World Health Organization

The World Health Organization (WHO) is the United Nations specialized agency for international public health, established in 1948 and headquartered in Geneva, Switzerland. It leads global efforts to promote health, set evidence-based norms and standards, provide technical guidance, monitor health trends, and support preparedness and response to public health emergencies.

For chemicals and environmental health, WHO develops science-based guidance on chemical risks, including Air Quality Guidelines and Guidelines for Drinking-water Quality; hosts the International Programme on Chemical Safety (IPCS), which produces toxicological assessments (e.g., Environmental Health Criteria), harmonizes risk-assessment methods, and supports poison centres; and publishes the WHO Recommended Classification of Pesticides by Hazard. With FAO, WHO underpins the Codex Alimentarius and convenes expert committees such as JECFA and JMPR that assess food additives, contaminants, veterinary drug residues, and pesticide residues. Through its cancer research arm, the International Agency for Research on Cancer (IARC), it evaluates carcinogenic hazards of chemicals, mixtures, and exposures. WHO also helps countries manage chemical incidents under the International Health Regulations and supports implementation of global chemicals initiatives, including the Minamata Convention on Mercury and SAICM.