One year after the tragedy of Mexico City's Metro Line 12 (L12), those responsible remain with impunity. The international consulting firm Det Norske Veritas (DNV), a company hired by the Mexico City government to identify what went wrong, delivered its third and final report on the collapse of the golden line, which highlights failure in inspections and maintenance as parralel causes of the tragedy.
DNV, a Norwegian consulting firm specializing in certification and risk management, sent its analysis of the root causes that led the railway structure of L12 to lose stability and collapse to the Mexico City government. Its latest report emphasizes the structural wear and tear caused over time by an alleged lack of maintenance and regular inspections.
The content analyzes facts covering three administrations that were in charge of the line: the Marcelo Ebrard administration, which built the line and was in power from 2006 to 2012, followed by the Miguel Ángel Mancera administration that governed from 2012 to 2018, during which the line was suspended for 1.5 years between 2014 and 2015 and, finally, the current administration of Claudia Sheinbaum, which started in 2018 and under which the collapse occurred.
The first two parts of the report were published by Claudia Sheinbaum's administration in June and Sept. 2021. The third report was not shared through official local government channels. Due to disagreements with DNV, the Mexico City government considered the results “false” and “politically biased.” DNV nevertheless supports the results of its report. Amid the break with Mexico City's government, the report's results were published by the Spanish newspaper El País.
DNV's report points to four "barriers" or factors that could have prevented the immediate causes of the incident, which include design features, administrative controls and a lack of preventative inspection.
According to DNV, the design did not conform to US specifications for bridge construction, which has been adopted as a global standard. In addition, the construction did not receive a suitable certification by an independent body and suffered from poor construction supervision. The company adds that in several cases, construction did not align with the original design, leading to supervisors reporting the issues during the line’s development.
The third barrier was that of the proper installation of bolts, which "compromised the integrity of the structure.” According to DNV's findings, two out of three bolts may not have fulfilled their function because they were inadequately placed, poorly welded or incorrectly installed within the collapsed section. This caused a "cascading failure" on the bolts that did work due to the wear accumulated during their nearly eight years of operation.
Finally, DNV identified a lack of maintenance and inspections on L12. The firm noted that no record regarding the necessary inspections exists between the line’s inauguration in Oct. 2012 and seven years later, in 2019, even though this was required by the maintenance manual.
DNV bases its findings on the Barrier-Based Systematic Causal Analysis Test (BSCAT) methodology. The method, a DNV trademark, consists of five steps: collecting evidence about the incident, generating a timeline of relevant moments before and after the accident, identifying barriers, evaluating the barriers and carrying out a causal analysis of the impact of the barriers. DNV argues that the collapse could not have been avoided if these problems were not addressed as a whole.
Mexico City’s Government Reacts
Claudia Sheinbaum's government has rejected the findings of DNV's third report. According to Mayor Sheinbaum, the company did not follow its methodology to analyze the root causes that led to the structure collapsing. Furthermore, the city’s government alleges that DNV confused preventative barriers with the causes of the incident and that the firm did not study other possible hypotheses. Sheinbaum's team disparages that the report gives the same value to design and construction failures.
Nevertheless, the publication the report has put pressure on Sheinbaum to resolve the catastrophe. So far, no authorities from the three past local administrations have been held accountable, nor have any of the companies that oversaw L12's construction, Ingenieros Civiles y Asociados (ICA) and Alstom and Carso Infraestructura y Construcción (CICSA). CICSA, a company owned by magnate Carlos Slim, agreed with Mexico's federal government to assume the cost of L12's reconstruction. It also paid millions of pesos in reparation agreements to most of the victims, without assuming responsibility for the disaster.
Mexico City’s government made the report public along with observations that they consider were not addressed days after El País published the results. The Sheinbaum administration announced that it will now proceed to file a civil lawsuit against DNV.