EXPLAINER: Here is why crowd surges can kill people

By STAN CHOE
AP Business Writer

NEW YORK (AP) — The crowd deaths at a Houston music festival have added to the long list of people who have been crushed at a major event. Such tragedies have been occurring around the world for a long time at concerts, sports events and religious gatherings. Experts who have studied such deaths say they’re often a result of density, with too many people packed into too small a space. Often, the crowd is running away from a perceived threat or toward something they want before hitting a barrier. That leads to chests getting crushed and victims being unable to breathe.