The state Department of Public Health has opened an investigation into a Rocky Hill nursing home after two residents were diagnosed with Legionnaires’ disease and one of them died.

DPH officials said they are coordinating a review with management at the facility, Apple Rehab. The department was notified on July 17 that a resident at the nursing home had contracted the disease.

Legionnaires’ is a type of pneumonia caused by ingesting water that contains Legionella bacteria. The bacteria are normally found in freshwater lakes and streams but can grow in man-made water systems. It was detected in samples tested at Apple Rehab, DPH officials said.

The health department did not identify the residents who contracted the disease.

“DPH and Apple Rehab personnel are continuing a joint investigation to identify the environmental source of Legionella bacteria to protect patients, staff and visitors,” DPH officials said in a statement Friday. “DPH personnel have reviewed Centers for Disease Control and Prevention recommendations and discussed implementation with Apple Rehab administrators.”

The nursing home’s water system has undergone chlorine treatment and further testing is underway, they said. Patients, staff and visitors have been notified of the problem.

“Moving forward, DPH will be monitoring Apple Rehab’s water quality and disease prevention measures,” the department said.

Records show Apple Rehab was fined twice in 2018 and twice in 2017 for deficiencies in care. The penalties amounted to $19,702 in 2018 and $33,745 in 2017.

The nursing home received a two-star rating – below average – by Medicare. The rating is based on heath inspections, staffing and quality measures.