A preliminary report issued by the Norwegian company DNV and other international experts—prepared at the request of the Mexican government—found that at least six construction violations led to the collapse of the metro train last month that killed 26.
DNV cited multiple issues with screws, beams, and planks used in the metro among the problems. They also mentioned poor or completely neglected bolt welds. Investigators also discovered missing bolts and mismatched concrete.
The city's public works secretary, Jesús Antonio Esteva Medina, spoke about the lab's ongoing investigation of materials taken from the collapsed site; they found deformed beams in a curving section of the metro. Other beams had slid out of position.
Claudia Sheinbaum, mayor of Mexico City, said that they must continue to investigate "not only because of our legal obligation but because of our ethical, human and moral commitment."
The former mayor, Marcelo Ebrard, who oversaw the construction of the metro, defended his management methods. He also committed to cooperating with the investigation. "I support the carrying out of the necessary expert and technical investigations to determine the causes of the accident and define the responsibilities that may arise."
Erbard reiterated that workers build the metro under the scrutiny of multiple committees. Ample documentation exists to support this assertion. Countering Erbard's statements, Esteva Medina pointed out evidence of improper bolt usage; they were not equidistantly spaced, many were not pushed through the beams, fewer bolts than necessary were used.
The Mexican news program Noticias Telemundo Investiga revealed a 2019 report that documents defective parts used to repair trains. The report also claims that unskilled laborers such as ticket takers performed maintenance tasks.
The Mexico City metro is one of the busiest globally, transporting six-million passengers a day. The structural collapse killing 26 caused investigators to gather information that can help prevent future structural accidents. Investigators will release the second report on July 14th and the final report on August 30th.