Six foreign and local workers were injured – three critically – when welding flakes set off a massive explosion on Tuesday morning at a factory in Taiwan.

At around 10am on May 28, the Pingtung County Fire Bureau was notified of a gas explosion, followed by a fire breaking out at a factory of Xiang Ming International in Pingnan Industrial Park in Fangliau Town of Pingtung, the United Daily News reported.

The fire was small-scale and officers put it down under 10 minutes. However, the gas explosion injured six men.

Three workers were critically injured, including a Taiwanese man, 42, a 34-year-old Vietnamese with 70% burns, and a 32-year-old Vietnamese man with 30% burns.

The remaining two Taiwanese men and a Vietnamese man were referred to Antai Tian-Sheng Memorial Hospital for treatment for minor injuries.

Preliminary investigations found that workers were doing gas welding. However, the sparks ignited some flammable packages nearby, which burned a soft pipe of acetylene gas and caused the gas explosion.

The six workers had been distracted by trying to extinguish the minor fire at the scene without realizing a bigger threat from the leakage.