Over half of the workers who die in confined spaces are trying to rescue another worker and succumb to invisible gases or a lack of oxygen. The type of respiratory protection that employers and firefighters use during a rescue can literally mean life or death.
Confined spaces need not be small, and utility contractors deal with them regularly. Below-grade vaults and pipes are among the most common confined spaces. But any space that has limited entry and exit, or lacks natural ventilation, can be considered a risk. Workers must be trained not to focus only on the "entry," or they may not recognize that a large space is also potentially hazardous.