 But Barab says they can be deadly. One cubic yard of soil weighs 2,000 to 3,000 pounds. And most trench collapses involve three to five cubic yards of soil. So you can do the math. If you get caught in a trench collapse, it's very likely you're going to die, either being crushed or suffocated or both. NPR and our partners reviewed hundreds of pages of OSHA inspection reports, court records, personnel files, and other documents.