Cal. Health and Safety Code § 114710

As used in this article the following terms have the meanings described in this section. (a) “Department” means the State Department of Health Services. (b) “Environment” means all places outside the control of the person responsible for the radioactive materials. (c) “Field tracer study” is any project, experiment, or study that includes provision for deliberate introduction of radioactive material into the environment for experimental or test purposes. (d) “Person” includes any association of persons, copartnership or corporation. (e) “Radiation,” or “ionizing radiation,” means gamma rays and X-rays; alpha and beta particles, high-speed electrons, neutrons, protons, and other nuclear particles; but not sound or radio waves, or visible, infrared, or ultraviolet light. (f) “Radioactive material” means any material or combination of materials that spontaneously emits ionizing radiation. (g) “Radioactive waste” means any radioactive material that is discarded as nonusable. (h) “Significant” or “significantly,” as applied to radioactive contamination, means concentrations or amounts of radioactive material as are likely to expose persons to ionizing radiation equal to or greater than the guide levels published by the Federal Radiation Council. (i) “Radiological monitoring” means the measurement of the amounts and kinds of radioactive materials in the environment.