On 26 February 1884 an outbreak of arsenic poisoning linked to milk distribution in Bradford, West Yorkshire, became one of the earliest well-documented cases of mass food contamination in Britain. Contemporary investigations connected the illness to milk churns that had been rinsed with water contaminated by arsenic used in a nearby dye works. The incident highlighted evolving public health risks in industrializing towns and contributed to later reforms in food safety oversight. Context and outbreak: Bradford in the 1880s was a rapidly industrializing textile town with dense working-class neighborhoods and many small-scale commercial milk suppliers. In late February 1884 multiple households reported sudden vomiting, diarrhea, and collapse among family members; several deaths occurred within days. Medical officials and local reporters quickly suspected a shared food source. Patterns in where the sick lived and what they had consumed pointed to milk distributed by particular dealers rather than to a contagious disease. Investigation and findings: Local health authorities and journalists traced the contaminated supply to milk churns returned from a suburban dairy. Investigation revealed that some churns and other dairy equipment had been rinsed in river water tainted by effluent from nearby industrial operations. At least one dye works in the district used arsenical compounds in textile-processing vats and disposed of residues into waterways or onto ground used for cleaning equipment. Chemical analyses of samples taken at the time reportedly found arsenic consistent with the symptoms seen in victims. The scale of exposure varied by household depending on the amount and source of milk consumed. Casualties and social impact: Contemporary reports estimated around 20 deaths and many more cases of serious illness, though precise casualty figures differ among period accounts. The victims included children and adults; children were especially vulnerable because smaller doses produced more severe effects. The shock of a widely distributed, invisible contaminant in a staple food aroused public alarm and intense scrutiny of industrial waste practices and dairy hygiene. Aftermath and significance: The Bradford episode did not immediately produce a comprehensive national food safety regime, but it fed into an expanding public health discourse about industrial pollution, municipal responsibility, and food-supply regulation. Local authorities increased inspections, and the case reinforced calls for cleaner water sources, safer disposal of industrial chemicals, and stricter controls on milk handling—issues that would be addressed more systematically in subsequent decades through public health legislation and improvements to urban sanitation. Limitations and sources: Surviving accounts of the Bradford incident come from contemporary newspapers, municipal health reports, and later historical summaries of industrial public health. Exact numbers and some specifics (for example, the precise point of entry of arsenic into the milk supply and the full list of implicated industrial operators) are variably reported in period sources; historians treat certain details as probable rather than conclusively documented. The broad conclusion—that arsenic contamination of milk in Bradford in February 1884 caused a lethal outbreak and helped draw attention to industrial contaminants in food—is supported by multiple period investigations and later public health histories. Legacy: The Bradford milk poisoning is cited in histories of food safety and public health as an early demonstration of how industrial pollutants could enter everyday foodstuffs and harm urban populations. It remains a cautionary episode about the intersection of industrial waste, municipal oversight, and the vulnerable food supply networks of rapidly growing 19th-century towns.