EXTERNAL RADIATION HAZARDS AND SHIELDING:

The Maximum range of these betas is – 1 ft in air and 0.0065 in (0.17 mm) in glass. The external hazard of this isotope is minimal, e.g., the glass vial holding the isotope will provide sufficient shielding to stop the betas. If skin is uniformly contaminated with C¹⁴, 1 microcurie/ cm² will deliver a dose of 1,100 mrems/hr to basal cells of the skin. (Porter Consultants to NRC).

HAZARDS IF INTERNALLY DEPOSITED:

The ALARA Annual Limit of Intake (ALI) which will result in a whole body exposure of 500 mrem or maximum recommended doses (by the NCRP) to the hematopoetic or speratolgonial stem cell nuclei is as follows:

Whole body 200 m Ci (inorganic, soluble)
Stem Cell Nuclei 1000 m Ci (CdR)
Stem Cell Nuclei 88 m Ci (other DNA and RNA precursors)

DOSIMETRY AND BIOASSAY REQUIREMENTS:

Film badges and dosimeter rings are not appropriate for monitoring C¹⁴ exposure.
Urine assays may be required after spills or contamination incidents.

SPECIAL PROBLEMS AND PRECAUTIONS:

1. Always wear protective gloves to keep contamination from skin. Change gloves often.
2. C¹⁴ beta particles have very low energies. G.M. survey meters are not very efficient at such energies. Smear surveys are required.
3. All waste in a C¹⁴ work area is considered to be contaminated. Keep work areas free of unnecessary items. Segregate wastes to those with H³ and C¹⁴ only.
4. Limit of soluble waste to sewer is 100 microcuries/day per lab