IOHA was established to improve, promote and develop occupational hygiene worldwide through its member organisations, and to improve and maintain a safe and healthy working environment for all. From its creation in 1987, IOHA has grown to 33 member organisations, representing over 20,000 occupational hygienists worldwide. IOHA provides an international voice of the occupational hygiene profession through its recognition as a non-governmental organisation (NGO) by both the ILO (International Labour Organisation) and WHO (World Health Organisation).