​Assoc Prof Ponampalam has spent most of his working years at Singapore General Hospital (SGH) as an Emergency Physician since 1995. Soon after he pursued his sub-speciality interest in Toxicology and was given the Health Manpower Development Program (HMDP) Award from Ministry of Health (MOH) for training in Emergency Toxicology in USA in 1998. Upon his return he has contributed to the hazardous materials disaster preparedness program both nationally and at the hospital level. He has been primarily responsible for having trained the personnel who make up the chemical casualty decontamination teams at SGH.

He was instrumental in having developed programs in Hazardous Materials Life Support (HMLS) courses which have been endorsed by the MOH as a national training program for emergency responders dealing with chemical disasters. He currently sits on MOH committees advising on toxicology matters. He currently chairs the Clinical Practice Guidelines in Poisonings work group and is a member of the Toxicology Advisory Team (TAT) which advises MOH on medical management aspects of hazardous material incidents. Academy of Medicine Singapore has also sought his expert views on toxic exposure management. Academically he is a senior clinical lecturer at National University of Singapore (NUS) medical faculty and adjunct lecturer at Nanyang Polytechnic (NYP) teaching nurses in the advanced diploma in nursing course.