A safety engineer at the World Cup stadium site in Sao Paulo, Brazil where a giant crane collapse killed two workers allegedly warned his supervisor that the crane was being operated on unstable ground, according to the Associated Press.
Workers have suggested that finishing Sao Paulo's Arena Corinthians by the end of December led to safety issues including 12-hour shifts and canceling vacations.
Antonio de Sousa Ramalho, president of Sao Paulo's civil industry workers' association, told The Associated Press in a phone interview that supervisors pressed ahead with the operation to use the crane to finish the roof after several days of rain soaked the soil. He said the engineer warned his supervisor that the ground was not stable enough to support the crane and the 500-ton piece of roofing.
"To his surprise, he was told by the supervisor that nothing was wrong and work should continue," said Ramalho, who declined to provide the worker's name for fear of possible reprisals. "They discussed the matter for a while but in the end the supervisor's decision stood."
Odebrecht, the Brazilian construction company in charge of constructing the stadium and three other World Cup venues, strongly denied the claims.
"Odebrecht and Sport Club Corinthians clarify that there was no warning previous to the accident," the statement said. The company added that Ramalho's union does not represent most of the workers involved in the crane operation.
The civil defense official in charge of inspecting the accident site on Thursday said there were no obvious signs that the ground was unstable.
"When we looked at it, it didn't seem like the ground shifted, maybe just a few millimeters," Jair Paca de Lima said in a television interview. "Maybe after an analysis with the equipment we will know more."
Brazilian media reports investigators are also looking into human or mechanical error as possible causes for the crane's collapse.