The Department of Veterans Affairs performs pre-employment reference checks as an assessment method used in the hiring process to verify information provided by a candidate (e.g., on resume or during interview or hiring process); gain additional knowledge regarding a candidates abilities; and assist a hiring manager with making a final selection for a position. A bachelors degree in a branch of engineering, physical science, or life science that included 12 semester hours in chemistry, including organic chemistry, and 18 additional semester hours of courses in any combination of chemistry, physics, engineering, health physics, environmental health, biostatistics, biology, physiology, toxicology, epidemiology, or industrial hygiene; or.