Dr. Singal had a long and illustrious career notable for his scientific achievements in occupational health. His public health career began in 1975 as an Epidemic Intelligence Service (EIS) Officer at the Kentucky Department of Health Services. In 1977, he transferred to the National Institute for Occupational Safety and Health (NIOSH) where he remained for the duration of his career. He served in many official capacities in the Hazard Evaluation and Technical Assistance Branch; however, none convey his impact on the countless number of individuals he informally educated and mentored at NIOSH and throughout the world.

He was an accomplished scientist and well recognized for his dedication to the field of occupational health. He was the principal author of the 1989 Exxon Alaskan oil spill report and the only comprehensive study of the work-related health effects among oil spill clean-up workers. He played an integral role in a groundbreaking investigation of the workplace health effects of indoor environmental quality (IEQ) and the development of a model for future IEQ investigations, which is used throughout the world today. He wrote about topics such as trichinosis and malaria outbreaks, psychogenic illness, chemical neuropathy, and cancer clusters in the workplace. He personally provided service to thousands of workers through identifying workplace hazards and providing practical recommendations to prevent occupational disease. He shared his knowledge in medicine, epidemiology, scientific ethics, and occupational health practice, and was committed to superior teaching, work performance, and leadership.

Dr. Singal participated in many local, national, and international activities including conducting lectures to medical students on the role of the primary physician in occupational health, teaching an occupational epidemiology workshop to occupational medicine fellows in Taiwan, volunteering with the International Medical Corps in Bosnia, and preparing testimony for standard-setting hearings. He is well published in the scientific literature, received specialty board certification in both general preventive medicine and occupational medicine, and was affiliated with numerous professional organizations throughout his career.

For 25 years, Dr. Singal showed unequaled professionalism and dedication to occupational health research, teaching, and public health service. His work has contributed to the training of occupational health professionals, improved the scientific understanding of occupational disease, and facilitated the control of hazardous exposures in the workplace. After retiring from NIOSH, he remained active in public health through teaching as well as providing scientific service to universities and peer-reviewed journals. Dr. Singal's diligence, integrity, intelligence, and foresight are a model for others in public health and elsewhere.