The facility in Town and Country, a St. Louis suburb, has been shut down while the problem is investigated, the St. Louis Post-Dispatch reported. The patients received the cleaning solution, which may have been bleach, on Monday.
U.S. Renal Care, which operates the dialysis center on the grounds of the Cedars of Town and Country nursing home, said seven patients were hospitalized, but all are expected to recover.
"We can confirm that a cleaning solution, commonly used in dialysis, was inadvertently added into our water supply due to a one-time human error," Tom Weinberg, Renal Care spokesman, said.
Dialysis machines function as external kidneys. Patients' blood is sent through the machine while purified water is pumped through the filter.
"Dialysis is scary to begin with. You have blood circulating out of your body," said Lori Hartwell, founder of the Renal Support Network. "If there is one lesson here, patients and family members and staff need to constantly make sure that safety is the highest factor."