This study investigated occupational risk factors and exposure–response relationships for airway disease among health workers (HWs) exposed to cleaning agents in two tertiary hospitals in South Africa and Tanzania. Previous studies have demonstrated an association between asthma or respiratory symptoms and exposure to broad categories of cleaning-related exposures in healthcare settings. However, few studies have identified the specific cleaning agents responsible for asthma and other health outcomes. Products used for medical instrument cleaning and disinfection such as glutaraldehyde, orthophthalaldehyde (OPA) and quaternary ammonium compounds (QACs) have been implicated in the causation and exacerbation of work-related asthma (WRA) and upper airway outcomes such as rhinitis.