At least 10 people lost their lives and 21 others were injured when a fire erupted on an oil tanker undergoing repairs in western Indonesia early Wednesday.

The blaze started around 4:30 a.m. local time aboard the Indonesian-registered MT Federal II while it was docked for maintenance at a shipyard on Batam Island, near Singapore. According to local police chief Zaenal Arifin, sparks inside one of the ship’s storage areas are believed to have triggered the fire. It took firefighters about an hour to bring the flames under control.

Those injured were rushed to nearby hospitals, and authorities have begun an investigation to uncover the cause of the incident. The tanker was not carrying oil at the time, as it had been emptied ahead of repair works, Arifin confirmed.

This marks the second deadly fire involving the same vessel in less than five months. In June, a similar explosion on the Federal II killed four workers after residual gas ignited during maintenance. Two shipyard safety staff were later named as suspects in that case.

Officials say the latest tragedy highlights persistent safety challenges in Indonesia’s ship repair industry, with investigators now examining whether proper safety procedures were followed during the operation.