Twenty-eight people were infected at a private pool party in Hillsdale County, Michigan, in July.

Rebecca Burns, environmental health protection direction for the Branch-Hillsdale-St. Joseph Community Health Agency (CHA), told Hillsdale.net the problem resulted from improper operation of a system that uses salts to create chlorine to disinfect the pool.

Burns said the owner was not running the system enough for the heavy load of people at the three-day party, “so the residual chlorine was not there.” She suggested owners either are not instructed on proper use, including how to keep chlorine levels safe, so her department wants to work with pool companies.


“You know how kids are in pools … there were a lot of organics going into that pool,” Burns said, adding that about one-half the people at the party got the disease.


CHA Prevention Services Director JoAnn Wilczynski said after officials checked with those infected, “the only commonality was the ingestion of pool water.”