An unidentified chemical worker has died in a tank truck explosion in the northwestern province of Gansu, local authorities said.

The tank trailer, which was carrying 58 cubic meters of liquefied petroleum gas, exploded near an LPG station in Xigu district of the provincial capital Lanzhou, the city’s safety administration said. It added that the blast occurred during nitrogen replacement.

The safety administration said an investigation was underway, and that no toxic gas leak was detected.