On February 1902, an 8-bed hospital called the Baguio Sanatorium - with a pioneering staff composed of American physicians, army nurses and hospital corpsmen headed by Dr. J. B. Thomas -- was established. It was set up as part Bureau of Civil Hospitals and Sanatorium of the Philippines primarily to serve the health needs of government officials, employees and American soldiers on vacation amidst pine trees in the cool climate of Baguio. A month later, the construction of a 15-bed capacity hospital consisting of six, three-room cottages was started.

This organization was found as The Industrial Nursing Unit of the Philippine Nurse's Association in 1950 and Ms. Magdalena Valenzuela was credited as the founder. The first chairperson was Ms. Perla Gorres. It became the Occupational Health Nurse's Association of the Philippines (OHNAP) on Sept. 10, 1969 with Ms. Annie Santos as the first president. It was registered with the Securities and Exchange Commission under registry #88653 on Sept. 25, 1979. It is probably the only nursing professional organization that confers a certified title to qualified members.