The collapse of a Mexico City metro overpass that left 26 people dead was caused by a structural failure, according to an initial investigation by independent experts published Wednesday.
The report by Norwegian engineering company DNV, which was presented at a news conference by Mexico City authorities, identified a number of deficiencies in the construction process linked to the May 3 disaster.
They include “unfinished and/or poorly executed welding,” insufficient bolts and the use of different types of concrete.
The metro line involved in the tragedy, in which dozens were injured when a section of elevated track collapsed and a train came crashing down, is the city’s newest.
It has been plagued by problems since it was opened in 2012.
The disaster has prompted accusations of negligence and demands for justice from devastated relatives.
DNV plans to deliver two more reports into the crash on July 14 and August 30, its Mexico director Eckhard Hinrichsen told the news conference.
Mexico City Mayor Claudia Sheinbaum said she would put together a technical team to reinforce and repair the 24.5-kilometer (15-mile) long line.
Prosecutors are also investigating the disaster but have yet to publish their findings.
– Political fallout –
The furor over the crash has engulfed two of President Andres Manuel Lopez Obrador’s political proteges and leading contenders to be his left-wing party’s candidate in the 2024 presidential elections.
Sheinbaum faces questions about whether the network has been properly maintained since she took office in 2018.
Foreign Minister Marcelo Ebrard oversaw the development and inauguration of the line in his former position as Mexico City mayor from 2006-2012.
Ebrard has said that his own administrative responsibility for the project ended when he left the job.
He has promised to cooperate fully with the investigation into the accident, saying the accusations against him are politically motivated.
Mexican billionaire Carlos Slim also faces scrutiny over the disaster as one of his companies was involved in the construction of the section that collapsed.
Lopez Obrador has promised an in-depth investigation to uncover the truth behind the crash, while urging people not to speculate about who is to blame.
He has rejected suggestions from an employers’ association that the accident was linked to public spending cuts.
The authorities have also come under fire from one of the metro labor unions, which said that its earlier warning about damage to the overpass was ignored.
The May 3 crash came just over a year after two subway trains collided in Mexico City, leaving one dead and around 40 injured.