National attention has focused in recent months on the widespread exposure of residents of Flint, Michigan, to water supplies contaminated by lead. But this is not the first time a lead poisoning epidemic has gained national attention. That distinction goes to Baltimore, Maryland, in the early 1930s. That incident demonstrated the vital roles non-experts sometimes play in discovering and drawing attention to public health problems.

On June 19, 1932, relatives brought a young girl to Johns Hopkins Hospital after she started convulsing and fell first into a stupor and then into unconsciousness. A tuberculin test indicated tubercular meningitis, but a lumbar puncture test—a procedure that tests spinal fluids– suggested possible lead poisoning. Such confusion over a diagnosis showed the diagnostic challenges of the era. The symptoms of acute lead poisoning included encephalopathy, convulsions, colic, vomiting, and loss of motor control. But those symptoms were not specific to lead poisoning. Moreover, diagnostic tests and indicators such as spinal taps, x-rays, blood cell stippling, and gum discoloration were unreliable because testing technologies were relatively new and because individuals presented varying reactions to excessive lead exposure. Finally, Americans of the era typically were exposed to lead over the course of their lives, which meant that its mere presence in the body was not usually considered worrisome.

To determine a case of lead poisoning, health experts looked to possible sources of exposure in an attempt to triangulate a diagnosis, calling for investigations of homes for signs of peeling paint, crumbling plaster, and painted toys and furniture, any or all of which could contain lead. In Baltimore, Miriam Brailey, an intern from Johns Hopkins, set out to try and determine what afflicted the girl who had been brought to the hospital. At the girl’s house, Brailey spoke with the child’s mother. The mother did not seem to have tuberculosis, as she likely would have if her daughter were ill from the disease, but she did seem “confused mentally” and who referred Brailey and her questions to a neighbor named Melrose Easter.

Easter was a coal ship loader who had moved from West Virginia to Baltimore sometime around 1920 as part of the Great Migration of African Americans out of the rural South. But despite holding down a job that called mostly for performing manual labor, he was the son of a military and railroad engineer and told Brailey he had studied at the Tuskegee Institute for “a year or so” and had considered studying medicine before his confusion over the complexities of the circulatory system led him to abandon the plan. After showing Brailey around the sick girl’s home and confirming that there was no loose plaster, fresh paint, or other obvious potential source of lead poisoning, Easter suggested another possibility. He said people in the neighborhood had been burning discarded wooden battery casings in their stoves, and he wondered if the “vapors” from them had made the girl sick.

Brailey’s impression of Easter oozed with unflattering stereotypes, as she reported that he was a “large Negro” whose “eyes were bloodshot and whose breath was strong with whisky,” and she concluded that his notions reflected the “piety of his race.” But she followed up on Easter’s hunch, tested the wooden casings, and found that they were indeed saturated with lead. And Brailey gave credit where it was due. When Baltimore’s health commissioner, Huntington Williams, drafted a medical article about the lead poisoning epidemic, which ultimately affected about forty children, almost all of whom were poor and black, he left Easter out. But Brailey insisted that she deserved none of the praise Williams accorded her. “It is very kind of you to link me at all with the storage battery situation,” Brailey told Williams, but “old Melrose Easter was the man with the idea.”

After discovering the source of the lead, public health officials turned their attention to how families came into possession of the casings and found that junk dealers who recycled lead batteries gave away the wooden battery casings to locals desperate for fuel during the Depression. Armed with this knowledge, the city of Baltimore stopped junkyards from giving away casings, the local Family Welfare Council provided families with alternative fuel instead, and Baltimore emerged as the most proactive city in the country in grappling with the potential of lead poisoning among the citizenry. Indeed, Baltimore’s example and alerts from public health officials such as Huntington Williams drew attention to similar problems in other cities in the United States.

But it was no single individual or agency bureaucracy that discovered the cause of what was poisoning the children of Baltimore. It was instead the working-class people such as Melrose Easter who discovered it, thanks to their knowledge and understanding of the environmental health dangers that chronically plagued them, their neighborhoods, and their families. As the lead water crisis in Flint continues to unfold, it is heartening to see some recognition among public health officials of the need to take non-expert community knowledge seriously, even as well-deserved praise is accorded to key scientists such as Mona Hanna-Attisha, the pediatrician who first alerted authorities to abnormally high blood lead levels in Flint’s children, and Marc Edwards, the Virginia Tech engineer who did much to show how the poisoning had happened.”

Many stories of public health discoveries are indeed stories of the applied genius of medical experts. But as the Baltimore lead poisoning epidemic of 1932 demonstrated, those discoveries are almost always at base the product of many people, including those rarely considered to be scientific or medical experts.