Beyond the hospital gate: a One Health narrative review of health care waste in Nigeria and its risks to workers, communities and the environment

The harm from health care waste does not stop at the ward. This narrative review brings together, from a One Health perspective, published Nigerian evidence on how health care waste is generated, segregated, treated and disposed of, who is exposed in the process, and what is known of its effects on communities and the environment. PubMed, the Directory of Open Access Journals, African Journals Online and the web were searched in October 2026, and 30 studies published between 2006 and 2026 were included. Health workers generally knew the principles of segregation, but practice lagged: in one hospital 21.7% always used colour-coded containers, and compliance was lowest for pharmaceutical waste. Written procedures, budgets and trained staff were present in a minority of facilities, and most waste was burned in pits, in the open or in small incinerators. Waste handlers were often injured, seldom reported injuries and were rarely vaccinated against hepatitis B, and workers exposed to incinerator emissions had higher blood levels of cadmium, mercury, lead and arsenic. Beyond the facility, studies found polycyclic aromatic hydrocarbons and toxic metals above international limits in air near incinerators, elevated lead in farmland where hospital waste was burned, arsenic and lead in a river below a teaching hospital, drug residues in nearby water, and antibiotic-resistant bacteria in hospital waste water. No facility in a Lagos study treated waste containing antimicrobials separately. Health care waste should be managed as a One Health responsibility, with procedures and budgets in every facility, protection for waste workers, control of pharmaceutical waste and waste water, and a move from burning to safer central treatment.