Undergraduate and Graduate Education: Major study -- safety or occupational health fields (safety, occupational health, industrial hygiene), or degree in other related fields that included or was supplemented by at least 24 semester hours of study from among the following (or closely related) disciplines: safety, occupational health, industrial hygiene, occupational medicine, toxicology, public health, mathematics, physics, chemistry, biological sciences, engineering, and industrial psychology. Certification as a Certified Safety Professional (CSP), Certified Industrial Hygienist (CIH), or Certified Health Physicist (CHP), or similar certification that included successful completion of a written examination meets the requirements for GS-5.