The death toll from a construction accident at a power plant in China last week has risen to 74, with 13 people being detained by Chinese authorities as a result of the ongoing investigation into the cause of the disaster.

Most of the deaths at the site of the coal-fired power plant under construction in the city of Fengchen occurred when scaffolding collapsed at an interior concrete wall of a massive circular cooling tower, according to news sources.

Three shifts of workers had been toiling round the clock to make progress on structure before the arrival of winter weather. The investigation is reportedly focusing on whether corners were cut in an effort to speed up the project.

Hebei Yineng, an engineering firm overseeing construction of the plant, has a history of workplace fatalities. Seven of its employees fell to their deaths in 2012 when scaffolding collapsed at a cooling tower in Yunnan province. In 2009, two employees of the company died after a vehicle accidentally backed into a scaffolding support beam at a cooling tower in Guangdong province.

Industrial accidents are common in China, and are often blamed by a lack of regulatory oversight and rapid economic growth.