The maximum permissible occupational dose limits for adult radiation workers are listed below. The limits apply to any combination of dose received from external or internal exposure. These limits do not apply to doses received from background radiation or from medical tests or procedures. An adult radiation worker is defined as an individual 18 years of age or older. Iowa child labor laws prohibit individuals under the age of 18 from working with certain types of radioactive materials or in certain areas where occupational radiation exposure may occur. It is EHS policy that minors are not normally permitted to work with sources of ionizing radiation at The University of Iowa. For further information regarding this policy, please contact EHS at 335-8517.