High school students should study mathematics, health and the sciences. A high school diploma or equivalent is required. Students must complete a bachelor of science (BS) degree usually in environmental and public health, industrial hygiene, chemistry, physics, chemical, mechanical, or sanitary engineering, or biology from a program approved by the American Board of Industrial Hygiene to receive certification. Industrial hygienists can qualify for two categories of certification – Certified Industrial Hygienist (CIH) or Industrial Hygienist in Training (IHIT) – through the American Board of Industrial Hygiene. Individuals who are Certified Industrial Hygienists have completed special education, experience, and proven professional ability in the comprehensive practice or chemical practice of industrial hygiene.