The first child to test positive for E. coli tied to the Chelsea Gentle Care Child Development Center in Westminster came on May 26 of 2015.
Two days later, three more would come to light, and ultimately state and county health agents would determine as many as 23, including one employee, may have been victims.
Now the parents of those four children, ranging in age from four to six years old, are suing the daycare.
Reached by telephone, Attorney Ron Simon says some of the children spent weeks on dialysis and could have suffered permanent kidney damage as a result of the outbreak.
According to the lawsuit, one child in particular was taken to the emergency room in Carroll County, almost immediately airlifted to Johns Hopkins Hospital in Baltimore and remained hospitalized for a month.
The suit alleges negligence at the daycare in providing safe and sanitary conditions, as well as failing to notify authorities of the illness in a timely manner.
It also challenges the employees' training, supervision and ability to adequately supervise the children there.
After the outbreak, the owner changed the name of the various Chelsea's Gentle Care Centers to Fresh Start Early Learning Centers, but the site of the E. coli contamination is now empty.
ABC2 attempted to reach the owner of the center for comment today, but our message went unanswered.