Aug 21 • HAC

Chicago Backflow Incident of 1933

The Chicago Backflow Incident of 1933 resulted in one of the deadliest backflow/cross connection events in modern recorded history. This event lead to almost 100 people losing their lives due to infection.

The Backflow Disaster

Two of the main hotels housing visitors lacked sufficient cross-connection protection, leading to a catastrophic outbreak of Amebic Dysentery. The tainted water affected nearly every occupant of these hotels, with an estimated 1,400 people falling ill and 98 tragically losing their lives. Given the time frame and limited information sharing, it’s likely these numbers were just a fraction of the actual cases.

The disaster's impact was exacerbated by the incubation period of Amebic Dysentery, which ranges from 12 to 30 days. As a result, symptoms did not appear until visitors had returned to their homes, spreading the outbreak far and wide. Despite the growing number of affected individuals flooding local hospitals, the local government attempted to suppress the news, fearing it would deter future visitors during the remaining three months of the Fair.

According to a U.S. Health Services report at the time,
"An epidemic of amebic dysentery had its origin in Chicago during the summer and fall of 1933. It was the first recognized water-borne outbreak, and the only known extensive epidemic of this disease in a civilian population."

The Importance of Protecting Our Water Supply

This tragic event underscores the critical importance of protecting our water supply—a responsibility that remains as vital today as it was then. Fortunately, modern plumbing systems are required to meet the rigorous standards set by the Clean Water Act, EPA regulations, and best practices outlined in plumbing codes.

Backflow preventers serve as our first line of defense against deadly cross-connections. Although not universally enforced across the U.S., ongoing education and improvements in plumbing systems are essential to preventing such disasters in the future.

This history serves as a powerful reminder of the stakes involved and the progress we've made, but also of the work still needed to safeguard public health through proper cross-connection control.

Updates

HAC Learning now offers the 2-hr Resiliency Overview course (self-paced, online) required by the Texas Commission on Environmental Quality. Register here. 

Do you need the class in bulk? Reach out to us HERE. We will provide you with a "Seat Manager" account at no cost where you will have access to all your purchased seats and manage student enrollments and training. Think of it as your own personalized Learning Management System for your organization. 

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