According to Miyamoto, the sorts of buildings that have fallen in Mexico City are typical of structural engineers: brick structures as well as brittle concrete buildings, particularly those with weak first floors. Many of the fallen structures, according to Miyamoto, are composed of fragile concrete. "In Japan, we don't have any examples like this," he said. Miyamoto also said that the construction industry in Mexico has been criticized for using substandard materials. He added that if the government wants to avoid more disasters like this one, they should set up regulations to ensure that builders use safe practices. Finally, Miyamoto said that his company is still analyzing data from the accident but that so far it appears that there was a problem with the rebar inside the building. This is something that engineers call "steel quality". If the steel is not up to code quality, then it will break under its own weight and collapse the building underneath it. Rebar is a type of metal rod used as reinforcement within concrete structures. It's usually made out of steel because it needs to be strong enough to carry all the weight of whatever is placed on top of it. So in conclusion, this building collapsed because it was built using substandard materials. There were no safety measures in place to prevent this sort of disaster happening again.