Twenty-two people and three companies will be punished for destroying evidence and fabricating parts of a report after a subway construction accident in southern China earlier this year claimed the lives of three workers, financial news outlet Caixin reported Sunday.

One afternoon in late January, a tunnel collapsed at the construction site of the 21st subway line in Guangzhou, the provincial capital of Guangdong. China Railway 14 Bureau Group — a subsidiary of state-owned China Railway Construction, a Forbes Global 500 company — reported the collapse as an unexpected accident in which three workers had been killed. But Guangdong’s work safety administration announced Friday that its investigation had found that in the wake of the accident, the company had destroyed evidence and covered up details in order to escape punishment.

According to the company’s report, the accident occurred on the morning of Jan. 26 — but the work safety administration found that it had actually happened the day before, after a fire caused a dangerous drop in air pressure inside the tunnel. The fire was reportedly caused by faulty wiring on a welding machine, which the workers had been using inside a small chamber. Items strewn about the work site soon caught the fire, but no one outside the tunnel noticed. With the fire consuming oxygen, the air pressure inside the chamber dropped, causing the tunnel to collapse. The three workers were trapped inside, unable to escape.

According to Caixin, the workers had been changing the cutting head of the tunnel boring machine when the cave-in occurred. A worker outside the tunnel radioed them at around 5 p.m. on the 25th to tell them they could come out. But a few minutes later, the air pressure gauge started displaying some unusual readings, and the worker noticed smoke billowing from the chamber, along with the smell of something burning. Before the construction team could rescue their fellow workers, the facade of the tunnel collapsed.

After the cave-in, China Railway 14 Bureau Group began covering up evidence that could point to the real cause. According to Caixin, pressure washers were used to eliminate traces of the fire, security camera footage was wiped, air pressure readings were forged, and other relevant information was destroyed. Workers say they were also asked to lie about the incident when interviewed afterward.

In February, the work safety administration’s investigators received an anonymous letter alleging that there were hidden details about the incident, and a follow-up investigation revealed evidence of the fire.

The administration found that the three companies involved in the project — the construction, supervision, and labor sourcing companies — were responsible for the accident, as they had failed to observe safety standards. Because the construction chamber had not been outfitted with a monitoring camera or smoke detector, it was already too late when the workers outside the tunnel started seeing smoke. In addition, the investigation found that the deceased workers had not been given emergency kits that could have helped them survive or escape in the event of a cave-in. Finally, the administration determined that the workers on the construction team had not been adequately trained in how to deal with emergencies or other safety issues.

The three deceased were all men in their 40s who came from the same county in Hubei province. In addition to these human casualties, the accident caused an estimated financial loss of over 10 million yuan ($1.5 million).

Five individuals who fabricated parts of the construction company’s report and destroyed evidence may face criminal charges. According to the work safety administration’s investigation, 22 people from the three companies involved will be punished.

In February, less than two weeks after the Guangzhou incident, there was another fatal tunnel collapse in the nearby city of Foshan: Eleven people died when a 30-meter stretch of highway tunnel caved in.

According to data from the Ministry of Housing and Urban-Rural Development, the number of safety incidents and deaths during construction projects in China is rising. The latest figures show that there were 503 accidents from January to August of this year resulting in 582 deaths — 48 more accidents and 33 more deaths compared with the same period last year.

Editor: David Paulk.

(Header image: The construction site of subway Line 21 in Guangzhou, Guangdong province, June 25, 2015. Chen Kunrong/VCG)