Indian authorities were investigating possible negligence after 18 hospital patients died when rainwaters from massive floods in southern Tamil Nadu state knocked out generators and switched off ventilators.

The patients were in the intensive care unit at MIOT International hospital in the state capital of Chennai when floodwaters seeped into the room with the generators, cutting off power to the building and the ventilators last week, the state health secretary said Saturday.

The worst flooding in a century in Tamil Nadu has left more than 280 people dead since November. In the deluge last week, authorities turned off power in some areas to prevent electrocutions that were blamed for several deaths. Although floodwaters have begun to recede, vast swaths of Chennai and neighboring districts were still under 8 to 10 feet of water, with tens of thousands of people in state-run relief camps. - AP