IOWA CITY (AP) — A nursing assistant who worked while sick likely brought the coronavirus into an Iowa nursing home where 15 residents later died, according to a new state inspection report.

The employee was allowed to keep working because the Crystal Heights Care Center in Oskaloosa failed to adequately screen staff for symptoms at the beginning of their shifts, inspectors wrote.

Rather than have an employee take temperatures and ask health questions, those arriving were “permitted to self-screen” without independent monitoring, their investigation found.

“The lack of effective screening resulted in a staff member being able to work while knowingly ill and failing to report it,” the inspection report said. “The spread of COVID-19, once introduced to the facility, was rampant.”

A total of 79 residents and staff members at the home have tested positive for the virus, one of the state’s largest nursing home outbreaks to date, the Iowa Department of Public Health says.

Fifteen residents died and the other 64 who were infected have recovered. Among the dead was 86-year-old Roger Coe, a U.S. Air Force veteran and grandfather whose daughter has said she believes his death was preventable.

The Iowa Department of Inspections and Appeals cited the facility last week for its alleged screening failure and proposed a $8,750 fine, which has been suspended pending potential further action from federal regulators.

Crystal Heights Care Center administrator Jay Wills said Monday that the home is disputing the violation and would appeal. He said the department previously approved its plan to screen employees, including the use of a self-assessment.