BEIJING, China (AP) — Scaffolding at a construction site in eastern China collapsed into a deadly heap on Thursday, sending iron pipes, steel bars and wooden planks tumbling down on about 70 workers in the country’s worst work-safety accident in over two years.

At least 67 people were killed by the collapse of the work platform at a power plant cooling tower that was under construction, state media reported. Two others were injured and one worker was missing.

The cooling tower was being built in the city of Fengcheng in Jiangxi province when the scaffolding tumbled down at about 7:30 am, an official with the local Work Safety Administration who would only give his surname, Yuan, said by telephone.

The reported death toll suggested that nearly all the construction workers at the cooling tower perished. Close to 70 people were working at the site when the scaffolding gave out, according to local media reports.

About 500 rescue workers, including paramilitary police officers, were digging through the debris with their hands, according to state broadcaster CCTV. It showed debris strewn across the floor of the cavernous, 165-meter (545-foot) -high concrete cooling tower, in the middle of which stood an unfinished structure.

Rescue dogs were seeking to locate survivors or the bodies of victims, while backhoes shifted wreckage to the margins of the massive round tower.

Chinese President Xi Jinping urged local governments to learn from the accident and hold those responsible accountable. He said that in the wake of recent work accidents, the State Council, China’s Cabinet, should carry out thorough inspections of work sites to reduce risks.

China has suffered several major work-safety accidents in recent years blamed on weak regulatory oversight, systemic corruption and pressure to boost production amid a slowing economy.

Also Thursday, Yang Dongliang, a former head of the State Administration of Work Safety, stood trial in a Beijing court for allegedly accepting US$4.3 million in bribes between 2002 and last year, as he rose through the ranks as an official in Tianjin before joining the regulatory agency.

Yang was sacked in August 2015 in connection with a massive explosion at an illegal chemical warehouse in the northern port of Tianjin that killed 173 people, most of them firefighters and police officers. The head of a logistics company was also handed a suspended death sentence over the case.

Earlier this month, 33 miners were killed in a gas explosion at a coal mine in Chongqing in China’s southwest. In 2014, a dust explosion at a metal production workshop killed 146 people.

Other accidents blamed on lax safety standards in recent years have also caused significant fatalities.

In June 2015, 442 people were killed in the capsize on the Yangtze River of a modified cruise ship blamed on poor decisions made by the captain and crew, while 81 people were killed in December when an enormous, man-made mountain of soil and waste collapsed on nearly three dozen buildings in the southern manufacturing centre of Shenzhen.

Construction of the 1,000-megawatt coal-fired power plant at the centre of Thursday’s accident began in Fengcheng in late 2015 and was expected to be finished in November 2017. Provincial officials held a televised news conference late Thursday at which they bowed to express condolences to the workers’ families.

The cause of the collapse is under investigation.

Hundreds of coal-fired power plants are under construction in China.

Beijing has vowed to solve a looming problem of power oversupply and cap greenhouse gas emissions in the medium term, but economic planners said earlier in November they intend to boost coal power generation capacity by a fifth over the next five years, or the equivalent output of hundreds of new coal-fired plants.