WUHAN -- Over 30 people have been punished after an investigation into a deadly power plant explosion in August last year, authorities said Thursday.

Fourteen other people are awaiting trial or are under investigation.

On Aug 11, 2016, 22 people died and four were seriously injured when a blast ripped through a power plant in the city of Dangyang in central China's Hubei Province. Workers were testing thermo-power facilities when the accident happened.

Yu Huaqiang, general manager of Huaqiang Chemical Group, the parent company, and eight others are currently awaiting trial.

"The shoddy quality of a pipe nozzle caused a leak which ultimately led to the blast," according to a statement from the Hubei Provincial Work Safety Bureau.

The factory design did not meet safety standards, and the control room was not properly reinforced to protect people inside, it said.

Workers did not follow standard procedure when testing the pipes, and supervision was lacking, it said.