A group of seven defendants who were implicated in a deadly kidney dialysis incident that killed nine patients in Vietnam have been sentenced.

On May 29, 2017, a group of 18 patients suffered severe symptoms including anaphylactic shocks, breathing problems, sudden loss of blood pressure and stomach problems while receiving kidney dialysis at the Hoa Binh General Hospital, Viet Nam News reported. Nine patients died as a result of the incident.

According to court documents, Bui Manh Quoc,  the director of Tram And Water Treatment Company, was in charge of maintaining the reverse osmosis filter system on the machines and had not purified the water supply tubes, which left chemical residue in the equipment.

Tran Van Son, the person in charge of supervising and maintenance of the filter system did not check up on the equipment throughout the course of the incident. Nephrologist Hoang Cong Luong allowed the dialysis treatment to continue without checking the systems properly.

The People’s Court of Hoa Binh City sentenced the three plus four others on January 30. Quoc was jailed for 54 months; Son and Luong were both sentenced to 42 months of jail time. Four others were sentenced to between 30 and 36 months.

Hoa Binh General Hospital and Thien Son JSC, the company responsible for maintaining water filters at the hospital, were also ordered to pay 1.7 billion Dong (US$73,000) and 728 million Dong respectively.