A safety expert, Carlos Fernandes, accused the owners, the Sonae retail and industrial group, of failing to observe safety standards in their rush to open.
Eyewitnesses said the weight of rainwater on the flat roof appeared to have caused a beam to collapse. Water began dripping in before the beam crashed down near a row of cash registers, causing panic. 'There were thousands of people inside and everyone tried to flee,' said Antonio Silva, who was nearby.
Sonae officials said they were not immediately able to comment on the accident's cause.
Mr Fernandes said that the hypermarket had also been at risk from fire because it did not have sprinklers. 'How is it possible to open a shopping centre of this size in 1994 without a network of sprinklers in place?' he asked.
This was the second serious accident in a Portuguese hypermarket this year. A hypermarket, at Palmela, burned down in April.Reuse content