the skin at 10 cm: None
  • Dose rate to epidermal basal cells from skin contamination of 1 mCi/cm2: None
  • Shielding: None needed.
  • Annual Limit on Intake (ALI): 80 millicuries via ingestion, assuming intake as tritiated water. The ingestion of one ALI will produce a dose of 5 rem.


Liquid scintillation counting is the preferred method for detecting H-3. Most G-M detectors will not detect the presence of H-3.


H-3 contamination cannot be detected with a G-M meter, and special precautions are needed to keep the work environment clean. The regular use of wipe testing, using a liquid scintillation counter, is the only way to insure that your work space does not contain contamination.

Waste Disposal

  • Solid Wastes/Liquid Scintillation Wastes: through the Off-Site Radioactive Waste Disposal Program
  • Liquid Wastes: through the Sewer Disposal Program. The laboratory disposal limit for H-3 is 3 mCi per month.