A total of 11 people have been killed between 2013 and 2016 on construction projects for the Rio Olympics, according to officials.
The fatalities are detailed in a report by Brazil’s labour office.
"It's a frightening number," said Robson Leite, an inspector for the labour office in the state of Rio de Janeiro.
He compared the toll in a single city to the eight killed during construction of sites for the 2014 World Cup, hosted by Brazil.
An official indicated that the most deadly project has been the extension of the new metro line, with three workers dying at the construction site and two others dying at Olympic Park, where the games will take place.
There were also deaths reported at two museums built as part of the Olympic legacy project and in roadwork.
An auditor from Leite's office said that the 11 deaths were "undoubtedly caused by lack of planning," in a statement to the G1 news site.
The Rio Olympics will be the first one held in South America, the opening ceremony will take place on August 5.