52 Radioactive Materials Safety Manual Environmental Health and Safety 55Fe IRON-55 Half - Life Phyisical Biological Effective 986.2 days 800 days 441.7 days Radiation Emitted Type Energy (max) Range (max) Gamma 5.9 keV (24.5%) 6.5 keV (3.3%) External Hazard None Internal Hazard Effective Committed Dose Ingestion Inhalation Equivalent per Unit Intake: 0.6 mrem/mCi (1.64 x 10-10 Sv/Bq) 2.7 mrem/mCi (7.26 x 10-10 Sv/Bq) Annual Limit on Intake: (ALI)* 9 mCi 2 mCi *ALIs expressed are from Appendix B, Table 1 – Iowa Administrative Code 641.40 (136C). Special Considerations • 55Fe emits very low gamma rays which can be difficult to detect with a survey meter. Radiation Safety Practices • Dosimetry – None • Bioassay – Required for individuals involved in spills or other incidents where significant uptake is suspected. • Shielding – None • Surveys – Wipes analyzed in an LSC or gamma counter. • General – Because 55Fe contamination is particularly difficult to detect, extra care should be taken in observing contamination control practices.